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ASME VIII Div. 1 Course Presented by:

XÇzA `É{tÅÅtw `t{ÜÉâá This material is provided for educational uses only. Only ASME can make code interpretations.

HISTORICAL BACKGROUND 

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Keene, NH Boiler Explosion May 22, 1898

Boiler explosions were common in the 1800’s to early 1900’s By early 1900’s thousands were killed across the United States. Commonwealth of Mass. Enacted the first set of rules. 1911, ASME Recognized the need for uniform rules regarding design and build of pressure vessels.

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1911 – ASME set up the B&PV Committee – to formulate std rules for c construction of boilers and pressure vessels 1915 – first Code issued – ASME 1 – Power Boilers 1923 – Heating Boilers – Section IV 1924 – Materials – Section II 1925 – Pressure Vessels – Section VIII Div 1 1941 – Welding & Brazing – Section IX 1963 - Nuclear Codes – Section III 1968 – Pressure Vessels – Section VIII Div 2 1971 - NDE – Section V 1997 - Pressure Vessels – Section VIII Div 3

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ASME establishes rules for new construction of pressure vessels that will perform in a safe & reliable manner. ASME also interprets these rules when questions arise regarding their intent. Code does not address all aspects and those not addressed should not be considered prohibited. Code does not fully address tolerances. Code is not a design handbook, designer must use engineering judgment consistent with Code philosophy which do not overrule mandatory requirements of the Code.

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Editions: Every 3 years new issuance (2004, 2007, 2010...) Addenda: Issuance every year. Replacement page format (colored). Mandatory 6 months after issuance. Interpretations: Issued by ASME Code committees upon request. Not part of the Code. Code Cases: Formulated by the ASME Code Committee to clarify existing requirements or to provide rules not covered by the existing Code. Errata: Are mandatory immediately

ASME Codes & Standards  

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Section I – Power Boilers Section II – Materials • Part A; Part B; Part C; Part D Section III – Rules for Constr. of Nuclear Power Plant Components • Div. 1 – 5 Section IV – Heating boilers Section V – Nondestructive Examination Section VI – Recommended rules for Care and Operation of Heating Boilers Section VII – Recommended guidelines for Care of Power Boilers Section VIII – Pressure Vessels • Div 1; Div 2; Div 3 Section IX – Welding and Brazing Qualifications Section X – FRP Pressure vessels Section XI – Rules for In-service Inspection of Nuclear Power Plant components Section XII – Rules for Construction and continued Service of transport Tanks

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SECTION VIII - Pressure Vessels: Division 1 - Provides requirements applicable to the design, fabrication, inspection, testing, and certification of pressure vessels operating at either internal or external pressures exceeding 15 psig. Division 2 - Alternative rules, provides requirements to the design, fabrication, inspection, testing, and certification of pressure vessels operating at either internal or external pressures exceeding 15 psig. Division 3 - Alternative rules for Construction of High Pressure Vessels, provides requirements applicable to the design, fabrication, inspection, testing, and certification of pressure vessels operating at either internal or external pressures generally above 10,000 psi.

INTRODUCTION Vessels, tanks, and pipelines that carry, store, or receive fluids are called pressure vessels.  A pressure vessel is defined as a container with a pressure differential between inside and outside. 

Types of Pressure Vessels (According to orientation) 1- Typical Pressure Vessel

2- Spherical Pressure Vessel

3- Horizontal

Types of Supports NOZZLES A

HEAD

SHELL

A SECTION A-A SADDLE SUPPORT (SLIDING)

SADDLE SUPPORT (FIXED)

Horizontal Drum on Saddle Supports

Vertical Vessel with Lug Support

HEAD

NOZZLE

NOZZLE TRAYS CONE

SHELL

NOZZLE

HEAD SKIRT SUPPORT

NOZZLE BASE PLATE

Column

HEAD NOZZLE

SHELL

HEAD SUPPORT LEG

Vertical Vessel with Leg Support

INLET NOZZLE HEAD UPPER CATALYST BED

SHELL

CATALYST BED SUPPORT GRID OUTLET COLLECTOR

LOWER CATALYST BED

OUTLET NOZZLE HEAD

SUPPORT SKIRT

Reactor

Pressure Vessels Internals • • • • • • •

Trays. Inlet Distributer. Anti-Vortex Baffle. Catalyst bed grid and support beams. Outlet collector. Flow distribution grid. Cyclone and plenum chamber system.

Design Procedure

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U-2 GENERAL (Factors affecting Design) (a) The user orr his designated agent shall establish the design requirements for pressure vessels, taking into consideration factors associated with normal operation, such other conditions as startup and shutdown, and abnormal conditions which may become a governing design consideration . Such consideration shall include but shall not be limited to the following:

(1) the need for corrosion allowances; (2) the definition of lethal services. (3) the need for post weld heat treatment (PWHT) beyond the requirements of this Division and dependent on service conditions; (4) for pressure vessels in which steam is generated, or water is heated, the need for piping, valves, instruments, and fittings to perform the functions covered by PG‐59 through PG‐61 of Section I. (5) the degree of nondestructive examinations(s) and the selection of applicable acceptance standards, when such examinations are applied, are beyond the requirements of this Division.

Parts UG, UW, and UCS

Material UG-4 to UG-9 

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Material used for Pressure vessel Parts, attachments, and internals specifications is given in Section II, Part D, Subpart 1, Tables 1A, 1B, and 3. Pressure vessel Parts and attachments like : Plates , Forged, Casted, Pipes, tubes and Welding material.

DESIGN

DESIGN UG-16 (Notes to be taken in concederation)  (a) The design of pressure vessels and vessel parts shall conform to the general design requirements in the following paragraphs and in addition to the specific requirements for Design given in the applicable Parts of Subsections B (UW) and C (UCS).  (b) Minimum Thickness of Pressure Retaining Components. Except for the special provisions listed below, the minimum thickness permitted for shells and heads, after forming and regardless of product form and material, shall be 1/16 in. (1.5 mm) exclusive of any corrosion allowance.

Exceptions are: 

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1) the minimum thickness does not apply to heat transfer plates of plate‐type heat exchangers; (2) this minimum thickness does not apply to the inner pipe of double pipe heat exchangers nor to pipes and tubes that are enclosed and protected from mechanical damage by a shell, casing, or ducting, where such pipes or tubes are NPS 6 (DN 150) and less. This exemption applies whether or not the outer pipe, shell, or protective element is constructed to Code rules. When the outer protective element is not provided by the Manufacturer as part of the vessel, the Manufacturer shall note this on the Manufacturer’s Data Report, and the owner or his designated agent shall be responsible to assure that the required enclosures are installed prior to operation. Where pipes and tubes are fully enclosed, consideration shall be given to avoiding buildup of pressure within the protective chamber due to a tube/pipe leak. All other pressure parts of these heat exchangers that are constructed to Code rules must meet the 1/16 in. (1.5 mm) minimum thickness requirements.

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(3) the minimum thickness of shells and heads of unfired steam boilers shall be 1/4 in. (6 mm) exclusive of any corrosion allowance; (4) the minimum thickness of shells and heads used in compressed air service, steam service, and water service, made from materials listed in Table UCS-23, shall be 3/32 in. (2.5 mm) exclusive of any corrosion allowance.

5) this minimum thickness does not apply to the tubes in air cooled and cooling tower heat exchangers if all the following provisions are met:   

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(a) the tubes shall not be used for lethal UW-2(a) service applications; (b) the tubes shall be protected by fins or other mechanical means. (c) the tube outside diameter shall be a minimum of 3/8 in. (10 mm) and a maximum of 11/2 in. (38 mm); (d) the minimum thickness used shall not be less than that calculated by the formulas given in UG-27 or 1-1 and in no case less than 0.022 in. (0.5 mm). (c) Mill Undertolerance. Plate material shall be ordered not thinner than the design thickness. Vessels made of plate furnished with an undertolerance of not more than the smaller by value of 0.01 in. (0.25 mm) or 6% of the ordered thickness may be used at the full design pressure for the thickness ordered.

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(d) Pipe Under-tolerance. If pipe or tube is ordered by its nominal wall thickness, the manufacturing under-tolerance on wall thickness shall be taken into account except for nozzle wall reinforcement area requirements in accordance with UG-37 and UG-40. (e) Corrosion Allowance in Design Formulas. The dimensional symbols used in all design formulas throughout this Division represent dimensions in the corroded condition. (f) Examples showing the application of the design rules of this Division are contained in ASME PTB-4, ASME Section VIII, Division 1, Example Problem Manual.

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UG-21 DESIGN PRESSURE

Each element of a pressure vessel shall be designed for at least the most severe condition of coincident pressure (including coincident static head in the operating position) and temperature expected in normal operation.

For this condition, the maximum difference in pressure between the inside and outside of a vessel, or between any two chambers of a combination unit, shall be considered.

UG-22 LOADINGS 

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The loadings to be considered in designing a vessel shall include those from: (a) internal or external design pressure (b) weight of the vessel and normal contents under operating or test conditions; (c) superimposed static reactions from weight of attached equipment, such as motors, machinery, other vessels, piping, linings, and insulation; (d) the attachment of:  (1) internals (see Nonmandatory Appendix D);  (2) vessel supports, such as lugs, rings, skirts, saddles, and legs (see Nonmandatory Appendix G); (e) cyclic and dynamic reactions due to pressure or thermal variations, or from equipment mounted on a vessel, and mechanical loadings;

……….Continue to Loading  f) wind, snow, and seismic reactions, where required;  (g) impact reactions such as those due to fluid shock;  (h) temperature gradients and differential thermal expansion;  (i) abnormal pressures, such as those caused by deflagration;  (j) test pressure and coincident static head acting during the test (see UG-99).

UG-27 THICKNESS OF SHELLS UNDER INTERNAL PRESSURE  (a) The minimum required thickness of shells under internal pressure shall not be less than that computed by the following formulas.

(b) The symbols defined below are used in the formulas  of this paragraph.  E = joint efficiency for, or the efficiency of appropriate joint in cylindrical or spherical shells, or the efficiency of ligaments between openings, whichever is less. For welded vessels, use the efficiency specified in UW-12.  For ligaments between openings, use the efficiency calculated by the rules given in UG-53.  P = internal design pressure (see UG-21)  R = inside radius of the shell course .  S = maximum allowable stress value (see UG-23 and the stress limitations specified in UG-24)  t = minimum required thickness of shell 

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(c) Cylindrical Shells and tubes.

The minimum thickness (tmin) or maximum allowable working pressure (MAWP) of cylindrical shells shall be the greater thickness or lesser pressure as given by (1) or (2) below.

