• Author / Uploaded
• augur886

• Categories
• Válvula
• Medición de flujo
• Tubería (transporte de fluidos)
• Transporte por tubería
• Instrumentación

Citation preview

CPG

Meter Station Design Guidelines

Columbia Pipeline Group Meter Station Design Guidelines

Revised: April 30, 2014

CPG

Meter Station Design Guidelines

Revision Date:

Revision By:

Description of Revision:

11/15/2007

STM

12/11/07 1/18/07 6/12/12 8/1/12 8/1/12 2/26/13 12/7/12

STM RAM RAM RAM RAM RAM RAM

2/26/13

RAM

3/15/13 3/25/13 4/18/13 4/30/14

RAM RAM RAM RAM

Updated Appendix A drawing list with Liquid Level Shutoff Devices, and revised USM drawings. Removed reference to Pikotek Insulating kits. Corrected Model Number on Spec 1.2. Corrected 3.2 Spec Revised tap and header velocities Section 10.2.1 Added RTU selection guidelines chart 9.1.2 Added Coriolis Meters as Appendix G Reference Columbia as per tracked changes Reference CPG Electronic Measurement and Gas Chromatograph Specifications Reference CPG DS-4006 Electronic Measurement and Gas Chromatograph Specifications General comments revised per comments revised per comments revised meter bypass language and converted OEP to CPG procedures

CPG

Meter Station Design Guidelines

Contents

1

2

3

SCOPE ............................................................................................................................................. 1 1.1 OBJECTIVES ...................................................................................................................... 1 1.2 OWNERSHIP AND DIVISION OF RESPONSIBILITIES .................................................... 2 1.2.1 CPG Meter Stations ......................................................................................... 2 1.2.2 Customer Meter Stations ................................................................................. 2 1.2.3 Flow Control and Custody Transfer Operations .............................................. 2 1.3 GAS CONDITIONING ......................................................................................................... 3 GENERAL DESIGN REQUIREMENTS........................................................................................... 3 2.1 LAWS, REGULATIONS, CODES AND STANDARDS ....................................................... 3 2.2 PRIMARY DESIGN REQUIREMENTS ............................................................................... 3 2.2.1 Design Drawing Requirements ........................................................................ 4 2.2.2 Documentation ................................................................................................ 4 2.2.3 Flow Rates ....................................................................................................... 4 2.2.4 Flow Metering .................................................................................................. 4 2.2.5 Meter Bypass ................................................................................................... 5 2.2.6 Flow Control .................................................................................................... 5 2.2.7 Remote Shut-In ............................................................................................... 5 2.2.8 Design Pressure .............................................................................................. 5 2.2.9 Design Temperature ........................................................................................ 6 2.2.10 Gas Quality ...................................................................................................... 6 2.2.11 Odorization ...................................................................................................... 7 2.2.12 Bi-Directional Meter Stations ........................................................................... 7 2.2.13 Meter Run End Closures ................................................................................. 7 2.2.14 Pipeline Taps ................................................................................................... 7 2.2.15 Automatic Shutoff Valves ................................................................................ 7 2.2.16 Check Valves ................................................................................................... 7 2.3 METER STATION SITE ...................................................................................................... 7 2.3.1 Location Considerations .................................................................................. 7 2.3.2 Site Preparation ............................................................................................... 8 2.3.3 Paving and Sidewalks ..................................................................................... 8 2.3.4 Landscaping .................................................................................................... 9 2.3.5 Fencing ............................................................................................................ 9 2.4 BUILDINGS/ENCLOSURES ............................................................................................... 9 2.4.1 General Requirements - RTU or Chromatograph Building (General purpose – no high pressure gas) .................................................................................... 10 2.4.2 General Requirements – Electric Equipment Enclosures ............................. 11 2.5 ELECTRICAL INSTALLATIONS ....................................................................................... 11 2.5.1 Area Classification ......................................................................................... 11 2.5.2 Grounding ...................................................................................................... 12 2.5.3 Lighting .......................................................................................................... 13 2.5.4 Electrical Installations .................................................................................... 13 2.5.5 Conduit and Wire Sizes ................................................................................. 14 2.5.6 Load Centers ................................................................................................. 15 2.5.7 Transient AC Power and Telecommunications Voltage Surge Suppression 15 ORIFICE METERS......................................................................................................................... 15 3.1 SIZING CRITERIA ............................................................................................................ 16

CPG

4

5

Meter Station Design Guidelines

3.1.1 Beta Ratio ...................................................................................................... 16 3.1.2 Orifice Differential .......................................................................................... 16 3.1.3 Multiple Orifice Meter Runs ........................................................................... 16 3.1.4 Single Orifice Meter Runs.............................................................................. 16 3.2 ORIFICE METER TUBES ................................................................................................. 16 3.2.1 Meter Tube Minimum Dimensions and Configuration ................................... 16 3.2.2 Orifice Fittings ................................................................................................ 17 3.2.3 Orifice Plates ................................................................................................. 17 3.2.4 Flow Conditioners .......................................................................................... 17 3.2.5 Pipe................................................................................................................ 17 3.2.6 Flanges .......................................................................................................... 17 3.2.7 Shop Testing and Inspection ......................................................................... 18 3.3 ORIFICE METER INSTRUMENTATION .......................................................................... 18 3.3.1 Static and Differential Pressure ..................................................................... 19 3.3.2 Flowing Gas Temperature ............................................................................. 19 3.4 INSTALLATION................................................................................................................. 19 3.4.1 General Arrangement .................................................................................... 19 3.4.2 Supports ........................................................................................................ 20 3.4.3 Inlet and Outlet Valves .................................................................................. 20 TURBINE METERS ....................................................................................................................... 20 4.1 SIZING CRITERIA ............................................................................................................ 20 4.1.1 Multiple Turbine Meter Runs ......................................................................... 20 4.1.2 Single Turbine Meter Runs ............................................................................ 21 4.2 TURBINE METER TUBES ................................................................................................ 21 4.3 TURBINE METER INSTRUMENTATION ......................................................................... 21 4.3.1 Turbine Meter Output .................................................................................... 21 4.3.2 Static Pressure .............................................................................................. 21 4.3.3 Flowing Gas Temperature ............................................................................. 22 4.4 INSTALLATION................................................................................................................. 22 4.4.1 General Arrangement .................................................................................... 22 4.4.2 Supports ........................................................................................................ 22 4.4.3 Inlet and Outlet Valves .................................................................................. 22 4.4.4 Meter Protection ............................................................................................ 22 4.4.5 Strainer .......................................................................................................... 22 4.4.6 Proving .......................................................................................................... 23 4.4.7 Turbine Module Lifting Mechanism ............................................................... 23 4.4.8 Automatic oiler ............................................................................................... 23 ULTRASONIC METERS................................................................................................................ 23 5.1 SIZING CRITERIA ............................................................................................................ 23 5.1.1 Multiple Ultrasonic Meter Runs ..................................................................... 24 5.1.2 Single Ultrasonic Meter Runs ........................................................................ 24 5.2 ULTRASONIC METER TUBES ........................................................................................ 24 5.2.1 Throttling Devices .......................................................................................... 24 5.2.2 Pipe................................................................................................................ 24 5.2.3 Flanges .......................................................................................................... 25 5.2.4 Auxiliary Connections .................................................................................... 25 5.2.5 Shop Testing and Inspection ......................................................................... 25 5.3 ULTRASONIC METER INSTRUMENTATION ................................................................. 26 5.3.1 Ultrasonic Meter Output................................................................................. 26 5.3.2 Static Pressure .............................................................................................. 26

CPG

Meter Station Design Guidelines

5.3.3 Flowing Gas Temperature ............................................................................. 27 INSTALLATION................................................................................................................. 27 5.4.1 General Arrangement .................................................................................... 27 5.4.2 Supports ........................................................................................................ 27 5.4.3 Inlet and Outlet Valves .................................................................................. 28 POSITIVE DISPLACEMENT METERS ......................................................................................... 28 6.1 METERS ........................................................................................................................... 28 6.1.1 Sizing Criteria ................................................................................................ 28 6.1.2 Multiple Rotary Meters................................................................................... 28 6.1.3 Single Rotary Meter Runs ............................................................................. 29 6.1.4 Shop Testing and Inspection ......................................................................... 29 6.2 INSTALLATION................................................................................................................. 29 6.2.1 General Arrangement .................................................................................... 29 6.2.2 Piping ............................................................................................................. 29 6.2.3 Supports ........................................................................................................ 29 6.2.4 Inlet, Outlet and Bypass Valves for Single Rotary Meter Setting .................. 29 6.2.5 Strainer .......................................................................................................... 30 6.2.6 Prover Connections ....................................................................................... 30 6.2.7 Over-Range Protection .................................................................................. 30 6.3 ROTARY METER INSTRUMENTATION .......................................................................... 30 6.3.1 Rotary Meter Pulse Output ............................................................................ 30 6.3.2 Static Pressure .............................................................................................. 30 6.3.3 Flowing Gas Temperature ............................................................................. 31 FLOW AND PRESSURE CONTROL ............................................................................................ 31 DEFINITIONS ................................................................................................................................ 31 8.1 METER RUN SEQUENCING ........................................................................................... 32 8.1.1 Meter Run Sequencing Valves ...................................................................... 33 8.1.2 Valve Actuators ............................................................................................. 33 8.2 FLOW CONTROL ............................................................................................................. 33 8.2.1 Flow Control Valves ....................................................................................... 33 8.3 PRESSURE CONTROL .................................................................................................... 34 8.3.1 Pressure Control Valves ................................................................................ 34 8.3.2 Regulation Bypass......................................................................................... 35 8.4 CONTROL VALVE SIZING AND SELECTION ................................................................. 35 8.5 CONTROL VALVE INSTALLATION ................................................................................. 35 8.5.1 General .......................................................................................................... 35 8.5.2 Piping ............................................................................................................. 35 8.6 OVERPRESSURE PROTECTION ................................................................................... 36 8.6.1 Criteria for Overpressure Protection .............................................................. 36 8.6.2 Selection of Overpressure Protection Devices .............................................. 37 8.6.3 Monitored regulator settings .......................................................................... 37 8.6.4 Over Pressure Shutdown Valves (Security Valves) ...................................... 38 8.7 SAFETY/RELIEF VALVES & OVER PRESSURE PROTECTION ................................... 39 8.7.1 Selection ........................................................................................................ 39 8.7.2 Set Pressure .................................................................................................. 39 8.7.3 Relieving Capacity ......................................................................................... 40 8.7.4 Safety/Relief Valve Installation ...................................................................... 41 8.8 REMOTE SHUTOFF VALVE ............................................................................................ 42 8.8.1 Remote Shutoff Valves (Station Isolation Valve) .......................................... 42 5.4

6

7 8

CPG

Meter Station Design Guidelines

8.9 9

10

11

FLOW DIRECTION VALVE .............................................................................................. 42 8.9.1 Remote flow direction valves ......................................................................... 42 INSTRUMENTATION .................................................................................................................... 43 9.1 PROCESS INSTRUMENT CONNECTIONS .................................................................... 43 9.1.1 Pressure Sensing Connections (Other than at Orifice Fittings) .................... 43 9.1.2 Temperature Sensing Connections ............................................................... 44 9.1.3 Sample Connections ..................................................................................... 44 9.2 TRANSMITTERS .............................................................................................................. 45 9.2.1 Multi-Variable Transmitters for Static Pressure, Differential Pressure & Temperature .................................................................................................. 45 9.2.2 Transmitters for Static Pressure Only ........................................................... 45 9.2.3 Temperature Sensing Elements (RTD’s) ...................................................... 46 9.3 CONTROLLERS ............................................................................................................... 46 9.3.1 Tube Switching Control ................................................................................. 46 9.3.2 Limit Switches ................................................................................................ 46 9.3.3 Flow Control .................................................................................................. 46 9.3.4 Pressure Control ............................................................................................ 46 9.3.5 Manual Control .............................................................................................. 46 9.3.6 Automatic Over-Ride Control ........................................................................ 47 9.4 ODORIZATION ................................................................................................................. 47 9.5 GAS SAMPLING ............................................................................................................... 47 9.6 INSTRUMENT GAS SUPPLY........................................................................................... 47 ELECTRONIC MEASUREMENT AND TELEMETERING ............................................................ 48 10.1 FLOW COMPUTERS ........................................................................................................ 48 10.1.1 General Requirements .................................................................................. 48 10.1.2 CPG RTU Types ............................................................................................ 48 10.2 GAS QUALITY DEVICES ................................................................................................. 48 10.2.1 Chromatograph .............................................................................................. 48 10.2.2 Moisture analyzer .......................................................................................... 49 10.2.3 Hydrogen sulfide ............................................................................................ 49 10.2.4 Oxygen sensors ............................................................................................. 49 10.2.5 Other Devices ................................................................................................ 50 10.3 TELEMETERING .............................................................................................................. 50 10.4 POWER SUPPLY ............................................................................................................. 50 10.4.1 UPS System .................................................................................................. 50 YARD PIPING AND HEADERS .................................................................................................... 50 11.1 DESIGN PRESSURE AND TEMPERATURE .................................................................. 50 11.2 PIPE SIZING ..................................................................................................................... 50 11.2.1 Station Main Gas Piping ................................................................................ 51 11.2.2 Regulation & Measurement Headers ............................................................ 51 11.2.3 Station Bypasses ........................................................................................... 51 11.2.4 Meter Tube Inlet/Outlet Piping ....................................................................... 51 11.2.5 Other Considerations..................................................................................... 51 11.3 GENERAL PIPING DESIGN ............................................................................................. 52 11.3.1 Configuration/Layout ..................................................................................... 52 11.3.2 Header Configuration .................................................................................... 52 11.3.3 Piping ............................................................................................................. 52 11.3.4 Flanged connections ..................................................................................... 52 11.3.5 Welding .......................................................................................................... 53

CPG

12

13 14 15 16 17 18 19 20

Meter Station Design Guidelines

11.3.6 Pressure Testing ........................................................................................... 54 11.3.7 Valves ............................................................................................................ 55 11.3.8 Branch Connections ...................................................................................... 56 11.3.9 Hot Taps ........................................................................................................ 56 11.4 PIPING MATERIALS......................................................................................................... 57 11.5 CATHODIC PROTECTION ............................................................................................... 57 11.5.1 Insulating Flanges ......................................................................................... 57 11.5.2 Cathodic Protection System .......................................................................... 57 11.5.3 Tubing-Insulating Unions ............................................................................... 57 11.5.4 Corrosion Coupons (Internal) ........................................................................ 58 11.5.5 Painting .......................................................................................................... 58 11.5.6 Coating of Buried Piping (CPG Owned or Cathodically Protected) .............. 58 11.5.7 Coating Hot Tap Flange ................................................................................ 59 11.5.8 Corrosion Coupon Test Station (External) .................................................... 59 11.5.9 Weld Over Sleeves ........................................................................................ 59 11.5.10 Concrete Sleepers ......................................................................................... 59 11.5.11 Below Grade to Above Grade Transition....................................................... 59 11.5.12 Above Grade Pipe Supports .......................................................................... 59 FILTER–SEPARATORS, HEATERS AND LIQUID HANDLING .................................................. 60 12.1 FILTER SEPARATOR....................................................................................................... 60 12.1.1 General .......................................................................................................... 60 12.1.2 Configuration ................................................................................................. 60 12.1.3 Performance .................................................................................................. 61 12.1.4 Controls and Instrumentation ........................................................................ 61 12.2 LIQUID LEVEL SHUTOFF ................................................................................................ 62 12.3 PROCESS GAS HEATING ............................................................................................... 62 12.3.1 Indirect Fired Heaters .................................................................................... 62 12.3.2 Catalytic Heaters ........................................................................................... 63 12.4 WATER AND HYDROCARBON DRAINS ........................................................................ 63 12.4.1 Drain Connections ......................................................................................... 63 12.4.2 Drain Collection Systems .............................................................................. 64 12.4.3 Liquid Storage ............................................................................................... 64 APPENDIX A - CPG STANDARD DRAWING LIST ..................................................................... 65 APPENDIX B – MATERIAL SPECIFICATIONS ........................................................................... 65 APPENDIX C – APPROVED MATERIAL LIST ............................................................................ 65 APPENDIX D – Meter Testing and Inspection ........................................................................... 65 APPENDIX E 1 - Restriction Plate Sizing – Rotary meters ....................................................... 66 APPENDIX E 2 - Restriction Plate Sizing – Turbine Meters ..................................................... 67 APPENDIX F – Corrosion Control Procedures ......................................................................... 68 APPENDIX G - CORIOLIS METERS ............................................................................................ 69 20.1 Sizing Criteria .................................................................................................................... 69 20.2 Coriolis Meter Runs & Installation ..................................................................................... 69 20.3 Calibration & Testing ......................................................................................................... 70

