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BS EN ISO 1 61 48:201 6

BSI Standards Publication

Gas cylinders — Refillable seamless steel gas cylinders and tubes — Acoustic emission examination (AT) and followup ultrasonic examination (UT) for periodic inspection and testing (ISO 1 61 48:201 6)

BS EN ISO 1 61 48:201 6

BRITISH STANDARD National foreword This British Standard is the UK implementation of EN ISO 1 61 48:201 6. It supersedes BS EN ISO 1 61 48:2006 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee PVE/3/7, Gas containers - Gas cylinder (receptacle) operations. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. © The British Standards Institution 201 6. Published by BSI Standards Limited 201 6 ISBN 978 0 580 75620 7 ICS 23.020.30

Compliance with a British Standard cannot confer immunity from legal obligations. This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 May 201 6.

Amendments issued since publication Date

Text affected

EN ISO 16148

EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM

April 2016

ICS 23.020.30

Supersedes EN ISO 16148:2006

English Version

Gas cylinders - Refillable seamless steel gas cylinders and tubes - Acoustic emission examination (AT) and follow-up ultrasonic examination (UT) for periodic inspection and testing (ISO 16148:2016) Bouteilles à gaz - Bouteilles à gaz rechargeables en acier sans soudure et tubes - Essais d'émission acoustique et examen ultrasonique complémentaire pour l'inspection périodique et l'essai (ISO 16148:2016)

Gasflaschen - Wiederbefüllbare nahtlose Gasflaschen und Großflaschen aus Stahl - Schallemissionsprüfung und nachfolgende Ultraschallprüfung für die wiederkehrende Inspektion und Prüfung (ISO 16148:2016)

This European Standard was approved by CEN on 28 November 2015. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION C O M I TÉ E URO PÉ E N D E N O RM ALI S ATI O N E URO PÄI S C H E S KO M I T E E FÜR N O RM UN G

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels © 2016 CEN

All rights of exploitation in any form and by any means reserved worldwide for CEN national Members.

Ref. No. EN ISO 16148:2016 E

BS EN ISO 1 61 48:201 6

EN ISO 16148:2016 (E)

European foreword This document (EN ISO 16148:2016) has been prepared by Technical Committee ISO/TC 58 “Gas cylinders” in collaboration with Technical Committee CEN/TC 23 “Transportable gas cylinders” the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 2016, and conflicting national standards shall be withdrawn at the latest by October 2016. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. This document supersedes EN ISO 16148:2006. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice

The text of ISO 16148:2016 has been approved by CEN as EN ISO 16148:2016 without any modification.

3

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

Contents Foreword

Page

........................................................................................................................................................................................................................................

Introduction

iv

..................................................................................................................................................................................................................................

v

1

Scope

2

Normative references . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1

3

Terms and de finitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1

4

Operational principles

3

5

Personnel quali fication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3

6

Special considerations to ensure valid tests

4

.................................................................................................................................................................................................................................

...................................................................................................................................................................................

............................................................................................................................

1

6.1

G e n e ral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

6.2

Aco u s ti c e m i s s i o n exam i n ati o n m e th o d s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

6.3

P re s s u ri z ati o n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

6.4

Safety precautions

................................................................................................................................................................................

5

7

Acoustic emission examination equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

8

Acoustic emission examination calibration and equipment veri fication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

8.1

C al i b rati o n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

8.2

Equipment veri fication

....................................................................................................................................................................

7

7

9

Overall procedure

10

Real-time evaluation criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8

11

AT test report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9

12

Follow-up ultrasonic examination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Annex A

(n o rm ative )

................................................................................................................................................................................................

Ultrasonic examination (UT) follow-up to acoustic emission

examination (AT)

..............................................................................................................................................................................................

Annex B

(n o rm ative )

AT equipment speci fications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Annex C

(n o rm ative )

Example instrument settings, examination methods and rej ection

criteria for MAE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Annex D

(i n fo rm ative )

Alternative method for source location

...........................................................................................

10 11 17 19 22

Distance amplitude correction procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24

Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

27

Annex E

(i n fo rm ative )

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

iii

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

Foreword I S O (the I n te r n atio n a l O r ga n i z atio n fo r S ta nd a rd i z atio n) i s a wo rl d w ide fe de r atio n o f n ati o n a l s t a n d a rd s

bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical c o m m i t te e

has

o r ga n i z atio n s ,

b e en

e s tab l i s he d

go ve r n me n ta l

has

a nd

the

r i gh t

to

be

no n- go ve r n me n ta l ,

re p re s e n te d

in

liaison

on

w i th

th at

I S O,

c o m m i t te e .

also

ta ke

I nte r n atio n a l

part

in

the

wo rk.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of e l e c tro te c h n i c a l s ta n d a rd i z ati o n .

T he

p ro c e du re s

used

to

de ve l o p

de s c r i b e d i n the I S O/ I E C

th i s

D i re c ti ve s ,

do c u m e nt

Part 1 .

a nd

tho s e

i nte n de d

fo r

i ts

fu r the r

m a i n te n a nc e

a re

I n p a r tic u l a r the d i ffe re n t ap p ro va l c r i te r i a ne e de d fo r the

different types of ISO documents should be noted. This document was drafted in accordance with the e d i to r i a l r u l e s o f the I S O/ I E C D i re c ti ve s , P a r t 2

(s e e w w w. i s o . o r g/d i re c ti ve s) .

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identi fied during the development of the document will be in the Introduction and/or o n the I S O l i s t o f p ate n t de c l a ratio n s re c e i ve d (s e e w w w. i s o . o r g/p ate n ts) .

Any trade name used in this document is information given for the convenience of users and does not c o n s ti tu te a n e ndo r s e me n t.

For an explanation on the meaning of ISO speci fic terms and expressions related to conformity a s s e s s me n t,

as

we l l

as

B a r r ie r s to Trade ( T B T )

T he

c o m m i t te e

i n fo r m atio n

ab o u t

I S O ’s

s e e the fo l l o w i n g U R L :

re s p o n s ib l e

fo r

th i s

do c u me n t

Operational requirements for gas cylinders

ad he re nc e

to

the

WTO

p r i nc ip l e s

in

the

Te c h n ic a l

Foreword - Supplementary information is

I S O/ T C

58,

Gas cylinders

,

S u b c o m m i t te e

SC

4,

.

This second edition cancels and replaces the first edition (ISO 16148:2006), which has been technically re v i s e d . T he c h a n ge s i nc l ude

a) b)

expansion of the scope to include tubes of water capacity up to 3 000 l used for compressed and lique fied gases, and add i tio n

o f p ro c e du re s

fo r

u l tr a s o n ic

e x a m i n atio n

(U T )

fo l l o w- up

du r i n g

p e r io d ic

i n s p e c ti o n ,

as

de s c r ib e d i n the ne w A n ne x A .

iv

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

Introduction I n re c e n t ye a r s , ne w no n- de s tr uc ti ve e x a m i n ati o n ( N D E ) as

an

a l te r n ati ve

to

the

c o nve n tio n a l

te s ti n g p ro c e du re s

te c h n i que s h ave b e e n s uc c e s s fu l l y i ntro duc e d o f ga s

c yl i n de r s ,

tu b e s

a nd

o the r c yl i n de r s

at

the ti m e o f p e r io d i c i n s p e c tio n a nd te s ti n g.

O ne

o f the

wh ic h

has

a l te r n ati ve p ro ve d

to

N DE

be

an

me tho d s

fo r

ac c e p tab l e

c e r ta i n

te s t

ap p l i c ati o n s

m e tho d

ap p l i e d

is

ac o u s tic

du r i n g

em i s s ion

p e r io d i c

e x a m i n atio n

i n s p e c ti o n

a nd

(AT ) ,

te s ti n g

in

s o me c o u ntr ie s .

T he te s t me tho d re qu i re s p re s s u r i z ati o n to a l e ve l g re ate r th a n the no r m a l

fi l l i n g

p re s s u re .

T he p re s s u r i z ati o n me d iu m c a n b e e i the r ga s o r l iqu i d .

Ac o u s tic

e m i s s io n

me tho d s

a re

(A E )

ne e de d

to

me a s u re m e nt s e va lu ate

the

a re

s ign i

used

fi c a nc e

to

de te c t

of AE

a nd

l o c ate

de te c te d

e m i s s io n

s o u rc e s .

O ne

s o u rc e s .

o f the

O the r

N DE

a l te r n ati ve

N DE

me tho d s u s e d a s a fo l l o w- up to AT i s u l tra s o n i c e x a m i n atio n ( U T ) , wh ic h h a s p ro ve d to b e a n ac c e p tab l e te s ti n g

me tho d

ap p l ie d

du r i n g

p e r io d ic

i n s p e c tio n

a nd

te s ti n g.

T he

purpose

of

th i s

I n te r n atio n a l

S t a n d a rd i s to p ro v i de a p ro c e du re fo r l o c ati n g , de te c ti n g a nd e va l u ati n g the re l e va nc e o f A E i nd i c atio n s s uc h a s

tho s e fro m l o n g i tud i n a l l y o r ie n te d c rac k- l i ke d i s c o n ti nu i ti e s .

T he s he a r wave

me tho d i s i n te nde d to b e u s e d i m me d i ate l y fo l l o w i n g AT to e va l u ate the s i g n i

This

I n te r n atio n a l

S ta n d a rd

de s c r ib e s

t wo

me tho d s

o f AT,

de

fi ne d

as

fic a nc e

M e tho d

A

(a n gl e

b e a m)

UT

o f A E i nd i c ati o n s .

a nd

M e tho d

B,

a nd

a

me tho d o f fo l l o w- up U T.

Wi th

the

a g re e me n t

of

the

te s ti n g

a nd

c e r ti fy i n g

b o dy

ap p ro ve d

by

the

c o mp e te n t

au tho r i t y

of

the

c o u n tr y o f ap p ro va l , the hyd rau l ic p re s s u re te s t o f c yl i n de r s a n d tu b e s c a n b e re p l ac e d b y a n e qu i va l e nt AT/ U T M e tho d A o r B .

T h i s I n te r n atio n a l S ta nd a rd i s i n te nde d to b e u s e d u n de r a va r i e t y o f n ati o n a l re g u l ato r y re g i me s , b u t h a s b e e n w r i t te n s o th at i t i s s u i tab l e fo r the ap p l ic atio n o f Re fe re nc e . in

the

speci

i n te n de d to

fi e d

re l e va n t

n atio n a l

re g u l atio n s

of

the

c o u ntr y

b e u s e d th at m i ght o ve r r ide the re qu i re me n ts

the re i s a ny c o n

fl ic t

[1 ]

At te n tio n i s d raw n to re qu i re me n ts

(c o u n tr ie s)

g i ve n i n th i s

whe re

the

c yl i n de r s

I nte r n atio n a l S t a n d a rd .

a re

W he re

b e t we e n th i s I n te r n atio n a l S ta nd a rd a nd a ny ap p l ic ab l e re g u l atio n , the re g u l atio n

a l ways t a ke s p re c e de nc e .