(1) Circumferential Stress (Longitudinal Joints).  When the thickness does not exceed one half of the inside radius, or P does not exceed 0.385SE, the following formulas shall apply: 

PR t= or SE - 0.6 P

SEt P= R + 0.6 t

(2) Longitudinal Stress (Circumferential Joints).  When the thickness does not exceed one half of the inside radius, or P does not exceed 1.25SE, the following formulas shall apply: 2SEt PR or P= t= 

2SE - 0.2 P

R + 0.2 t

(WE WILL NOT USE THIS FORMULA)

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(d) Spherical Shells. When the thickness of the shell of a wholly spherical vessel does not exceed 0.356R, or P does not exceed 0.665SE, the following formulas shall apply:

Appendix 1 Supplementary Design Formulas External Formula

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(1) For cylindrical shells (circumferential stress), PRo t= SE  0.4 P

OR

SEt P= Ro - 0.4 t

Where Ro is outside Diameter.

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(e) When necessary, vessels shall be provided with stiffeners or other additional means of support to prevent overstress or large distortions under the external loadings listed in UG-22 other than pressure and temperature. (f) A stayed jacket shell that extends completely around a cylindrical or spherical vessel shall also meet the requirements of UG-47(c). (g) Any reduction in thickness within a shell course or spherical shell shall be in accordance with UW-9 DESIGN OF WELDED JOINTS.

Comparing Internal and External Formulae 

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Example: Given a cylindrical shell with the following variables, solve for the MAWP of the cylinder using both formulas. P=? * The question mark defines what is being solved for. t = 0.500" S = 15,000 psi E = 1.0 R = 18.0“ and Routside = 18.5"

SEt 15,000 x 1.0 x 0.500 7500 App 1 (1 - 1) P =    409.8 psi Ro - 0.4t 18.5 - (0.4 x 0.500) 18.3

UG-31 TUBES, AND PIPE WHEN USED AS TUBES OR SHELLS  (a) Internal Pressure. The required wall thickness for tubes and pipe under internal pressure shall be determined in accordance with the rules for shells in UG-27.  (b) External Pressure. The required wall thickness for tubes and pipe under external pressure shall be determined in accordance with the rules in UG-28.  (c) The thickness as determined under (a) or (b) above shall be increased when necessary to meet the following requirements:  (1) Additional wall thickness should be provided when corrosion, erosion, or wear due to cleaning operations is expected.  (2)Where ends are threaded, additional wall thickness is to be provided in the amount of 0.8/n in. (20/n mm) [where n equals the number of threads per inch (25.4 mm)].

UG-32 Formed Heads, and sections, pressure on concave side 

(a) The minimum required thickness at the thinnest point after forming of ellipsoidal, torispherical, hemispherical, conical, and tori-conical heads under pressure on the concave side (plus heads) shall be computed by the appropriate formulas in this paragraph.

There are three types of calculations for formed heads listed in the Body of Knowledge: Ellipsoidal, Torispherical and Hemispherical. A sketch and the formulae for thickness of each kind are below.

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PD t= 2SE - 0.2 P

0.885PL t= SE - 0.1P

PL t= 2SE - 0.2P

Efficiency “E” Definition E is

joint efficiency ,

or The efficiency of appropriate joint in cylindrical or spherical shells “UW-12”, or The efficiency of ligaments “UG-53” between openings, whichever is less.

What we need to Get the Efficiency “E” 1. Review and understand the terms joint "category“ and "type". 2. Determine the correct "E" value based on joint type and degree of radiography. 3. Review ASME stamping requirements when radiography is performed.

UG-27 Shells under internal under pressure. UG-32 Formed heads, pressure on the concave side. UW-3 Welded joint category. Figure UW-3 Illustration of Welded Joint Location. UW-12 Joint efficiencies Table UW-12 Maximum allowable joint efficiencies UG-116(e) Required marking (nameplates or direct stamping)

UW-3 Welded Joint Category   

The term Category as used herein defines the location of a joint in a vessel, but not the type of joint. Categories are assigned based on the type and degree of stresses imposed at various locations within a vessel. Joints included in each category are designated as A, B, C or D.

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(a) Category A Longitudinal joints within the main shell, communicating chambers (eg. sumps), transitions in diameter, or nozzles, any joint in a sphere, formed or flat head or side plates in flat sided vessels, circumferential welded joints connecting hemispherical heads to shells, nozzles, or to communicating chambers. (b) Category B Circumferential welded joints within the main shell, communicating chambers or transitions in diameter, circumferential welded joints connecting formed heads other than hemispherical to main shells, transitions in diameter, to nozzles, or to communicating chambers.

(c) Category C  Welded joints connecting flanges, Van Stone laps, tube sheets, or flat heads to:  main shells, to formed heads,  to transitions in diameter, to nozzles or to communicating chambers,  Any welded joint connecting one side plate to another side plate of a flat sided vessel. (d) Category D  Welded joints connecting communicating chambers or nozzles to: main shells, spheres, transitions in diameter, to heads, flat sided vessels, and nozzles to communicating chambers

Joints Categories

UW-2 Service Restrictions 

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UW-2 Service Restrictions is a very important section for lethal service vessels and must be read in its entirety. A few brief points from UW-2: UW-2(a) and UW-11(a)(1) - All butt welds shall be 100% radiographed. UW-2(a) - Electric Resistance Welded (ERW) pipe (like some grades of SA-53) is not permitted but interpretation VIII-1-01-118 says it is acceptable if the long seam is fully radiographed. UW-2(a) - Post weld heat treatment is required for CS and Low Alloy UW-2(a)(1)(a) - Category A welds shall be type 1 only (butt welded with no permanent backing strip)

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UW-2(a)(1)(b&c) &Interpretation VIII-1 92-211 Category B & C welds shall be type 1 or 2 only (butt welded). No slip on flanges! No Figure UW-13.2 Flange or Head to Shell attachments.

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Interpretation VIII-I-98-23 - Category D welds (typically nozzles) shall be full penetration. UW-2(a)(1)(c) - Category C joints for stub ends have a long list of requirements UW-2(a)(2 and 3) - Heat exchangers have a long list of requirements Read all of UW-2 for more restrictions...

Note : Visit also the following page : http://pveng.com/home/asme-code-design/comments/lethalservice-quick-guide/ 

UW-2 Service Restrictions If determined as lethal, …………. (1) The joints of various categories (see UW-3) shall be as follows. (a) Except under the provisions of (a)(2) or (a)(3) below, all joints of Category A shall be Type No. (1) of Table UW-12. (b) All joints of Categories B and C shall be Type No. (1) or No. (2) of Table UW-12.

Applying UW-2

Weld Joints Types

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These are the only two types which are considered acceptable for radiography by Section VIII Div.1

Type 1 Double Welded butt joint or equivalent. Backing if used must be removed.

Type 2 Single welded butt joint with backing which remains in place.

UW‐11  :RT and UT EXAMINATIONS  Full Radiography is required in following cases  :         All butt welds of vessels for lethal substances       If  thickness  exceeds given in  table UCS‐57,  UHA ‐ 33,       Butt welds of unfired  boilers.      For all other vessels, All cat. A welds full radiography .     Cat. B & C welds which intersect the Cat. A welds shall be                                   spot radiographed.       Radiography is not required of category B and C  butt          welds in nozzles less than NPS 10 or 1 1/8 in. thick. 

1          Spot  Radiography    :  Spot  RT  of  Butt  joints  if    design  efficiency is selected for spot radiography.     2        No Radiography : No RT of weld joints if design efficiency   is  selected  for  no  radiography  or  vessel  is  designed  for  external pressure      3  Ultrasonic  examination  :    ultrasonic  examination  in  accordance with UW‐53 may be substituted for radiography  for  the  final  closure  seam  of  a  pressure  vessel  if  the  construction  of  the  vessel  does  not  permit  interpretable  radiographs  in  accordance  with  Code  requirements.  The  absence  of  suitable  radiographic  equipment  shall  not  be  justification or such substitution. 

UW-11 Radiographic and Ultrasonic Examinations of Weld Joints (a) Full Radiography. The following welded joints shall be examined radiographically for their full length …. (1) all butt welds in the shell and heads of vessels used to contain lethal substances [see UW-2(a)]; Remember, UW-2(a) demands that in lethal service the welds be of Type 1 for Category A and must be of either Type1 or 2 for Categories B and C. Type 1

Type 2

Examples: Type 1, Butt welded, both sides must be visible

Examples: Type 2, butt welded with backing

Fig. UW-13.1 sketch (k) "joggle joint"

backing left in place

Examples: Type 3, single welded butt welded without backing

not viewed internally -eg. small diameter pipe or assemblies with space or visibility restrictions Examples: Type 4, double full fillet lap joint

Examples: Type 5, single full fillet lap joints with plug welds

Plug Weld Examples: Type 6,single full fillet lap joint without plug welds

Joints Types  8 Joint types are identified.

 Type 1 has the highest efficient, type 6 has the lowest efficient. Types 7 and 8 have no assigned efficiency.  Types 1 through 3 are butt joints, types 4 through 6 are lap joints. Type 7 is a corner joint and 8 is an angle joint. Only type 1 and 2 butt joints may be radiographed in order to improve efficiency.

Summary of weld types: Type 1: Full penetration welds (Typically Double welded) Type 2: Welds with backing strip Type 3: Single welded partial penetration welds Type 4, 5 and 6: Various Lap welds (rarely used)

UW-11 Radiographic and Ultrasonic Examinations of Weld Joints Lethal Service

Full Radiography

UW-11 Radiographic and Ultrasonic Examinations of Weld Joints Page 117 (a) Full Radiography. The following welded joints shall be examined radiographically for their full length …. (2) all butt welds in vessels in which the nominal thickness [ see (g) below] at the welded joint exceeds 1-1/2 in. (38mm), or exceeds the lesser thicknesses prescribed in UCS57…. * This paragraph is on the examination. (g) For radiographic and ultrasonic examination of butt welds, the definition of nominal thickness at the welded joint under consideration shall be the nominal thickness of the thinner of the two parts joined. Nominal thickness is defined in 3-2.

(3) all butt welds in the shell and heads of unfired steam boilers ………Steam Boilers are NOT on the Exam. (4) all butt welds in nozzles, communicating chambers, etc., attached to vessel sections or heads that are required to be fully radiographed under (1) or (3) above; however, .....Categories B and C butt welds in nozzles and communicating chambers that **neither exceed NPS 10 (DNS 250) nor 1-1/8 in. (29mm) wall thickness do not require any radiographic examination; ** This only applies to circumferential welds in small (NPS 10 / 1-1/8” thick.) nozzles and chambers. Longitudinal seams are not exempted by this rule.