CPG

1

Meter Station Design Guidelines

SCOPE This Meter Station Design Guidelines document applies to new station design and construction. This document does not apply to previously constructed and in-service facilities. These Meter Station Design Guidelines provide minimum requirements for the design, materials and construction of meter stations for the measurement of gas delivered to or from Columbia Pipeline Group (CPG) pipelines. Companies delivering gas into or receiving gas from CPG pipelines shall hereafter be designated Customer. Point of Delivery (POD) stations are locations where CPG delivers gas to customers. CPG owns and operates the tap valve on the CPG pipeline and the pipe on the CPG Right-of-Way (ROW). Generally, the customer installs (in the following order) the station piping adjacent to the CPG ROW, separator, measurement setting, flow control setting (if required), heater (if required) and overpressure protection setting (to protect the customer’s downstream facilities). Point of Receipt (POR) stations are locations where CPG receives gas from producers or non-affiliated transmission companies (customers). CPG owns and operates the tap valve on the CPG pipeline and the pipe on the CPG Right-of-Way (ROW). Generally, the producer installs (in the following order) separator, heater (if required), overpressure protection setting (to protect CPG’s downstream facilities), measurement setting, flow control setting (if required), and station piping to the CPG ROW. Point of Receipt (POR) stations which incorporate ultrasonic measurement settings (USM) shall install the USM upstream of the overpressure protection setting. Check valves and static pressure transmitters are typically installed in the station piping downstream of the measurement and overpressure protection equipment but prior to the CPG ROW. The check valve assures gas will not backflow into the producer’s pipeline. Furthermore, the pressure transmitter will provide CPG pressure sense on the CPG pipeline which could be different than the pressure sense on the meter setting (under certain circumstances). Because of the wide variety of measurement facilities to which these guidelines apply and the continuing advances in technology and changing regulations, these guidelines are necessarily general, and are not meant to be a substitute for the application of good Engineering judgment to specific design situations and must adhere to the appropriate CPG company tariff. A CPG design engineer will conduct a review of all design and drawings. Discussions must be held with the CPG Engineering department before any deviations from this guideline can occur. 1.1

OBJECTIVES These guidelines are intended to ensure:  Minimal uncertainty in custody transfer gas measurement  Department Of Transportation (DOT) Pipeline and Hazardous Materials Safety Administration (PHMSA) Code compliant Overpressure Protection (OPP)  Cost effective operation of the pipelines and related facilities in compliance with applicable laws, regulations, codes and standards  Safe working conditions for CPG and Customer personnel

1

CPG

Meter Station Design Guidelines

1.2

OWNERSHIP AND DIVISION OF RESPONSIBILITIES Meter stations may be designed, constructed and owned by CPG or by Customer, or designed and constructed by CPG for the Customer’s account and owned by the Customer. The ownership of the facilities and the division of responsibilities for design, construction, operation and maintenance shall be as prescribed by the applicable contracts (Attachments A and B to the interconnect agreement) or interconnect agreements between CPG and Customers. The latest revision of the CPG Point of Delivery and Point of Receipt drawings shall be followed unless otherwise specified in the Meter Set Agreement (MSA) between both companies. 1.2.1

CPG Meter Stations Meter stations owned by CPG shall be designed and constructed in accordance with these guidelines, and shall be operated and maintained by CPG.

1.2.2

Customer Meter Stations Meter stations owned by the Customer, operated and maintained by CPG, shall be designed and constructed to meet the requirements of these guidelines. 





 

  1.2.3

All meter station design calculations and drawings prepared by Customer/Customer’s Design Firm shall be reviewed by CPG prior to fabrication or construction of the facilities. Such review by CPG shall in no way diminish Customer’s responsibility for compliance with these guidelines, or with all applicable laws, regulations, codes and standards. Provision of this document by CPG to Customer for Customer’s use shall in no way diminish Customer’s responsibility for compliance with all Federal, State, and Local laws, regulations, codes, and standards as may be applicable. CPG shall be afforded the opportunity to participate in shop or source inspections of meter tubes, orifice fittings, ultrasonic meters, and other critical materials and equipment items. CPG’s Approved Vendors shall be used. Meter stations owned, operated and maintained by the Customer shall be designed and constructed to meet the requirements of the current AGA specifications, and all PHMSA codes. CPG shall review all design drawings. CPG shall be allowed to participate in witness testing of all meter calibrations and inspections.

Flow Control and Custody Transfer Operations For all meter stations, whether owned and operated by CPG or by Customer, CPG shall retain operational responsibility for flow control and for operations related to custody transfer as follows: 

Calibration and testing of instruments for measurement of flow

2

CPG

Meter Station Design Guidelines

 

1.3

parameters and for recording and/or computation of flow. Inspection and changing of orifice plates and inspection of meter tubes. Collection and analysis of gas samples and determination of gas quality parameters including: specific gravity, heating value, water vapor content, and excessive amount of diluents such as H2S, O2, N2 and CO2.

GAS CONDITIONING Gas delivered to or from CPG pipelines shall be sweet, clean, dry, pipeline quality gas, free of harmful contaminants. The specific gas quality requirements shall conform to the applicable gas contracts or interconnect agreements. Facilities for dehydration, sweetening, stripping and other gas conditioning equipment that may be necessary to achieve the required gas quality are beyond the scope of these guidelines; however, meter stations shall include appropriate equipment for gas quality monitoring. See Section 2.2.10, “Gas Quality”. Filter separators are covered in Section 12.1, “Filter Separator”.

2

GENERAL DESIGN REQUIREMENTS This section prescribes requirements generally applicable to all types and sizes of meter stations. 2.1

LAWS, REGULATIONS, CODES AND STANDARDS Meter stations shall be designed and constructed in accordance with all applicable Federal, State and local laws and regulations; in accordance with all applicable permits; in accordance with the latest edition of the basic codes and standards listed below and in accordance with more specific codes and standards referenced in succeeding sections of these guidelines.      

2.2

Title 49 CFR Part 192, “Transportation of Natural and Other Gas by Pipeline: Minimum Federal Safety Standards” (PHMSA) API Manual of Petroleum Measurement Standards, Chapter 14 “Natural Gas Fluids Measurement” API Manual of Petroleum Measurement Standards, Chapter 21 “Flow Measurement Using Electronic Metering Systems” ANSI/NFPA 70, “National Electrical Code” AGA Catalog No. XL1001, “Classification of Locations for Electrical Installations in Gas Utility Areas” AGA Report Number 3, 7, 8, 9, and 10

PRIMARY DESIGN REQUIREMENTS Meter stations shall be designed to implement the requirements for measurement, flow control, pressure regulation, data acquisition, telemetering, odorization and other conditions of the contractual arrangements between CPG and the Customer.

3

CPG

Meter Station Design Guidelines

2.2.1

Design Drawing Requirements Installation drawings submitted for CPG’s review shall be of sufficient scope and detail that a contractor could use them to install the equipment. The following elements shall be included as a minimum:  

     2.2.2

Plot plan showing location of all piping and equipment, to include production equipment and pipeline interconnect Piping drawings with elevations and sections as necessary to fully describe the piping configuration leading to and away from the meter station Civil/Structural Drawings Instrumentation diagram to show the interconnection of all measurement and control elements Electrical schematic and plot plan including Hazardous Location Plan. Electrical/Instrumentation Wiring Diagrams Bill of Material listing all equipment

Documentation All equipment that CPG shall own or operate shall be accompanied by:    

2.2.3

Installation, operation and maintenance manuals with complete parts lists and diagrams Certification of hazardous area compliance for all installed equipment Dimensional drawings of equipment Safety/relief valve capacity calculations including consideration of inlet and outlet pressure losses and back pressure on valve capacity and operational stability using CPG’s relief valve capacity calculation program (SWRI-Rev 5.xls – Contact CPG engineering department)

Flow Rates The primary design parameter for any meter station is the flow rate. The meter station must be designed for the expected maximum, minimum and normal flow rates. The criticality of maintaining uninterrupted flow is an important design consideration.

2.2.4

Flow Metering Measurement shall normally be accomplished using orifice meters, ultrasonic meters, gas turbine meters, positive displacement meters or Coriolis meters.  

Electronic Flow Measurement (EFM) and telemetry is required for all meter stations. Positive displacement rotary meters may be employed for flow rates below 3,000 ACF/H base volumes with approval of CPG.

4

CPG

Meter Station Design Guidelines

2.2.5

Meter Bypass A meter bypass shall be installed at all meter stations. This includes measuring stations where a) flow cannot be interrupted, b) which have only a single meter run or c) may have multiple meter runs. At a minimum, the bypass valve shall be a full port ball valve with body bleed valve that can be used to check for seat leakage. The bypass must be locked shut during normal station operation. Where practical, the meter run bypass shall be configured with two block valves and meter run top-works such that a flanged spool piece can be replaced with a meter in the future.

2.2.6

Flow Control Although the Customer can control flow in their piping system, CPG reserves the right to control flow into or out of the CPG piping system. Remote flow control equipment operated by CPG shall be installed at all meter stations designed for flow rates of 10 mmcfd or greater, and may be provided for smaller meter stations where required by the specific conditions or contract requirements.

2.2.7

Remote Shut-In CPG requires the capability of remote shut-in by CPG Gas Control of all interconnect facilities with flow rates greater than 10 mmcfd in Columbia Gulf Transmission. The remote shut-in valve shall consist of a full port ball valve with actuator with snap action full open/full close control.

2.2.8

Design Pressure All meter station piping (and other pressure containing components) shall have a design pressure, and shall be tested for a maximum allowable operating pressure (MAOP) equal to or greater than the highest pressure the piping will be subjected to. 



For any POD meter station receiving gas from a CPG pipeline, the piping (upstream of any pressure regulation) shall have a design pressure and MAOP equal to or greater than that of the CPG pipeline. Any piping downstream of pressure regulation that has a design pressure or MAOP lower than that of the CPG pipeline shall be protected by suitable pressure limiting devices and/or security valves. (Reference PHMSA Part 192.195.) The Customer is not permitted to use relief valves for overpressure protection to preclude venting gas to atmosphere. For any POR meter station delivering gas into a CPG pipeline, the piping shall have a design pressure and MAOP equal to or greater than that of the CPG pipeline. Suitable pressure limiting devices and/or security valves shall be installed to protect the meter station, the CPG pipeline, and any ASME code pressure vessels included in the facility from overpressure. (Reference PHMSA Part 192.195.) The Customer is not permitted to use relief valves for overpressure protection to preclude venting gas to atmosphere.

5

CPG

Meter Station Design Guidelines





2.2.9

All ASME code vessels' MAWP (maximum allowable working pressure) shall be designed to 110% or more of the station or pipeline MAOP. Meter station gas piping shall be based on a design factor of 0.50 in Class Locations 1, 2 and 3, and a design factor of 0.4 in Class Location 4 in accordance with PHMSA Part 192.111.

Design Temperature Meter stations shall be designed for the maximum and minimum gas temperatures (+120° to –20°F) and for the maximum and minimum ambient temperatures (+120° to –20°F). Consideration shall be given to the necessity for gas heating during low ambient temperatures, particularly for meter stations with pressure regulation and for instrument gas supply systems. All ASME vessels shall be designed for a Minimum Design Metal Temperature (MDMT) of –20°F. The MDMT is the lowest ambient temperature (per specific application location) that an ASME vessel is designed to encounter without making the vessel’s metal subject to brittle failure.

2.2.10

Gas Quality Meter stations shall be designed to ensure that gas delivered into any CPG pipeline meets the gas quality requirements of the CPG Tariff and the interconnect agreement. The meter station design shall include gas conditioning equipment (filters, separators, dehydrators, heaters, etc.) as necessary to ensure the required gas quality or as otherwise required in succeeding sections of these guidelines. 









A filter-separator is required at any measuring station flowing more than 1,000 Dth/day and shall be installed immediately upstream of the meter that delivers gas into a CPG pipeline. See Section 12.1, “Filter - Separators”. A liquid level shutoff device may be installed immediately upstream of any meter four-inch or smaller, delivering gas into a CPG pipeline. See Section 12.2 “Liquid Level Shutoff””. At the discretion of CPG, a continuous gas sampler or chromatograph may be required at meter stations and shall be installed at the time of the station construction or afterwards for cause. See Section 9.5, “Gas Sampling” and 10.2.1 “Chromatographs”. Other devices for monitoring gas quality such as moisture analyzers (See Section 10.2.2), etc. shall be installed where required by the contract provisions or by other special situations. Gas quality monitoring shall be installed at meter stations where the gas source is a treatment facility (sweetening, etc.), or where the gas source otherwise has the potential for delivering gas with a hydrogen sulfide content (H2S), Oxygen (O2),Nitrogen (N2), Carbon Dioxide (CO2) or other contamination that exceeds the gas quality requirements of the receiving pipeline. All such

6

CPG

Meter Station Design Guidelines

monitors shall be arranged to automatically shut in the meter station in the event that the monitored parameter(s) exceed(s) preset levels. See Sections 2.2.15, 10.2.4 & 10.2.5 2.2.11

Odorization The meter station design shall include suitable facilities for the odorization of gas when such odorization is required by the applicable Meter Set Agreement (MSA), contract or by Federal, State or local regulations. See Section 9.4,”Odorization”.

2.2.12

Bi-Directional Meter Stations Meter stations requiring bi-directional flow shall have piping and valves installed to allow gas from either direction to be routed through the meter runs, gas conditioning equipment, and flow control (when possible) in only one direction. Limit switches shall be installed on all valves used to route the gas and shall be wired to the CPG flow computer so that flow direction can be determined. Bi-directional meter runs shall not be installed without CPG approval. Any gas conditioning equipment shall treat the gas flow in both flow directions.

2.2.13

Meter Run End Closures All meter runs shall have full opening end closures equipped with safety bleeds to ensure that the closure shall not be opened under pressure.

2.2.14

Pipeline Taps Consideration shall be given to installing additional taps, where parallel CPG lines are present, for stations where flow continuation is critical or for capacity considerations. The maximum design velocity through the tap is limited to 80 ft/s at maximum flow and minimum pressure.

2.2.15

Automatic Shutoff Valves In certain applications, by agreement, valves shall be installed for the sole purpose of shutting in a measuring station based on conditions such as high moisture dew point or hydrogen sulfide levels. These valves shall be designed to remain shut until a CPG employee determines the condition has abated and the valve can be reset (opened).

2.2.16

Check Valves Check valves shall be installed in uni-directional stations to preclude backflow when upset conditions occur.

2.3

METER STATION SITE 2.3.1

Location Considerations The selection of a meter station site is constrained by the location of the CPG pipeline and the location where gas is to be delivered or received. Final site selection shall be approved by CPG and shall consider the following. 

The site should be immediately adjacent to the CPG pipeline

7

CPG

Meter Station Design Guidelines

 

  2.3.2

right-of-way. Where this is not practical, the site shall be as close to the pipeline right-of-way as practical. If the site is not immediately adjacent to the CPG pipeline right-of-way, then right-of-way will have to be obtained for the pipeline connecting the meter station to the CPG pipeline. The site shall be accessible from an all weather road (when possible). The site must be large enough for the proposed meter station facilities; large enough to provide for necessary parking and for truck and equipment access; and large enough to provide buffer zones between the above ground facilities and adjacent properties in accordance with the codes and standards referenced herein, and in accordance with local zoning and environmental regulations. The site must be elevated if necessary in Federal Flood zone. The site shall be in a well-drained area, not subject to inundation. Environmentally sensitive areas shall be avoided where practical. Sound pressure levels (noise) should be considered when selecting the size and location of the station site.

Site Preparation Meter station sites shall be cleared and graded as required to accommodate the facilities and to provide for drainage. Consideration shall be given to leaving trees and other natural vegetation in buffer or peripheral areas to provide screening, noise attenuation, and to reduce storm water run-off.

2.3.3

Paving and Sidewalks Access from the nearest all-weather road and parking for vehicles shall be prepared to provide all weather access. Sidewalks or pavement shall be provided for outside areas that are routinely accessed by operating personnel. 





Pavement for vehicle access and parking may be concrete, asphalt, gravel or other suitable material. Sub-grade and pavement shall be designed to accommodate the heaviest vehicles expected. As a minimum, parking shall be provided for at least one passenger vehicle (automobile or pickup truck). Parking may be inside or outside the meter station fence. If parking is outside the fence, it must be on meter station property and clear of public right-of-ways. If odorant delivery trucks, vacuum trucks, or other large vehicles are expected to visit the meter station site in the course of normal operations, then adequate parking and turn-around space shall be provided for such vehicles. For safety, Columbia company policy requires driving forward out of parking spaces (which may require backing into spaces while parking vehicles.) Sidewalks and other outdoor walking areas may be concrete, gravel or crushed stone and shall be designed to provide

8

CPG

Meter Station Design Guidelines



2.3.4

operating personnel with safe and convenient access to building entries and to outside operating areas. Stiles and elevated walkways shall be provided where necessary for convenient operational access. Areas covered with gravel, crushed stone or similar material shall be under-laid with geotextile fabric to prevent the growth of vegetation.

Landscaping Normally, landscaping will be limited to re-vegetating cleared and unpaved areas with vegetation suitable for the local area.  In accordance with the above Section 2.3.2, “Site Preparation”, trees and other natural vegetation may be left in buffer or peripheral areas to provide screening, noise attenuation, and to reduce storm water run-off.  If site permits or local agencies prescribe special landscaping requirements, then such requirements shall be adhered to in lieu of or in addition to that specified herein.

2.3.5

Fencing Each meter station site shall be fenced. The fenced area shall be large enough to enclose all above ground facilities; to provide space for operational and maintenance access; and to enclose all classified hazardous areas. 