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

v

BS EN ISO 1 61 48:201 6

BS EN ISO 1 61 48:201 6 INTERNATIONAL STANDARD

ISO 1 61 48: 2 01 6(E)

Gas cylinders — Re fillable seamless steel gas cylinders and tubes — Acoustic emission examination (AT) and followup ultrasonic examination (UT) for periodic inspection

and testing 1 Scope

This International Standard gives procedures for the use of acoustic emission examination (AT) and ultrasonic examination (UT) follow-up during the periodic inspection and testing of seamless steel cylinders and tubes with a water capacity of up to 3 000 l used for compressed and lique fied gases. This examination provides acoustic emission (AE) indications and locations that are evaluated by a secondary examination using UT for a possible flaw in the cylinder or tube. Methods other than UT for the secondary examination are not covered by this International Standard. This International Standard does not cover composite cylinders. C AUTION — Some of the tests speci fied in this International Standard involve the use of processes which could lead to a hazardous situation.

2

Normative references

The following documents, in whole or in part, are normatively referenced in this document and are indispensable for is application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 5577, Non-destructive testing — Ultrasonic inspection — Vocabulary ISO 6406, Gas cylinders — Seamless steel gas cylinders — Periodic inspection and testing ISO 9712, Non-destructive testing — Qualification and certification o f NDT personnel ISO 12716, Non-destructive testing — Acoustic emission inspection — Vocabulary ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories EN 13477-1, Non-destructive testing — Acoustic emission — Equipment characterisation — Part 1: Equipment description EN 13477-2, Non-destructive testing — Acoustic emission — Equipment characterisation — Part 2:

Verification of operating characteristic

ASTM E1419, Standard Practice for Examination of Seamless, Gas-Filled, Pressure Vessels using Acoustic

Emission

Recommended Practice for Personnel Qualification and Certification in Nondestructive Testing ASNT SNT-TC-1 A,

3

Terms and de finitions

For the purposes of this document, the terms and de finitions given in ISO 5577, ISO 12716 and the following apply.

© ISO 2016 – All rights reserved

1

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

3 .1 critical

flaw

i mp e r fe c tio n

or

d a m a ge

th at

is

l a rge

e no u gh

to

e xh ibit

u n s t ab l e

c rac k

g ro w th

u nde r

cer ta i n

s e r v ic e

c o nd i tio n s

3.2

working pressure settled pressure of a compressed gas at a uniform reference temperature of 15 °C in a full gas cylinder Note 1 to entry: In North America service pressure is often used to indicate a similar condition, usually at 21,1 °C ( 70 ° F ) .

Note 2 to entry: In East Asia, service pressure is often used to indicate a similar condition, usually at 35 °C.

[SOURCE: ISO 10286:2015, de finition 736] 3.3 normal

filling pressure

level to which a cylinder or tube is pressurized during filling Note 1 to entry: This is usually greater than the marked working pressure due to the heat of compression. 3 .4 acoustic emission test pressure AT pressure m a x i mu m p re s s u re at wh ic h ac o u s tic e m i s s i o n te s ti n g i s p e r fo r me d

3.5 acoustic emission pressure test range r a n ge o f p re s s u re du r i n g wh ic h ac o u s ti c e m i s s io n i s mo n i to re d

3 .6 Method A ac o u s tic

filling

e m i s s io n

te s ti n g

p e r fo r me d

us ing

p ne u m atic

p re s s u r i z atio n

to

at

le a s t

110

%

o f the

no r m a l

pressure

Note 1 to entry: Normally performed on an assembly of cylinders (e.g. bundle) or tubes (e.g. tube trailer). 3 .7 Method B

acoustic emission testing performed during the hydrostatic proof pressurization to the re-test pressure on each cylinder or tube 3.8 secondary AE sources

emissions not generated by actual crack propagation and plastic deformation Note 1 to entry: Contact between the surfaces of a discontinuity as the cylinder expands, fracture or rubbing of mill scale within a discontinuity as the cylinder expands are examples of secondary AE sources. 3 .9 calibration ring

section cut from similar cylinder material used for the calibration of the follow-up UT 3 .10 distance amplitude correction curve DAC curve c u r ve

ge ne r ate d

du r i n g

the

s ta n d a rd i z ati o n

p ro c e s s

th at

ac c o u n ts

fo r

the

lo s s

of

a mp l i tude

of

the

re tu r n i n g s i g n a l a s a re s u l t o f s i g n a l trave l d i s t a nc e

2

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

3 .11 shear wave ultrasonic search unit b lo ck

of

m ate r i a l

th at

c o n fo r m s

to

the

c u r vatu re

of

the

s u r fac e

of

the

te s t

obj ec t

a nd

o r ie n ts

the

u l tra s o n ic tr a n s duc e r at a n a n gl e wh i c h tr a n s m i ts a n d re c e i ve s s he a r wave s

3 .1 2

ultrasonic couplant f l u id

me d iu m th at fo r m s a th i n , b ub b l e - fre e l aye r b e t we e n the s e a rc h u n i t a n d the te s t o b j e c t

3 .13

skip distance i n a n gl e b e a m (s he a r wave)

e x a m i n ati o n , d i s ta nc e a l o n g the te s t s u r fac e fro m the s o u nd e n tr y p o i n t to

the p o i n t at wh i c h the s o u n d re tu r n s to the s a me s u r fac e

N o te 1 to e n tr y: I t c a n b e c o n s i de r e d th e to p s u r fac e d i s t a nc e o f a c o mp l e te wave p ath o f s o u n d i n th e te s t m ate r i a l .

3 .14 modal acoustic emission M AE b ra nc h

of

AE

(ac o u s tic

e m i s s io n)

fo c u s e d

on

the

de te c tio n

a nd

a n a l ys i s

of

the

ac tu a l

s o u nd

wave s

p ro duc e d at frac tu re s i te s fro m c rac k g ro w th s o r s u r fac e r u b b i n g

4 Operational principles W he n c yl i nde r s o r tub e s c o n ta i n i n g d i s c o n ti nu i tie s a re p re s s u r i z e d , s o u n d wave s (A E ) c a n b e p ro duc e d b y s e ve ra l d i ffe re nt s o u rc e s (e . g. s e c o nd a r y s o u rc e s o r ac tu a l p ro p a gatio n o f c rac ks) . T he s e s o u rc e s c a n p ro duc e

AE

i nd i c ati o n s

at p re s s u re s

le s s

th a n ,

e qu a l

to

or

g re ate r

th a n

wo rki n g

p re s s u re .

T he

s o u nd

wave s trave l th ro u gho u t the s tr uc t u re .

P ie z o e l e c tr ic c o n ne c te d

to

s en s ors a

s ignal

mo u n te d

on

p ro c e s s o r,

a

c yl i nde r

wh i c h

re c o rd s

or

tub e

the

s u r fac e

s ignal

re s p o nd

p a ra me te r s

to

s o u nd

a s s o c i ate d

wave s .

w i th

the

T he y

a re

p a s s a ge

of

the wave s u nde r the s e n s o r. S o u nd wave s trave l at a s s u me d c o n s ta nt s p e e d s . Wi th at l e a s t t wo s e n s o r s , o ne

mo u n te d

at

e ac h

e nd

of a

c yl i nde r

or

tu b e ,

the

ap p ro x i m ate

l o c ati o n

o f e ve nt

s o u rc e s

is

de r i ve d

fro m the m e a s u re d a r r i va l ti me o f s o u nd wave s at the s e n s o r s .

If

me a s u re d

s uc h

e m i s s io n s

l o c ati o n s

d i s c o n ti nu i ti e s d i s c o n ti nu i t y

shall a nd

e xc e e d

u nde rgo to

a

the

s peci

s e cond a r y

me a s u re

the i r

the

fi e d

e xc e e d s

s p eci

fie d

l e ve l s

i n s p e c ti o n

d i me n s io n s .

li mit

(th at

o ve r (e . g.

F ro m

is,

a

a by

th i s

l im it

l i ne a r UT)

d i s t a nc e

in

o rde r

s e cond a r y

based

on

a

to

on

i n s p e c ti o n ,

nu m b e r

the

ve r i fy

of

c yl i n de r,

the

i f the

fac to r s ,

the n

p re s e nc e de p th i.e.

of

o f the

c yl i n de r

m ate r i a l , wa l l th ic kne s s , fati g ue c rac k g ro w th rate e s ti m ate s , frac tu re c r i tic a l s i z e c a l c u l atio n s a n d a ny p rac tic a l e x p e r i e nc e) , the n the c yl i nde r s h a l l b e re mo ve d fro m s e r v ic e .

I f,

a fte r

the

e xa m i n ati o n ,

a

re c a l i b ratio n

o f the

AT

e qu ip me n t

s h a l l b e re - e x a m i ne d b y a no n- de s tr uc ti ve e x a m i n atio n ( N D E )

5

p ro ve s

ne gati ve ,

the

re l e va nt

c yl i n de r

me tho d o the r th a n AT M e tho d A .

Personnel quali fication

T he AT a nd U T e qu ip me n t s h a l l b e o p e rate d , a n d i ts o p e ratio n s up e r v i s e d , b y c o mp e te n t p e r s o n ne l who me e t the re qu i re me nt s

of I S O

9 71 2

o r a n e qu i va l e n t s ta n d a rd (e . g. , A S N T S N T T C

1 A)

a s au tho r i z e d b y

the L e ve l I I I o p e rato r. T he o p e rato r s h a l l me e t the re qu i re m e nt s fo r L e ve l I a n d s h a l l b e s up e r v i s e d b y a L e ve l I I p e r s o n . T he te s ti n g o rga n i z atio n s h a l l re t a i n a L e ve l I I I o p e r ato r (c o mp a ny e mp l o ye e o r a th i rd p a r t y)

to o ve r s e e the e n ti re AT a nd U T p ro g ra m me .

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

3

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

6 Special considerations to ensure valid tests 6.1

General

In order to prevent invalid AT when using Method A and to overcome the Kaiser effect, the AT pressure shall exceed that pressure previously exerted on the cylinder or tube during service, i.e. normal filling p re s s u re fo r c o mp re s s e d ga s e s , a n d the de ve l o p e d p re s s u re at the m a x i mu m s e r v i c e te mp e ratu re (e . g.

65 °C) for lique fied gases. NOTE 1

The Kaiser effect is characterized by the absence of AE until the previous maximum applied load level

h a s b e e n e xc e e de d .

If the pressure of the cylinder or tube exceeds 110 % of its normal filling pressure, e.g. exposure to high a m b i e n t te mp e ratu re s , i t s h a l l b e re c o rde d [s e e N O T E to C l au s e 1 1 d ) ] .

After pressurization to more than the AT pressure, Method A shall not be performed within a time period of less than one year or before a sufficient number of pressurization cycles have occurred, since such practice can decrease the sensitivity of the examination. NOTE 2 The number of pressurization cycles is related to the design parameters, particularly the material composition, of the cylinder or tube undergoing periodic inspection and testing. This number of pressurization cycles at the working pressure of the cylinder or tube is typically between 75 and 100.

If a pressure greater than the normal filling pressure has been applied and a time period equal to or greater than one year or a sufficient number of pressurization cycles has not elapsed, then the AT shall be 10 % above this excessive pressure, but shall not exceed the design test pressure (TP) of the cylinder or tube. If at any stage a receptacle for lique fied gases has been over filled, this shall be reported to the re-tester by the cylinder or tube owner or operator. If the AT would result in a pressure greater than TP, then Method A shall not be applied. Only Method B or a hydrostatic proof pressure test shall be p e r fo r me d .