UW-11 (4) all butt welds in nozzles, communicating chambers, etc., attached to vessel sections or heads that are required to be fully radiographed under (1) or (3) above; however, Categories B and C butt welds in nozzles and communicating chambers that neither exceed NPS 10 (DNS 250) nor 1-1/8 in. (29mm) wall thickness do not require any radiographic examination;

(5) all Category A and D butt welds in vessel sections and heads where the design of the joint or part is based on a joint efficiency permitted by UW - 12(a), in which case: (a) Category A and B welds connecting the vessel sections or heads shall be of Type No. (1) or Type No. (2) of Table UW12; * Just means they must be radiographable. (b) Category B or C butt welds [but not including those in nozzles or communicating chambers except as required in (2) above] which intersect the Category A butt welds in vessel sections or heads or connect seamless vessel sections or heads shall, as a minimum, meet the requirements for spot radiography in accordance with UW-52 (Will be explained in Inspection and testing part).

(5) all Category A and D butt welds in vessel sections and heads where the design of the joint or part is based on a joint efficiency permitted by UW 12(a), in which case: * This paragraph is only mandatory when it is desired by the designer to use the highest joint efficiency possible for calculations of thickness required or pressure allowed. It is a choice the designer makes when there are no mandatory requirements based on service or material as found in UW-11 (a) (1)*Lethal Service, (2)*Thickness exceeded

This means that; If the material of construction is not one of those referenced UW-11(a)(2) then the default value for the thinner thickness exceeded becomes 1-1/2”. Since the API 510 examination is restricted to UCS materials (carbon and low alloy steels) this rule will be demonstrated using a Carbon Steel that is classified as a P-Number 1.

From Mandatory Appendix 3 Definitions (c) nominal thickness – …….For plate material, the nominal thickness shall be, at the Manufacturer’s option, either the thickness shown on the Material Test Report {or material Certificate of Compliance [UG-93(a)(1)]} before forming, or the measured thickness of the plate at the joint or location under consideration. * Information only this is not on the exam.

(6) all butt welds joined by… electrogas welding is not on the exam. 7) ultrasonic examination in accordance with UW53 may be substituted for radiography for the final closure seam of a pressure vessel if the construction of the vessel does not permit interpretable radiographs in accordance with Code requirements. The absence of suitable radiographic equipment shall not be justification for such substitution.

(8) exemptions from radiographic examination for certain welds in nozzles and communicating chambers as described in (2), (4), and (5) above take precedence over the radiographic requirements of Subsection C of this Division. Note: This means that even though P-No. 5 for example requires RT in all thicknesses the small/thin nozzles are exempt. (b) Spot Radiography. Except as required in (a)(5)(b) above, butt welded joints made in accordance with Type No. (1) or (2) of Table UW-12 which are not required to be fully radiographed by (a) above, may be examined by spot radiography. Spot radiography shall be in accordance with UW52. * If full RT is not mandatory Spot Radiography done because the the designers choose it.

If spot radiography is specified for the entire vessel, radiographic examination is not required of Category B and C butt welds in nozzles and communicating chambers that exceed neither NPS 10 nor 1-1/8 in. wall thickness (c) No Radiography. Except as required in (a) above, no radiographic examination of welded joints is required when the vessel or vessel part is designed for external pressure only, or when the joint design complies with UW-12(c). * The designer can choose not to do RT if there is no mandatory requirement such as lethal, thickness, or desire for a higher joint E.

UCS-57 Section VIII From paragraph UCS-57: In addition to the requirements of UW-11, complete radiographic examination is required for each butt welded joint at which the thinner of the plate or vessel wall thicknesses at the welded joint exceeds the thickness limit above which full radiography is required in Table UCS-57.

Section VIII

UCS-57 For P No.1 materials the thinner of the two must exceed 1.25” The girth weld at the 1.25 to 1.5” joint and all above it are exempt.

Class Quiz UW-11 Radiographic and Ultrasonic Examinations 1. In the drawing below the paragraph that applies is; a. UW-11(a)(1) Lethal Service b. UW-11(a)(2) Thickness limit exceeded c. UW-11(a)(5) The desire to take E from Column A of Table UW-12

Class Quiz UW-11 Radiographic and Ultrasonic Examinations 2. In the drawing below the paragraph that applies is; a. UW-11(a)(1) Lethal Service b. UW-11(a)(2) Thickness exceeded c. UW-11(a)(5) Design using E from Col. A Table UW-12

UW-12 Joint Efficiencies Page 119 Table UW-12 gives the joint efficiencies E to be used in the formulas of this Division for joints completed by an arc or gas welding process. Except as required by UW-11(a)(5), a joint efficiency depends only on the type of joint and on the degree of examination of the joint and does not depend on the degree of examination of any other joint. (a) A value of E not greater than that given in column (a)* of Table UW-12 shall be used in the design calculations for fully radiographed butt joints [seeUW-11(a)], except that when the requirements of UW-11(a)(5) are not met, a value of E not greater than that given in column (b) of Table UW-12 shall be used. * Known as Full Radiography So now we are sent back to UW-11(a)(5)…….

UW-12 Joint Efficiencies Table UW-12 gives the joint efficiencies "E" to be used in the formulas of this Division for joints completed by gas or an arc welding process. Except as required by UW-11(a)(5), a joint efficiency depends only on the type of joint and the degree of examination of the joint and doesn't depend on the degree of examination of any other joint.  The user or his designated agent [U-2(a)] shall establish the type of joint and the degree of examination when the rules of this Division do not mandate specific requirements.

Weld Joints Efficiencies (from table UW-12)

Butt Joints as attained by doubleType 1-Cat. A,B,C,&D welding or by other means which will obtain the same quality on the inside and outside. Backing strip if used must be removed after Type 2-Cat. A,B,C,&D welding is completed.

Single-welded butt joint with backing strip which remains in place after welding is completed. Limitations apply see table UW12.

Full Col. A

Spot Col. B

None Col. C

Full RT

Spot RT

No RT

E = 1.0

E = .85

E = .70

E = .90

E = .80

E = .65

UW-12(a) A value of E not greater than that given in column (a) of Table UW-12 shall be used in the design calculations for fully radiographed butt joints [see UW-11(a)], except that when the requirements of UW-11(a)(5) are not met, a value of E not greater than that given in column (b) of Table UW-12 shall be used. 

 UW-12(b) Spot radiography  Per column (b) of Table UW-12  Performed per UW-52* [see UW11(b)]

* Minimum one film (at least 6 inches long) per welder for each 50 foot increment of deposited weld metal.

 UW-12(c) No Radiography

 Per column (c) of Table UW-12

 UW-12(f) Pressure Welding Processes

 A value of E not greater than 0.80 for welds completed by any of the pressure welding processes listed in UW-27(a).

 UW-12( a) Full Radiography

 Use the efficiency specified in column (a) of Table UW12, except when the requirements of UW-11(a)(5) are not met, a value not greater than that listed in column (b) of Table UW-12 shall be used.

UW-11(a)(5) All Category A and D butt welds in the shell and heads of vessels where the design of the joint or part is based on a joint efficiency permitted by UW12(a), in which case:  (a) Category A and B welds connecting vessel sections or heads shall be Type 1 or 2 of Table UW-12.  (b) Category B or C butt welds which intersect category A butt welds in vessel sections or heads, or connect seamless vessel sections or heads shall as a minimum, meet the requirements for spot radiography in accordance with UW-52.  UW-52(b)(4) Radiographs required at specific locations to satisfy the rules of other paragraphs, such as UW9(d), UW11(a)(5)(b). and UW-14(b), shall not be used to satisfy the rules for spot radiography.

Use column (a) of Table UW-12, when UW-11(a)(5) is met only, use column (b) of Table UW-12.

UW 12(d) Seamless Vessel Sections and Heads are considered equivalent to welded parts of the same geometry, in which and all Category A welds are type 1.

Formed head other than hemi

Hemi head

UW-12(d) can't... For calculations involving circumferential stress in vessel sections or for the thickness of seamless heads, E = 1.0 when the spot radiography requirements of UW 11(a) (5)(b) are met, or 0.85 when they are not met.

Formed head other than hemi

UW-11(a)(5)(b) spot RT performed, E= 1.0 UW-11(a)(5)(b) spot RT not met, E= 0.85

Hemi head

UW-12(d) Seamless vessel …………. E= 0.85 when the spot radiography requirements of UW11(a)(5)(b) are not met, or when the Category A or B welds connecting seamless vessel sections or heads are Type No. 3, 4, 5, or 6 of Table UW-12. * 3 to 6 are can not be radiographed by Code rules.

UW-12(e) Welded pipe or tubing* shall be treated in the same manner as seamless, but with the allowable tensile stress taken from the welded product values of the stress tables, and the requirements of UW-12(d) applied. • Manufactured in accordance with a material specification permitted by this Division, not fabricated by the vessel manufacturer as a vessel part. (eg. ERW pipe)

Welded, but treated like seamless [UW-12(d)] UW-11(a)(5)(b) spot RT performed, E= 1.0 UW-11(a)(5)(b) spot RT not met, E= 0.85

UW-12(e) Welded pipe or tubing shall be treated in the same manner as seamless, but with allowable tensile stress taken from the welded product values of the stress tables, and the requirements of UW-12(d) applied. If the spot RT is applied use E = 1.0, if not E = 0.85

Remember Remember that there only two (2) joint efficiencies possible for Seamless Shell and Seamless Heads they are;

1.0 or 0.85 1.0 when the rules of UW-11(a)(5)(b) have been applied (UW-52 Spot RT applied). 0.85 when the rules have not been applied. (UW-52 Spot RT not applied) DO NOT GO TO TABLE UW-12 FOR THE E TO USE IN SEAMLESS HEADS OR SEAMLESS SHELLS

Class Quiz UW-12 Joint Efficiencies 1. A Type 1 weld has received Spot Radiographic Testing the resulting Joint E _______? a. 1.0 b. 0.80 c. 0.85 2. A Type 3 weld can be spot radiographed. ___True ___False 3. A Type 2 weld has been Fully Radiographed, the Weld Joints E is ______. a. 0.85 b. 0.90 c. 0.80

Class Quiz UW-12 Joint Efficiencies 1. A Type 1 weld has received Spot Radiographic Testing the resulting Joint E _______? c. 0.85 2. A Type 3 weld can be spot radiographed. ___False 3. A Type 2 weld has been Fully Radiographed, the Weld Joints E is ______. b. 0.90

Class Quiz UW-12 Joint Efficiencies 4. A Type 2 weld has received Spot Radiographic Testing resulting in a Joint E of 0.80, this E could be improved to a 1.0 by _____________________. a. applying full radiography b. removing the backing and double welding and then applying Spot RT. c. removing the backing, double welding thus creating a Type 1, and then applying Full RT.