  

 

2.4

Unless otherwise required by site permits or local codes, the fence shall be a chain link fence, at least 6 feet high, and topped with a three-strand barbed wire barrier. At least one vehicle gate with a minimum width of 12 feet, and at least one pedestrian gate shall be provided at all meter stations. Placement of entrances shall provide access to all facilities within the fenced area. Pedestrian gates shall open outward. All gates shall be equipped for locking with a padlock. A warning marker in accordance with PHMSA Part 192.707 shall be placed on the main entrance gate. The marker shall show the name and emergency numbers of the meter station operator along with the other required information. Pipe barriers will be installed as necessary to protect equipment from damage. Fencing shall be grounded per CPG Grounding Standard Drawing (See CPG Standard FA Drawings).

BUILDINGS/ENCLOSURES For specific material requirements, please refer to the latest revision of CPG Design Standard DS-4006 - Electronic Measurement and Gas Chromatograph Specifications.

9

CPG

Meter Station Design Guidelines

To protect sensitive electrical and electronic components from excessive heat and moisture, meter stations that meet any of the following conditions shall have a walk-in EFM building installed at stations utilizing electronic measurement equipment (except Low Cost Electronic Measurement (LCEM) applications where EFM equipment is mounted directly to measurement runs). Stations employing a gas chromatograph require a walk-in building (unless waived by CPG Engineering and Operations). 2.4.1

General Requirements - RTU or Chromatograph Building (General purpose – no high pressure gas) 

   













Buildings shall be of non-combustible materials. Pre-engineered or pre-fabricated metal buildings are preferred, but masonry buildings are acceptable. Buildings shall conform to the Building Officials and Code Administrators (BOCA) National Building Code, and to all applicable local codes. Metal buildings shall be insulated and conform to the Metal Building Manufacturer’s Association “Recommended Design Practices Manual”. Skid mounted, pre-fabricated insulated metal buildings are preferred and shall have non-skid steel flooring. All chromatograph buildings shall be obtained from CPG approved vendors per CPG’s specification. Chromatograph buildings shall be designed for erection on a concrete sonotube or pier foundations. Buildings shall be properly grounded and all building electrical installations shall conform to the requirements of Section 2.5, “Electrical Installations”. The building shall be adequately sized to accommodate the contained equipment with a minimum size of 8’-0” by 12’-0” for chromatograph and RTU housing. Minimum eve height shall be 8’0” for both types of buildings. Doors shall be lockable, equipped with stainless steel hinges and operable from inside the building. Any batteries with the capability of emitting hazardous or corrosive gas shall be installed in a box with the batteries vented outside of the building. Recombinant batteries do not need to be vented. Where commercial power is available, the building shall have a standard 100 amp power service, a distribution panel, interior lighting and two GFCI protected duplex receptacles. If lighting cannot be provided, meter/chromatograph buildings must have windows or skylights to provide adequate light inside the building during the day. Where non-classified electrical equipment is to be installed inside the building, the building shall be located outside classified hazardous areas. Chromatograph and RTU buildings shall be equipped with an HVAC unit where possible. If power is not available, the building

10

CPG

Meter Station Design Guidelines

 2.4.2

shall have properly located screened vent louvers of sufficient number and size to provide fresh air flow into the building. The building shall not be installed over meter runs. A canopy shall be installed over ultrasonic meter runs.

General Requirements – Electric Equipment Enclosures All electronic panels and enclosures shall meet NEMA 4 requirements as a minimum and shall have the following labels:  

2.5

A warning label specifying maximum internal voltage An enclosure function label, i.e., RTU Breaker Panel, Intrinsic Safe Equipment etc.

ELECTRICAL INSTALLATIONS All meter station electrical equipment and electrical installations shall conform to the requirements of the latest edition of ANSI/NFPA 70, “National Electrical Code” (NEC), and to the following codes and standards as applicable:        2.5.1

American Petroleum Institute (API) Institute of Electrical and Electronics Engineers (IEEE) National Electrical Manufacturers Associations (NEMA) National Fire Protection Association (NFPA) Underwriters Laboratory (UL) and/or Canadian Standards Association (CSA) Factory Mutual (FM) Area Classification All areas in a meter station shall be classified in accordance with NEC Article 500 and AGA Catalog #XL1001, “Classification of Locations for Electrical Installations in Gas Utility Areas”. It must be understood that the following AGA definitions are guidelines only (as outlined by AGA Catalog #XL1001.) These guidelines shall be used with sound engineering judgment for final determination of hazardous area boundaries. 





The hazardous area around a full pipeline pressure vent and power gas vents is Div. I to a spherical radius of 5 feet and Div. II to a spherical radius of 15 feet. The hazardous area around all gas process valves and flanges in a non-enclosed, open, adequately ventilated area is Div. II to a spherical radius of 15 feet. The hazardous area around gas process valves and flanges in an adequately ventilated building area is Div. II to the extent of the interior of that building.

11

CPG

Meter Station Design Guidelines













 2.5.2

The hazardous area around gas process valves and flanges in a poorly ventilated building area is Div. I to the extent of the interior of that building. The hazardous area around low-pressure instrument vents in a non-enclosed, open, adequately ventilated area is Div. I to a spherical radius of 1.5 feet and Div. II a spherical radius of 5 feet. The hazardous area around a pig trap vent valve and door is Div. I to a spherical radius of 5 feet and Div. II to a spherical radius of 15 feet. The interior of a transmitter’s protective enclosure shall be defined as Class 1, Group D, Division II if all routine transmitter venting of hydrocarbons is carried to the outside of its enclosure. In addition, the enclosure shall be adequately ventilated in accordance with Section 2.4.2, “General Requirements – Electrical Equipment Enclosure”. The area outside the meter’s transmitter enclosure shall be a Class 1, Group D, Division II area, unless a Division 1 classification is required by other equipment or facilities in the area. The classified area shall extend to at least 1.5 feet spherical radius in all directions from the enclosure. (See PC-11 of AGA Catalog XL1001.) The EFM Building shall not be located in a Class 1, Group D, Division 1 area. The meter building may be located in a Class 1, Group D, Division II area ONLY IF ALL ELECTRIC EQUIPMENT WITHIN THE BUILDING MEET THE REQUIREMENTS FOR DIVISION II HAZARDOUS AREA. If so placed, the interior of the meter building shall also be classified Class 1, Group D, Division II. Areas beyond the defined boundaries of hazardous areas are unclassified.

Grounding All buildings, structures and equipment shall be grounded in accordance with the applicable codes and standards to minimize equipment damage and personnel hazards from lightning and electrical faults. (See Appendix A for Standard Drawings) 

  

A grounding loop shall be placed around each building and around other equipment structures, with 32# magnesium anodes placed at opposite corners. Ground loop shall be stranded, bare, minimum gauge #2/0 HMWPE coated copper wiring. The minimum size conductor to be used in a grounding loop is #2/0 AWG. The minimum size grounding conductor to be used for connecting buildings and other large structures to the ground loop shall be #2 AWG.

12

CPG

Meter Station Design Guidelines

 

2.5.3

All electrical equipment shall be connected to the grounding grid in accordance with NEC Article 250. All electrical connections made to the ground loop underground shall be made with thermally fused bonds (e.g. "Cadweld" connections) and such connections shall be insulated using "Scotch Cast" or equivalent splice insulation.

Lighting Where lighting is provided for a meter station, the lighting design shall provide symmetrical and uniform illumination for the various areas. All sites with flow control, where practical, shall have outdoor lighting with a switch or breaker inside the RTU building. The average illumination levels for specific meter station areas shall be as follows: EFM Building

25 to 35 candle

Equipment Area Floodlighting

10 to 15 candle

Open Area Floodlighting

5 to 10 candle





2.5.4

Outdoor lighting shall be HID luminaries with metal halide (MH) preferred. All HID luminaries shall have high power-factor ballasts. Building interior lighting shall consist of incandescent or fluorescent fixtures. All lighting fixtures shall be suitable for operation in the hazardous area classification in which they are installed.

Electrical Installations All electrical installations shall conform to the referenced codes and standards and shall be in accordance with the following minimum requirements: 





A conduit run between pull points shall not contain more than the equivalent of three one-quarter bends (270 degrees total). The radii of all conduit bends shall be in accordance with the current NEC specifications. All field bends are to be made with an approved conduit bender. Conduits shall be securely supported at intervals not exceeding 10 feet. Vertical, exposed risers shall be supported at the top and bottom and at intervals not exceeding 20 feet. Conduit shall be firmly supported within 3 to 5 feet of any conduit termination, such as at a conduit fitting, outlet body, junction box, cabinet, or device. Conduit fittings, devices, and junction boxes shall be installed with openings faced outward, allowing full interior access without

13

CPG

Meter Station Design Guidelines



  2.5.5

disassembly of conduit or fittings. Power and control circuits for the same device, (e.g. 240 V motor power with its 120 VAC controls) can be installed in the same conduit; however, all conductors in the same conduit shall have the same insulation level. AC and DC circuits shall not be placed into the same conduits. Intrinsic safe circuits shall be routed in dedicated conduits. Nonintrinsic safe wiring shall not be run with intrinsic safe circuits.

Conduit and Wire Sizes 

 

 











The minimum size for aboveground conduit shall be 3/4". Conduits running to devices with a 1/2" NPT connection shall be reduced at the device. Conduit installed underground shall not be smaller than 1" size and shall be installed at a minimum depth of 18”. Conduit shall be hot dipped galvanized steel. All conduit installed below grade shall be Robroy Red or Permacoat PVC coated or CLX plastic coated. In above ground installations where flexibility is required, the use of approved flexible conduits is permitted (in Class 1, Division 1 areas use ECLK style conduit. In Class 1 Division 2 areas use Liquid tight flexible conduit). At buried conduit crossings with foreign company facilities, a minimum of 1-ft separation is required. Conduits buried in highly corrosive soil can be protected by encasement in concrete. The concrete shall be colored red for identification of electrical conduit encasement. Conduits buried in areas of heavy traffic can be protected by being covered with a concrete slab. The concrete shall be colored red for identification of electrical conduit underneath. Wiring to be connected to compression type terminal strips shall be terminated with wire ferrules. Wiring to be connected to screw type terminal strips shall be terminated with forked tongue terminals. All wiring shall be labeled with its next destination (e.g., TS 1A25). The wiring shall not be labeled with its present location or its ultimate destination. Signal wiring for current-loop (2-wire) or voltage (3-wire) instrumentation transducers shall be #18 or #16 AWG, with/drain wire shielding. [Belden 9318 (18 gauge) or Belden 9316 (16 gauge) or equal]. Signal wiring for RTD temperature sensors shall be #18 or #16 AWG with foil/drain wire shielding. For cable distances to the RTD sensor less than 50 feet, a 3-wire RTD is acceptable. If the cable distance is over 50 feet, a 4-wire RTD is required if the associated instrument will accommodate 4 wires [Belden 9365 (18 gauge) or Belden 9366 (16 gauge) or equal]. Signal wiring for thermocouple temperature sensors shall be #22

14

CPG

Meter Station Design Guidelines

 

 

2.5.6

to #18 AWG twisted pair with foil/drain wire shielding. This cable shall be thermocouple compensation, extension cable compatible with the type thermocouple used. Copper wire shall never be used for thermocouple extension cable [Belden 9365 (18 gauge) or Belden 9366 (16 gauge) or equal]. Control wiring for position, limit, pressure, temperature, or flow switches shall be #18 AWG minimum. Control wiring for 24 VDC solenoid valves shall be a #16 AWG (or larger if necessary for voltage drop considerations). A suppression diode shall be installed across the coil of each solenoid control valve at the valve. Include 20% spare conductors to allow for future needs. All electrical devices installed on a skid should have conduits installed and routed to a bulkhead area at the edge of the skid for customer connections in the field.

Load Centers A distribution panel shall be installed at sites that use commercial power and have an RTU/Chromatograph building. The lighting distribution panel shall be single phase, minimum 100 Amp, 8 circuit, and 240/120 volt. 

 2.5.7

Transient AC Power and Telecommunications Voltage Surge Suppression  



3

Circuit breakers for lighting circuits and receptacles shall be 120 volts, single pole, 15 or 20 Amp rating based on associated loads or capacity. The lighting panel load center shall be solidly grounded as per Section 2.5.2, “Grounding”.

Heavy duty, industrial grade, surge suppressors shall be installed on all incoming AC power and telephone/telecommunications circuits. AC surge suppressors shall be connected to a double pole 240 VAC, 30 Amp breaker in the lighting load distribution center. Suppressor power wiring lead lengths to the breaker shall be kept to 1 ft. length or less for optimal surge protection. Each surge suppressor shall be solidly grounded to the station’s ground grid.

ORIFICE METERS This section describes requirements for orifice meters for measurement of natural gas. Meter tube assemblies, orifice fittings and orifice plates shall be designed, fabricated, tested and inspected in accordance with all applicable requirements of the latest edition of AGA Report Number 3 and per the CPG Standard drawings. CPG Design Standard DS4003 should also be referenced

15

CPG

Meter Station Design Guidelines

3.1

SIZING CRITERIA The number and size of orifice meter runs shall be selected to measure the maximum flow rate at the minimum pressure and the minimum flow rate at the maximum pressure, with Beta ratios and differential pressures within the ranges specified below. 3.1.1

Beta Ratio Typically, orifice plate bores shall be selected to provide a Beta ratio in the range of 0.2 to 0.60.

3.1.2

Orifice Differential Sizing of meter tubes and orifice plates shall be such that the orifice differential is within the range of 10 to 200 inches of water column, over the range of specified design flow rates.

3.1.3

Multiple Orifice Meter Runs Multiple orifice meter runs shall be installed where necessary for the maximum design flow rates and as required for turndown between maximum and minimum flow rates. Except in cases where extreme turndown ratios are required or in other special circumstances, it is preferred that multiple orifice meter runs be of the same size and configuration. Automatic tube switching shall be provided for stations with multiple orifice meter runs to automatically bring tubes on line, or take tubes off line as required to maintain the orifice differential in the range specified in Section 3.1.2. Run sequencing valves shall be butterfly valves installed downstream of the orifice meter in the meter’s normal flow direction. Using the outlet meter run block valve for run sequencing is not recommended. Multiple orifice meter runs shall be installed with a ball valve bypass as specified in Section 2.2.5.

3.1.4

Single Orifice Meter Runs Single orifice meter runs shall be installed with a ball valve bypass as specified in Section.2.2.5

3.2

ORIFICE METER TUBES Meter tube components shall be manufactured and meter tubes assembled and tested by an approved vendor capable of ensuring that the completed meter tube assemblies meet all applicable requirements of API MPMS 14.3-2 and AGA Report Number 3. 

3.2.1

All meter tube welds shall be ground smooth internally, to match the contour of the pipe wall. Meter Tube Minimum Dimensions and Configuration Meter tube dimensions and configurations shall be as shown on the

16

CPG

Meter Station Design Guidelines

CPG Standard Drawings (see Appendix A for Drawing List). Only meter run diameters shown in the illustrations are permitted without prior approval from CPG. A drip pan and liquid collection system shall be provided to catch liquids that may fall from the orifice fitting. 3.2.2

Orifice Fittings Orifice fittings shall be either single or dual chamber as delineated in the CPG standard drawings. Orifice flanges will not be permitted. Daniel "Senior” orifice fittings with a weld end on the inlet and a male face flange on the outlet are approved for use in 8 and 10” sizes. Daniel Simplex, TMCO Sure Shot, Canalta and Precision Solo single chamber orifice fittings are approved for use in 2, 4 and 6” sizes.  

3.2.3

Orifice fittings shall have a pressure rating suitable for the meter station design pressure and MAOP. Orifice fittings shall be "telemetering" type fittings having four pairs of differential pressure taps, tapped 1/2" FNPT.

Orifice Plates Orifice plates shall be concentric, square edge orifice plates conforming to the requirements of AGA-3/API 14.3.2.    

3.2.4

Orifice plate material shall be Type 304 stainless steel. Orifice plate thickness shall be equal to the recommended thickness given in Table 2-4 of API 14.3.2. Orifice plates shall be stamped by the manufacturer with a serial number assigned by CPG. Orifice plates shall be compatible with elastomer sealing units as well as compatible with all constituents of the gas stream.

Flow Conditioners Flow conditioners shall be a Canada Pipeline Accessories CPA 50E.

3.2.5

Pipe Pipe used in the fabrication of meter tubes shall be select pipe, meeting the dimensional and surface finish tolerances of API MPMS 14.3.2, and manufactured per ASTM Standard A106 or API Specification 5L. The wall and grade pipe shall be specified to meet the design pressure and factor.

3.2.6

Flanges Flanges for meter tubes shall be weld neck flanges, bored to match the meter tube inside diameter. 



All flanges shall be raised face flanges, except that the flange mating with the male orifice-fitting flange shall have a mating female flange to ensure accurate alignment. Normally flanges shall be ASTM A105 forged steel flanges in accordance with ASME/ANSI B16.5, “Pipe Flanges and Flanged

17

CPG

Meter Station Design Guidelines

Fittings”. Where A105 flanges are to be welded to high yield strength pipe, (SMYS > 35000 psi) flange hubs shall be specially prepared to develop the full strength of the pipe. Alternately, flanges shall be in accordance with MSS SP-44, “Steel Pipeline Flanges”, and have a yield strength matching that of the pipe to which they are welded. 3.2.7

Shop Testing and Inspection Meter tubes shall be tested and inspected in the fabricator’s shop in accordance with the referenced codes and standards, Appendix D, and as outlined in Section 11.3.6, “Pressure Testing”. CPG shall be afforded the opportunity to witness all of these tests and inspections whether the meter tubes are purchased by CPG or by the Customer. All tests and inspections shall be thoroughly documented and copies of all test and inspection reports shall be furnished to CPG. 