WARNING — Take appropriate measures to ensure safe operation and to contain any energy that could be released during pressure testing. It should be noted that pneumatic pressure tests require more precautions than hydrostatic proof pressure tests since, regardless of the size of the container, any error in carrying out this test is highly likely to lead to a rupture under gas pressure. Therefore, these tests should be carried out only after ensuring that the safety measures satisfy the safety requirements.

6.2

Acoustic emission examination methods

One of the two AT methods (A or B) may be used during periodic inspection and testing of seamless steel cylinders in accordance with this International Standard. In both methods, UT follow-up of the AE i n d ic atio n s s h a l l b e i n ac c o rd a nc e w i th the ap p l i c ab l e te s t me tho d de s c r i b e d i n A n ne x A .

Once a method (A or B) has been selected, its result shall be final. 6.3

Pressurization

General practice in the gas industry is to use low pressurization rates. This practice promotes safety a nd

re duc e s

e qu ip me n t i nve s tme n t.

AT

s ho u l d

be

p e r fo r me d

w i th

p re s s u r i z ati o n

rate s

l o w e no u gh

to

allow cylinder deformation to be in equilibrium with the applied load. Pressurization should proceed at rates that do not produce noise from the pressurizing medium. For Method A, typical current practice is to use pressurization rates that approximate 35 bar/h (3,5 MPa/h) 1)

NOTE all

fo r tub e s .

For smaller cylinders a higher pressurization rate can be suitable provided it is demonstrated that

de tr i m e n ta l

d e fe c t s

can

be

de te c te d

a nd

th e

p r e s s u r i z ati o n

r a te

is

s lo w

e n o u gh

to

a l lo w

th e

p r e s s u r i z a ti o n

to be stopped before bursting of the cylinder. Pressure holds are not necessary; however, they can be useful for r e a s o n s o th e r th a n m e a s u r e m e n t o f A E .

1)

4

1 bar = 0,1 MPa = 0,1 N/mm

2

= 10

5

N /m

2

.

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

S e c o nd a r y

AE

s o u rc e s

can

p ro duc e

e m i s s io n s

th ro u gho u t

p re s s u r i z atio n .

fi l l i n g

p ro duc e s e m i s s io n s at p re s s u re s h i ghe r th a n the no r m a l

W he n p re s s u re w i th i n a ve s s e l i s l o w a nd ga s i s the p re s s u r i z i n g m e d iu m , h i gh .

F l o w i n g ga s

(tu rb u l e nc e)

can

p ro duc e

me a s u rab l e

C rac k

g ro w th

no r m a l l y

p re s s u re .

em i s s ion s .

flo w

ve l o c i tie s a re re l ati ve l y

C o n s i de r i n g th i s ,

ac qu i s i ti o n

of AE

d ata s h a l l c o m me nc e at s o me p re s s u re g re ate r th a n the s ta r ti n g p re s s u re (fo r e x a mp l e , o ne - h a l f o f the AT p re s s u re) .

S e c o nd a r y

s o u rc e s

p re s s u r i z e d , p re s s u re

in

f l aws

th at i s

s e r io u s

can

f l aws

p ro duc e

at l e a s t

10

%

g re ate r

fro m s e c o nd a r y s o u rc e s i n

f l aws

E xc e s s

can

b ac kg ro u nd

no i s e

can

p ro duc e

e m i s s io n s th a n

a nd fro m

d i s to r t

AE

at

mo re

p re s s u re s

no r m a l

f l aw

fi l l i n g

AE

th a n

le s s

f l aw

th a n

p re s s u re

g ro w th .

no r m a l

a l l o ws

W he n

fi l l i n g

c yl i n de r s

p re s s u re .

m e a s u re me nt

a re

An

AT

o f e m i s s io n s

g ro w th .

d ata

or

re n de r

the m

u s ele s s .

Us ers

shall

be

awa re

of

the

fo l l o w i n g c o m mo n s o u rc e s o f b ac kg ro u n d no i s e :

fi l l

rate (me a s u rab l e

flo w

—

h i gh ga s

no i s e) ;

—

me c h a n ic a l c o n tac t w i th the ve s s e l b y o b j e c ts ;

—

e l e c tro m a g ne tic i nte r fe re nc e a n d r ad io fre que nc y i nte r fe re nc e fro m ne a rb y b ro adc a s ti n g fac i l i tie s a nd fro m o the r s o u rc e s ;

—

l e a ks at p ip e o r ho s e c o n ne c tio n s ;

—

a i rb o r ne s a n d p a r tic l e s , i n s e c t s , ra i n d ro p s o r s no w, e tc .

fic ie n tl y

A n AT s h a l l no t b e u s e d i f b ac kg ro u n d no i s e c a n no t b e e l i m i n ate d o r s u f

6.4

c o ntro l l e d .

Safety precautions

W he n

p e r fo r m i n g

the

AT

(e s p e c i a l l y

p ne u m atic a l l y) ,

s a fe t y

p re c au ti o n s

shall

be

ta ke n

to

p ro te c t

p e r s o n ne l c a r r y i n g o u t the e x a m i n ati o n b e c au s e o f the c o n s ide rab l e d a m a ge p o te n ti a l fro m the s to re d e ne rg y th at c a n b e re l e a s e d . be

t a ke n

whe n

f l a m m ab l e

the

Add i tio n a l l y,

p re s s u r i z atio n

s i nc e AT e qu i p me n t i s

me d iu m

is

f l a m m ab l e

a

ga s

no t e x p l o s i o n- p ro o f, due

to

the

p re c au tio n s

p o s s ibi l ity

of a

shall

l e a ka ge

of

ga s .

I t i s e s s e nti a l th at go o d , i n s ta n ta ne o u s c o m mu n ic atio n e x i s t du r i n g m a nu a l te s t o p e r ati o n b e t we e n the AT o p e rato r a nd the p re s s u r i z ati o n o p e rato r s o

p re s s u r i z atio n c a n b e p au s e d o r the p re s s u re re duc e d

i f ne c e s s a r y. D u r i n g au to m ate d te s t o p e ratio n s , th i s s h a l l b e e n s u re d b y the au to m ate d te s t e qu ip me n t.

7

Acoustic emission examination equipment

Ty p i c a l fe atu re s o f the e qu ip m e n t re qu i re d fo r b o th M e tho d A a n d B o f AT a re p ro v i de d i n F i g u re 1 . F u l l speci

fi c atio n s

a re de s c r ib e d i n A n ne x B .

M o d a l ac o u s ti c e m i s s io n ( M A E ) c a n b e u s e d fo r the p e r i o d ic i n s p e c tio n a nd te s ti n g o f re s te e l

ga s

c yl i nde r s

a nd

tu b e s

in

b o th

M e tho d

A

a nd

M e tho d

B.

T he

c o r re s p o nd i n g

fi l l ab l e

speci

s e a m le s s

fi c ati o n s

fo r

M A E a re p ro v ide d i n A n ne x C .

A n o p ti o n a l ap p ro ac h fo r s o u rc e l o c atio n whe n M e tho d A o r B i s u s e d i s s p e c i

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

fie d

i n A n ne x D .

5

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

Key 1

p re s s u re tran s d u ce r

2

aco u s ti c e m i s s i o n s e n s o rs wi th i n te gral p re am p l i

3

tu b e wi th s e n s o rs m o u n te d o n s i d e wal l

4

tu b e wi th s e n s o rs m o u n te d o n e n d

5

p ri n te r

6

vi d e o m o n i to r

7

co m p u te r

8

aco u s ti c e m i s s i o n s i gn al p ro ce s s o r

fi e r

(two fo r e ach tu b e )

fl an ge s

Figure 1 — Essential features of acoustic emission examination equipment

T he a re a o f the c yl i n de r whe re s e n s o r s a re p l ac e d s h a l l b e c l e a n a n d fre e fro m d i r t a nd c o n ta m i n atio n .

A c o up l a nt s h a l l b e u s e d to c o n ne c t s e n s o r s ac o u s tic a l l y to the c yl i nde r o r tub e s u r fac e . O n l y ad he s i ve s th at h ave the

acc e p tab l e

c yl i n der

wa l l

ac o u s tic

to

e n s u re

p ro p e r tie s ade qu ate

shal l

be

ac o u s ti c

used

(s e e

c o up l i n g ,

B . 3) .

e . g.

S en s ors

w i th

shall

be

m a g ne ts ,

he l d

in

ad he s i ve

c o n tac t w i th

t ap e

or

o the r

m e c h a n ic a l me a n s .

A

p re a mp l i

p re a mp l i

fie r

fier

m ay

be

e nc l o s e d

in

the

s en s or

ho u s i n g

or

in

a

s e p a rate

e nc l o s u re .

If

a

s e p a rate

i s u s e d , c ab l e c h a rac te r i s ti c s a re c r i tic a l (s e e B . 4 a n d E N 1 3 47 7-1) .

P o we r/s i g n a l

c ab l e

l e n g th

—

i.e.

c ab l e

b e t we e n

the

p re a mp l i

fi e r

a nd

s ignal

p ro c e s s o r

—

shall

no t

e xc e e d 1 5 0 m (s e e B . 5 a nd E N 1 3 47 7-1) .

Signal

p ro c e s s o r s

c o nve r t a n a l o g ue shall

h ave

speed

add i tio n ,

it

s i tu ati o n

ari s e

6

shal l

a re

c o mp u te r i z e d

i n fo r m atio n a nd no t

whe re

i n to

c ap ac i t y

s to p

to

i n s tr u m e nt s

d i g i ta l

p ro c e s s

p ro c e s s i n g

c o n ti nuo u s

fo r m

a nd

no i s e

d ata shal l

s uc h

as

w i th

i n de p e nde nt

fo r d i s p l ay a nd

i nde p e nde n tl y u n a m b i g uo u s l y

fro m

va l ve

c h a n ne l s

th at

p e r m a ne n t s to r a ge . fro m

all

ide nti fy

l e a ka ge ,

fl o w

s en s ors to

the

no i s e

fi l te r,

m e a s u re

A s igna l

s i mu l ta ne o u s l y.

o p e r ato r, or

a nd

p ro c e s s o r

h i gh

s ho u l d

em i s s ion

In the

rate

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

has rendered the signal permanently above the system threshold. The signal processor shall provide capability to filter data for replay. A video monitor should display processed test data in various formats. The display format may be selected by the equipment operator. A data storage device such as a compact disc may be used to provide data for replay or for archives. Hard-copy capability shall be available from a graphics/line printer or equivalent device. 8

Acoustic emission examination calibration and equipment veri fication

8.1

Calibration

The pressure sensors shall be calibrated annually in a laboratory that meets the requirements of I S O/ I E C

170 2 5 .

T he

s en s or

c a l ib ratio n

shall

i nc l ude

c he c ki n g

the

p ro p e r

fu nc tio n i n g

of

the

l o ad i n g

apparatus. The Level III operator may authorize the calibration of sensors in accordance with the practice de fined in an appropriate standard, e.g., paragraph 9.1 of ASTM E2191/E2191M:2016. The competency of personnel is de fined in C l au s e 5 .

NOTE

This does not prohibit calibration of the pressure sensors off-site from the laboratory, e.g., at the

m ac h i n e l o c ati o n .