Class Quiz UW-12 Joint Efficiencies 4. A Type 2 weld has received Spot Radiographic Testing resulting in a Joint E of 0.80, this E could be improved to a 1.0 by _____________________. c. removing the backing, double welding thus creating a Type 1, and then applying Full RT.

UG-116(e) Required Marking  When a vessel has been radiographed in accordance with UW-11, marking shall be applied under the Code symbol

as    

follows: RT-1 RT-2 RT-3 RT-4

UG-116(e) Required Marking RT-l, Full radiography of all pressure retaining butt welded joints, except Category B & C butt welds in nozzles and communicating chambers that neither exceed IMPS 10 (DN 250) nor 1-1/8 in. (29mm).

RT-2, when the complete vessel satisfies the requirements of UW 11(a)(5) and when spot RT rules of UW 11(a)(5)(b) have been applied.

Formed head, Other than Hemi

Hemi head

UG-116(e) Required Marking

RT-3,

when the complete vessel satisfies the spot radiography rules of UW-11(b). Formed head, Other than Hemi

Hemi head

RT-4, when only part of the complete vessel has satisfied the radiographic requirements of UW-11(a) or where none of the markings RT-1, RT-2, or RT 3 are applicable Formed head, Other than Hemi

Hemi head

UG-16 and UW-12 Joint Efficiencies according to Marking For the purposes of choosing joint efficiencies when doing vessel section or head calculations. RT 1 Full Use 1.0 if joints are of Type 1 or 0.90 if Type 2 RT 2 Case 1: Use 1.0 with Seamless Heads and Shells Case 2: Seamed Shells/Seamless Heads • Shells Use 1.0 if joints are Type 1or if Type 2 Use 0.90 • Use 1.0 for seamless heads

RT 3 Use 0.85 if Joints are of Type 1 or 0.80 if of Type 2 Use 0.85 for Seamless heads RT 4 * Special case of selective radiography * Use Table UW-12 based on Joint Type and RT described in the exam question. No RT Go to Table UW-12 and look up the E to be used for the type of weld under consideration. Case1: Type 1 Use 0.70 Case 2: Type 2 Use 0.65 Seamless heads use 0.85 Per UW-12(d)

ASME Pressure Vessel Joint Efficiencies for Seamless Heads

Class Quiz UW-2 Service Restrictions 1. Which of the following types of welds are required if a vessel is determined to be in lethal service? a. Category A and B welds shall be of Type 1. b. Category A and B welds must be of Type 1 or 2. c. Category A shall be of Type 1 only, B and C can be of Type 1 or Type 2. 2. Lable these welds by Type

Class Quiz UW -3 Welded Joint Category 1. The category of a joint depends on: a. What kind of weld was made, fillet or butt. b. The process used to make the weld. c. Whether it is vertical or horizontal in the vessel d. None of the above. 2. A circumferential weld to attach a flange is what Category? a. D b. C c. E d. A

Class Quiz UW -3 Welded Joint Category

3. A circumferential weld used to attach a seamless head is of what Category? a. b. c. d.

B C E A

4. The circumferential weld to attach a Hemispherical head to a shell is a Category ____.

Class Quiz UW -3 Welded Joint Category

3. A circumferential weld used to attach a seamless head is of what Category? a. B 4. The circumferential weld to attach a Hemispherical head to a shell is a Category A .

5. Label these weld joints by Category A,B, C or D

5. Label these weld joints by Category

Class Quiz 

Find the Maximum Allowable Working Pressure (MAWP) of a 12 inch inside diameter shell. This shell is seamless and is stamped RT 2. It has an allowable stress value of 16,600 psi and the wall thickness is .406”. No corrosion is expected.

OPENING AND REINFORCEMENT

UG-36 OPENINGS IN PRESSURE VESSELS



UG-36(a) Shape of Opening (1) Openings in cylindrical or conical portions of vessels, or in formed heads, shall preferably be circular, elliptical, or obround. (2) Openings may be of other shapes than those given in (1) above, and all corners shall be provided with a suitable radius. the part of the vessel affected shall be subjected to a proof hydrostatic test as prescribed in UG-101.



(b) Size of Openings  (1) Properly reinforced openings in cylindrical and conical shells are not limited as to size except with the following provisions for design. The rules in UG-36 through UG-43 apply to openings not exceeding the following:  For vessels 60 in. (1 500 mm) inside diameter and less, onehalf the vessel diameter, but not to exceed 20 in. (500 mm);  for vessels over 60 in. (1 500 mm) inside diameter, one‐third the vessel diameter, but not to exceed 40 in. (1 000 mm). (For conical shells, the inside shell diameter

UG-37 REINFORCEMENT REQUIRED FOR OPENINGS IN SHELLS AND FORMED HEADS



Finally you need to calculate the summation of additional areas and check if such summation is equal or greater than the total cut area from shell wall at E=1.0 , if yes there is no need for reinforcement if no you need to add reinforcement to reach the cut area.

FABRICATION





UG-80 PERMISSIBLE OUT-OF-ROUNDNESS OF CYLINDRICAL, CONICAL, AND SPHERICAL SHELLS (a) Internal Pressure. The shell of a completed vessel shall be substantially round and shall meet the following requirements:  (1) The difference between the maximum and minimum inside diameters at any cross section shall not exceed 1% of the nominal diameter at the cross section under consideration.

 





UG-82 LUGS AND FITTING ATTACHMENTS All lugs, brackets, saddle type nozzles, manhole frames, reinforcement around openings, and other appurtenances shall be formed and fitted to conform reasonably to the curvature of the shell or surface to which they are attached. (a) When pressure parts, such as saddle type nozzles, manhole frames, and reinforcement around openings, extend over pressure retaining welds, such welds shall be ground flush for the portion of the weld to be covered. (b) When nonpressure parts, such as lugs, brackets, and support legs and saddles, extend over pressure retaining welds, such welds shall be ground flush as described in (a) above, or such parts shall be notched or coped to clear those welds.

Impact Testing

UG-84 CHARPY IMPACT TESTS 

(a) General. Charpy V‐notch impact tests in accordance with the provisions of this paragraph shall be made on weldments and all materials for shells, heads, nozzles, and other vessel parts subject to stress due to pressure for which impact tests are required by the rules in Subsection C.

This is why we impact test!







The question becomes, is this metal in this thickness and heat treated condition, prone to brittle fracture at the desired MDMT ? So the task becomes evaluating a given material for exemptions from testing. This a four step process, ending with a ‘yes you must’ or ‘no you don’t’ solution. The four steps are; 1. The exemption given in paragraph UG-20(f). 2. The exemptions listed in UCS-66 (Table UCS-66). 3. The reduction in temperature provided by Table UCS-66.1 to Table UCS-66 4. The reduction in temperature to Table UCS-66 given in paragraph UCS-68(c).



If at the end of the 4 steps, impact testing is required, then they must be conducted in accordance with the rules described in the paragraph UG-84.

What we need to know? 

1. Are they required? • 2. If the tests are required  How must they be conducted and,  What passes and what is considered to have failed the tests?

Impact Testing Exemptions 

The search will begin in UG-20(f) and progress through UCS 66, and 68. If no exemption is found impact tests are required. The best approach is to list these by steps.

Step 1 Paragraph UG-20 UG-20(f) lists an exemption from impact testing materials that meet “All” of the following requirements.



for

1. Material is limited to P-No.1 Gr. No.1 or 2 and the thicknesses don't exceed the following: •

(a) 1/2 in. for materials listed in Curve A of Fig. UCS-66;

•

(b) 1 in. for materials from Curve B, C or D of Fig. UCS-66;

2. The completed vessel shall be hydrostatically tested 3. Design temperature is no warmer than 650°F nor colder than 20°F. 4. The thermal or mechanical shock loadings are not controlling design. 5. Cyclical loading is not a controlling design requirement.

Reminder 

All of the conditions of UG-20(f) must be met to take this exemption from impact testing.

Step 2 Fig. UCS-66 Material Curves UCS-66 (a) Turn your attention to Fig. UCS-66 Impact Test Exemption Curves and Table UCS-66. The Graph or Table are used to determine the minimum temperature a material thickness can be operated at without mandatory impact testing.. The graph has four curves: A, B, C and D. In Fig. UCS-66 along with the graph is a listing of carbon and low alloy steels. This listing of materials is used to determine the curve on the Graph or in the Table for a given material. After finding the curve for the material, there are two choices.





You may use the graph of Fig. UCS 66 or the Table UCS 66 to determine the minimum temperature for a given thickness. It is recommended to use the Table. The Table is a lot easier to use with accuracy. If the material thickness is operated at or above the temperature listed in Table UCS-66, impact tests are not required. If the material thickness is to operate below the given minimum temperature, impact testing is required. The temperature found in the table is the MDMT of that material thickness without impact testing being required.

Example  A material that has been assigned to Curve B which is 2 inches (51 mm) thick. Using the table we find the column for Curve B materials, move down until we find the thickness row for 2 inches and across to find the MDMT that this material can be used without impact testing is 63oF (17oC).



That doesn’t seem like an acceptable minimum design temperature for most vessels. This makes a Curve B material a poor choice at 2” thickness.

Class Quiz What is the lowest temperature that a 1.5 inch thickness Curve D material can be designed for without impact tests?





Using the Coincident Ratio given in a problem we enter the graph on the left side at that value. The across to intersect the curve then down to find a temperature given. We take that temperature back to Table UCS-66 and reduce the temperature given there for the material of interest by the amount we found using Table UCS-66.1. Example: The Coincident Ratio is given as .60. Now using our previous Table UCS-66 2” Curve B material that has a MDMT of 63oF we adjust and find a new MDMT. Like this!

Step 3

Reduction in Minimum Design Metal Temperature Without Impact Testing (Figure UCS-66.1)

63 – 40 = 23oF our adjusted MDMT



Class Quiz Table UCS-66.1

1. What would be the adjusted MDMT for a vessel 1.5” thick from Curve D with a Coincident Ratio of .90 ?

– 14oF lowered by 10oF = -24oF “Algebraic Sum”. The adjusted “New MDMT”!

Step 4 



UCS-68(a) Design rules for carbon and low alloy steels stipulates requirements about construction of the vessel or part. The main points are: mandatory joint types, required post weld heat treatments below -55 °F unless the vessel is installed in a fixed (stationary) location, and the coincident Ratio of stress is less than 0.35. UCS-68(b) Welded joints must be postweld heat treated when required buy other rules of this Division or when the MDMT is colder than -55 °F and for vessel installed in a fixed (stationary) location the coincident Ratio is 0.35 or greater.