The meter tube and orifice fitting shall be inspected to determine the measured meter tube diameter and to confirm that dimensions and surface finishes comply with Section 2.5 of API MPMS 14.3.2. Bypass checks shall be conducted in accordance with Section 2.5.3.4 of API MPMS 14.3-2 and CPG’s “High Pressure Orifice Plate Leak Test” (Appendix D), to establish that there is no leakage across the orifice plate seal and no communication or leakage between pressure taps. The high-pressure nitrogen leak test is optional for facilities delivering into CPG’s pipeline.

In addition to documentation for tests and inspections described above, the fabricator shall provide certification that the meter tube assemblies comply with all applicable requirements of API MPMS 14.3.2, certify that materials and fabrication comply with PHMSA Part 192, and furnish CPG with copies of radiographic reports and other applicable quality control documents. Fabricators shall fill out an Orifice Meter Tube Inspection Report. (See Appendix D “OP Master Mic Sheet (new).xls” ). 3.3

ORIFICE METER INSTRUMENTATION Electronic Flow Measurement (EFM) shall be employed at all orifice meter stations. Each orifice meter run shall be equipped with instrumentation to measure differential pressure, static pressure and flowing gas temperature for the computation of flow rate. General installation requirements are outlined below. Specific requirements for transmitters, recorders, computers, controllers, and other instruments are included in Section 9, “Instrumentation”, and Section 10, “Electronic Measurement and Telemetering”, of these guidelines. For specific material requirements, please refer to the latest revision of CPG Design Standard DS-4006 - Electronic Measurement and Gas Chromatograph Specifications.

18

CPG

Meter Station Design Guidelines

3.3.1

Static and Differential Pressure At Columbia Gulf Transmission stations, Rosemount 3095 multi-variable (PDPTT) transmitter shall be used for measuring static pressure, flowing gas temperature and orifice differential pressure and shall be direct mounted on the five valve manifold which is direct mounted on the orifice fitting. Where necessary, stainless steel tubing connections shall be 0.5” diameter, as short as practical and sloped to drain back to the orifice fitting. At Columbia Gas Transmission stations, Rosemount 3051 differential pressure transmitter shall be used for measuring differential and shall be direct mounted on the five valve manifold which is direct mounted on the orifice fitting. Where necessary, stainless steel tubing connections shall be 0.5” diameter, as short as practical and sloped to drain back to the orifice fitting. At Columbia Gas Transmission stations, Rosemount 3051 static pressure transmitter shall be used for measuring static pressure and shall be direct mounted on the two valve manifold which is direct mounted on the orifice fitting. Where necessary, stainless steel tubing connections shall be 0.5” diameter, as short as practical and sloped to drain back to the orifice fitting.

3.3.2

Flowing Gas Temperature At Columbia Gulf Transmission stations, flowing gas temperature shall be measured with the Rosemount 3095 multi-variable transmitter at the first auxiliary connection downstream of the orifice fitting. At Columbia Gas Transmission stations, flowing gas temperature shall be measured with the Rosemount 3144 temperature transmitter at the first auxiliary connection downstream of the orifice fitting.   

3.4

All thermal elements shall be installed in thermometer wells that extend into the central third of the gas stream. Wiring for the thermal element shall be installed to the temperature transmitter for the same meter run. A test thermowell shall be provided on each meter tube. The test well shall be immediately downstream of the sensing thermal element.

INSTALLATION 3.4.1

General Arrangement Meter tubes shall be installed square and level with the height of the centerline between 3 feet and 4 feet above grade. Spacing between outside diameter of each run shall be a minimum of 4 feet for operational and maintenance access.

19

CPG

Meter Station Design Guidelines

3.4.2

Supports Meter tubes shall be adequately supported with adjustable pipe supports. As a minimum, one support shall be provided on the downstream section near the orifice fitting, and a minimum of one support shall be provided on the upstream section. Support design must provide for removal of the upstream section of the tube for inspection and must ensure that the other tube sections are adequately supported, even when the upstream section is removed.

3.4.3

Inlet and Outlet Valves Each meter run shall have an inlet valve and an outlet valve so that the run can be isolated. These valves shall be full port double block and bleed ball valves with raised face-flanged ends. Six-inch and larger valves shall have either a gear or pneumatic operator. 



4

Outlet valves on secondary meter runs may be used for automatic tube switching, and in this event, will be equipped with double-acting, pneumatic actuators. (See Section 8.1, “Meter Run Sequencing”.) A 1 inch loading valve shall be installed across the inlet block valve to insure the integrity of the ball valve seats.

TURBINE METERS This section describes requirements for turbine meters for measurement of natural gas. Single or dual rotor Sensus turbine meters are acceptable for use by CPG. (Columbia Gas Transmission limits use to single rotor turbine meters.) Meter tube assemblies and turbine meters shall be designed, fabricated, tested and inspected in accordance with all applicable requirements of the latest edition of AGA Transmission Measurement Committee Report No. 7, Measurement of Gas by Turbine Meters. CPG Design Standard DS-4007 should also be referenced 4.1

SIZING CRITERIA The number and size of turbine meter runs shall be selected to measure the maximum flow rate at the minimum pressure and the minimum flow rate at the maximum pressure, while maintaining flow rates of individual meters within the range recommended by the manufacturer. 4.1.1

Multiple Turbine Meter Runs Multiple turbine meter runs shall be installed where necessary for the maximum design flow rates and as required for turndown between maximum and minimum flow rates. Except in cases where extreme turndown ratios are required or in other special circumstances, it is preferred that multiple turbine meter runs be of the same size and configuration. Automatic tube switching shall be provided through the flow computer for stations with multiple meter runs to automatically bring tubes on line, or take tubes off line as required to maintain flow

20

CPG

Meter Station Design Guidelines

rates through individual meters within the range recommended by the manufacturer. Run sequencing valves shall be butterfly valves installed downstream of the turbine meter in the meter’s normal flow direction. Using the outlet meter run block valve for run sequencing is not recommended. Multiple turbine meter runs shall be installed with a ball valve bypass as specified in Section 2.2.5. 4.1.2

Single Turbine Meter Runs Single turbine meter runs shall be installed with a ball valve bypass as specified in Section 2.2.5.

4.2

TURBINE METER TUBES Turbine meter tubes for custody transfer measurement shall only be installed at delivery points from CPG and require engineering approval. Meter tube components shall be manufactured and meter tubes assembled and tested by an approved vendor capable of ensuring that the completed meter tube assemblies meet all applicable requirements of AGA 7.  

4.3

All meter tube welds shall be ground smooth internally, to match the contour of the pipe wall. Spare turbine meter modules shall be supplied with all turbine meter run station installations.

TURBINE METER INSTRUMENTATION For specific material requirements, please refer to the latest revision of CPG Design Standard DS-4006 - Electronic Measurement and Gas Chromatograph Specifications. Electronic Flow Measurement (EFM) shall be employed at all turbine meter stations. 4.3.1

Turbine Meter Output The turbine meter shall output uncorrected pulse to the CPG flow computer that will do billing flow calculations. The pulse should originate from the meter slot sensor. An external pulser may be used by the customer for check measurement. Sensus (dual rotor) Auto Adjust Turbine meters shall not be used for Columbia Gas Transmission applications. Sensus (dual rotor) Auto Adjust Turbine meters may be used for Columbia Gulf Transmission applications.

4.3.2

Static Pressure At Columbia Gulf Transmission and Columbia Gas Transmission stations, Rosemount 3051 static pressure transmitter shall be used for measuring static pressure and shall be direct mounted on the two valve manifold which shall be tapped into the pressure connection on the meter body where practical. Where necessary, stainless steel tubing connections shall be 0.5” diameter, as short as practical and sloped to drain back to the turbine meter.

21

CPG

Meter Station Design Guidelines

4.3.3

Flowing Gas Temperature At Columbia Gulf Transmission and Columbia Gas Transmission stations, Rosemount 3144 temperature transmitter shall be used for measuring flowing gas temperature with appropriately sized thermowell. The thermal element shall be located at the first auxiliary connection downstream of the meter on each turbine meter run.   

4.4

All thermal elements shall be installed in thermometer wells that extend into the central third of the gas stream. Wiring for the thermal element shall be installed to the multivariable transmitter for the same meter run. A test thermowell shall be provided on each meter tube. The test well shall be downstream of the sensing thermal element.

INSTALLATION 4.4.1

General Arrangement Meter tubes shall be installed square and level with a centerline height between 3 feet and 4 feet above grade. Minimum spacing between and around meter tubes shall be adequate for operational and maintenance access.

4.4.2

Supports Meter tubes shall be adequately supported using adjustable pipe supports.

4.4.3

Inlet and Outlet Valves Each meter run shall have an inlet valve and an outlet valve so that the run can be isolated. These valves shall be full port double block and bleed ball valves with raised face-flanged ends. Six-inch and larger valves shall have either a gear or pneumatic operator.  Outlet valves on secondary meter runs may be used for automatic tube switching and, in this event, will be equipped with double-acting, pneumatic actuators. (See Section 8.1, “Meter Run Sequencing”.)  A 1 inch loading valve shall be installed across the inlet block valve to insure the integrity of the ball valve seats

4.4.4

Meter Protection The meter tube blow down size shall be limited as specified by AGA 7. A restriction plate shall be installed as specified in AGA 7 and found in Appendix E.

4.4.5

Strainer Each turbine meter station shall be equipped with a strainer upstream of each meter inlet.

22

CPG

Meter Station Design Guidelines

 

 

4.4.6

Strainers shall be basket-type and shall be equipped with a drain valve. Strainer elements shall be perforated carbon steel with a 304 stainless steel #100 mesh screen liner, and having an open area not less than 200% of the meter tube cross section. Strainers shall have raised face-flanged ends. Strainers having a lid/bonnet weighing in excess of 100 pounds shall be provided with a lifting device capable of fully suspending the lid/bonnet to allow removal of the strainer basket.

Proving Gas turbine meters normally are not be proved in the field. Normally turbine meters, or meter internals will be replaced with shop-proved units. In the event that field meter proving is contemplated for a particular meter station, then appropriate meter prover connections shall be provided.

4.4.7

Turbine Module Lifting Mechanism A McMaster Carr jib crane shall be provided for 8” and larger meters to provide for removal and installation of the turbine meter module. This crane (P/N 3244T1) shall have a lifting capacity of 1000 lbs., and a 10’ high x 10’ span arm that shall be constructed of 10” x 4.66” steel I-beam. This crane shall be fitted with a 1000 lb. hoist (P/N 3094T12) and a 1000 lb. chain hoist trolley flyer (P/N 3269T5).

4.4.8

Automatic oiler A Welker automatic oiler, model number OIP-2BK is required on every turbine meter.

5

ULTRASONIC METERS This section describes requirements for ultrasonic meters for measurement of natural gas. Meter tube assemblies and ultrasonic meters shall be designed, fabricated, tested and inspected in accordance with all applicable requirements of the latest edition of AGA Transmission Measurement Committee Report No. 9, Measurement of Gas by Multipath Ultrasonic Meters, (AGA 9). CPG Design Standard DS-4004 should also be referenced. Ultrasonic meters shall be used on gas flow only. Care should be taken to preclude two phase flow across ultrasonic measurement intended for gas service. 5.1

SIZING CRITERIA The number and size of ultrasonic meter runs shall be selected for an optimum operating range between 5 fps and 75 fps with a maximum operating range between 3 fps to 85 fps. The maximum operating range should not occur more than 5% of the meter in-service time. Size determination is also based on the maximum flow rate at the minimum pressure and the minimum flow rate at the maximum pressure.

23

CPG

Meter Station Design Guidelines

5.1.1

Multiple Ultrasonic Meter Runs Multiple ultrasonic meter runs shall be installed where necessary for the maximum design flow rates and as required for turndown between maximum and minimum flow rates. Multiple ultrasonic meter runs shall be of the same size and configuration. Automatic tube switching shall be provided to automatically bring tubes on line, or take tubes off line as required to maintain flow rates through individual meters within the range recommended by the manufacturer. Run sequencing valves shall be meter run diameter full port ball valves installed downstream of the ultrasonic meter in the meter’s normal flow direction. Using the outlet meter run block valve for run sequencing is not recommended. Multiple ultrasonic meter runs shall be installed with a ball valve bypass as specified in Section 2.2.5.

5.1.2

Single Ultrasonic Meter Runs Single ultrasonic meter runs shall be installed with a ball valve bypass as specified in Section 2.2.5.

5.2

ULTRASONIC METER TUBES Ultrasonic meter tubes for custody transfer measurement shall be per the drawings in the CPG Standard Drawing Book (see Appendix A for Drawing List). The tubes will include a Daniel Profiler or Canada Pipeline Accessories CPA 50E flow conditioner, and a Daniel Senior Sonic or Sic Maihak Flowsic ultrasonic meter, with raised face flanged inlet and outlet. Meter tube components shall be manufactured and meter tubes assembled and tested by an approved vendor capable of ensuring that the completed meter tube assemblies meet all applicable requirements of AGA 9. A 16-inch ultrasonic is the largest acceptable meter unless CPG Engineering gives written approval. 5.2.1

Throttling Devices A throttling device such as a regulator or partially closed valve shall not be installed in close proximity to the ultrasonic meter. A header assembly shall separate multiple meter settings from the control/regulator setting. The meter station shall be designed to incorporate 50 D of pipe and a minimum of two noise abatement fittings (deadheaded tee with blind flange or weld cap) between the noise generator and meter.

5.2.2

Pipe Pipe used in the fabrication of meter tubes shall be select pipe, meeting the dimensional and surface finish tolerances of AGA 9, and manufactured under ASTM Standard A106 or API 5L. Pipe wall thickness and yield strength shall be selected to provide the required design pressure with a 0.5 design Factor after the meter tube is honed.. The meter tube ID shall match the internal diameter of the ultrasonic meter after the meter tube is honed. The meter tube shall be honed with an average internal surface roughness of 50 to 250 microinches.

24

CPG

Meter Station Design Guidelines

5.2.3

Flanges Flanges for meter tubes shall be raised face weld neck flanges, bored to match the meter tube inside diameter. 

5.2.4

Normally flanges shall be ASTM A105 forged steel flanges in accordance with ASME/ANSI B16.5, “Pipe Flanges and Flanged Fittings”. Where A105 flanges are to be welded to high yield strength pipe, (SMYS > 35000 psi) flange hubs shall be specially prepared to develop the full strength of the pipe. Alternately, flanges shall be in accordance with MSS SP-44, “Steel Pipeline Flanges”, and have a yield strength matching that of the pipe to which they are welded. Furthermore, the flanges at the USM and the flow conditioner shall be dowel pinned for precise meter tube alignment.

Auxiliary Connections Meter tubes shall have auxiliary connections for vents, instrument gas taps, temperature instruments and sample probes. The size and location of these taps shall be as shown on the CPG Standard Drawings (see Appendix A for Drawing List). 

5.2.5

All meter tube welds shall be ground smooth internally, to match the contour of the pipe wall.

Shop Testing and Inspection Meter tubes shall be tested and inspected in the fabricator’s shop in accordance with the referenced codes and standards and as outlined in Section 11.3.6, “Pressure Testing”. CPG shall be afforded the opportunity to review all of these tests and inspections whether the meter tubes are purchased by CPG or by the Customer. All tests and inspections shall be thoroughly documented and copies of all test and inspection reports shall be furnished to CPG. 





The meter tube, ultrasonic meter and accessories furnished by the fabricator shall be inspected to confirm compliance with AGA 9 and the purchase documents. Ultrasonic meters shall be flow calibrated at anticipated operating pressure and temperature. The meter test configuration shall include as a minimum, the ultrasonic meter, the upstream and downstream meter tube sections, the flow conditioner and the temperature transmitter. Meter run flow testing shall be conducted at an approved facility. The CEESI, Iowa facility is preferred. The TransCanada Calibrations facility in Winnipeg or Southwest Research in San Antonio may be used with prior CPG approval. A four week notice of calibration to the CPG Design Engineer is required. Design drawings shall be received from fabricator prior to sending unit for flow calibration.

25

CPG

Meter Station Design Guidelines











After fabrication and non-destructive testing of the meter run, provisions shall be made for CPG to witness the “wet” calibration of the ultrasonic meter either in person or remotely The ultrasonic meter and meter run shall be flow calibrated in the same configuration as intended for operation. This includes installation of all test/temperature wells, flow conditioner, etc. The USM should be fabricated and assembled prior to wet calibration and not disassembled unless the length of the entire setting precludes safe shipping. Ultrasonic meter and run should be dowel pinned by the meter run fabricator to ensure proper line up and reassembly in the field if required. The flow calibration test rates are as follows: minimum flow of 3 fps, 10 fps, 25 fps, 40 fps, 60 fps, 75 fps and 100 fps. The flow calibration facility shall use the manufacturer’s ultrasonic meter correction factors upon consultation with the CPG witness. See Appendix D for additional Testing Requirements. The flow calibration facility shall verify correction factors have been applied to the ultrasonic meter at two flow rates of 25 and 65 fps.