The performance of the complete AT system shall be checked according to EN 13477-2 or an equivalent standard (i.e. ASTM E1419) and also shall be adjusted so it conforms to the equipment manufacturer’s speci fications. Equipment veri fication

8.2

Before and after the examination, the performance of the AT equipment shall be veri fied. Before and after the examination, the response of each sensor with the adjoining measurement chain and source location accuracy shall be veri fied by measuring the response according to an arti ficial, induced AE signal. The preferred technique for conducting this veri fication check is the Hsu-Nielsen source (see ISO 12716 or ASTM E1419). The diameter of the pencil lead, the distance to the sensors and the expected peak amplitude response are interrelated; they shall be speci fied in the written test instructions. The veri fication shall be performed at a distance where the obtained peak amplitude is within the dynamic range of the measurement chain. The maximum variation allowed shall be ± 3 dB between all channels. Any deviation outside the allowed range shall be corrected. The use of an electronic pulser to check that there is no subsequent change in sensitivity, by comparison w i th th at o b t a i ne d p r io r to the e x a m i n ati o n , i s a n ac c e p t ab l e a l te r n ati ve to the H s u- N i e l s e n s o u rc e c he c k.

If the pulser is used, an approved procedure shall be provided that clari fies its use and calibration. For the testing of similar cylinders, the electronic pulser may also be used for the first sensitivity check b a s e d o n p r io r p e r fo r me d e xa m i n ati o n s .

9 Overall procedure All accessible external surfaces of the cylinders shall be visually examined. Record observations in a test report. (See ISO 6406 or equivalent for the rejection criteria.) The procedure is as follows. NO TE

a)

Accessible

implies that the trailer need not be dismantled at time of testing when applying Method A.

Mechanically isolate the cylinder to prevent any contact with the surface of other cylinders, hardware, etc. When cylinders cannot be completely isolated, indicate in the test report external s o u rc e s th at c o u l d h ave p ro duc e d e m i s s io n s .

b)

Connect the fill hose and the pressure transducer. Eliminate any leaks at connections.

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

7

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

c)

P l ac e the s e n s o r o n a s m o o th s u r fac e , b u t no t ne c e s s a r i l y o n b a re me ta l . A s a p re c au ti o n , the c o a x i a l c ab l e

s ho u l d

be

s up p o r te d

so

i ts

we i ght

wi l l

no t

c au s e

the

s en s or

to

b e c o me

s e p a rate d

fro m

the

c yl i nde r o r tub e (s e e F i g u re 1) .

d)

Adj u s t s i g n a l p ro c e s s o r s e t ti n gs .

e)

C he c k

the

s ys te m

e l e c tro n ic th at

peak

th re s ho l d me a n on

a mp l i tude ab o ve

peak

the

p e r fo r m a nc e

pu l s er on

e xc e e d s

o f the

b re a ki n g

70

dB AE

Fo r

to

p e nc i l

0,3

T he

mm

A,

it i s

peak

l e ad

p e nc i l

o f the

to

is

10

the

used.

fro m

a

at

10

by

u s i ng

s e n s o r.

s ignal

s e t ti n g

is

of 40

cm;

fo r

an

Ve r i fy

p ro c e s s o r

d i ffe re nc e

th re s ho l d

b re a k

or

the

Adj u s t

b y the

th re s ho l d

h ave

l e ad

s o u rc e)

cm

de s c r i b e d

a nd

re c o m me nde d

th a n

l e ad

ra n ge

s o u rc e)

a mp l i tude

( H s u- N ie l s e n

no t l e s s

d y n a m ic

H s u- N i e l s e n

M e tho d

m a x i mu m

a

at a d i s t a nc e

whe n

p e a k no i s e .

(re s p o n s e

(A o r B ) .

va l ue

by

c yl i n de r o r tu b e

b ac kg ro u n d

a mp l i tude

me tho d

m i n i mu m

the

b e t we e n

de p e n de n t

dB

b e l o w the

M e tho d

B,

the

re c o m me nde d th re s ho l d i s 3 0 d B b e l o w the p e a k a mp l i tude o f the l e ad b re a k at 1 0 c m .

f)

Ve r i fy

th at

the

AT

s ys te m

d i s p l ays

a

c o r re c t

l o c ati o n

fo r

the

me c h a n ic a l

de v ic e

th at

is

used

to

p ro duc e s o u nd wave s . Fo r th i s p u r p o s e , l e ad b re a ks s h a l l b e p e r fo r me d o n the c yl i nde r o r tu b e wa l l w i th i n

the

a xia l

d i s t a nc e

o f the

t wo

s en s o r s .

T he

d i ffe re nc e

b e t we e n

the

a xia l

l o c ati o n

d i s p l aye d

b y the AT s ys te m a nd the re a l l o c atio n o n the c yl i nde r o r tu b e re l ate d to the s e n s o r p o s i tio n s s h a l l be

de te r m i ne d

i n ac c u rac y

fo r e ac h

b e t we e n

l e ad

ac tu a l

b re a k. a nd

T he

l o c ate d

ac c u rac y s h a l l p o s i tio n s

be

shall

w i th i n

no t

±

5

e xc e e d

%

±

o f the

5

%

s e n s o r s p ac i n g.

o f the

s en s or

T he

d i s ta nc e

du r i n g c a l i b rati o n . I f th i s ac c u rac y c a n no t b e at ta i ne d , mo re s e n s o r s s ho u l d b e adde d to re duc e the s e n s o r s p ac i n g , wh i c h c a n re duc e the o ve r a l l i n ac c u r ac y.

g)

B egin

p re s s u r i z i n g the

c yl i n de r.

I n te r r up t p re s s u r i z atio n

i f the re

is

an

e x p o ne n ti a l

i nc re a s e

in

AE

ac ti v i t y, fro m a ny c h a n ne l , a s a fu nc tio n o f p re s s u re . T he p re s s u r i z ati o n r ate s h a l l b e l o w e no u gh to

flo w

e n s u re th at

h)

no i s e i s no t re c o rde d .

M o n i to r the e x a m i n ati o n b y o b s e r v i n g d i s p l ays a x i a l l o c ati o n .

th at s ho w p l o ts

of AE

d ata b e i n g ge ne rate d ve r s u s

I f the A E i n d ic atio n s me e t the c r i te r i a o f C l au s e 1 0 , s to p p re s s u r i z ati o n a nd c o n duc t

a n i nve s ti gatio n .

In

the

case

o f au to m ate d

s up e r v i s io n

of

a re

or

re ac he d

p re s s u re

an

fro m

c o ntro l

au tho r i t y

e xc e e de d , the

the

s ys te m .

o f the s ys te m ,

(e . g.

no ti

s ys te m

At

the

fie d is

s a me

c r i ti c a l

b o d y) .

set

to

ti me ,

s ignal s

W he n

i m me d i ate l y an

a re

du r i n g

o p tic a l

s to re d i n

the

te s t

i nte r r up t

( l a mp)

a nd

the

s ys te m

p ro c e du re s

the

te s t

ac o u s tic

run

u n de r the

the s e

a nd

s ignal

s ignals

re duc e

wi l l

a ler t

the the

p e r s o n ne l re s p o n s i b l e fo r the te s ti n g.

D e p e nd i n g o n the s ub s e que nt e x a m i n atio n o f the ve s s e l b y o the r N D E me a n s , e . g. U T, the ve s s e l w i l l b e re j e c te d o r c a n re m a i n i n s e r v ic e .

i)

S to re

all

d ata

on

mass

s to ra ge

me d i a .

S to p

p re s s u r i z i n g

whe n

p re s s u re

re ac he s

the

AT

p re s s u re .

P re s s u re s h a l l b e mo n i to re d w i th a n ac c u r ac y o f ± 2 % o f AT p re s s u re .

1 0 Real-time evaluation criteria 1 0.1 a

The

p au s e

s to p

c ri te ri a

fo r

th at

fu rth e r

cri te ri a

s h al l

wi l l

re s u l t

an alys i s be

in

o f AE

avai l ab l e

a

s to p

d ata

fro m

p ro ce d u re can b e ap p l i e d i n vari o u s

o f th e

s h al l

an

be

p re s s u ri z ati o n

cl e arly

ap p ro p ri ate

j u ri s d i cti o n s

de

fi n e d .

d atab as e ,

s e qu e n ce

fo r

S u p p o rti n g s tan d ard

re j e cti o n

d ata

or

fo r

th e

i n s p e cti o n s ch o i ce

exp e ri e n ce .

The

or

o f te s t te s ti n g

wh e re th e re j e cti o n cri te ri a can vary b u t are s p e ci

fi e d

b y re gu l ati o n s .

1 0.2

The

cri te ri a

th at

wi l l

re s u l t

in

a

re j e cti o n

of

p re s s u ri z ati o n s e qu e n ce fo r fu rth e r i n s p e cti o n s are i n

—

t y p e o f c yl i n de r o r tu b e ,

—

m ate r i a l a nd he at tre atme n t,

8

th e

te s te d

fl u e n ce d

cyl i n d e r

or

tu b e

or

in

a

s to p

of

th e

b y facto rs s u ch as

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

—

first

or subsequent pressurization.

1 0.3 Rejection criteria shall be de fined clearly before the examination based on an appropriate database, existing standards or experience. Cylinders that have rejectable AE indications shall be examined by UT as d e s cri b e d i n An n ex A.

T he re a l- ti me e va l u atio n c r i te r i a s h a l l b e b a s e d o n at l e a s t o ne o f the fo l l o w i n g o b s e r vatio n s :

— increase in AE activity and/or energy as a function of the pressure at any channel; —

nu m b e r va l ue

—

A

1

nu m b e r va lue

A

2

N

of located burst signals with a distance-corrected peak amplitude above a “high” speci fic

N

of located burst signals with a distance-corrected peak amplitude above a “low” speci fic

1

;

2

w i th i n a n i n te r va l o f s i z e

X

% o f the m a x i mu m d i s t a nc e b e t we e n s e n s o r s .

X depends on the accuracy of the AT equipment used, number of sensors and the size of the cylinder or tube (e.g. diameter size).

NO TE

1 0.4

T he

va l u e

of

Furthermore, for Method A, the pneumatic pressurization shall be stopped immediately if

— the AE energy increases in incremental steps from a de fined value of energy, which means it doubles i n t wo c o n s e c u ti ve p re s s u re i n te r va l s o f 5 % o f the m a x i mu m te s t p re s s u re , o r

— one of the speci fic prede fined values for either N

1

A n ne x E

NO TE

g i ve s

t wo

e xa mp le s

o f p r o c e du r e s

or

N

2

i s e xc e e de d .

fo r m e a s u r i n g th e

wave

at te nu ati o n

in

o r de r to

c a l c u l ate

th e d i s ta nc e - c o r r e c te d p e a k a mp l i tu de (s e e E N 145 8 4) .

1 0.5

—

For Method A, the cylinder or tube shall be rejected when

five

or more acoustic emission events occur on the cylindrical portion of the cylinder or tube within

a 2 0 0 m m a x i a l s e g m e nt, o r

—

five

or more acoustic emission events are detected at both transducers on any cylinder or tube end

o u tb o a rd o f the tra n s duc e r s .

For Method B, the cylinder or tube shall be rejected when — the rate of emission exceeds two events per 7 bar regardless of signal amplitude at any one point on the cylinder or tube, and — the flaw is deemed active according to ASTM E569 (or equivalent) or activity is con firmed using the Kaiser effect. Alternative rejection criteria may be established with approval by the competent authority. 1 1 AT test report P re p a re a re p o r t fro m e ac h AT c o n ta i n i n g the fo l l o w i n g i n fo r m atio n :

a)

name(s) of owner(s) of cylinders;

b)

serial number(s) and manufacturer(s);

c)

examination date and where examination was performed;

d) previous examination date and previous test pressure; NOTE If the operator is aware of situations where the cylinder or tube was subjected to pressure that exceeded normal filling pressure, these situations should be described in the report.