UCS-68(c) Notice a reduction of 30 °F below that of Figure UCS-66 for P-1 materials if post welded heat treatment is performed when it is not otherwise required in the Code. This means that 30 °F can be subtracted from the temperature found in Table UCS-66. If the adjusted temperature is below that desire, Impact Tests are not required. It is exempt. If a statement about heat treatment is made in a particular problem the task becomes finding out if heat treatment was required or not. If it is not mentioned, it must be concluded that it was not performed and therefore the exemption cannot be taken.

Example       

Example: Givens: Material SA-516-70 normalized (plate) Thickness 2" Min. Yield 38 KSI MDMT -25 °F Coincident Ratio = .85

  

Step 1: Check for the exemptions of UG-20(f) Our material applies to Curve D of Figure UCS-66 and exceeds the 1“ limit for exemption. It also exceeds and lower temperature limits - 20 °F.

Our Material 516 Normalized is on Curve D below

Step 2: Checking Table UCS-66 and entering at our thickness of 2 inches on the left and moving across to Curve D column, we find the MDMT of this thickness to be -4 °F. This exemption does not apply our goal is -25 °F.



Step 3: Checking Fig. UCS-66.1 and entering at our stated Coincident Ratio of .85 and then down to read the temperature reduction permitted we find 15 °F.



Step 3: This 15 °F is subtracted directly from the table UCS-66.

So we now have -4 from Table UCS-66  And …………… -15 from Table UCS-66.1  -19 °F 



Not there yet, we need -25 °F to be exempt from testing.

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

UCS-68 (c) If postweld heat treating is performed when it is not otherwise a requirement of this Division, a 30°F (17 °C) reduction in impact testing exemption temperature may be given to the minimum permissible temperature from Fig. UCS-66 for P-No.1 materials. P-1 materials (only) if post welded heat treatment is performed when it is not otherwise required. This would occur if the note 2(b) of table UCS-56 for P No. 1 materials is complied with or if the vessel is in general service and has no mandatory heat treatment requirements in the Code.

Finally 







Step 4: Checking UCS-68 (c), we find that we cannot take a reduction because PWHT is a requirement of UCS-56 for this material's thickness of 2 inches. Answer:

Impact tests are required for the desired MDMT of -25 °F. So how must they be done?

(c) Test Specimens 







(1) Each set of impact test specimens shall consist of three specimens. (2) The impact test specimens shall be of the Charpy V‐notch type and shall conform in all respects to Figure UG-84. The standard (10 mm × 10 mm) specimens, when obtainable, shall be used for nominal thicknesses of 7/16 in. (11 mm) or greater, except as otherwise permitted in (-a) below. (-a) For materials that normally have absorbed energy in excess of 180 ft‐lbf (240 J) when tested using full size (10mm× 10 mm) specimens at the specified testing temperature, subsize (10 mm × 6.7 mm) specimens may be used in lieu of full size specimens. However, when this option is used, the acceptance value shall be 75 ft‐lbf (100 J) minimum for each specimen and the lateral expansion in mils (mm) shall be reported. (3) For material from which full size (10 mm × 10 mm) specimens cannot be obtained, either due to the material shape or thickness, the specimens shall be either the largest possible standard subsize specimens obtainable or specimens of full material nominal thickness which may be machined to remove surface irregularities.



(b) Test Procedures  (1) Impact test procedures and apparatus shall conform to the applicable paragraphs of SA-370 or ISO 148 (Parts 1, 2, and 3).  (2) Unless permitted by Table UG-84.4, impact test temperature shall not be warmer than the minimum design metal temperature [see UG-20(b)]. The test temperature may be colder than the minimum specified in the material specification of Section II.

Class Quiz 

1. What specification must impact testing procedures conform to?



2. What type of Impact Test does the Code recognize?



 

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

3. What are the dimensions of a standard Charpy Impact specimen? 4. How many specimens comprise a single set? 5. How many sets of specimens are required for a weld procedure test coupon 1 3/4 inches thick? 6. When welding a procedure test plate for impact testing what must the P No. and Group No. be? What type of heat treatment must be applied to the test plate? 7. Name the two types of test specimens required for all welding procedures. Hint: Where do they come from?

Solution  

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 

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

1. SA‐370 ( second paragraph of UG‐84) 2. Charpy V‐notch (only one mentioned in UG‐84, first paragraph UG‐84 Charpy impact tests shall be performed) 3. 2.165” long x 0.394” (51mm long10mm x10 mm) thick see Fig UG‐84 4. Three make a set 5. Three sets, two from the weld metal and one set of heat affected zone specimens 6. The P No. and the Group No. must be the same as will welded in production and be in the same heat treated condition. 7. Weld Metal and Heat Affected Zone

Post Weld Heat treatment

Post Weld Heat Treatment PWHT 

Post-weld heat treatment (PWHT), or stress relief as it is sometimes known, is a method to improve mechanical properties and reduce and redistributing the residual stresses in the material that have been introduced by welding.

UW-10 Postweld Heat treatment Pressure vessels and pressure vessel parts shall be heat treated as prescribed in UW-40 when PWHT is required in the applicable part of Subsection C.

UW-40 Procedures of PWHT (a) In the procedures that follow, the minimum soak band shall contain the weld (W), heat affected zone (HAZ) and a portion of the base metal adjacent to the weld being heat treated.

UW-40 Definition of Nominal Thickness for Butt Welds (1) When the welded joint connects parts of the same thickness, using a full penetration butt weld, the nominal thickness is the total depth of the weld exclusive of any permitted weld reinforcement.

Depth of weld

UW-40 Methods of PWHT

(b) The temperatures and rates of heating and cooling to be used are given in UCS-56, UHT-56, UNF-56 and UHA-32. (c) The minimum PWHT temperatures shall be the minimum temperature of the plate material of the shell or head (furnace gas temperature measurement alone is not considered sufficiently accurate).  Where more than one pressure vessel or part are treated in one furnace charge, thermocouples shall be placed in the bottom, center and top of the charge, or in other zones of possible temperature variation.

(d) When pressure parts of two different P-Number Groups are joined by welding, the PWHT shall be that specified according to UCS-56 or UHA-32, for the material requiring the higher PWHT temperature. (e) PWHT, when required, shall be done before the hydrostatic test and after any welded repairs except as permitted by UCS56(f).  A preliminary hydrostatic test to reveal leaks prior to PWHT is permissible. (f) The term nominal thickness is the thickness (t) of the welded joint as follows.  For pressure vessels or parts being post weld heat treated in a furnace charge, t is the greatest weld thickness in any vessel or part which has not previously been post weld heat treated.

UW-40 Procedures of PWHT

(f) Nominal Thickness

(f) Nominal Thickness continued...

UW-49 Check of PWHT Practice The Inspector shall satisfy himself that all PWHT has been correctly performed and that the temperature readings conform to the requirements.

UCS-56(a) Requirements for PWHT Requires WPS qualification per Section IX. Everything requires PWHT unless exempted by Tables UCS-56 or UCS-56.1. Exemptions to PWHT do not apply when:  PWHT is a service requirement (UCS-68),  joining material of certain P-Numbers and thicknesses welded with either the electron beam, inertia and continuous drive friction, electroslag or electrogas welding processes. Heating and cooling rates do not apply for P-No. 1 welded materials heat treated in the austenitizing range.

UCS-56(b) Requirements for PWHT Holding times and temperatures may exceed stated values unless prohibited by Table UCS-56. Intermediate PWHT need not conform to Table UCS-56. Heat treatment may be performed in multiple PWHT cycles.

UCS-56(c) Requirements for PWHT When welding pressure parts of different P-Numbers, use the table with the higher PWHT temperature. When welding non-pressure parts to pressure parts, the PWHT temperature for the pressure part shall govern. Furnace temp, shall not exceed 800°F (425°C) at the time the vessel or part is placed in it.

UCS-56(d) Requirements for PWHT Above 800°F (425°C), the heat up rate shall not exceed 400°F per hour (222°C) divided by the maximum metal thickness of the shell or head in inches, but in no case more than 400°F per hour (222°C). During the heating period, there shall not be a variation in temperature greater than 250°F (120°C) throughout the vessel within any 15 foot (4.6 meter) interval of length. Holding times and temperatures per Table UCS-56orUCS56.1.

Class Quiz UCS 56 1. In the example below what is the shortest amount of time allowed to raise the weldment to a PWHT of 1100 °F if the furnace is at 800°F when the part is inserted? Answer:_________________________________ __

Solution 1. In the example below what is the shortest amount of time allowed to raise the weldment to a PWHT of 1100 °F if the furnace is at 800°F when the part is inserted? 1100 - 800°F = 300°F/200°F = 1-1/2 Hours

TABLE UCS-56.1 ALTERNATIVE POSTWELD HEAT TREATMENT REQUIREMENTS FOR CARBON AND LOW ALLOY STEELS Applicable Only When Permitted in Table UCS-56

NOTES: (1) Minimum holding time for 1 in. (25 mm) thickness or less. Add 15 minutes per Inch (25 mm) of thickness for thicknesses greater than 1 In. (25 mm). (2) These lower post weld heat treatment temperatures permitted only for P-No. 1 Gr. Nos. 1 and 2 materials.

UCS-56 PWHT Thicknesses Up to 2 in. The Code sets the minimum thickness of a vessel at 1/16” (1.6 mm) in paragraph UG-16, one exception is for an Unfired Steam Boiler which has a 1/4” (6 mm) minimum.

UCS-56 PWHT Thicknesses Over 2” The second thickness range: •

Over 2 in. (51 mm) to 5 in. (127 mm) the PWHT is held for a flat 2 hours for the first 2 inches (51 mm) of thickness with an additional 15 minutes per inch over 2 inches. Let’s look at a graphic of this thickness range.

UCS-56 PWHT Thicknesses Over 5 in. The third thickness range: •

Over 5 in. (127 mm) the PWHT is held for a flat 2 hours for the first 2 inches (51 mm) of thickness with an additional 15 minutes per inch over 2 inches. For P-Number 1 there is no change from the previous example. This third range does changes for some of the other P-Numbers. Look at the PNumber 4 Table for example;

Class Quiz UCS-56 PWHT 1. What is the minimum PWHT time and the minimum holding temperature for a P-Number 5A material that is 3” (inches) thick (75 mm)? 2. What is the PWHT normal holding temperature and time for a P-Number 3 material that is 3” (76 mm) thick? 3. What is the required time at the minimum holding temperature for a P-Number 1 Gr.1 weld that has a nominal governing thickness of 1-1/4” ? The vessel will not be in a lethal service.