In addition to documentation for tests and inspections described above, the fabricator shall provide the following to CPG: ultrasonic meter calibration curves/reports; certification that the meter tube assemblies comply with all applicable requirements of AGA 9; certification that materials and fabrication comply with PHMSA Part 192; and copies of radiographic reports and other applicable quality control documents. 5.3

ULTRASONIC METER INSTRUMENTATION For specific material requirements, please refer to the latest revision of CPG Design Standard DS-4006 - Electronic Measurement and Gas Chromatograph Specifications. Electronic Flow Measurement (EFM) shall be employed at all ultrasonic meter stations. Each ultrasonic meter run shall be equipped with instrumentation to measure ultrasonic meter output pulses, static pressure and flowing gas temperature for the computation of flow rate. General installation requirements are outlined below. Specific requirements for transmitters, computers, controllers, and other instruments are included in the CPG Electronic Measurement and Gas Chromatograph Specifications. 5.3.1

Ultrasonic Meter Output The ultrasonic meter shall output uncorrected pulse to the CPG flow computer that will perform the flow calculations. A Data valid signal will also be required for ultrasonic measurement. With CPG approval, ultrasonic meters can be set up for bidirectional gas flow measurement with flow direction input to the CPG flow computer.

5.3.2

Static Pressure At Columbia Gulf Transmission and Columbia Gas Transmission stations, Rosemount 3051 static pressure transmitter shall be used for measuring

26

CPG

Meter Station Design Guidelines

static pressure and shall be direct mounted on the two valve manifold which shall be tapped into the pressure connection on the meter body where practical. Where necessary, stainless steel tubing connections shall be 0.5” diameter, as short as practical and sloped to drain back to the ultrasonic meter. (see CPG Electronic Measurement and Gas Chromatograph Specifications) 5.3.3

Flowing Gas Temperature At Columbia Gulf Transmission and Columbia Gas Transmission stations, Rosemount 3144 temperature transmitter shall be used for measuring flowing gas temperature with appropriately sized thermowell. The thermal element shall be located at the first auxiliary connection downstream of the ultrasonic meter within 3 to 5 pipe diameters downstream of the USM (see CPG Electronic Measurement and Gas Chromatograph Specifications) on each Ultrasonic meter run.   

5.4

Each meter run shall have a dedicated thermal element installed for the same meter run. All thermal elements shall be installed in thermometer wells that extend into the top third diameter of the meter tube. A test thermowell shall be provided on each meter tube. The test well shall be downstream of the sensing thermal element.

INSTALLATION 5.4.1

General Arrangement Meter tubes shall be installed square and level with the centerline at a height between 3 feet and 4 feet above grade. Spacing between the outside diameters of the runs shall be a minimum of 4 feet for operational and maintenance access. A canopy or cover designed for the location and loads shall be installed over the ultrasonic meter runs to keep sunlight off the meter runs to prevent thermal currents in the meter tube. The piping design shall allow for the addition of a temporary or permanent check meter such as a clamp-on ultrasonic meter.

5.4.2

Supports Meter tubes shall be adequately supported. Adjustable pipe supports are preferred. As a minimum, one support shall be provided on the meter tube on either side of the ultrasonic meter, and at least one additional support shall be provided on the upstream section. Support design must provide for removal of the upstream section of the meter tube, and/or the ultrasonic meter, for inspection and must ensure that the other tube sections are adequately supported, even when the upstream section and/or ultrasonic meter are removed.

27

CPG

Meter Station Design Guidelines

5.4.3

Inlet and Outlet Valves Each meter run shall have an inlet valve and an outlet valve so that the run can be isolated. These valves shall be full port double block and bleed ball valves with raised face-flanged ends. Six-inch and larger valves shall have either a gear or pneumatic operator. 



6

Outlet valves on secondary meter runs may be used for automatic tube switching and, in this event, will be equipped with double-acting, pneumatic actuators. (See Section 8.1, “Meter Run Sequencing”, of these guidelines.) A 1 inch loading valve shall be installed across the inlet block valve to insure the integrity of the ball valve seats.

POSITIVE DISPLACEMENT METERS Positive displacement meters (rotary) shall be designed and installed in accordance with all applicable requirements of the latest edition of ANSI B109.3, “Rotary Type Gas Displacement Meters”. Rotary meter tubes for custody transfer measurement shall only be installed at delivery points from CPG and require engineering approval. High pressure cartridge type rotary meters with internal bypass should be used to preclude loss of market. Meter tube components shall be manufactured and meter tubes assembled and tested by an approved vendor capable of ensuring that the completed meter tube assemblies meet all applicable CPG requirements. 6.1

METERS Positive displacement meters shall be Dresser - Roots or Instromet or approved equal with a rated working pressure equal to the design pressure of the meter station piping in which the meter is to be installed. Meters shall be equipped with an internal bypass. 6.1.1

Sizing Criteria Meters shall be selected to measure the maximum flow rate at the minimum pressure, and the minimum flow rate at the maximum pressure, while maintaining the flow rates through the individual meter within the range recommended by the manufacturer.

6.1.2

Multiple Rotary Meters Multiple Rotary meters will not normally be installed in a single meter station, unless the station is serving multiple delivery points. Where volumes to a single delivery point are large enough to justify multiple Rotary meters, orifice or turbine meters are preferred, or combinations of rotary and turbine or rotary and orifice meters. Run sequencing valves shall be butterfly valves installed downstream of the rotary meter in the meter’s normal flow direction. Using the outlet meter run block valve for run sequencing is not recommended. Each rotary meter run shall be installed with an underslung ball valve bypass that meets the intent of the meter bypass per Section 2.2.5.

28

CPG

Meter Station Design Guidelines

6.1.3

Single Rotary Meter Runs Each rotary meter run shall be installed with an underslung ball valve bypass that meets the intent of the meter bypass per Section 2.2.5

6.1.4

Shop Testing and Inspection Rotary meters shall be tested and inspected in the fabricator’s shop in accordance with the referenced codes and standards and as outlined in Section 11.3.6, “Pressure Testing”. CPG shall be afforded the opportunity to witness all of these tests and inspections whether the meter tubes are purchased by CPG or by the Customer. All tests and inspections shall be thoroughly documented and copies of all test and inspection reports shall be furnished to CPG. 

   

6.2

The meter and accessories furnished by the manufacturer shall be inspected to confirm compliance with ANSI B109.3 and the purchase documents. In addition to documentation for tests and inspections described above, the manufacturer shall provide the following to CPG: Meter calibration and differential pressure curves/reports with test points at 10, 25, 50, 75 and 100% of meter capacity. Certification that the meter complies with all applicable requirements of ANSI B109.3. Certification that materials and fabrication comply with PHMSA Part 192 Copies of applicable quality control documents.

INSTALLATION 6.2.1

General Arrangement Positive displacement meters shall be installed square and level, and in accordance with ANSI B109.3 and the manufacturer’s instructions.

6.2.2

Piping Normally, piping for Rotary meters is shop fabricated. Piping materials, fabrication, welding, painting and testing shall be in accordance with the general piping requirements given in Section 11, “Yard Piping and Headers”.

6.2.3

Supports The rotary meter and related piping shall be adequately supported. Support design must ensure that the meter is level, and that piping loads are not transferred to the meter flanges.

6.2.4

Inlet, Outlet and Bypass Valves for Single Rotary Meter Setting Each meter shall have full port double block and bleed ball valves on the inlet and outlet valves and a bypass so that the meter can be isolated and the flow bypassed.

29

CPG

Meter Station Design Guidelines

6.2.5

Strainer A strainer shall be installed upstream of each rotary meter.  

 6.2.6

Strainers shall be "Y" type or basket type strainers Strainer elements shall be perforated carbon steel and contain a 304 S.S. #100 mesh screen housed in a basket, and having an open area not less than 200% of the meter tube cross section Strainers shall have raised face-flanged ends

Prover Connections A 2” weld x thread nipple with cap shall be provided on each side of the meter so that a meter prover or master meter can be temporarily connected in series with the rotary meter. The downstream prover connection shall be at an elevation of at least 7' above grade to allow safe venting of gas during testing.

6.2.7

Over-Range Protection Rotary meters shall be protected from over-range with a critical flow orifice provided by the meter manufacturer and properly sized to prevent meter over-range. The critical flow orifice shall be a steel paddle type orifice plate, designed for mounting between raised face flanges, and shall be installed downstream of the meter outlet, normally at the upstream flange of the outlet valve. See Appendix E for sizes.

6.3

ROTARY METER INSTRUMENTATION For specific material requirements, please refer to the latest revision of CPG Design Standard DS-4006 - Electronic Measurement and Gas Chromatograph Specifications. Electronic Flow Measurement (EFM) shall be employed at all rotary meter stations. 6.3.1

Rotary Meter Pulse Output The rotary meter shall output uncorrected pulse to the CPG flow computer that will do billing flow calculations. The pulse should originate from the meter pulser.

6.3.2

Static Pressure At Columbia Gulf Transmission and Columbia Gas Transmission stations, Rosemount 3051 static pressure transmitter shall be used for measuring static pressure and shall be direct mounted on the two valve manifold which shall be tapped into the pressure connection on the meter body where practical. Where necessary, stainless steel tubing connections shall be 0.5” diameter, as short as practical and sloped to drain back to the rotary meter. (see CPG Electronic Measurement and Gas Chromatograph Specifications). At meter stations with a single meter run, Low Cost Electronic Measurement (LCEM) with integral pressure temperature sense will be

30

CPG

Meter Station Design Guidelines

used with integral multivariable transmitters. 6.3.3

Flowing Gas Temperature At Columbia Gulf Transmission and Columbia Gas Transmission stations, Rosemount 3144 temperature transmitter shall be used for measuring flowing gas temperature with appropriately sized thermowell. At meter stations with a single meter run, temperature will be measured with a. Low Cost Electronic Measurement (LCEM) multivariable transmitter The thermal element shall be located in the thermalwell provided on the rotary meter run (see CPG Electronic Measurement and Gas Chromatograph Specifications). .  

7

Wiring for the thermal element shall be installed to the temperature transmitter for the same meter run if applicable. A test thermowell shall be provided on each meter tube. The test well shall be downstream of the sensing thermal element.

FLOW AND PRESSURE CONTROL Equipment for automatic control of flow and pressure and for automatic meter tube switching shall be provided as outlined below. Any related requirements of contracts or interconnect agreements shall also be adhered to.

8

DEFINITIONS Overpressure protection – System by which regulators or control valves control the pressure from a higher MAOP pipeline to a lower MAOP pipeline. Two types of overpressure protection are permitted by this guideline – both specified by PHMSA 192.199. See Section 8.6 – “Over Pressure Protection”. Monitored set of regulation – Two regulators or control valves are installed in series. The primary or overpressure control valve is the downstream valve and shall be set at the lower MAOP pipeline’s pressure which is to be protected. The upstream regulator or control valve is the monitor valve that will take over if the primary control valve fails to control correctly. See Section 8.6.3 – “Monitored Regulator Settings”. Over pressure shutdown valve – Also known as a security valve, the Overpressure shutdown valve acts as the monitor control valve and will close upon sensing its setpoint and remain closed until manually reset. The Overpressure shutdown valve is used where the customer has provided control of the higher MAOP pipeline so as not to over pressure the lower MAOP pipeline. See Section 8.6.4 – “Over Pressure Shutdown Valves” Remote shutoff valve – A standalone valve that can be remotely closed when a station needs to be shut in at the discretion of CPG. See Section 8.8 – “Remote Shutoff Valve” Flow Control valve - The flow control valve receives a remote flow set point to control the flow rate of gas using measurement at the facility. See Section 8.2.1 – “Flow Control Valves”

31

CPG

Meter Station Design Guidelines

Flow Control valve with overpressure control - The flow control valve receives a remote flow set point to control the flow rate of gas using measurement at the facility. However, this setpoint can be over ridden with overpressure control signal from either a local pneumatic pressure controller or a local electronic pressure controller. See Section 8.2.1 – “Flow Control Valves” Pressure control valve – The pressure control valve receives a remote pressure set point to control the pressure of gas using pressure sense at the facility. However, this control valve can be over ridden with overpressure control signal from either a local pneumatic pressure controller or a local electronic pressure controller. See Section 8.3.1 – “Pressure Control Valves” Run Sequencing Valve - The Run Sequencing Valve is fully opened or closed based on a signal from the flow computer that determines if the meter run is required to accurately gauge flow rate. See Section 8.1.1 – “Meter Run Sequencing Valves” Flow Direction Valve – The Flow Direction Valve is fully opened or closed based on a signal from the flow computer that determines direction of flow through a bidirectional station. See Section 8.9 – “Flow Direction Valves” Relief Valve – A valve that relieves gas to the atmosphere when a set pressure is sensed. See Section 8.7 – “Relief Valves” Set Pressure – The pressure set point at which an over pressure device actuates. a) Where the overpressure protection criterion is 110% of the maximum allowable operating pressure, the overpressure protective device(s) may be set to function at a pressure slightly higher than the maximum allowable operating pressure, but in no case to exceed a set pressure of 105% of the maximum allowable operating pressure. The maximum allowable operating pressure and the specified minimum yield strength shall apply to the weakest element of the system being protected. b) It shall be recognized that in a Class 1 Location, design criteria permits a maximum specified minimum yield strength of 72%. Limitations of 199.211(a) will not in all cases permit a set pressure as high as 105% of the maximum allowable operating pressure because of the 75% specified minimum yield strength limitation imposed by Section 192.201(a)(2)(i) that will apply in a Class 1 Location. c) The set pressure of a relief valve protecting a code stamped, unfired pressure vessel contained within the pipeline system being protected cannot exceed the stamped pressure rating of the vessel. MAOP in this context means the lowest maximum allowable operating pressure, determined in accordance with the applicable codes and standards, of any component of the protected piping or equipment. 8.1

METER RUN SEQUENCING Automatic meter run sequencing (switching additional meter tubes on or off) shall be provided at meter stations with multiple meter runs when necessary to accurately measure the entire station flow range.

32

CPG

Meter Station Design Guidelines

8.1.1

Meter Run Sequencing Valves A separate downstream meter run sequencing valve in addition to the outlet block valve is preferred for meter run switching. Meter run outlet isolation valves may be used for tube switching with the approval of CPG. Butterfly valves may be used for run sequencing on orifice and turbine meter runs in addition to the full port ball valve outlet block valve. Only meter run diameter full port ball valves may be used for run sequencing on ultrasonic meter runs in addition to the full port ball valve outlet block valve. Full port ball valves shall be used as meter run inlet / outlet isolation valves.

8.1.2

Valve Actuators Valve actuators for meter run switching shall be double-acting pneumatic actuators. 







8.2

For safety reasons, power gas for valve actuators for the meter run shall be taken from the blow down connection on the meter tube that is being sequenced. A block valve and an instrument supply system are required to reduce the line pressure to the level required by the valve actuator (normally 100 psig) shall be provided, and connected with ½ inch stainless steel tubing to provide valve actuator power gas. See Section 8.6, “Instrumentation Gas Supply”. Actuators on tube switching valves will be controlled electronically using signals from the flow computer to solenoid valves. The solenoids shall be latched until the desired valve position is reached (typically this is full open) and then deenergized. It is also acceptable (depending upon the circumstances) that double acting solenoids may be used to pulse open double acting actuators on ball valve run sequencing valves. A shunting diode (Motorola 1N-5407 or equivalent) shall be installed across each solenoid valve coil to suppress inductive voltage transients.

FLOW CONTROL Although the Customer may control flow in their piping system, CPG reserves the right to override flow control into or out of the CPG piping system. Consequently, flow control equipment operated by CPG shall be installed at all meter stations designed for flow rates of 10 mmcfd or greater. Flow control may be provided for smaller meter stations where required by the specific conditions or contract requirements. Flow control valves shall be equipped with manual bypass piping and valves for flow volumes of 10 mmcfd or greater. 8.2.1

Flow Control Valves Flow control valves shall be globe or ball-type control valves with

33

CPG

Meter Station Design Guidelines

double-acting pneumatic piston or diaphragm actuators. 









8.3

Flow control valves at meter stations shall be controlled electronically using a signal directly from the flow computer to the valve positioner/actuator, or via a motor controlled regulator type electronic-to-pneumatic transducer (Fairchild Model 24XFM No Bleed Remote Set Regulator RSR). Refer to CPG Electronic Measurement and Gas Chromatograph Specifications. In general, flow control valves shall be arranged to fail in last position, but the specific failure mode shall be evaluated for each meter station. Flow control valves may also be used with an alternate control signal and appropriate relaying to provide pressure over-ride of the flow control function. Power and pilot gas for flow control valves shall be filtered, dried gas from the instrument gas supply system. See Section 9.6, “Instrument Gas Supply”. Position feedback equipment shall be installed on flow control valves. This equipment should include full open and full closed limit switches as well as analog valve position feedback.

PRESSURE CONTROL Pressure control shall be provided where necessary to control downstream pressure at a specific value. A single pressure control valve does not constitute over pressure protection. 8.3.1

Pressure Control Valves Pressure control valves shall be globe or ball-type control valves with double acting pneumatic piston or diaphragm actuators. If fail open or fail closed actuation is desired, single acting, spring return actuators shall be employed. 