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

9

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

e)

no r m a l

fi l l i n g

p re s s u re

(to

be

s up p l i e d

by

the

c yl i n de r

or

tu b e

o w ne r)

a nd

m a rke d

wo rki n g

p re s s u re ;

f)

p re s s u r i z atio n m e d i u m ;

g)

p re s s u r i z atio n r ate ;

h)

p re s s u re at wh i c h d at a ac qu i s i ti o n c o m me nc e d ;

i)

AT p re s s u re ;

j)

l o c ati o n o f AT s e n s o r s ;

k)

l o c ati o n s

of

AE

s o u rc e s

th at

e xc e e d

ac c e p ta nc e

c r i te r i a ,

i nc l ud i n g

d i s ta nc e

fro m

the

end

of

the

c yl i nde r o r tub e th at b e a r s the s e r i a l nu m b e r (u s u a l l y th i s i s s ta mp e d o n the c yl i nde r o r tu b e) ;

l)

a ny ac c e p tab l e va r i atio n fro m the AT p ro c e du re ;

m)

n a me , qu a l i

n)

s tac ki n g

fic atio n

ch a r t

a nd s i g n atu re o f e x a m i n atio n o p e rato r;

th at

s ho ws

re l ati ve

l o c atio n s

of

c yl i n de r s

a nd

a s s o c i ate d

c h a n ne l

nu mb e r,

if

ap p ro p r i ate ;

o)

e x te r n a l v i s u a l e x a m i n atio n re s u l ts ;

p)

AT re s u l t s i nc lud i n g

—

e ve n ts ve r s u s l o c ati o n p l o t fo r e ac h c yl i n de r,

—

d i s ta nc e - c o r re c te d a mp l i tude s ve r s u s l o c ati o n p l o t fo r e ac h c yl i n de r,

—

c u mu l ati ve e ve n ts ve r s u s p re s s u re (o r ti me)

—

p l o t fo r e ac h c h a n ne l o f e ac h c yl i n de r, a nd

c u mu l ati ve e ne r g y ve r s u s p re s s u re p l o t fo r e ac h c h a n ne l o f e ac h c yl i n de r o r e ne r g y d i s tr ib u tio n h i s to g ra m s fo r e ac h c h a n ne l ;

q)

e x a m i n atio n p ro c e du re a n d re v i s io n nu m b e r;

r)

t y p e o f AT e qu i p me n t (i n s tr u me n t, s e n s o r s , e tc .) ;

s)

de s c r ip tio n o f the p re s s u re e qu ip me n t;

t)

s ke tc h w i th d i me n s i o n s s ho w i n g s e n s o r a nd s i mu l ate d s o u rc e l o c ati o n s ;

u)

re s u l ts o f s ys te m ve r i

fic atio n s

i nc l ud i n g do c u m e nt atio n o n ac h i e ve d l o c atio n ac c u rac y.

1 2 Follow-up ultrasonic examination Up on

c o mp l e ti o n

of

AT

us ing

e i the r

M e tho d

A

or

M e tho d

B,

e ac h

AE

s o u rc e

l o c ati o n

e xc e e d i n g

the

ac c e p ta nc e c r i te r i a s h a l l b e e x a m i ne d a s de s c r i b e d i n A n ne x A .

NO TE

10

I f the ac c e p ta n c e c r i te r i a a r e e xc e e de d , th e c yl i n de r i n qu e s ti o n c a n b e c o n d e m n e d w i tho u t U T.

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

Annex A (no rm ative )

Ultrasonic examination (UT) follow-up to acoustic emission examination (AT)

A.1

UT follow-up

A.1 .1

Summary of methodology

UT is used to follow up AT to determine the severity of AE indications. When cylinders containing flaws are pressurized, sound waves can be produced by several different sources (e.g. secondary sources or ac tu a l p ro p a gatio n o f c rac ks) . T he s e s o u rc e s c a n p ro duc e ac o u s tic s i g n a l i nd i c atio n s th at a re re c o rde d du r i n g AT.

The purpose of this follow-up UT is to con firm the location of the AE event, detect and estimate the relevance of the indications which have been detected by the AT. The follow-up UT is based on ultrasonic pulse-echo contact angle-beam, shear wave technique with the beam directed circumferentially, and is used to locate surface breaking discontinuities in the cylindrical wall. The amplitude of the re flected signal from a discontinuity is compared to that of a known reference notch. Scanning is performed in both clockwise and counter clockwise directions to detect and con firm the position of the discontinuity identi fied in the AT report. This International Standard may be used for a cylinder or tube that is situated in such a way as to limit access to the sidewall wall. Typical examples include tube trailers, ISO modules and gaseous tube trailers and tanks on rail vehicles. Since the cylinders or tubes are stacked horizontally or vertically in a frame, with limited space between them, the circumferential location of a discontinuity can be a distance away from the probe (several skip distances). This practice has been shown to be effective for cylinders between 229 mm and 610 mm in diameter and wall thicknesses between 5 mm and 26 mm with discontinuities that are oriented longitudinally in the cylinder sidewall. To be reliably detected by the procedure in this practice, a signi ficant part of the re flecting surface of the discontinuity shall be tr a n s ve r s e to the b e a m d i re c tio n .

A.1 .2

Equipment

Typical features of the equipment required for follow-up UT are as follows. a)

T he

u l tra s o n ic

p u l s e - e c ho

i n s tr u me nt

shall

be

c ap ab l e

o f e xa m i n i ng

at

c e n tre

fre que nc ie s

fro m

2 MHz to 5 MHz. The instrument, probes and related equipment shall be cable of displaying the p e a k a mp l i tude o f the i n d ic ati o n fro m the re fe re nc e no tc he s i n the c a l i b rati o n r i n g , a s de s c r ib e d i n A .1 .4,

a nd

l o c ati n g i ts

c i rc u m fe re n ti a l

p o s i ti o n

o ve r the

fu l l

s we e p

r a n ge

re qu i re d

fo r

c o ve r a ge

of

the cylinder to be examined. b)

Each probe used for this technique shall have the appropriate frequency and refracted angle for the material and geometry of the gas cylinder that is being examined. The frequency and angle of the probe is selected during standardization and is related to diameter, wall thickness and the type of steel used for the cylinder and corresponding calibration rings.

c)

The angle and frequency of the probe to be used shall be determined by utilizing different probes on a reference ring that represents the cylinder to be examined. A probe that can satisfactorily detect and display the indication from the notches in the reference ring at the maximum distance to b e u s e d du r i n g the e x a m i n atio n s h a l l b e s e l e c te d fo r s e t ti n g up ( DAC )

the d i s ta nc e

a mp l i tude

c o r re c tio n

c u r ve .

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

11

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

d)

S ele c t

p ro b e s

re frac te d

fo r

a ngle s

e va l u ati o n

of

45 °

to

fro m

75 °

in

tho s e

s te e l ,

h av i n g

a nd

in

fre que nc ie s

ava i l ab l e

b e t we e n

c o m me rc i a l

2

MHz

sizes .

a nd

T ho s e

5

MHz

w i th

p ro duc i n g

the

re qu i re d s e n s i ti v i t y a n d DAC re s p o n s e o n the ap p ro p r i ate re fe re nc e r i n g a re ac c e p tab l e .

e)

T he

p ro b e

h ave

shal l

be

c o nti nuo u s

c o mp r i s e d

ac o u s tic

of

a

c o up l i n g

tra n s duc e r

b e t we e n

mo u nte d

the

s e a rc h

on

a

p l a s tic

u n i t a nd

the

we d ge

c yl i nde r

th at wa l l .

is

de s i g ne d

This

is

to

us ual ly

ac c o mp l i s he d w i th a we d ge th at i s m ac h i ne d to m atc h the c yl i nde r d i a me te r.

f)

T he

c o up l a n t

c yl i nde r

wa l l

fo r to

th i s

p r ac ti c e

re mo ve

the

shall

air

a nd

be

a

l iqu id

tra n s m i t

th at

is

used

u l tra s o n i c

b e t we e n

wave s .

Wate r

the is

u l tra s o n i c

the

p ro b e

p re fe r re d

a nd

c o up l a n t;

ho we ve r, a d i ffe re n t c o up l a n t s uc h a s o i l o r gl yc e r i n m ay b e u s e d . T he c o up l a nt s h a l l b e the s a m e fo r b o th

c a l i b r ati o n

a nd

ac tu a l

e x a m i n atio n .

fre e z e whe n the e x a m i n ati o n i s

C a re

shall

be

t a ke n

to

e n s u re

c o nduc te d at l o w te mp e ratu re s .

th at the

c o up l a nt do e s

no t

T he c o up l a nt s h a l l b e re p l e n i s he d

c o n ti nuo u s l y du r i n g U T.

A.1 .3

Calibration ring with reference notches

To p e r fo r m U T fo l l o w- up i n ac c o rd a nc e w i th th i s I n te r n ati o n a l S t a nd a rd , a c a l ib rati o n r i n g th at i nc lude s i n te r n a l a n d e x te r n a l no tc he s s h a l l b e p re p a re d a nd u s e d to me e t the fo l l o w i n g re qu i re me n ts .

a)

T he

c a l ib ratio n

T h at i s ,

ri ng

shal l

be

fab r ic ate d

fro m

the

s a me

typ e

i t s h a l l b e a s e c tio n o f a c o nve n ie n t l e n g th no t l e s s

o f c yl i n de r

th a n 1 0 0

th at

is

b ei ng

e x a m i ne d .

m m c u t fro m a s e a m l e s s

c yl i nde r w i th the s a m e no m i n a l d i a me te r, wa l l th i c kne s s , e x te r n a l s u r fac e

fi n i s h

s te e l

a nd m ate r i a l w i th

s i m i l a r ac o u s tic p ro p e r tie s a s the c yl i n de r u nde r te s t.

b)

Re fe re nc e F i g u re

no tc he s

A . 1) .

p ro c e s s .

T he

a re

p l ac e d

i n to

b o th

i n te r n a l

a nd

e x te r n a l

p re fe r re d no tc h fab r i c ati o n me tho d i s

s u r fac e s

o f the

c a l i b rati o n

b y the e l e c tr ic d i s c h a r ge

r i n g (s e e

m ac h i n i n g ( E D M )

N o tc h de p th s h a l l b e m e a s u re d u s i n g the re c ip ro c i t y m e tho d a nd s ta mp e d o n the e d ge o f

the r i n g. T he m i n i mu m l e n g th fo r a l l re fe re nc e no tc he s i s 2 5 m m .

c)

O ne

c a l ib rati o n

ri ng

m ay

i nc l ude

b o th

i nte r n a l

a nd

e x te r n a l

no tc he s

(s e e

F i g u re

A .1) .

H o we ve r,

whe re p rac tic a l , s e p a rate r i n gs s ho u l d b e u s e d .