Solution 1. 3 hours at 1250 oF (677 oC). 2. 1100 oF (593oC) 2 hours -15 minutes? 3. There is no mandatory heat treatment in this thickness, it must exceed 1-1/4”

UCS-56(d) Requirements for PWHT During the holding period, there shall not be a greater difference than 150°F (83°C) in temperature between the highest and lowest readings. During the heating and holding periods, the furnace atmosphere shall be so controlled as to avoid excessive oxidation of the vessel surface. The furnace shall be designed as to prevent flame impingement on the vessel. Above 800°F (425°C), cooling shall be done in a closed chamber or cooling chamber. Cooling rates above 800°F (425°C) shall not exceed 500°F per hour (278°C) divided by the maximum shell or head thickness in inches, but in no case more than 500°F per hour (278°C). From 800°F (425°C) the vessel may be cooled in still air.

UCS-56(e) Requirements for PWHT Repairs to vessels in the post weld heat treated condition require the repaired area to be re-heat treated, except as permitted in UCS-56(f).

UCS-56(f) Requirements for PWHT, Alternatives & Exemptions Exemptions to re-heat treating repaired areas are as follows:  P-No. 1, Group No's, 1, 2 and 3 materials,  P-No. 3, Group No's. 1, 2 and 3 materials, and the weld metals used to join the above, provided the repair is made before the final pressure test and provided PWHT was not a service requirement per UW(2)(a) or UCS-68. The exemptions of Table UCS-56 apply.  The welded repairs shall meet the requirements of (1) through (6) below.

 These requirements do not apply when the welded repairs are

minor restorations of the material surface, such as those required after removal of construction fixtures, and provided that the surface is not exposed to the vessel contents.  (1) The Manufacturer shall give prior notification to the user or his designated agent and shall not proceed until acceptance has been obtained. Such repairs shall be recorded on the Data Report.  (2) Repair depth shall not exceed 1 ½ in. (38mm) for P-No. 1, Groups 1, 2 and 3 materials and 5/8 inch (16mm) for P-No. 3, Group 1, 2 and 3 materials. The total depth is measured from both sides of a weld at a given location.  (3) MT or PT examine the excavated area per Appendix 6 or 8 respectively.  (4) Use Section IX qualified groove weld procedure and :  (a) use the manual SMAW process with low hydrogen electrodes, conditioned per SFA 5.5. The maximum bead width shall be 4 times the electrode diameter,  (b) maintain 200°F (95°C) minimum preheat and interpass for P-No. 1, Groups 1, 2, and 3 materials.

 (4) continued..  (c) maintain a 350°F (175°C) minimum preheat and interpass, and maximum interposes temperature of 450°F (230°C) for P-No. 3, Groups 1, 2 and 3 materials,  For P-No. 3 materials, the welding technique is limited to the "half bead weld repair and weld temper bead reinforcement technique." Step 1: The initial layer of weld metal shall be deposited over the entire area using 1/8 in. (3mm) maximum diameter electrodes. Step 2: Remove approximately one-half the thickness of the first layer by grinding.

Temper bead Step 3: Subsequent layers shall be Reinforcement Deposited with welding electrodes no larger than 5/32 in. (4mm) Dia. Bead deposition shall be as shown to assure tempering of the prior weld beads and their HAZ's. A final temper bead weld shall be applied to a level above the surface being repaired without contacting the base material but close enough to the underlying weld bead to assure tempering of the base material heat affected zone.  After completing all welding, the repair area shall be maintained at a temperature of 400°F-500°F (205°C-260°C) for a minimum period of 4 hours.  The final temper bead reinforcement layer shall be removed substantially flush with the surface of the base material.

 (5) After the finished weld has reached ambient temperature, PT or MT examine the finished weld surface.  If the material is P-No. 3,Group 3, the re-examination is performed after 48 hours to determine possible delayed cracking of the weld.  If RT was required originally, and the depth of the repair exceeds 3/8 in. (10 mm), perform RT of the repaired area (per UW-51).  (6) Perform hydrostatic test after repair.

UCS-56.1 Alternative PWHT We will first examine a 50oF (28oC) drop from 1100 to1050oF. Below is the holding time from our previous 3” coupon based on 1100oF. How long would we be required to hold it at 1050oF?

UCS-56.1 Alternative PWHT Which leads to this total time, up from 2:15 min. to 2:30 min. Now how about 100oF reduction to 1000oF? Lowered PWHT at 1000 F

Class Quiz UCS-56.1 What is the total PWHT time at 950oF for a 5 inch thick P-No 1 Group 2 material?

Solution What is the total PWHT time at 950oF for a 5 inch thick P-No 1 Group 2 material?

INSPECTION AND TESTS

UW-51 Radiographic and Radioscopic Examination of Weld Joints Page 152 (a) All welded joints to be radiographed shall be examined in accordance with Article 2 of Section V except as specified below. (1) A complete set of radiographs and records, ……shall be retained by the Manufacturer until the Manufacturer’s Data Report has been signed by the Inspector. (2) The Manufacturer shall certify that personnel have been qualified and certified in accordance with their employer’s written practice…… SNT-TC-1A shall be used as a guideline.

UW-51 Radiographic and Radioscopic Examination of Weld Joints …Alternatively, the ASNT Central Certification Program (ACCP), or CP-189 may be used to fulfill the examination and demonstration requirements of SNT-TC-1A and the employer’s written practice. (3) A written radiographic examination procedure is not required. Demonstration of density and penetrameter image requirements on production or technique radiographs shall be considered satisfactory evidence of compliance…..

UW-51 Radiographic and Radioscopic Examination of Weld Joints (4) The requirements of ASME V T-285 of Article 2 ….used only a guide. Final acceptance of radiographs shall be based on the ability to see the prescribed penetrameter image and the specified hole or the designated wire of a wire penetrameter.

UW-51 Radiographic and Radioscopic Examination of Weld Joints (b) Indications shown on the radiographs of welds and characterized as imperfections are unacceptable under the following conditions and shall be repaired as provided in UW-38, and the repair radiographed to UW-51 or, at the option of the Manufacturer, ultrasonically examined in accordance with the method described in Appendix 12….

UW-51 Radiographic and Radioscopic Examination of Weld Joints (1) any indication characterized as a crack or zone of incomplete fusion or penetration ;

UW-51 Radiographic and Radioscopic Examination of Weld Joints (1) any indication characterized as a crack or zone of incomplete fusion or penetration ;

UW-51 Radiographic and Radioscopic Examination of Weld Joints (1) any indication characterized as a crack or zone of incomplete fusion or penetration ;

UW-51 Radiographic and Radioscopic Examination (2) any other elongated indication on the radiograph which has length greater than: (a) 1/4 in. for t up to 3/4 in. (b)1/3t for t from 3/4 in. to 2-1/4 in. (c) 3/4 in. for t over 2-1/4 in. Where; t = the thickness of the weld excluding any allowable reinforcement.

UW-51 Radiographic and Radioscopic Examination of Weld Joints For a butt weld joining two members having different thicknesses at the weld, t is the thinner of these two thicknesses. Since the value of t must be the lesser thickness this decreases the size of the maximum acceptable indication.

UW-51 Radiographic and Radioscopic Examination of Weld Joints (3) any group of aligned indications that have an aggregate (total) length greater than t in a length of 12t,.. Example: t = 1” total length (L) cannot exceed 1” in 12” Also individual lengths cannot exceed the following: (b)1/3t for t from 3/4 in. to 2-1/4 in. * In this example none of the individual indications can exceed 1/3 x 1” = 1/3” (.333”)

UW-51 Radiographic and Radioscopic Examination of Weld Joints (3) ..except when the distance between the successive imperfections exceeds 6L where L is the length of the longest imperfection in the group; * This means that if the two groups are isolated from each other they can be evaluated separately within a length of 12t.

UW-51 Radiographic and Radioscopic Examination of Weld Joints (4) rounded indications in excess of that specified by the acceptance standards given in Appendix 4. Example from Appendix 4: More on this during the Section V Coverage.

Class Quiz 1. All welded joints to be radiographed shall be examined in accordance with _______of Section _____except as otherwise specified. 2. A complete set of radiographs and records, shall be retained by the Manufacturer until the Manufacturer’s Data Report has been signed by the____________. a. Manufacturer b. Inspector c. Manufacturer and Inspector 3. While reviewing a radiograph an elongated indication was found to have a length of .375” in a .750” thick plate weld. This indication is Rejectable because the maximum allowed is _______ for this thickness.

Solutions UW-51 Radiographic and Radioscopic Examination of Weld Joints 1. All welded joints to be radiographed shall be examined in accordance with Article 2 of Section V except as otherwise specified. 2. A complete set of radiographs and records, shall be retained by the Manufacturer until the Manufacturer’s Data Report has been signed by the Inspector. 3. While reviewing a radiograph an elongated indication was found to have a length of .375” in a .750” thick plate weld. This indication is Rejectable because the maximum allowed is .250” for this thickness.

Class Quiz Radiographic and Radioscopic Examination of Weld Joints 4. The welded joint below was radiographed and found to have an elongated indication that was .243” in length. The maximum allowable length of an indication for this combination of thicknesses is ______ and this weld considered _______________. a. 1/3 t and this weld is considered acceptable. b. 1/4 in. and this weld is considered acceptable. c. 1/4 in. and this weld is considered rejectable.

Class Quiz Radiographic and Radioscopic Examination of Weld Joints 4. The welded joint below was radiographed and found to have an elongated indication that was .243” in length. The maximum allowable length of an indication for this combination of thicknesses is 1/4” and this weld considered acceptable. b. 1/4 in. and this weld is considered acceptable.

Class Quiz Radiographic and Radioscopic Examination of Weld Joints

5. The length L, of the longest imperfection in the figure below is .259”. Based on this value the largest imperfection is _________ and since the aggregate (total) length is .504” that is __________ but the weld is____________. a. acceptable - also acceptable - acceptable b. unacceptable - also unacceptable -rejectable c. unacceptable – acceptable - rejectable

Class Quiz Radiographic and Radioscopic Examination of Weld Joints 5. The length L, of the longest imperfection in the figure below is .259”. Based on this value the largest imperfection is unacceptable and since the aggregate (total) length is .504” that is acceptable but the weld is rejectable. a. acceptable - also acceptable - acceptable b. unacceptable - also unacceptable -rejectable c. unacceptable – acceptable - rejectable

Class Quiz Radiographic and Radioscopic Examination of Weld Joints

6. What is the minimum distance D, between these two groups of aligned imperfections for the groups to be evaluated separately? a. 7.5” b. 1.872” c. .312”

Class Quiz Radiographic and Radioscopic Examination of Weld Joints 6. What is the minimum distance D, between these two groups of aligned imperfections for the groups to be evaluated separately? b. 1.872”

UW-52 Spot Examinations of Weld Joints (b) Minimum Extent of Spot Radiographic Examination (1) One spot shall be examined on each vessel for each 50 ft increment of weld or fraction thereof for which a joint efficiency from column (b) of Table UW-12 is selected. However, for identical vessels, each with less than 50 ft of weld for which a joint efficiency from column (b) of Table UW-12 is selected, 50 ft increments of weld may be represented by one spot examination.