Pressure control valves with remote pressure set point shall be controlled electronically by the station flow computer in conjunction with a pneumatic pressure controller where required for overpressure protection. In general, pressure control valves shall be arranged to fail last position upon loss of power or pilot, but the specific failure mode shall be evaluated for each meter station. Pressure control valves may also be used with an alternate control signal and appropriate relaying to provide over pressure protection when used in conjunction with a monitor control valve. See Section 8.6, “Overpressure Protection” Power and pilot gas for pressure control valves shall be filtered, dried gas from the instrument gas supply system. See Section 9.6, “Instrument Gas Supply”.

34

CPG

Meter Station Design Guidelines

 

8.3.2

Individual taps and instrument supply systems shall be used for all pneumatic valve actuators in pressure control service. Position feedback equipment shall be installed on pressure control valves. This equipment should include full open and full closed limit switches as well as analog valve position feedback.

Regulation Bypass Regulation bypass shall be installed at all pressure control settings where flow cannot be interrupted and which have only a single regulator run. The bypass run shall be designed with two plug valves. The first plug valve can be manually throttled for pressure control while the regulation is inspected and the second plug valve can be greased to prevent leakage and can be locked shut. A pressure indicator shall be installed between the plug valves for pressure indication. Consider installing of a regulator between the plug valves for more accurate control while the primary regulator run is being inspected.

8.4

CONTROL VALVE SIZING AND SELECTION The size and number of pressure and flow control valves shall be determined based on the following design conditions: maximum flow rate at the minimum pressure and the minimum flow rate at the maximum pressure. 





8.5

Pressure and flow control valves shall be sized to operate between 20% and 80% open over the range of design flow rates and pressures. Multiple parallel valves shall be installed as required to achieve the required turndown. Sizing calculations shall include noise calculations. Noise abatement trim, acoustic insulation, or other noise abatement measures shall be implemented if predicted noise levels exceed 85 db at three feet, or if noise levels exceed lower limits specified by federal, state or local regulations. Control valves shall have raised face-flanged ends. Ball type control valves may be "flangeless" (i.e. Fisher V-200) for mounting between raised face flanges.

CONTROL VALVE INSTALLATION 8.5.1

General Flow and pressure control valves shall be installed above grade. However, if noise is a consideration, the valves may be installed below grade but only with CPG written approval.

8.5.2

Piping Control valve piping shall be in accordance with the general requirements of Section 11, “Yard Piping and Headers”, of these guidelines and shall conform to the specific requirements outlined below. 

Flow and pressure control valves shall be installed downstream of measurement.

35

CPG

Meter Station Design Guidelines

  











8.6

Control valves mounted in parallel shall be installed using headers in the inlet and outlet piping. Piping shall be arranged to be self-draining to the headers. Block valves shall be installed on each side of control valves settings. Block valves shall be full port, double block and bleed ball valves with raised face-flanged ends. The control valve body, downstream block valve, and piping between the control valve and the downstream block valve shall be rated for the maximum inlet pressure to the control valve. Each pressure control valve shall have a separate valve tap connection on the downstream piping or header as a pressure sensing point for each of the pressure controllers. A pressure sense connection with tap valve and pressure indicator shall be installed on either side of pressure control valves within the block valves. A blow down tap with valve shall be provided for each control valve on the piping between the control valve and the downstream block valve. Position feedback equipment shall be installed on both monitor and primary pressure control valves when used for overpressure protection. This equipment should include full open and full closed limit switches as well as analog valve position feedback.

OVERPRESSURE PROTECTION Each meter station and/or pipeline that is connected to a gas source so that the maximum allowable operating pressure could be exceeded as the result of a pressure control failure or some other type of failure, must have pressure relieving or pressure limiting devices installed that meet the requirements of PHMSA Part 192.199 and PHMSA Part 192.201. 8.6.1

Criteria for Overpressure Protection Overpressure protection shall be provided for the following situations: 





All cases where the delivering system has the capability of exceeding the MAOP of the receiving system. Documentation of overpressure protection device design parameters and relief valve capacity shall be provided for review and approval by CPG Engineering. All cases where valve actuator power gas, instrument gas and other auxiliary gas systems may be over pressured by the delivery system. All piping that can be isolated and made "bottle-tight” or PODs that have small gas take away capacities (has the potential for overpressure from valve leakage) shall be protected by safety/relief valves in lieu of pressure monitor or over pressure shutdown valves.

36

CPG

Meter Station Design Guidelines

 8.6.2

Rupture discs shall not be used.

Selection of Overpressure Protection Devices Overpressure protection should be provided by monitored regulator settings or over pressure shutdown valves as described in Sections 8.6.3, “Monitored regulator settings” and 8.6.4, “Over pressure shutdown valves”, (CPG’s preferred methods). Overpressure protection may also be provided by safety/relief valves as described in Section 8.7, “Safety/Relief Valves, or by a combination of these devices by code. However, use of safety/relief valves for overpressure protection is discouraged by CPG due to the possible unintended release of gas to the atmosphere. Overpressure protection devices shall meet the minimum requirements of PHMSA Part 192.

8.6.3

Monitored regulator settings Monitored regulator settings are monitor pressure control valves placed upstream of and in series with primary pressure control valves that will automatically take over the pressure regulating function in the event of failure or malfunction of the primary pressure control system. 











Control valves in a monitored regulation setting may consist of instrument controlled valves, pilot operated or self-operated regulators. Monitored regulator settings shall be dedicated to monitor service and shall not be used for any normal operational function. Controls, power and pilot gas supply, and pressure sensing taps shall be separate from primary control regulation and any normal operational devices. Position feedback equipment shall be installed on both monitor and primary pressure control valves. This equipment should include full open and full closed limit switches as well as analog valve position feedback. Monitored regulator settings shall be globe or ball-type control valves. Normally they will be similar to the primary control valve that they are monitoring, and must have the same pressure rating. Control valves shall have pneumatic piston or diaphragm actuators as appropriate for the specific valve. Single-acting, spring return, fail open actuators are preferred. Double-acting actuators shall be provided with a volume tank to provide an emergency supply of power gas to operate the valve in the event of power gas supply interruption. Volume tanks shall be equipped with a check valve installed in the power gas supply line to prevent volume tank bleed-down in the event of power gas supply interruption. Local pneumatic pressure controls shall be used for monitored regulator settings. The primary control valve may be equipped with a remote set pressure control depending on the operations

37

CPG

Meter Station Design Guidelines





 

8.6.4

requirements of the facility The maximum set pressure for the primary pressure control valve shall be set at the MAOP pressure or lower if required by operations. The set pressure for the monitor control valve shall be higher than that of the primary pressure control valve that they are monitoring (but not higher than 105% of the MAOP or 75% SMYS of the protected piping) such that the monitor valve will remain fully open when the primary pressure control is functioning properly. Set pressures must also be below the set pressure of any associated safety/relief valves. See Section 7 “Definitions – Set Pressure”. CPG Engineering will approve all set points for over pressure protection equipment. Primary and monitor control valves shall normally be arranged to fail open on loss of power or pilot, but the specific failure mode shall be evaluated by CPG for each meter station.

Over Pressure Shutdown Valves (Security Valves) Over pressure shutdown valves monitor line pressure and are designed to fully close when the pressure set point is exceeded to protect piping or equipment from overpressure resulting from the failure of other devices or equipment that normally control the pressure. Over pressure shutdown valves must be manually reset after the over pressure condition has been investigated and resolved. Over pressure shutdown valves are not a good choice for stations that have a firm transportation contract or deliveries to customers. 





 

Over pressure shutdown valves shall be dedicated to this service and shall not be used for any normal pressure regulating function; however, they may be used as block valves to isolate piping or equipment for maintenance or inspection. Controls, power and pilot gas supply, and pressure sensing taps shall be separate from those used for normal operational devices. Over pressure shutdown valves may be globe or ball-type control valves, or they may be conventional ball valves with power actuators. Over pressure shutdown valves shall have pneumatic piston or diaphragm actuators as appropriate for the specific valve. Single-action, spring return actuators are preferred. Doubleacting actuators shall be provided with a volume tank to provide an emergency supply of power gas to operate the valve in the event of power gas supply interruption. Local pneumatic pressure controls shall be used for over pressure shutdown valves. Set pressure for over pressure shutdown valves shall be set sufficiently above typical pipeline operating pressure but not higher than 100% of MAOP or 75% SMYS of the protected

38

CPG

Meter Station Design Guidelines

 

8.7

piping. The over pressure shutdown valve shall remain fully open while the monitored pressure is within the specified normal range. The over pressure shutdown valve set point must also be below the set point of any associated safety/relief valves. See Section 8.7.2 – Set Pressure. CPG Engineering will approve all set points for over pressure protection equipment. Over pressure shutdown valves and associated controls shall be arranged to fail closed on loss of power or pilot. Specific failure modes shall be evaluated for each meter station.

SAFETY/RELIEF VALVES & OVER PRESSURE PROTECTION Safety/Relief valves shall not be used as pipeline over pressure protection unless an exception is granted by CPG Engineering. Safety/relief valves shall be provided to protect piping and equipment from overpressure where adequate protection cannot be obtained with pressure monitoring or pressure limiting devices. In general, piping and equipment that is "dead-ended" or that can be made "bottle-tight" and that has the potential for being over pressured as a result of valve leakage, malfunction or other reason, will require a safety/relief valve for protection. 8.7.1

Selection Safety/relief valves may be spring-loaded safety/relief valves or pilotoperated safety/relief valves and shall be certified by the manufacturer as conforming to the requirements of Section VIII of the ASME Boiler and Pressure Vessel Code, “Pressure Vessels” - Division 1.

8.7.2

Set Pressure a)

b)

c)

Where the overpressure protection criterion is 110% of the maximum allowable operating pressure, the overpressure protective device(s) may be set to function at a pressure slightly higher than the maximum allowable operating pressure, but in no case to exceed a set pressure of 105% of the maximum allowable operating pressure. The maximum allowable operating pressure and the specified minimum yield strength shall apply to the weakest element of the system being protected. It shall be recognized that in a Class 1 Location, design criteria permits maximum specified minimum yield strength of 72%. Limitations of 199.211(a) will not in all cases permit a set pressure as high as 105% of the maximum allowable operating pressure because of the 75% specified minimum yield strength limitation imposed by Section 192.201(a)(2)(i) that will apply in a Class 1 Location. If a Code stamped, unfired pressure vessel is contained within the pipeline system being protected, the set pressure of the overpressure protective device(s) cannot exceed the stamped pressure rating of the vessel. MAOP in this context means the

39

CPG

Meter Station Design Guidelines

lowest maximum allowable operating pressure, determined in accordance with the applicable codes and standards, of any component of the protected piping or equipment. 8.7.3

Relieving Capacity Safety/relief valves shall have a relieving capacity sufficient to prevent the pressure of the protected piping from exceeding 110 % of the MAOP, or 75% of pipeline specified minimum yield strength (SMYS), whichever is lower, based on the largest source of overpressure that may result from any single failure. 











If the source of potential overpressure is a pressure control valve, other valve, or orifice; then the minimum required relief capacity is the maximum flow rate that can be achieved through the valve or orifice. This assumes an upstream pressure equal to the MAOP of the upstream piping (or to the maximum source pressure if lower) and assumes a downstream pressure equal to the MAOP of the protected piping. In the case of multiple pressure reductions, the rationale of the preceding paragraph shall be applied to the piping associated with each successive pressure reduction to the extent that successive piping sections have lower MAOP’s. In the case of multiple parallel pressure control valves, the safety/relief valve capacity shall be based on the control valve having the largest capacity. If a single control failure has the potential to cause more than one control valve to fail open, the capacity of the safety/relief valve must be based on the total capacity of the valves that can fail open. Where the potential overpressure source is other than a control valve, valve, or orifice, the safety/relief valve capacity shall be based on the maximum flow rate that can be achieved through the particular piping or equipment. This assumes an upstream pressure equal to the upstream MAOP (or source pressure if lower) and the downstream pressure equal to the MAOP of the protected piping. Capacities of safety/relief valves shall be calculated in accordance with Section VIII of the ASME Boiler and Pressure Vessel Code using manufacturer’s certified capacity data and CPG’s relief valve capacity calculation program (SWRI-Rev 5.xls – Contact CPG engineering department).. Capacity calculations must consider flowing inlet pressure drop between the safety/relief valve and the facilities to be protected, and backpressure resulting from discharge piping, connected vent lines, or blowdown silencers. Safety/relief valves shall be designed and installed in a manner that prevents hammering. Documentation of design review consideration of potential hammering shall be provided to CPG for review prior to acceptance of design.

40

CPG

Meter Station Design Guidelines

8.7.4

Safety/Relief Valve Installation Safety/relief valve piping shall conform to the general requirements in Section 11, “Yard Piping and Headers”, of these guidelines and to the following: 









Inlet piping for safety/relief valves shall be as short as practical and shall be designed to minimize pressure drop in the inlet piping. Where safety/relief valves are installed on buried headers, oversize risers shall be employed. Except where limited by header size, suggested sizes for such risers are follows: Safety/Relief Valve Nominal Inlet Size

Nominal Riser Size

2”

4”

3”

6”

4”

8”

6”

10”

8”

12”

Transition from riser pipe diameter to safety/relief valve inlet size shall be achieved using a concentric reducer installed immediately upstream of the safety/relief valve inlet or block valve. Block valves shall be installed under safety/relief valves to provide for routine testing in situations where the safety/relief valve cannot readily be removed from service. In such cases a test ring and bleed valve shall be installed between the block valve and the safety/relief valve. Block valves installed under safety/relief valves shall be full opening valves of the same size as the safety/relief valve inlet, except in cases where excessive inlet pressure drop would result, whereupon a valve with I.D. equal to nominal riser size may be used. Such block valves shall be locked, car-sealed or otherwise secured in the full open position at all times other than when testing or maintaining the safety/relief valve. Safety/relief valves shall discharge at a safe location. A square ended stack discharging locally at not less than 8 feet above grade, or above any adjacent walking/working surface, and equipped with a rain cap is the preferred method; but where necessary the discharge shall be connected to a vent or flare header, or to a blow down silencer. Effect of backpressure on safety/relief valve operation shall be considered when connecting a safety/valve to a vent or flare header. Consideration shall also be made when multiple discharge points are connected to a common header, and when multiple

41

CPG

Meter Station Design Guidelines



8.8

discharges could occur as a result of a single control or component failure. Safety/relief valve inlet and outlet piping shall be adequately supported to provide for thrust loads.

REMOTE SHUTOFF VALVE CPG Columbia Gulf Transmission requires the installation of a remote controlled isolation valve at meter stations with flow rates greater than 10 mmcfd. These will be used to prevent gas from -leaking through when the flow control valve(s) is/are closed. 8.8.1

Remote Shutoff Valves (Station Isolation Valve) Remote shutoff valves shall be full port double block and bleed ball valves with double-acting pneumatic piston actuators. 







8.9

Remote shutoff valves at meter stations shall be controlled electronically using open/close signals directly from the flow computer to the solenoid valves interfaced with the valve actuator. In general, remote shutoff valves shall be arranged to fail in last position, but the specific failure mode shall be evaluated for each meter station. Power gas for remote shutoff valves shall be filtered, dried gas from the instrument gas supply system. See Section 8.6, “Instrument Gas Supply”. Position feedback equipment shall be installed on remote shutoff valves. This equipment should include full open and full closed limit switches.

FLOW DIRECTION VALVE CPG requires the installation of remote controlled flow direction valves that will be used to route gas in the proper direction through a bi-directional measurement station. 8.9.1

Remote flow direction valves Remote flow direction valves shall be full port ball valves with doubleacting pneumatic piston actuators. 



Remote flow direction valves at meter stations shall be controlled electronically using open / close signals directly from the flow computer to the solenoid valves interfaced with the valve actuator. In general, remote flow direction valves shall be arranged to fail in last position, but the specific failure mode shall be evaluated for each meter station.

42

CPG

Meter Station Design Guidelines





9

Power gas for remote flow direction valves shall be filtered, dried gas from the instrument gas supply system. See Section 9.6, “Instrument Gas Supply”. Position feedback equipment shall be installed on remote flow direction valves. This equipment should include full open and full closed limit switches.

INSTRUMENTATION This section describes general requirements for meter station instrumentation. For specific material requirements, please refer to the latest revision of CPG Design Standard DS4006 - Electronic Measurement and Gas Chromatograph Specifications. 9.1

PROCESS INSTRUMENT CONNECTIONS Instrument connections to main gas piping shall be made in accordance with the guidelines below: 



9.1.1

All instrument, control and sampling lines shall be installed, supported and routed to prevent damage from temperature variations and physical disturbances. Instrument, control and sampling lines shall not span long distances or be easily damaged by passing personnel. A separate control line/pressure source must be designed and installed on each overpressure protection device to ensure a single failure does not incapacitate both the monitor and control. Pressure Sensing Connections (Other than at Orifice Fittings) Each pressure sensing connection on main gas piping shall have a valve at the main gas piping.  





Where only a pressure gauge is to be installed, a two valve stainless steel manifold shall be used. Where a pressure sensing device is to be connected to the same tap in addition to a pressure gauge, install a stainless steel three valve manifold. Where a differential pressure sensing device is to be connected to the main gas piping, a stainless steel five-valve block manifold shall be used. Instrument control lines above grade shall be made with stainless steel tubing-

43

CPG

Meter Station Design Guidelines

Tensile Strength (Minimum) psi

Maximum Working Pressure (100°F) psi

Size

O.D.