A.1 .4 To

Calibration procedure

p e r fo r m

UT

fo l l o w- up

in

ac c o rd a nc e

w i th

th i s

I n te r n ati o n a l

S t a nd a rd ,

the

UT

s ys te m

shal l

be

c a l i b rate d u s i n g the fo l l o w i n g p ro c e du re .

a)

T he

i n s tr u me n t’s

ra n ge

shall

be

adj u s te d

to

e nc o mp a s s

the

s ou nd

p ath

to

be

used

du r i n g

the

e x a m i n ati o n .

b)

P l ac e

c o up l a n t

(s e n s i ti v i t y) te mp e r atu re

a nd

p ro b e

on

the

o u t s ide

s u r fac e

of

the

c a l i b r ati o n

ri ng

a nd

adj u s t

the

a nd l o c atio n o f the p ro b e u nti l the i n d ic ati o n fro m the i n te r n a l no tc h i s ide n ti o f the

c a l i b ratio n

r i n g du r i n g th i s

p ro c e du re

s ho u l d

be

the

s a me

as

the

ga i n

fie d .

T he

te mp e ratu re

ra n ge o f the c yl i nde r u nde r te s t.

c)

T he p ro b e i s

l o c ate d at a c l o s e d i s ta nc e ( h a l f- s kip

d i s ta nc e)

fro m the de s i g n ate d i nte r n a l no tc h o n

the s u r fac e o f the c a l i b ratio n r i n g. T he ga i n i s i nc re a s e d u nti l the s i g n a l i s m a x i m i z e d at 8 0 % o f the fu l l s c re e n he i gh t a s s ho w n i n F i g u re A . 2 .

d)

Fo r

fic u l t- to - re ac h

dif

m ay

be

mo u nte d

c a l ib ratio n

shall

at

be

l o c atio n s

the

end

on

of an

c o nduc te d

c yl i n de r s e x te n s io n

w i th

a nd

(tu b e s) ro d .

th at a re

I f an

w i tho u t a n

s tac ke d

e x te n s io n

e x te n s io n

ro d

ro d .

in is

T he

the

m i dd l e

used

fo r

ro w,

the

p ro b e

e x a m i n atio n ,

h i ghe r ga i n

is

used

the

fo r the

ac tu a l e x a m i n ati o n .

12

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

D i m e n s i o n s i n m i l l i m e tre s

a) Top view of calibration ring

b) Front view of calibration ring

c) Cross section of calibration ring (“A–A” )

Key

external EDM notches internal EDM notches

1 an d 2

3 an d 4

t

m i n i m u m gu aran te e d wal l th i ckn e s s

min

distance from edge of calibration ring ≥ 13 mm NOTE 1 Internal and external notches shall be adjacent to each other but 180° apart on circumferential position. d) for notches 1 and 3 is ≤ 20 % of the minimum guaranteed wall thickness (d d ≤ 20 % t ) for a typical 56 cm diameter medium strength seamless carbon steel tube with 150 bar working pressure. a

N O TE 2

Th e d e p th (

min

Th e d e p th (

N O TE 3

d

)

fo r n o tch e s 2 an d 4 i s fo u r ti m e s th e d e p th o f n o tch 1 (

1

d

2

=

d

4

= 4 X

d

1

)

=

3

fo r th e s am e tu b e .

D rawi n g i s n o t to s cal e .

Figure A.1 — E xample of calibration ring with internal and external reference notches

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

13

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

Dimensions in millimetres

a) E xample of maximizing ultrasonic signals for 0,60 0 mm internal notch — At point 1 (1/2 skip distance) and point 2 (several skip distances)

14

© ISO 2016 – All rights reserved

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

b) E xample of maximizing ultrasonic signals for 2 , 5 mm internal notch — At point 1 (1/2 skip distance) and point 2 (several skip distances)

Key A

DAC cu rve fo r n o tch 3

B

DAC cu rve fo r n o tch 4

1, 2

p ro b e p o s i ti o n s

3

p e ak am p l i tu d e re fe rri n g to p o s i ti o n s 1 (h al f s ki p )

4

p e ak am p l i tu d e re fe rri n g to p o s i ti o n s 2

X

ti m e b as e

Y

e ch o am p l i tu d e i n % o f s cre e n h e i gh t

d d

3

4

d e p th o f i n te rn al n o tch 3 (s e e F i gu re A. 1 )

d e p th o f i n te rn al n o tch 4 (s e e F i gu re A. 1 )

N O TE 1

A s i m i l ar p ro ce d u re wi l l b e u s e d fo r s e tti n g u p th e D AC cu rve fo r th e cal i b rati o n ri n g wi th e xte rn al s u rface

n o tch e s (1 an d 2 ) .

N O TE 2

D rawi n g i s n o t to s cal e .

Figure A. 2 — E xample of calibration procedure using calibration ring for setting up distance amplitude correction (DAC ) curves of a typical gas cylinder with inner surface notches

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

15

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

e)

A ny

UT

i n d ic ati o n s

p o te n ti a l in

at

fo r

le a s t

p o s i ti o n

t wo

of

s ho w i n g

re j e c tio n .

A fte r

d i re c tio n s .

the

an the

T he

d i s c o n ti nu i t y

a mp l i tude

th at

e xc e e d s

d i s c o nti nu i t y h a s

s ignal

shal l

be

a mp l i tude

b e en

as

re c o rde d .

A

the

D AC

l o c ate d ,

we l l

as

the

c yl i nde r

c u r ve

it shal l

s ho u l d

be

c i rc u m fe re n ti a l

c o n ta i n i n g

a

be

c o n s ide re d

e va l u ate d a nd

a

by s canning l o n g i tud i n a l

p o te n ti a l l y

re j e c tab l e

d i s c o nti nu i t y s h a l l b e re mo ve d fro m the s t ac k to a l l o w ac c e s s to the d i s c o n ti nu i t y l o c ati o n .

f)

I t i s p o s s i b l e to e s ti m ate the l e n g th o f the d i s c o n ti nu i t y b y re duc i n g the ga i n a n d mo v i n g the s e n s o r a l o n g the l e n g th o f the c yl i n de r u n ti l the s i g n a l d ro p s b e l o w 1 0 % o f the s c re e n he i ght.

g)

W he n

the

re mo va l

u n s e r v ic e ab l e

or

of a

c yl i nde r

e x a m i ne d

in

fro m

the

s er vice

c r i ti c a l

is

z o ne

i nd ic ate d , whe re

a

the

c yl i n de r

d i s c o nti nu i t y

e i the r has

shall

b e en

be

re nde re d

l o c ate d

w i th

a

me tho d i n ac c o rd a nc e w i th I S O 6 4 0 6 .

A.2

Test report

P re p a re a re p o r t th at c o n ta i n s the fo l l o w i n g i n fo r m atio n fo r e ac h c yl i n de r:

a)

b)

s e r i a l nu m b e r(s)

d ate

a nd

a nd m a nu fac tu re r(s) ;

re s u l ts

of

the

AT

i nc l ud i n g

the

l o n g i t ud i n a l

a nd

c i rc u m fe re n ti a l

l o c atio n s

of

the

AE

i nd i c atio n s ;

c)

d ate o f the e x a m i n atio n a nd n a me o f the e x a m i ne r;

d)

re fe re nc e ga i n (s e n s i ti v i t y) ;

e)

i nd i c atio n s i g n a l a mp l i tude , c i rc u m fe re n ti a l a nd l o n g i tud i n a l l o c ati o n s o f the i n d ic atio n ;

f)

l ate ra l p ro b e mo ve me n t (e s ti m ate d l e n g th o f the c o n ti nu i t y) .

16

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

Annex B (no rm ative )

AT equipment speci fications

B.1

Sensors

T he AT s e n s o r s s h a l l b e re s o n a n t i n a 1 0 0 kH z to 4 0 0 kH z fre que nc y b a n d .

S e n s i ti v i t y s h a l l b e g re ate r th a n −7 7 d B (re fe r re d to a s 1

V/μb a r, de te r m i ne d b y fac e - to - fac e U T )

o ve r a

fre que nc y ra n ge o f 1 0 0 kH z to 4 0 0 kH z .

S e n s i ti v i t y

at

the

re s o n a nc e

fre que nc y

shal l

no t

va r y

m o re

th a n

3

dB

o ve r

the

i n te nde d

ra n ge

of

te mp e rat u re s i n wh ic h the s e n s o r s a re u s e d .

S en s ors

shal l

be

s h i e l de d

a ga i n s t

d i ffe re n ti a l (a n ti c o i nc i de nc e)

e l e c tro m a g ne tic

i n te r fe re nc e

th ro u gh

p ro p e r

de s i g n

p rac tic e

or

e l e me n t de s i g n , o r b o th .

S e n s o r s s h a l l b e e l e c tr ic a l l y i s o l ate d fro m c o nduc ti ve s u r fac e s b y me a n s o f a s ho e (a we a r p l ate) .

B.2 T he

Sensor cable s en s or

s ignal

c ab l e ,

I n te g ra l p re a mp l i

fie r

T he

shall

s ignal

c ab l e

wh ic h

c o n ne c t s

s en s or

a nd

p re a mp l i

fi e r,

shal l

no t

be

l o n ge r

th a n

1,80

m.

s e n s o r s me e t th i s re qu i re m e nt . T he y h ave i n he re ntl y s ho r t, i n te r n a l s i g n a l c ab l e s .

be

s h ie l de d

a ga i n s t

e l e c tro m a g ne ti c

i n te r fe re nc e .

S ta n d a rd

co a xia l

“no

no i s e ”

c ab l e i s ge ne ra l l y ade qu ate .

B.3

Couplant fi c i e nc y

T he c o up l a n t s h a l l p ro v i de ade qu ate u l tra s o n ic c o up l i n g e f

th ro u gho u t the e xa m i n ati o n .

T he c o up l a n t s h a l l b e te mp e ratu re - s t ab l e o ve r the te mp e r atu re r a n ge i n te nde d fo r u s e .

Ad he s i ve s

m ay

be

used

if

the y

s ati s fy

u l tra s o n ic

c o up l i n g

fic ie nc y

ef

a nd

te mp e ratu re

s tab i l i t y

re qu i re me n ts .

B.4

Preampli fier

T he p re a mp l i

fi e r

s h a l l h ave no i s e l e ve l no g re ate r th a n 3

μV r. m . s . (re fe r re d to a s ho r tc u t i np u t)

w i th i n

the b a n dp a s s ra n ge s tate d i n B . 1 .

T he

p re a mp l i

fi e r

ga i n

shall

va r y

no

m o re

th a n

±

1

dB

w i th i n

the

fre que nc y

b a nd

s tate d

in

B .1

a nd

te mp e ratu re ra n ge o f u s e .

T he p re a mp l i

P re a mp l i

T he

fie r

fie r s

p re a mp l i

s h a l l b e s h ie l de d fro m e l e c tro m a g ne tic i n te r fe re nc e .

o f d i ffe re n ti a l de s i g n s h a l l h ave a m i n i mu m o f 4 0 d B c o m mo n mo de re j e c tio n .

fie r

shall

i nc l ude

a

b a n dp a s s

fi l te r

ab o ve a nd b e l o w the s e l e c te d fre que nc y b a nd . fro m the p re a mp l i

fie r

w i th

a

m i n i mu m

A l te r n ati ve l y,

of 2 4

d B/o c tave

the b a n dp a s s

s ignal

at te nu atio n

c a n b e l o c ate d do w n s tre a m

i n the m e a s u re me n t c h a i n .