UW-52 Spot Examinations of Weld Joints

(b) Minimum Extent of Spot Radiographic Examination (1) One spot shall be examined on each vessel for each 50 ft increment …….. * The idea of this rule is that each 50’ increment is to be a hold point for approval, the next increment is not to be started until the previous one has been accepted. The drawing below is the simplest case, you will not see this often.

(b) Minimum Extent of Spot Radiographic Examination (1) One spot shall be examined….. However, for identical vessels, each with less than 50 ft of weld for which a joint efficiency from column (b) of Table UW-12 is selected, 50 ft increments of weld may be represented by one spot examination. * This rule addresses smaller, often machine welded vessels such as small air receivers. One is picked at random for spot radiography. If it passes all are approved.

UW-52 Spot Examinations of Weld Joints (2) For each increment of weld to be examined, a sufficient number of spot radiographs shall be taken to examine the welding of each welder or welding operator. Under conditions where two or more welders or welding operators make weld layers in a joint, or on the two sides of a doublewelded butt joint, one spot may represent the work of all welders or welding operators. (3) Each spot examination shall be made as soon as practicable…... The location of the spot shall be chosen by the Inspector,… except that when the Inspector cannot be present or otherwise make the selection, the fabricator may exercise his own judgment in selecting the spots.

UW-52 Spot Examinations of Weld

(2) For an increment of weld to be examined, a sufficient number of spot radiographs shall be taken to examine the welding of each welder or welding operator. ……… * Every welder in a given 50’ increment must have his work radiographed. It can be a individual photo (radiograph) or a group picture. Here welder A was radiographed alone and B & C’s work was examined on the same radiograph.

UW-52 Spot Examinations of Weld Joints (4) Radiographs required at specific locations to satisfy the rules of other paragraphs, such as UW9(d), UW-11(a)(5)(b), and UW-14(b), shall not be used to satisfy the requirements for spot radiography. Note: UW-11(a)(5)(b), will be covered in depth later in this lesson.

UW-52 Spot Examinations of Weld Joints UW-9(d) (d) Except when the longitudinal joints are radiographed 4 in. each side of each circumferential welded intersection, vessels made up of two or more courses shall have the centers of the welded longitudinal joints of adjacent courses staggered or separated by a distance of at least five times the thickness of the thicker plate. * Longitudinal Welds Aligned must be radiographed for at least 4 inches on each side of the joint.

UW-52 Spot Examinations of Weld Joints UW-14(b) Single openings meeting the requirements given in UG-36(c)(3) may be located in head-to-shell or Category B or C butt welded joints, provided the weld meets the radiographic requirements in UW-51 for a length equal to three times the diameter of the opening with the center of the hole at midlength. Defects that are completely removed in cutting the hole shall not be considered in judging the acceptability of the weld. ** UW-51, not 52 to grade film. * UG-36 (c)(3) addresses small opening which do not require reinforcement calculations.

UW-52 Spot Examinations of Weld Joints Summary

The special radiography requirements given in UW-9 (d), UW-11(a)(5)(b) and UW-14 (b) cannot be substituted for any of the spot radiography required by UW-52.

UW-52 Spot Examinations of Weld Joints (c) Standards for Spot Radiographic Examination. Spot examination by radiography shall be made in accordance with the technique prescribed in UW51(a). The minimum length of spot radiograph shall be 6 in. (c)(3) Rounded indications are not a factor in the acceptability of welds that are not required to be fully radiographed.

UW-52 Spot Examinations of Weld Joints (d) Evaluations and Retests When a spot, radiographed as required in (b)(1) or (b)(2) above has been examined and the radiograph discloses welding which does not comply……….The locations shall be determined by the Inspector… if the two additional pass, repair the failed spot, if either of the two additional spots fail the entire rejected weld shall be removed and the joint re-welded or the entire increment completely radiographed and all defects corrected.

UW-52 Spot Examinations of Weld Joints (d) Evaluations and Retests When a spot, radiographed as required in (b)(1) or (b)(2) above has been examined and the radiograph discloses welding which does not comply……..two additional spots shall be examined at locations away from the original spot.

UW-52 Spot Examinations of Weld Joints

(d) Evaluations and Retests

…The locations shall be determined by the Inspector… if the two additional pass, repair the failed spot, ….

UW-52 Spot Examinations of Weld Joints (d) Evaluations and Retests …, if either of the two additional spots fail the entire rejected weld shall be removed and the joint rewelded or the entire increment completely radiographed and all defects corrected.

UW-52 Spot Examinations of Weld Joints (d) Evaluations and Retests …, if either of the two additional spots fail the entire rejected weld shall be removed and the joint rewelded or the entire increment completely radiographed and all defects corrected.

Class Quiz Spot Radiography 1. Minimum number of Spot Radiographs is/are __spot (s), this rule must be applied on each vessel for each _____ ft increment of weld or fraction thereof for which a joint efficiency from column (b) of Table UW12 is selected. 2. Who shall choose the location of Spot Radiographs? a. The manufacturer and the Inspector will agree on the locations. b. The manufacturer or the Inspector depending on the type of welds made. c. The Inspector shall choose unless he is not available and then the Manufacturer may do so.

Class Quiz Spot Radiography

1. Minimum number of Spot Radiographs is one spot, this rule must be applied on each vessel for each 50 ft increment of weld or fraction thereof for which a joint efficiency from column (b) of Table UW-12 is selected. 2. Who shall choose the location of Spot Radiographs? c. The Inspector shall choose unless he is not available and then the Manufacturer may do so.

Class Quiz Spot Radiography

3.

In the drawing below the total number of spot radiographs needed to meet the minimum requirements is/are ____? * Keep in mind the goal is to Radiographically Test every welder’s work in a 50’ increment.

Class Quiz Spot Radiography

3. In the drawing below the total number of spot radiographs needed to meet the minimum requirements are 2. * Keep in mind the goal is to Radiographically Test every welder’s work in a 50’ increment.

Hydrostatic Head of Water 

What is hydrostatic head pressure? Let’s examine the words to better understand the meaning.

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Hydro meaning liquid Static meaning unchanging.

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Pressure is a force exerted over an area.

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Hydrostatic Head of a Water Tower

140’ x 0.433 = 60.6 psig and 100’ x 0.433 = 43.3 psig

Now for a pressure vessel filled with water. No external pressure. 0 psi at top, the bottom is 100 feet x 0.433 = 43.3 psi

External pressure of 100 psi is now applied resulting in a gage pressure at the bottom of 143.3 psi. The 43.3 psi is static, never changing.

1. What would be the pressure at the bottom of this vessel if an external pressure of 235 psi were applied ?

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Case 1: To determine hydrostatic head based on an elevation from a stated problem it must be understood that elevations are normally taken from the ground level to a vessel’s very top. You must subtract the Given elevation from theTotal elevation to determine vertical feet of hydrostatic head above the given elevation. Example: A vessel has an elevation of 18 feet and is mounted on a 3 foot base. What is the hydrostatic head pressure of water at the 11 foot elevation which is located at the bottom of the top shell course?

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Remember it is the number of vertical feet above the given elevation in question which causes the hydrostatic head at that point. To find the hydrostatic head you must subtract the elevation of the Given point from the Total elevation given for the vessel.

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18' feet total -11' desired point 7' total hydrostatic head Hydrostatic head pressure at 11' elevation is: 7 x 0.433psi = 3.03 psi

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Case 2: Hydrostatic head at a point in a vessel must be added to the pressure used (normally vessel MAWP) when calculating the required thickness of the vessel component at that elevation. Example: Determine the required thickness of the shell course in Case 1. The vessel's MAWP (Always measured at the top in the normal operating position) is 100 psi. The following variables apply: Givens: t = ? Circumferential stress from UG-27(c)(1) P = 100 psi + Hydrostatic Head S = 15,000 psi E = 1.0 R = 20"

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Since the bottom of this shell course is at the 11 foot elevation the pressure it will see is 100 psi + the hydrostatic head.  100 + 3.03 = 103.03 psi Also our basic formula becomes;

( P  H . H .) R t SE - 0.6( P  H . H .) 103.03 x 20 20606 t   .1379" (15,000 x1.0)  (0.6 x103.03) 14938.18

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Case 3 You must subtract hydrostatic head pressure when determining the MAWP of a vessel. If given a vessel of multiple parts and the MAWP for each of the parts, the MAWP of the entire vessel is determined by subtracting the hydrostatic head pressure at the bottom of each part to find the part which limits the MAWP of the vessel.

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Example: A vessel has an elevation of 40 feet including a 4 foot base. The engineer has calculated the following part’s MAWP to the bottom of each part based on each part's minimum thickness and corroded diameter. Determine the MAWP of the vessel as measured at the top.

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Calculated Part MAWP at the bottom of:

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Top Shell Course 28' Elev. 406.5 psi Middle Shell Course 16.5' Elev. 410.3 psi Bottom Shell Course 4' Elev. 422.8 psi

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Bottom of top shell course:

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40.0' elev. -28.0' elev. 12.0' of hydrostatic head

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12' x 0.433 psi = 5.196 psi of H.H. We ignored the base height. We are only interested in the distance from the very top to the bottom of the top shell course.

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Bottom of the middle shell course: 40.0' elev. -16.5' elev. 23.5' of hydrostatic head

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23.5' x 0.433 psi = 10.175 psi of Hydrostatic Head

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Here again we ignore the base being interested only in the column of water from the very top to the bottom of the middle shell course.

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Bottom of bottom shell course: 40.0' elev. -4.0' elev. 36.0' of hydrostatic head

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36' x 0.433 psi = 15.588 psi of Hydrostatic Head Finally from the very top to the bottom of the bottom shell course.

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The final step in determining the MAWP of the vessel at its top is to subtract the hydrostatic head of water from each of the calculated Part MAWPs. The lowest pressure will be the maximum gauge pressure permitted at the top of the vessel.