Wall Thickness

Material Type

Yield Strength (Minimum) psi

1/8”

.125"  .005"

.028"  .005"

316 SS

30,000

75,000

8,500

¼"

.250"  .005"

.035"  .005"

316 SS

30,000

75,000

5,250

3/8"

.375"  .005"

.035"  .005"

316 SS

30,000

75,000

3,500

½"

.500"  .005”

.035"  .005"

316 SS

30,000

75,000

2,625

½"

.500"  .005”

.049"  .005"

316 SS

30,000

75,000

3,675



 

9.1.2

High quality, double-ferrule, stainless steel Swagelok tube fittings shall be used. Tubing shall be kept as short as practical and sloped to drain to the main gas line. Instrument control lines below grade shall consist of 1” carbon steel welded valves and carbon steel pipe to above grade. Any below grade tubing lines shall be PVC coated coiled tubing. No tubing connections shall be made below grade. Tubing shall be protected from damage by inserting through an appropriate conduit.

Temperature Sensing Connections All temperature sensing connections on main gas piping shall be equipped with a thermometer well. 



 9.1.3

Thermometer wells shall be stainless steel bar stock wells, with 1 inch MNPT external threads, internal ½ inch threads and bored to match the particular temperature element to be installed. Well shank shall be straight. Stepped wells are unacceptable. Thermowells shall be dimensioned to provide a representative gas temperature and shall extend into the central third of the gas stream. Test wells shall be equipped with a threaded plug and chain.

Sample Connections Connections for gas samplers, gas chromatographs or other gas analysis instruments shall be located so as to obtain a representative sample under all normal operating conditions.   

The sample tap shall be located such that it is preceded by a minimum length of 5D of straight pipe. Sample taps for multiple run meter stations shall be located on the primary run or in gas piping where gas flow is continuous. Standard sample connections shall be equipped with a probe

44

CPG

Meter Station Design Guidelines

 



 



9.2

that extends into the central third of the gas stream. The standard sample probe tip shall be cut on a 45o angle and installed with the longest side downstream. Where the connection is in piping that cannot conveniently be isolated and removed from service, consideration shall be given to using retractable sample probes equipped to allow their insertion or removal while the piping remains pressurized. Sample connections for chromatographs and moisture analyzers shall use a Mustang gas sampling system that regulates the gas stream while heating the gas above the hydrocarbon dew point temperature. Regulator type probes that regulate the sample pressure at the probe tip such as the Genie insertion probe regulator may be used if equipped with suitable heat tracing lines and with the specific approval of CPG Engineering. The Mustang sampling system shall be located adjacent to the tap. Sample line length shall be limited to 50' unless prior written CPG approval is obtained. Speed loops shall be required at the chromatograph building on any sampling lines in excess of 50 ft. All gas sample lines shall conform to the chromatograph manufacturer’s instructions. Insulated, heat traced stainless steel tubing lines 1/8 inch diameter shall be used. All gas sample lines shall be equipped with a Genie moisture membrane filter.

TRANSMITTERS For specific material requirements, please refer to the latest revision of CPG Design Standard DS-4006 Electronic Measurement and Gas Chromatograph Specifications. 9.2.1

Multi-Variable Transmitters for Static Pressure, Differential Pressure & Temperature Multi-Variable Transmitters for Static Pressure, Differential Pressure & Temperature shall only be used on orifice runs on Columbia Gulf Transmission stations. Individual transmitters shall be used on all other measurement at Columbia Gas Transmission and Columbia Gulf Transmission stations. Multi-Variable transmitters (Rosemount 3095) shall be used for orifice, measurement applications at Columbia Gulf Transmission. Transmitters shall be direct mounted on the meter run with an integral five valve manifold.

9.2.2

Transmitters for Static Pressure Only Transmitters with integral two valve manifold (Rosemount 3051) shall be used for applications where only a pressure measurement is required, such as ultrasonic, turbine, Coriolis positive displacement meter static pressure and pressure downstream of a pressure control

45

CPG

Meter Station Design Guidelines

valve. Transmitters shall be mounted on the meter bodies or as near the process connection point as practical on a 2” instrument stand. 9.2.3

Temperature Sensing Elements (RTD’s) When using the Rosemount 3095, the temperature sensing element, Rosemount 0068, shall be 100-ohm platinum, 3-wire RTD’s with 316 stainless steel 0.25” diameter sheaths complete with a spiral stainless steel armored extension cable. The Rosemount 0068 sensor shall be direct mounted to a Rosemount 3144P transmitter for ultrasonic, turbine, and positive displacement measurement. The sensors shall be inserted into the thermowell that shall extend into the middle third of the gas stream.

9.3

CONTROLLERS 9.3.1

Tube Switching Control Open/close signals to valve actuators on tube switching valves shall be provided from the electronic flow measurement equipment. Manual open/close valve actuation shall be provided on the valve controls allowing manual lockout. (See Section 9.6, “Instrument Gas Supply”, for power gas requirements.)

9.3.2

Limit Switches Use of valve position limit switches in the control process will be coordinated with CPG Engineering to insure the flow computer load will be compatible with their use. Proximity limit switches (Go or equal) will be used. Any modulating control valve shall send actual valve position feedback to the CPG RTU indicating the valve percentage open. Microswitches shall not be used.

9.3.3

Flow Control Control signals to the positioner/actuator on flow control valves shall be provided either directly from the electronic flow measurement equipment or via a motor controlled regulator type electronic -topneumatic transducer. The electronic signal to pneumatic signal transducer for flow control shall be a Fairchild Model 24XFM No Bleed Remote Set Regulator (RSR).

9.3.4

Pressure Control Control signals for pressure control valves will be provided by either electronic flow measurement equipment as described in Section 9.3.3, or a pneumatic pressure controller sensing pressure directly from the process connection and providing a direct pneumatic output to the valve positioner/actuator. Local pneumatic pressure controllers shall come equipped with an auto manual station – see below.

9.3.5

Manual Control The pneumatic control signal to the actuator or positioner shall have an “Auto/Manual” control station or loading regulator to allow the valve to be manually positioned.

46

CPG

Meter Station Design Guidelines

9.3.6

Automatic Over-Ride Control Automatic over-ride control is accomplished by providing automatic selection of control signal output between dual controllers using a pneumatic signal selector switch/relay capable of selecting either the higher or lower control pressure signal. Automatic over-ride control can also be accomplished using electronic selection.

9.4

ODORIZATION  





9.5

Where customer gas odorization is required, the customer shall install, own and operate said equipment. Where Columbia gas odorization is required (such as PORs into Columbia), the customer shall install and own said equipment. Columbia will operate said equipment at PORs. The odorization equipment shall be located downstream of the measurement and regulation equipment but upstream of the meter station outlet block valve. The customer must execute a Meter Set Agreement at new stations (or at existing sites an EM Agreement) with CPG if handoff of measurement signals is necessary for customer odorization control.

GAS SAMPLING Where continuous gas sampling for measurement purposes is required, (at stations that flow less than 10 mmcfd) a gas sampler (PGI Interceptor Model PF3GL-Z2) shall be used. Sample connections shall be in accordance with Section 9.1.3, “Sample Connections”, above, and in accordance with the sampler manufacturer’s instructions. The continuous sampler shall be installed in an insulated heated enclosure.

9.6

INSTRUMENT GAS SUPPLY Pneumatic instruments and control valves will normally be powered with natural gas tapped from the meter station piping. A separate supply line for each instrument operated control valve or pilot operated valve (PHMSA 192.203 (b) (9)) is required. The system shall be designed such that one failure will not make both the regulator and the overpressure protective device inoperative. The tap will be located upstream of the control valve. The supply line shall be ½ inch stainless steel tubing if above grade, and pipe or coated tubing if below grade. No tubing connectors shall be installed below grade. Instrument supply systems will provide pneumatic pressure to the control valve actuator or positioner (typically 100 psig) and a lower pressure (typically 20 or 35 psig – a 6 to 30 psig output signal is preferred over the 3 to 15 psig signal) to the pneumatic pressure controller. These supply systems will include a filter to ensure a clean supply gas (see CPG standard drawing IN-IS-2). In some cases, especially in systems where the gas contains liquids, a catalytic heater should be included as part of the system. If a relief valve is included as part of the system, the outlet must be piped outside of the building. 

For safety, the power gas tap for each shutoff / sequencing valve shall be located so that the source of that valve’s power gas is also blown down

47

CPG

Meter Station Design Guidelines

along with the piping isolated by the shutoff / sequencing valve. Thus, the valve cannot be accidentally opened to pressurized piping.

10

ELECTRONIC MEASUREMENT AND TELEMETERING   

10.1

Electronic Flow Measurement (EFM) and Telemetry is required for all new meter stations. Gas Quality measurement devices will be determined based upon the requirements of each individual meter station. See Section 10.2 Gas Quality Devices. The customer must execute an “EM Agreement” with CPG for handoff of measurement signals where CPG has the only available measurement. FLOW COMPUTERS 10.1.1

General Requirements Flow computers shall accept inputs from the appropriate instruments described in Section 9, “Instrumentation”, of these guidelines and from gas chromatographs or other analytical instruments where installed.

10.1.2

CPG RTU Types For specific flow computer selection criteria and material specifications, please refer to the latest revision of CPG Design Standard DS-4006 Electronic Measurement and Gas Chromatograph Specifications. CPG shall select the specific equipment to be used.

10.2

GAS QUALITY DEVICES For specific material requirements, please refer to the latest revision of CPG Design Standard DS-4006 - Electronic Measurement and Gas Chromatograph Specifications. Note new receipts shall submit a gas sample analysis representing expected gas composition. Should the gas composition change, CPG reserves the right to install gas quality devices determined necessary by the CPG engineer. 10.2.1

Chromatograph A chromatograph shall be installed if any of the following criteria is met:  Flow rates of 10 mmcfd or more  Ultrasonic meter station  Gas Quality outside of Tariff specifications  Gas quality variances of 10 BTU or more  Bi-directional meter station Where 120 volt power is available a Rosemount Danalyzer 570 chromatograph shall be installed. Where only 24 volt power is available a

48

CPG

Meter Station Design Guidelines

Rosemount Danalyzer 700 chromatograph shall be installed. An ABB 8206 chromatograph may only be installed with written permission of the local M&R Engineer. Station flowrates between 1 mmcfd and 10 mmcfd require installation of an automatic gas sampler. Below 1 mmcfd a gas sample for billing is required before the station can be placed in service and anytime thereafter should it be suspected that the gas quality has significantly changed. Chromatograph sample connections shall be in accordance with Section 9.1.3, “Sample Connections”. Calibration gas shall be verified and approved by CPG. Calibration gas shall be installed so that it will not be exposed to temperatures below its hydrocarbon dew point. 10.2.2

Moisture analyzer Moisture analyzers shall be installed at all meter stations delivering 100 mmcfd or more into CPG and at smaller stations with a moisture reading of 7 lbs per mmcf or greater after dehydration. In some applications, an automatic shutoff valve may be required to shut in the measuring station if the gas dew point exceeds set point for a specified time period. 

 10.2.3

A Spectrasensors SS500 Moisture analyzer with an extended range of 0.5 to 100 lbs of water per mmcf gas plus or minus 2% of reading is required for stations (over 10 mmcfd) or if required by CPG in specific applications by agreement. A Spectrasensors SS2000 Moisture analyzer with an extended range of 0.5 to 100 lbs of water per mmcf gas plus or minus 2% of reading is required for large capacity stations (over 100 mmcfd). The gas sample inlet pressure to these devices is limited to 10 psig.

Hydrogen sulfide Hydrogen Sulfide analyzers shall be installed at all meter stations with initial gas sample indicating the presence of hydrogen sulfide in the amount of 1/4 grain per hundred cubic feet. An automatic shutoff valve is required to shut in the measuring station if the gas received into the CPG systems exceeds the hydrogen sulfide limit. 

10.2.4

Hydrogen sulfide analyzers shall employ chemical cell hydrogen sulfide analyzers.

Oxygen sensors Oxygen sensors shall be installed at all meter stations with initial gas sample indicating the presence of oxygen in the amount of 1% by volume or greater.  Oxygen sensors shall employ a replaceable chemical sensor which is exposed to a low pressure gas sample.

49

CPG

Meter Station Design Guidelines

10.2.5

Other Devices Hydrocarbon Dewpoint and/or CO2 analyzers requirement will be determined by the CPG Engineer and Operations.

10.3

TELEMETERING For specific material requirements, please refer to the latest revision of CPG Design Standard DS-4006 - Electronic Measurement and Gas Chromatograph Specifications. Data may be telemetered via telephone, cellular data unit, satellite or radio. CPG shall be responsible for selection of the communication method(s) to be used and shall select the specific equipment to be employed. Necessary permits shall be obtained by Customer or as specified in the Interconnect Agreement.

10.4

POWER SUPPLY For specific material requirements, please refer to the latest revision of CPG Design Standard DS-4006 - Electronic Measurement and Gas Chromatograph Specifications. Purchased power (120 VAC) shall be used whenever available to power the electronic measurement and SCADA equipment. Refer to table 10.1.2 for Power supply options 10.4.1

UPS System The UPS system shall include batteries and battery charger to provide DC power. The UPS system shall be equipped with system “trouble” alarm that define AC input voltage loss and low DC power output. Battery chargers shall be equipped with over voltage protection. Sufficient battery capacity shall be provided to power the EFM load for a minimum of 48 hours.

11

YARD PIPING AND HEADERS This section describes requirements for the design, installation and testing of meter station piping. All process piping shall be designed, installed and tested in accordance with all applicable requirements of Title 49 CFR Part 192. 11.1

DESIGN PRESSURE AND TEMPERATURE The design pressure and design temperature for all piping systems within the meter station shall be established based on the most severe conditions applicable to the specific piping systems. See Sections 2.2.8, “Design Pressure” and 2.2.9, “Design Temperature”. The design of all meter station process piping shall be based on a design factor of 0.50 in a Class 1, 2 or 3 location, and a design factor of 0.4 in a Class 4 location in accordance with PHMSA Part 192.111.

11.2

PIPE SIZING All piping shall be conservatively designed for the maximum flow rate as per

50

CPG

Meter Station Design Guidelines

Section 2.2.3, “Flow Rates”, by using appropriate flow equations and applying the following guidelines. 11.2.1

Station Main Gas Piping Main gas piping and pipeline taps shall be sized so that the maximum gas velocity falls within a range of 65 to 80 FPS. This velocity shall be evaluated at the minimum pressure and maximum temperature associated with the design flow rate.

11.2.2

Regulation & Measurement Headers Regulation & Measurement headers shall be sized so that the maximum gas velocity falls within a range of 30 to 40 FPS. This velocity shall be evaluated at the minimum pressure and maximum temperature associated with the design flow rate.

11.2.3

Station Bypasses Higher gas velocities are acceptable for bypasses and other piping that is in service only intermittently or for short durations; but consideration must be given to potential for noise and erosion resulting from high velocity in such piping. Velocities above 200 feet per second shall be avoided.

11.2.4

Meter Tube Inlet/Outlet Piping Risers and other inlet/outlet piping to individual meter tubes will normally be sized based on the size of the meter tube, rather than on specific pressure drop considerations. For new installations, meter tube inlet/outlet piping and valves shall have the same nominal diameter as the meter tube. The number of bends in piping (immediately, i.e. 50 pipe diameters) upstream of the meter shall be minimized. Multiple out of plane bends shall not be allowed at the meter runs and consideration shall be given to installation of above grade inlet headers on USM installations.

11.2.5

Other Considerations Engineering judgment must be exercised in applying the guidelines above. For specific situations good design requires consideration of all the factors applicable to the design of a particular facility. Such factors might include:     

The economics of selecting a larger or smaller pipe size and the impact of the resulting lower or higher pressure drop on the specific piping The percentage of time that the maximum design flow rate will actually prevail Connection to or compatibility with existing facilities Availability of existing stock or surplus materials Future growth

51

CPG

Meter Station Design Guidelines

11.3

GENERAL PIPING DESIGN 11.3.1

Configuration/Layout Piping must be designed to accommodate the process requirements and must be designed within the constraints of the site dimensions and profile, and the location of station inlet and outlet connections. Each meter station shall have an inlet and outlet valve to allow the meter station to be isolated from connected facilities, and shall have at least one blow down valve to allow the isolated station piping to be vented.   

 11.3.2

Header Configuration    

11.3.3

An appropriately sized blow down along with tap for valve and pressure gauge shall be provided on all piping sections capable of being isolated. A check valve shall be provided near the tap valve on the CPG pipeline for both deliveries and receipts in unidirectional stations. Meter tubes and regulator runs shall be arranged to drain to the headers. All such headers, and other piping low points, shall have valved drains/siphons, so that they can be checked for liquid, and any accumulated liquid removed. Piping dead ends and low areas where liquids and other corrosive elements can collect are not permitted.

When multiple meter runs are used, the headers shall be installed as F or T type configurations. Header piping shall be configured to eliminate dead legs where debris collects and promotes corrosion. Headers with multiple inlets/outlets for meter tubes shall be symmetrical and arranged to equalize flow through the meter tubes. Consideration shall be given to installation of above grade inlet headers at the same elevation as the USM installations.