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

17

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

B.5

Power/signal cable

P o we r/s i g n a l

c ab l e s

p ro v ide

p o we r

to

p re a mp l i

fi e r s

a nd

c o nduc t

a mp l i

fie d

s igna ls

to

the

main

p ro c e s s o r. T he s e s h a l l b e s h i e l de d a ga i n s t e l e c tro m a g ne tic i n te r fe re nc e .

S i g n a l l o s s s h a l l b e l e s s th a n 1 d B p e r 3 0 m o f c ab l e l e n g th . S ta nd a rd c o a x i a l “no no i s e ” c ab l e i s ge ne ra l l y ade qu ate . S i g n a l l o s s fro m a p o we r/s i g n a l c ab l e s h a l l no t b e g re ate r th a n 3 d B .

B.6 A

Power supply

s tab le ,

gro u nde d

p o we r

s up p l y

t h at

me e ts

the

s ignal

p ro ce s s o r

m a nu fac t u r e r ’s

speci

fi c a t i o n

shall

be used.

B.7

Signal processor

T he e l e c tro n ic c i rc u i tr y ga i n s h a l l b e s tab l e w i th i n ± 2 d B i n the te mp e ratu re ra n ge fro m 0 ° C to 4 0 ° C .

Tr i g ge r th re s ho l d s h a l l b e ac c u r ate w i th i n ± 2

M e a s u re d i nc l ude

AE

h i ts

du rati o n

p a ra me te r s

a nd

shall

th re s ho l d

i nc l ude

c ro s s i n g

dB .

peak

c o u n ts .

a mp l i tude , Also,

e ne r g y

c yl i n de r

or

a nd tub e

a r r i va l

ti me ,

i nte r n a l

a nd

also

p re s s u re

m ay

shall

be

m e a s u re d .

T he c o u n te r c i rc u i t s h a l l c o u n t th re s ho l d c ro s s i n gs w i th i n a n ac c u rac y o f ± 5 % o f tr ue c o u n ts .

Pe a k a mp l i tude s h a l l b e ac c u r ate w i th i n ± 2 d B A E .

A r r i va l ti m e at e ac h c h a n ne l s h a l l b e ac c u rate to w i th i n ± 1 μ s .

D u ratio n s h a l l b e ac c u rate to w i th i n ± 1 0 μ s .

P a ra me tr ic

vo l t a ge

re ad i n gs

fro m

p re s s u re

tra n s duc e r s

shal l

be

ac c u rate

to

w i th i n

±

2

%

o f m a rke d

wo rki n g p re s s u re .

18

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

Annex C (no rm ative )

Example instrument settings, examination methods and rej ection criteria for MAE

C.1

MAE information

C.1 .1

Introduction to MAE

A n ne x C e s tab l i s he s c e r ta i n te s ti n g c r i te r i a fo r the M A E e x a m i n ati o n o f s o me c yl i nde r s . I t i nc o r p o rate s M AE

te c h n ique s

in

the

e va l u atio n

c rac k g ro w th i n s te e l c yl i n de r s speci

fi c a l l y

o f the

l e ad s

to

s o u rc e

l o c atio n .

It

is

no w

e s tab l i s he d

the re l e a s e o f u l tra s o n ic wave s

the l o we s t o rde r e x te n s io n a l a nd

fl e x u r a l

in

AT

th at p ro p a gate

l i te ratu re as

th at

p l ate wave s ,

mo de s , a s i s s ho w n i n F i g u re C .1 .

Key 1

exte n s i o n al m o d e

2

fl exu ral

mo de

3

fl exu ral

m o d e re

fl e cti o n

Figure C .1 — Waveform showing extensional and

C.1 .2

flexural modes and flexural mode re flection

Source location analysis

E qu i p me n t s p e c i

fie d

i n s i g n a l p a r a me te r b a s e d AT de te r m i ne s the a r r i va l ti me u s i n g a h a rd wa re ti m i n g

c i rc u i t th at i s tr i g ge re d whe n a ny p a r t o f the tra n s duc e d s i g n a l c ro s s e s a p l ate s h ap e

wave s

e x h ib i t

s ign i

c o n s ide rab l y a s

fic a n t

d i s p ers ion ,

i t p ro p a gate s

(s e e

an

i n i ti a l l y

F i g u re

C .2) .

sharp

S o u rc e

pulse

at

l o c atio n

fi xe d

the

vo l ta ge th re s ho l d . S i nc e

origi n

e r ro r s

s p re ad s

o c c u r whe n

a nd

the

c h a n ge s

th re s ho l d

c ro s s i n g i s no t o n the s a me p h a s e p o i n ts fo r the wave a r r i va l s at the s e n s o r s . M A E m e a s u re m e nt s a l l o w the u s e r to s e l e c t the a r r i va l o f the wave fo r m b a s e d o n wave mo de . I n s tr u me n t s p e c i

fic atio n s

a re g i ve n

i n Tab l e C .1 .

T he

s en s ors

we re

30

cm

ap a r t,

a nd

a

l e ad

b re a k

wa s

p e r fo r m e d

ne a r

s en s or

nu m b e r

1.

Un l i ke

bul k

wave s , p l ate wave p ro p a gatio n ve l o c i tie s a re a fu nc tio n o f fre que nc y, a nd thu s the wave i s d i s to r te d a s i t p ro p a gate s .

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

19

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

Figure C . 2 — Waveforms showing change in pulse due to dispersion

Table C .1 — Modal acoustic emission equipment, characteristics and set-up conditions

Value

Parameter S e n s o r s e n s i ti v i t y

−7 7 d B V r e f. 1 V/μb a r

C o up l a nt

S i l ico ne g re a s e

P re a mp l i

fi e r fi l te r

2 0 k H z to 1 0 0 0 k H z b a n dp a s s

fi l te r

S i g n a l p ro ce s s o r

2 0 k H z to 1 0 0 0 k H z b a n dp a s s

S i g n a l p r o c e s s o r th r e s ho l d

3 2 d B V (1 μV = 0 d B a t p r e a mp . i n p u t)

B ac kg r o u n d no i s e

< 2 7 d B V (1 μV = 0 d B at p r e a m p . i np u t)

S e n s i ti v i t y ch e c k

> 8 0 d B V (1 μV = 0 d B a t p r e a mp . i n p u t)

A/ D r e s o l u ti o n

1 6 b i t s , 1 V p p r a n ge

A/ D d y n a m i c r a n ge

> 80 dB

A/ D s a m p l i n g r ate

> 5 MHz

P a r a m e tr i c s a mp l i n g r a te

> 1 Hz

P a r a m e tr i c ac c u r ac y

2 % o f ve s s e l o p e r a ti n g p r e s s u r e

Extensional- versus flexural-mode source location

C.1 .3

T he E a nd F wave s (e x te n s i o n a l a nd tu b e s .

B o th

mo de s

fl e x u r a l

e x h i b i t d i s p e r s io n ,

wave s , re s p e c ti ve l y)

wh ic h

me a n s

the

Fo u r ie r

a re the A E wave mo de s fo u n d i n s te e l fre que nc y c o mp o ne n ts

in

the

E

a nd

F

wave s tr ave l at d i ffe re n t ve l o c i tie s , a nd thu s the wave s s p re ad o u t a n d c h a n ge s h ap e a s the y p ro p a gate . To

o b ta i n a n ac c u rate

use

the

p ro p e r

s o u rc e

ve l o c i t y.

T he

mo de a nd fre que nc y. T he the

F

wave

ve l o c i t y c u r ve s tho u gh

in

fro m

a nd th i s

s te e l the

m athe m ati c a l

a nd

ve l o c i t y.

no t the

fi r s t

is

A r r i va l

a r r i va l

s o ft wa re

the

typ e

s h a l l de te r m i ne

o f s te e l

tub e

b o th a n ac c u rate

(e . g.

ISO

111 2 0)

a nd

a r r i va l ti me s e l e c ts

the

a nd

wave

i s the E wave b e c au s e i t i s l e s s d i s p e r s i ve at l o we r fre que nc i e s th a n

a l ways

c u r ve s

p re fe r re d

the

s e l e c ts

fi r s t c ho i c e

d i s p e r s io n

i np u t a is

tub e s

l o c atio n , u s er

fo r

the the

ti me

me tho d .

th re s ho l d

fi r s t

mo de

s e l e c te d

to

de te r m i n atio n H o we ve r,

te c h n i que s

a r r i ve .

tub e

can

s i nc e

(s m a r t

typ e

T he

or

also

the

E

s o ft wa re

the

be

wave

th re s ho l d )

u s er

do ne is

s e l e c ts

a re

the

no t

the

i n s p e c t the

b y s e t ti n g a

a l ways

th at

the n

can

fi xe d

fi r s t

fi xe d

p ro p e r

d i s p e r s io n th re s ho l d ,

a r r i v i n g mo de ,

th re s ho l d- b a s e d

a re ac c e p tab l e . T he p e nc i l l e ad b re a k s ho u l d b e u s e d to ve r i fy the ac c u rac y o f the c ho i c e s m ade .

C.1 .4 Re

Re flections/wrap waves

f l e c ti o n s

the

s o u rc e

or

wave s

l o c atio n

th at

w rap

a n a l ys i s

a ro u nd

(s e e

the

F i g u re

c yl i nde r

C .1) .

Wrap

or

tu b e

wave s

c o n s tr uc ti ve i n te r fe re nc e a nd , i f u s e d to de te r m i ne ti m e - o f-

as

the y

can

f l i ghts

p ro p a gate

h ave

ve r y

s ho u l d

l a r ge

no t

be

a mp l i tude s

fo r the l o c ati o n a n a l ys i s

used

in

due

to

w i l l l e ad to

l a r ge l o c atio n e r ro r s . M A E a n a l ys i s a l l o ws the u s e r to i de n ti fy a n d e l i m i n ate the s e fro m the a n a l ys i s .

20

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BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

C.1 .5

Source characteristics

T he s o u rc e i n the

f l ue nc e s

o u t- o f- p l a ne

the wave s o b s e r ve d .

n atu re

o f the

s o u rc e .

L e ad b re a k c re ate s wave s w i th l a rge

C rac k g ro w th ,

due

to

i ts

l a r ge r

i n- p l a ne

f l e x u ra l

mo de s due to

c o mp o ne n t,

wi l l

c re ate

wave s w i th l a r ge r e x te n s io n a l mo de c o mp o ne n ts . T he u s e r s h a l l b e awa re o f ho w the s o u rc e a ffe c t s the wave m o de s to e n s u re ac c u rate s o u rc e l o c ati o n c a l c u l atio n s b a s e d o n the wave mo de s .

C.2

MAE instrument settings and data analysis

C.2 .1

Input velocity

T he ve l o c i t y u s e d i n the l o c ati o n c a l c u l atio n s h a l l b e de te r m i ne d . To de te r m i ne the ve l o c i t y, a l e ad b re a k is

p e r fo r me d

o u ts ide

the

s en s or

a r ray

in

l i ne

w i th

the

s en s ors .

T he

ti me - o f-

f l i gh t

mo de i s me a s u re d , a nd the d i s ta nc e b e t we e n the s e n s o r s i s d i v i de d b y the ti me - o f-

fo r

a

f l i ght.

s peci

fic

wave

T h i s re s u l ts i n

the p ro p a gatio n ve l o c i t y a nd i s p e r fo r me d fo r e ac h c yl i n de r o r tu b e to b e te s te d .