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Bottom of top shell course 406.5 - 5.196 = 401.3 psi Bottom of mid shell course 410.3 - 10.175 = 400.125 psi Bottom of btm. shell course 422.8 - 15.588 = 407.212 psi

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Therefore the bottom of the middle shell course’s MAWP limits the pressure at the top and, determines the MAWP of the vessel.

The MAWP of the vessel is 400.125 psi

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Example: A vertical vessel shell course has an MAWP of 200 psi, and an allowable stress of 14,800 psi. The original inside radius was 84”. The nameplate is stamped RT1 . The shell has corroded down to 1.28 inches. Its original t was 1.375". There exists 21.9964 psi H.H. at the bottom of the shell course. What is its current calculated minimum thickness of this shell course in accordance with rules of Section VIII Division 1 considering both corrosion and hydrostatic head?

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t=

Basic Formula: UG-27 ( c )(1)

PR t= SE - 0.6 P

Modified to consider Hydrostatic Head and increased radius due to internal corrosion. Givens: (P  H.H.) (R  corrosion ) = t t =? SE - 0.6 (P  H.H.) P = 200 S = 14,800 psi E = 1.0 RT 1 R = 84” = 84” + (1.375-1.28) = 84.095” H.H.= 21.9964 rounded to 22 psi

(200  22) (84  .095) (222) (84.095)   (14,800)(1.0) - (0.6) (222) (14,800)(1.0) - (0.6) (200  22) 18669.09 18669.09  1.273"  14,800 - 133.2 14,666.8

Its present thickness is 1.28” and its minimum calculated thickness is 1.273, very close to repair or retire.

Pressure testing requirements are established by: UG-99 Standard Hydrostatic Test UG-100 Pneumatic Test Pneumatic testing may only be performed when the vessels are so designed and/or supported that they cannot be safely filled with water; not readily dried, used in services where traces of the testing liquid cannot be tolerated. A hydrostatic test shall be conducted on all vessels after: (1) All fabrication has been completed, except for cosmetic grinding on the base material which does not affect the required thickness; and (2) All examinations have been performed.

UG-99(b) Standard hydrostatic tests are conducted at a pressure which at every point is at least equal to: 1.3 x MAWP x lowest ratio of Stest / Sdesign permitted stress value for the materials of which the vessel is constructed. Example Applying The Rules of UG-99(b) MAWP = 375PSI @ 800° F

UG-99(c) ■ A hydrostatic test based on calculated Test pressure (3-2) may be used under the following conditions: Highest permissible internal pressure is determined using nominal thickness (including corrosion allowance) of each element of the vessel and using the allowable stress @ test temperature; The hydro test pressure at the top of the vessel shall be the minimum of the calculated test pressures; multiplied by 1.3 and reducing this value by the hydrostatic head ■ these provisions are by agreement between the user and the Manufacturer; ■ the Inspector shall reserve the right to require the Manufacturer or designer to provide calculations used in determining the hydrostatic test pressure of any part of the vessel.

UG-99(d) ■ UG-99(b) are minimum requirements, while UG-99(c) is a

special test based on calculations. Any intermediate value may be used. ■ This Division does not specify an upper limit for hydrostatic test pressure. However, if the hydrostatic test pressure is allowed to exceed, either intentionally or accidentally, the value determined as prescribed in (c) above to the degree that the vessel is subjected to visible permanent distortion, the Inspector shall reserve the right to reject the vessel.

UG-99(g) ■ Following the application of the hydrostatic test pressure, an inspection shall be made of all joints and connections. ■ This inspection shall be made at a pressure not less than the test pressure divided by 1.3.

■ Except for leakage at temporary test closures for those

openings intended for welded connections, leakage is not allowed. ■ Leakage from temporary seals shall be directed away so as to avoid masking leaks from other joints.

UG-99(h) ■ It is recommended that the metal temperature during the

hydrostatic test be maintained at least 30° F (17° C) above the minimum design metal temperature, but need not exceed 120° F (48° C), to minimize the risk of brittle fracture. ■ The test pressure shall not be applied until the vessel and it's contents are at about the same temperature.

CAUTION: a small liquid relief valve set to 1.3 times the test pressure is recommended for the pressure test system, in case a vessel, while under test, is likely to be warmed up materially with personnel absent.

UG-99(i) ■ Vents shall be provided at all high points of the vessel in the test position to purge possible air pockets while the vessel is filling.

UG-99( j) ■ Before applying pressure, the test equipment shall be examined to see that it is tight and that all low pressure filling lines and other appurtenances that should not be subject to the test pressure have been disconnected.

UG-99(k) ■ Vessels, except for those in lethal service [(UW-2(a)], may be painted or otherwise coated either internally or externally, and may be lined internally, prior to the pressure test. ■ The user is cautioned that such painting or coating may mask leaks that would otherwise have been detected during the pressure test.

Class Quiz Problem: Calculate the required hydro test pressure for a vessel using the following conditions: Material Carbon Steel Design Temp. 700 °F Test Temp 85 °F MAWP 350 psi Step 1 Determine the ratio of stresses for the test and design temperatures. (a) From Table 1A Section II Part D. Stress allowed at 700 °F = 15,500 psi Stress allowed at 85 °F = 16,300 psi

UG-99 Standard Hydrostatic (b) Per UG‐99 the ratio equals Stress at Test Temp. Stress at Design Temp.

16,300  1.05 15,500

(c) Per UG‐99 the ratio equals Step 2 UG‐99(b) Test pressure equals 1.3 x MAWP x ratio

1.3 x 350 psi x 1.05 = 477.75 psi at the top of the vessel.

UW-50 NDE of Welds for Pneumatically Tested Vessels Look at the reference next to UG‐100 (See UW‐50) This is what is referred to as a parenthetical reference in the ASME Codes. You must read these to see what modifiers the Code has placed on subject paragraph. On welded pressure vessels to be pneumatically tested in accordance with UG‐100, the full length of the following welds shall be examined for the purpose of detecting cracks: (a) all welds around openings; (b) all attachment welds, including welds attaching nonpressure parts to pressure parts, having a throat thickness greater than 1/4 in….

UG-100, Pneumatic test Subject to the provisions of UG-99(a)(1) and (a)(2), a pneumatic test prescribed in this paragraph may be used in lieu of the standard hydrostatic test prescribed in UG-99 for vessels: that are so designed and/or supported that they cannot safely be filled with water; not readily dried, that are to be used in services where traces of the testing liquid cannot be tolerated and the parts of which have, where possible, been previously tested by hydrostatic pressure to the pressure required in UG-99.

Except for enameled vessels, the pneumatic test pressure shall be at least equal to: 1.1 x MAWP x lowest ratio of Stest/ Sdesign S = permitted stress value for the materials of which the vessel is constructed. In no case shall the pneumatic test pressure exceed 1.1 times the basis for calculated test pressure (3-2).

The metal temperature during the pneumatic test shall be maintained at least 30 ° F (17° C) above the MDMT to minimize the risk of brittle fracture.

The pressure in the vessel shall be gradually increased: to not more than one-half of the test pressure; thereafter, the test pressure shall be increased in steps of approximately 1/10 of the test pressure until the required pressure is reached. After the test pressure is reached, the pressure shall be reduced to the value equal to the test pressure divided by 1.1 and held for a sufficient time to permit inspection of the vessel

An indicating gage shall be connected directly to the vessel. If the indicating gage is not readily visible to the operator controlling the pressure, an additional gage shall be provided where it is visible to the operator.

Dial indicating pressure gauges shall be graduated over a range of about double the intended maximum test pressure, but in no case shall the range be the test pressure. less than 1 1/2 times, nor more than 4 times the test pressure.

Digital reading pressure gages having a wider range of pressure may be used provided the readings give the same degree of accuracy as obtained with dial pressure gages.

All gages shall be calibrated against a: - standard dead weight tester, or - calibrated master gage. Gages shall be calibrated any time there is reason to believe they are in error.

UG-100 Calculating Pneumatic Test Pressure Problem: Calculate the required pneumatic test pressure for a vessel using the following conditions. Material Carbon Steel Design Temp. 700 o F Test Temp 85 o F MAWP 350 psi Step 1: Determine the ratio of stresses for the test and design temperatures. (a) From Table 1A Section II Part D. Stress allowed at 700 o F= 15,500 psi Stress allowed at 85 o F= 16,300 psi

UG-100 Calculating Pneumatic Test Pressure (b) Per UG-100 the ratio equals Stress at TestTemp. Stress at Design Temp

16,300  1.05 15,500

Step 2 Per UG-100(b) Test pressure equals 1.1 x MAWP x

Stress at Test Temp. Stress at Design Temp.

1.1 x 350 psi x 1.05 = 404.25 psi

Pneumatic Test Procedure 1. Slowly raise the pressure to approximately one-half 404.25 psi which equals 202.125. Next raise the pressure in steps of one-tenth of the test pressure. 2. 202.125 + 40.425 = 242.55 psi 3. 242.55 + 40.425= 282.975 psi 4. 282.975 + 40.425 = 323.40 psi 5. 323.40 + 40.425 = 363.825 psi 6. 363.825 + 40.425 = 404.25 psi There are a total of 6 steps when raising up to pneumatic test pressure. Finally lower to the inspection pressure of 404.25/1.1 = 367.5 psi

Class Quizzes UG-99/UG-100/102 1. A vessel made of Stainless Steel is being hydrostatically tested after an alteration. The vessel's MAWP is 225 psi at 400 o F. The allowable stress at operating is 14,700 psi and 16,700 psi at the test temperature. Answer the following: a. What is the required test pressure? b. What is the least pressure for the inspection? c. In psi, what is the min. and max. range of the test gage?

Class Quizzes UG-99/UG-100/102 2. A pneumatic test of a vessel will be conducted to a pressure of 310 psi. Describe the steps for raising the vessel to the test pressure. At what pressure shall the visual examination take place?

Solutions 1. Hydrostatic Test a.

b.

1.3 x 225 x

16,700  332.295 psi 14,700

332 . 295  255 . 61 psi 1 .3

c. Min. gage range 1.5 x 332.295 =

498.4 ( 500 psi ) Max. gage range 4 x 332.295 = 1329.18 ( 1000 psi ) the gage pressure at the 4X range would be rounded down to closest standard range!

Solutions 2. Pneumatic Test Step 1 Raise the pressure to ½ the test pressure, ½ x 310 psi = 155 psi, then raise in steps of 1/10 to full test pressure. Step 2 155+31=186 psi Step 3 186+31=217 psi Step 4 217+31=248 psi Step 5 248+31=279 psi Step 6 279+31=310 psi The inspection pressure is 310/1.1 = 281.8 psi for visual inspection.