Piping To the maximum extent practical, main gas piping shall be buried to provide for maximum protection and minimum maintenance.  Process piping shall be joined by welding or with flanges.  Flanges rated ANSI 600 and lower shall be raised face flanges. Ring-joint facing is preferred for flanges rated ANSI 900 and higher, except where raised facing is required for assembly/disassembly or to mate with raised face flanges on equipment.  The flange yield strength shall be equal or better than the pipe to which it will be welded.  Flanged joints (with the exception of flanges on hot tap valves) threaded joints, or tubing fittings shall not be installed underground.  Flanges on hot tap valves shall be raised face.

11.3.4

Flanged connections Flanges shall be weld neck, raised face and bored to meet the wall

52

CPG

Meter Station Design Guidelines

thickness of the connecting pipe. 

Normally flanges shall be ASTM A105 forged steel flanges in accordance with ASME/ANSI B16.5, “Pipe Flanges and Flanged Fittings”. Where A105 flanges are to be welded to high yield strength pipe, (SMYS > 35000 psi) flange hubs shall be specially prepared to develop the full strength of the pipe. Alternately, flanges shall be in accordance with MSS SP-44, “Steel Pipeline Flanges”, and have a yield strength matching that of the pipe to which they are welded. Reference CPG flange specs FLG-103 & FLG 104.



Bolts shall be ASTM A193 Grade B7 full thread studs, with ASTM A194 Grade 2H heavy hex nuts and cadmium plating. Reference CPG spec BLT-103. Flange gaskets shall be precision spiral wound gaskets, with non-asbestos filler, stainless steel winding and 1/8” thick internal and external stainless steel gauge rings. The bolt torque guide below shall be used. The following recommended torque values apply to ASTM A193, Grade B7 stud bolts and ASTM A194; Grade 2H hex nuts, with the threads cleaned and a lubricant applied to them. For torque requirements using other bolt types, contact the CPG Engineering Department or reference CPG Flange Gasket and Bolting Spec CMJT-1.



 

Bolt Size

Threads

Torque Ft. Lbs.

Bolt Size

Threads

Torque Ft. Lbs.

½

13

15-30

1 3/8

8

660-890

5/8

11

50-65

1½

8

890-1,050

¾

10

100-130

1 5/8

8

1,035-1,215

7/8

9

175-215

1 7/8

8

1,565-1,845

1

8

220-280

2

8

2,215-2,585

1 1/8

8

370-470

2½

8

3,755-4,145

8

435-570

1¼

11.3.5

Welding All welding shall be done in accordance with the CPG Welding Manual. All relevant test documentation shall be forwarded to the CPG

53

CPG

Meter Station Design Guidelines

representative prior to installation of prefabricated assemblies or tie in welds. All test documentation of onsite installation will likewise be forwarded to the CPG representative. All welded piping shall meet the following requirements: Qualified welders shall perform all welding using qualified procedures in accordance with the Columbia Pipeline Group Welding Manual. A copy of that document shall be provided with these Meter Station Design Guidelines to fabrication shops and contractors responsible for the design, fabrication, or installation of CPG Meter Stations. All butt welds six inch and larger on pipe operating at a stress level of 20% and greater shall be 100 % radiographically examined. Four inch and smaller welds, or welds on pipe with a stress level of less than 20% shall be visually inspected or spot checked. Welds that cannot be effectively examined by radiography shall be nondestructively examined by dye penetrant, magnetic particle, ultrasonic or other appropriate means. Alternate means of NDT inspection shall be approved by CPG prior to use. All radiography and other non-destructive examinations shall be performed and interpreted by qualified technicians, using qualified procedures in accordance with API Standard 1104. Welds failing to meet the acceptance criteria of API Standard 1104 shall be repaired (to the extent allowed by API Standard 1104) or replaced. All weld repairs and replacement welds shall be subjected to the same examination as the original weld. Alternately, welding may be done by welders and procedures qualified under Section IX of the ASME Boiler and Pressure Vessel Code, “Welding Qualifications”, in which case non-destructive examinations shall conform to Section V of the ASME Boiler and Pressure Vessel Code, “Nondestructive Examination”. The X-ray report(s) shall include sketches of the meter and other process piping and shall clearly identify each x-ray relative to each weld. Structural welds shall meet the requirements AWS D1.1 11.3.6

Pressure Testing All process piping shall be subjected to hydrostatic strength and leak tests in accordance with PHMSA Part 192.501 through 192.517 and in accordance with the following: 

After the tests described in Section 11.3.5 “Welding” are

54

CPG

Meter Station Design Guidelines

completed, field hydrostatic tests shall be conducted when the process piping installations are essentially complete, using water as the test medium. The hydrostatic test pressure shall be a minimum of 1.5 times the design pressure of the process piping. The maximum test pressure shall not exceed the maximum allowable test pressures of any of the components. The test duration shall be at least 8 hours, as documented by a continuous recorder.





HYDROSTATIC TEST EQUIPMENT AND REPORT REQUIREMENTS: Test reports:  Shall be legible.  Shall have both pressure and temperature recorded on the same chart.  Shall include calibration reports for the pressure and temperature recorders and shall evidence that calibration within 30 days of the hydrostatic test date.  Shall include National Institute of Standards and Technology (NIST) certification papers for the pressure and temperature standards used in the above pressure and temperature recorders’ calibrations. The accuracy of these standards shall be traceable to NIST within the last 24 months.  Meter tubes, vessels or other equipment or components that have been subjected to an adequate hydrostatic test prior to installation, may be excluded from the field hydrostatic tests.  Turbine, Ultrasonic or rotary meters shall not be included in hydrostatic tests.  Instruments shall be excluded from the hydrostatic tests, but instrument root valves shall be included.  All piping and equipment shall be thoroughly drained and dried when hydrostatic testing has been successfully completed.

NOTE Nitrogen testing is allowable under certain conditions with prior written approval from a CPG Design Engineer.

11.3.7

Valves All valves shall be purchased to CPG Valve Specification VAL-101 and Appendix C - Approved Vendor List. Valves in main gas piping may be ball, gate or plug valves, except as otherwise provided herein.

55

CPG

Meter Station Design Guidelines

  



11.3.8

Full-opening ball valves shall be used for meter tube isolation valves. Valves for above grade installation may be flanged end, weld end, or weld end by flange end. Valves 6” and larger shall be provided with gear operators. Valves for underground installation shall have weld ends with the exception of valves used for hot tapping which shall be weld end by raised face flange end. For large diameter weld end valves, consideration shall be given to having the valves furnished with pipe pups welded on and tested by the valve manufacturer. Valves installed below grade shall be equipped with stem extensions to elevate the manual or power operators to an elevation 3 to 4' above grade. Buried valves requiring lubrication shall be equipped with extended lube lines and extended body bleed lines.

Branch Connections Branch connections shall meet the requirements of the applicable codes and standards and shall be in accordance with CPG Standard DST-101 and the following: 







11.3.9

Forged straight tees and reducing outlet tees are preferred for branch connections where the branch connection exceeds the mainline diameter by 67% and where economically feasible (considerable gas loss or service outage is unacceptable). Headers with multiple outlets may be extruded outlet headers or may be made using tees. Depending on the size and configuration, extruded outlet headers may be more economical when installation costs are considered. When extruded headers are used, consideration shall be given to including risers, drains and other connections fabricated and tested as a part of the header assembly at the manufacturer’s shop. Where the branch to header ratio is smaller than that available with standard tees, branches may be made with a standard tee with a reducer on the branch; through the use of an extruded outlet tee; or except as limited below, with a forged branch outlet fitting. Welding outlet fittings (weld-o-lets, thread-o-lets, etc.) are limited to branches 2" nominal size and smaller unless written permission from the CPG Design engineer is obtained. Weldolets greater than 4” should not be used.

Hot Taps Hot taps on CPG pipelines shall be made only by CPG personnel following established CPG design and procedures, or by a CPG approved Contractor under CPG supervision. The nominal branch diameter should not be greater than 67% of the nominal header diameter. The flange on the hot tap valve shall be raised face. The design and installation of the hot tap shall conform to all CPG Plans and

56

CPG

Meter Station Design Guidelines

Procedures and the Welding Manual. 11.4

PIPING MATERIALS Pipe, valves, fittings, flanges and other pressure containing components used in process piping shall conform to all relevant CPG Specifications and the recognized industry codes and standards applicable to the particular material and to the codes and standards referenced in the PHMSA Title 49 CFR 192 Appendix B.

11.5

CATHODIC PROTECTION Companies designing cathodic protection at CPG stations shall utilize the latest specifications and materials provided by the CPG Integrity Management Department. Piping in meter stations shall be cathodically protected as follows: 11.5.1

Insulating Flanges Meter station piping shall be electrically isolated from the connected pipelines or other facilities through the use of insulating flanges installed at the inlet and outlet of the meter station, on the station side of the inlet and outlet valves. Use of underground insulation joints is discouraged and insulating flanges underground shall be prohibited.   

11.5.2

Insulating flanges shall be assembled with full-faced insulating gaskets with O-rings, insulating sleeves and double insulating washers on the flange bolts. A test station in accordance with CPG Drawing CP-IJ-2 shall be installed at each insulation joint. Insulated flanges should be protected with non-metallic flange protectors and the void filled with dielectric grease per CPG procedure 70.001.041. All other above grade flanges shall be protected with metallic flange protectors per CPG procedure 70.001.041.

Cathodic Protection System The meter station piping owned or operated and maintained by CPG shall be protected with an impressed current cathodic protection system; either with a dedicated system, or where practical, by bonding to the cathodic protection system of a connected pipeline. Also acceptable is the use of magnesium anodes provided the station piping is isolated from any impressed current CP systems. Pipelines susceptible to induced current from power lines shall be isolated from stations and the stations protected using magnesium anodes.

11.5.3

Tubing-Insulating Unions Electrically insulated tubing unions shall be installed to isolate transmitters located outside of the meter station isolation flanges, from the meter station piping. Any electrical connections for power or communications must be isolated from station piping by either a dielectric tube fitting or dielectric flange insulators on top-works.

57

CPG

Meter Station Design Guidelines

11.5.4

Corrosion Coupons (Internal) A corrosion coupon holder shall be installed in the main gas stream at each meter station that delivers gas into the CPG pipeline when required by the CPG Design Engineer.

11.5.5

Painting On CPG owned or operated and maintained facilities, all above ground piping shall be abrasive blasted to SSPC SP-10 or NACE No 2 near white metal finish and painted with the following coating specifications as per the latest edition of CPG Procedure 70.001.029. All paint materials shall be stored, thinned, applied and cured in accordance with the manufacturer’s instructions. Piping and equipment furnished with an acceptable and compatible shop applied primer need not be re-blasted and re-primed. In such cases, defects in shop primer shall be repaired and intermediate and finish paint applied as above. Instruments, nameplates, stainless steel, galvanized steel, brass, aluminum and glass shall not be painted and shall be masked and protected during abrasive blasting and painting. Masking material shall be removed upon completion of coating.

11.5.6

Coating of Buried Piping (CPG Owned or Cathodically Protected) All buried piping shall be coated as outlined below. Underground coating shall extend between 6 and 12 inches above grade. 







Piping to be field coated shall be thoroughly cleaned and surfaces prepared. Abrasive blasting to SSPC SP-10 or NACE No 2 "nearwhite" metal is the required surface preparation method for all field applied coatings and is required for coal tar epoxy. Acceptable coatings for underground piping include: Fusion-bonded, thin-film epoxy Coal-tar epoxy (for coal tar coated pipe and valves) Denso Protal 7200 SPC SP-2888 Primer, Wax Tape, Glass Outer Wrap (for over coating transition areas between coal tar and epoxy coatings) Surface preparation, application and curing of primers and application and curing of field applied coatings and field joints shall be in accordance with the manufacturer’s instructions and CPG Procedure 70.001.026. All coatings on buried piping shall be visually inspected and inspected with an electronic holiday detector per CPG Procedure 70.001.046. Any damaged coating or holidays discovered shall be repaired and re-inspected prior to backfilling the piping.

58

CPG

Meter Station Design Guidelines

11.5.7

Coating Hot Tap Flange The hot tap flange will be coated with Denso Protal 7200 per CPG Procedure 70.001.026. The flange will be filled with Trenton Innercoat Flange Fill. Six inches on both sides of the flange, the pipe, bolts, nuts and flange will be coated with Denso Paste Primer. The area between the pipe and the flange will be over-coated with Denso Profiling Mastic to create a smooth transition. Starting at the edge of the primer, the area will be coated with Denso Densyl Tape. The taped area will then be over-coated with Denso Glass Overwrap.

11.5.8

Corrosion Coupon Test Station (External) A corrosion coupon test station will be installed at the measuring station per standard drawing CP-CC-1. Wires will be connected to the pipe using a Thermite (i.e. Cadweld) connection per CPG Procedure 70.002.043. Thermite welds will be coated per CPG Procedure 70.001.026.

11.5.9

Weld Over Sleeves Hot tap full encirclement reinforcing sleeves must be greased and coated as per CPG Procedure 70.001.042.

11.5.10

Concrete Sleepers Below grade piping resting on concrete supports shall be coated per CPG Procedure 70.001.026 with 40 mils DFT of either Denso Protal 7200 two part epoxy completely around the circumference of the pipe for a length of 6 inches past each end of the concrete form. If the pipe was mill coated with FBE, apply 30 mils DFT per CPG procedure 70.001.032 of either the Denso Protal 7200 directly over top of the FBE completely around the circumference of the pipe for a length of 6 inches past each end of the concrete form.

11.5.11

Below Grade to Above Grade Transition The below ground to above ground transition piping will be coated with either FBE or a two part epoxy. The coating will be protected with a Tapecoat T/R Riser Jacket. The Riser Jacket will be positioned so 10 inches of the Jacket is below grade and the remainder is above grade. The Riser Jacket will be installed per the manufacturer's installation instructions and be held in place with stainless steel banding. An alternate transition coating is to use Trenton #2 Wax Tape with primer applied over the pipeline corrosion coating from 6” above grade to 18” below grade.

11.5.12

Above Grade Pipe Supports The above ground pipe supports will be epoxy chocks with Vibalon bonded to it. Pipe straps will have Vibalon bonded to the surface facing the pipe. The piping at all above ground pipe supports with operating temperatures up to 200oF will be protected by applying Denso Protal 7200 two part epoxy (40 mils) and a topcoat of Carboline Carbothane 134HG (2-3 mils) around the circumference of the pipe. The Denso

59

CPG

Meter Station Design Guidelines

Protal epoxy coating will be applied per CPG Procedure 70.001.026 and will extend a minimum of 6 inches beyond the edge of the support surface. The Denso Protal epoxy will be brush blasted before the application of the Carboline Carbothane topcoat per CPG Procedure 70.001.029. The piping at all above ground pipe supports shall be protected per CPG Procedure 70.001.042. .

12

FILTER–SEPARATORS, HEATERS AND LIQUID HANDLING Filter-separators shall be located at the inlet of all meter stations with main gas piping larger than six-inch diameter that deliver gas into a CPG pipeline unless deemed unnecessary after a joint review by the CPG design and operation engineers. Refer to the specific interconnect agreement between CPG and Customer for details. 12.1

FILTER SEPARATOR 12.1.1

General One or more filter-separators shall be installed, and shall have an aggregate design capacity equal to or greater than the maximum station flow rate. Filter - separators shall be designed for operation over the range of pressures, temperatures and flow rates required. Filter-separator vessels shall be designed, fabricated, inspected and tested in accordance with Section VIII of the ASME Boiler and Pressure Vessel Code, “Pressure Vessels” - Division 1 and shall be code stamped. However, after installation, the separator will be operated as a pipeline component - not as an ASME Section VIII pressure vessel.  



 12.1.2

Each filter-separator shall be designed (at a minimum) at 105% of the MAOP of the attached piping. Each filter-separator shall be installed with an inlet and outlet valve to allow the vessel to be isolated from the station piping for maintenance and inspection. If only a single filter-separator is installed, a manual bypass shall be provided. The bypass piping shall be configured to preclude the accumulation of liquids or pipeline debris upstream of the bypass valve. If a filter-separator is not installed initially, provisions (space) will be made for the installation of the filter-separator in the future.

Configuration Filter-separators shall be of horizontal configuration with an upstream filter section separated with a bulkhead from a downstream separator or mist extractor section. Each section shall connect to a separate liquid collection sump. 

The filter section shall contain multiple tubular fibrous filter elements arranged for parallel gas flow. The filter elements

60

CPG

Meter Station Design Guidelines





12.1.3

shall be arranged for convenient replacement through a quick opening closure located on the end of the vessel. The closure shall be the same diameter as the vessel to allow for ease of filter replacement unless otherwise approved by the CPG engineer. The separator section shall employ high-efficiency vane type separator elements or other suitable mist extractor elements to remove liquid droplets. Inspection openings shall be provided as required by the ASME Code and as necessary to inspect vessel internals. Blind flanged connections shall be provided for clean out of the sump sections.

Performance Over the range of specified operating conditions, filter-separators shall be capable of removing solid particles and entrained liquid droplets from the gas stream with the following efficiency: Particles/droplets 3.0 microns and larger:

100% removal

Particles/droplets >0.5 microns and