C.2 .2 T he

MAE source location — Cylindrical portion of cylinder or tube

u s e r i np u t s

a

p ro p a gatio n

ve l o c i t y fo r the

mo de

o f i nte re s t a nd

the

s e n s o r s p ac i n g.

T he

a r r i va l

of

th at mo de i s s e l e c te d o n the c ap tu re d wave fo r m s , a nd the a r r i va l ti m e d i ffe re nc e o f the t wo wave fo r m s i s c a l c u l ate d . T he s o u rc e l o c atio n i s c a l c u l ate d u s i n g a l i ne a r l o c atio n a l go r i th m b a s e d o n the d i ffe re nc e i n a r r i va l ti me s , the i np u t ve l o c i t y a n d s e n s o r s p ac i n g.

C.2 .3 Fo r

MAE source location — Ends of cylinder or tube

s o u rc e s

a r r i va l

o u tb o a rd

ti me s

de te r m i ne d

o f the

b e t we e n

us ing

a

the

s en s ors ,

the i r

e x te n s i o n a l

ra n g i n g

a l go r i th m

a nd

l o c ati o n

fl e x u r a l

b ased

on

can

be

m o de s .

the

c a l c u l ate d T he

by

d i s t a nc e

p ro p a gati o n

me a s u r i n g the

ve l o c i t y

wave

o f the

the

has

t wo

d i ffe re nc e

in

p ro p a gate d

mo de s

a nd

is

the

a r r i va l ti m e d i ffe re nc e .

C.3

Follow-up examination criteria

C.3 .1 If

Cylindrical portion of cylinder or tube

fi ve

o r mo re A E e ve n ts o c c u r w i th i n a 2 0

c m a x i a l d i s ta nc e o n the c yl i n d r ic a l p o r tio n o f the c yl i nde r

o r tub e , the n th at p o r tio n o f the c yl i nde r o r tu b e s h a l l b e e x a m i ne d u s i n g a s e c o nd a r y N D E me tho d (e . g. U T ) . A ny

C.3 .2 If

f l aw

th at i s de te c te d s h a l l b e p re c i s e l y l o c ate d a nd

f l aw

d i me n s i o n s s h a l l b e de te r m i ne d .

Ends of cylinder or tube

fi ve

or

mo re

AE

o f tho s e

e ve n ts

shall

i n s p e c te d ,

be

e ve n ts

shall

be

the

a re

de te r m i ne d

de te r m i ne d .

f l aw

to

h ave

I f the y h ave

p re c i s e l y

l o c ate d

o r i g i n ate d

the

a nd

s a me

f l aw

o u t s ide

ra n ge ,

the

s en s or

a r ray,

the n

the

r a n ge

the n th at e n d o f the c yl i n de r o r tu b e

d i me n s i o n s

de te r m i ne d

us ing

s e co nd a r y

N DE

me tho d s (fo r e x a mp l e , U T ) .

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

21

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

Annex D (i nfo rm ative )

Alternative method for source location

D.1 T he

Sensors AT

s en s ors

shal l

h ave

h i gh

s e n s i ti v i t y

re s p o n s e s h a l l no t va r y b y m o re th a n 1 2

S e n s i ti v i t y m e tho d )

shall

be

g re ate r

th a n

−7 7

o ve r

the

fre que nc y

b a nd

of

50

kH z

to

350

kH z .

S ens or

d B o ve r th i s fre que nc y ra n ge .

dB

(re fe r re d

to

as

1

V/μb a r,

de te r m i ne d

by

the

tra n s fe r

b lo ck

w i th i n the fre que nc y ra n ge o f 5 0 kH z to 3 5 0 kH z .

T he d i a me te r o f the s e n s i ti ve a re a o f the s e n s o r s h a l l b e 1 3 m m o r l e s s to e l i m i n ate ap e r tu re e ffe c t s .

S e n s i ti v i t y w i th i n

the

ra n ge

o f i n te nde d

use

shal l

no t va r y mo re

th a n

3

dB

o ve r the

i n te n de d

r a n ge

of

te mp e ratu re s i n wh i c h s e n s o r s a re u s e d .

S en s ors

shal l

be

s h i e l de d

a ga i n s t

d i ffe re n ti a l (a n ti c o i nc i de nc e)

e l e c tro m a g ne tic

i n te r fe re nc e

th ro u gh

p ro p e r

de s i g n

p rac tic e

or

e l e me n t de s i g n o r b o th .

S e n s o r s s h a l l b e e l e c tr ic a l l y i s o l ate d fro m c o nduc ti ve s u r fac e s b y me a n s o f a s ho e (we a r p l ate) .

D.2

Sensor cable

T he s e n s o r s i g n a l c ab l e th at c o n ne c t s the s e n s o r a n d p re a mp l i mo re th a n 3 d B o ve r i ts l e n g th . I n te g ra l p re a mp l i

Signal

c ab l e s

shall

fie r

fie r

s h a l l no t at te nu ate the s e n s o r o u t p u t

s e n s o r s me e t th i s re qu i re me n t.

b e s h i e l de d a ga i n s t e l e c tro m a g ne ti c i nte r fe re nc e .

S t a nd a rd c o a x i a l

“no

no i s e ”

c ab l e

i s ge ne ra l l y ade qu ate .

D.3

Couplant fic ie nc y

T he c o up l a nt s h a l l p ro v ide ade qu ate u l tra s o n i c c o up l i n g e f

th ro u gho u t the e x a m i n atio n .

T he c o up l a nt s h a l l b e te mp e ratu re - s t ab l e o ve r the te mp e ratu re ra n ge i n te nde d fo r u s e .

Ad he s i ve s

m ay

be

used

if

the y

s ati s fy

u l tra s o n i c

c o up l i n g

fic ie nc y

ef

a nd

te mp e ratu re

s tab i l i t y

re qu i re me nt s .

D.4

Preampli fier

T he p re a mp l i

fie r

s h a l l h ave a no i s e l e ve l no g re ate r th a n 3 μV r. m . s . (re fe r re d to a s ho r te d i np u t)

w i th i n

the b a ndp a s s ra n ge s t ate d i n D . 1 .

T he

p re a mp l i

fie r

ga i n

shall

va r y

no

mo re

th a n

±

1

dB

w i th i n

the

fre que nc y

ra n ge

s tate d

in

D .1

a nd

te mp e ratu re ra n ge o f u s e .

T he p re a mp l i

D.5

fi e r

s h a l l b e s h ie l de d fro m e l e c tro m a g ne ti c i n te r fe re nc e .

Post-ampli fier and filtering

T he e l e c tro n ic c i rc u i tr y s h a l l b e s t ab l e to w i th i n ± 2 d B i n the te mp e ratu re r a n ge fro m 4 ° C to 4 0 ° C .

22

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

Trigger threshold shall be accurate to ± 2 dB. The post-ampli fier shall include a bandpass filter with a minimum of 6 dB/octave signal attenuation above and below the frequency band stated in D .1 .

The post-ampli fier gain shall vary no more than ± 1 dB within the frequency range stated in

D . 1 a nd the

te mp e r atu re ra n ge o f u s e .

The post-ampli fier shall be shielded from electromagnetic interference. D.6

Power/signal cable

The power/signal cables between the preampli fier and post-ampli fier shall be shielded against e l e c tro m a g ne ti c

i n te r fe re nc e .

Signa l

lo s s

shall

be

le s s

th a n

1

dB

p er

30

m

o f c ab l e

l e n g th .

S ta n d a rd

coaxial “no noise” cable is generally adequate. Signal loss from a power/signal cable shall be no greater th a n 3 d B .

D.7

Digital acquisition electronics

The analog-to-digital (A/D) converter shall meet the following speci fications: — resolution no less than 16 bits over 1 V pp; — clock speed no less than 5 MHz; — dynamic range no less than 80 dB; — stable (to the dynamic range stated previously) over the temperature range stated in —

D. 5

;

c ap ab l e o f ac qu i r i n g d ata i n p re - tr i g ge r m o de .

The system shall be capable of digitizing and recording transient signals of no less than 6 ms duration over a 10 m axial length if both channels are triggered at the same time; or digitizing and recording tra n s ie nt

s ignal s

of

no

le s s

th a n

3

ms

o ve r

a

10

m

a xia l

l e n g th

a nd

ti m e

s t a mp i n g

e ac h

re c o rde d

transient signal to 0,2 μs if channels are triggered independently. Parametric voltage readings from pressure transducers shall be accurate to within ± 2 % of the marked wo rki n g p re s s u re .

P re s s u re d at a s h a l l b e ac qu i re d at a rate o f no l e s s th a n 1 H z .

D.8

Signal processing

MAE data shall consist of digitized waveforms. The system shall have the capability to allow the user to input the propagation velocity for the wave mo de to b e u s e d fo r the s o u rc e l o c atio n .

The system shall allow the user to specify the sensor spacing. The system shall allow the user to identify the time of arrival of the selected wave mode to the accuracy required for the lead break veri fication to be used for the source location in the digitized signal. C ap t u re d wave fo r m s s h a l l b e m a rke d w i th the p re s s u re at wh ic h the e ve nt o c c u r re d .

Source location time resolution shall be no less than 0,2 μs. The system shall perform source location calculations using standard linear source location algorithms.

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

23

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

Annex E (i n fo rm ative )

Distance amplitude correction procedures

Two p ro c e du re s a re g i ve n a s e x a mp l e s .

a)

Procedure 1 — Use of measured attenuation curve Us e the d i s ta nc e fro m the s o u rc e to the c l o s e s t s e n s o r (at wh ic h the a mp l i tude s a re me a s u re d ) , o n the at te nu atio n c u r ve (s e e F i g u re E .1) , me a s u re the at te nu atio n th at o c c u r s o ve r th i s d i s ta nc e a n d add to the s o u rc e a mp l i tude s .

b)

Procedure 2 — Calculate using approximation T he

g i ve n

to 1 0 0

This

e xa mp le

can

be

ap p l i e d

to

ga s

fi l l e d

e qu ip ment wi th

a

wa l l

th i ckne s s

r a n ge

of 2 0

mm

mm.

a s s u me s

ne a r-

fie l d

at te nu ati o n

ap p ro x i m ate l y 2 5 d B . T he fa r-

fie l d

b e t we e n

the

s o u rc e

a nd

20

e

(2 0

ti me s

the

wa l l

th ic kne s s)

is

at te nu atio n i s c a l c u l ate d u s i n g the m e a s u re d d i ffe re nc e b e t we e n the

s i g n a l a mp l i tude o f a H s u- N ie l s e n s o u rc e at 2 0

e

a n d the m a x i mu m de te c tio n d i s ta nc e .

It is

a s s u m e d to

b e l i ne a r. T he a mp l i tude i s c o r re c te d u s i n g the fo l l o w i n g e qu atio n :

Ac = Am + A 20 e + α∆d whe re

A

c

i s the c o r re c te d s o u rc e a mp l i tude (d B A E ) ;

A

m

i s the me a s u re d s o u rc e a mp l i tude (d B A E ) ;

A

20

Δd α

e

i s the me a s u re d at te nu ati o n o f H s u- N ie l s e n s o u rc e b e t we e n 2 0 m m a nd 2 0

i s the d i s ta nc e fro m A E s o u rc e to s e n s o r −2 0

fi c i e nt

i s the at te nu atio n c o e f

b e t we e n 2 0

e

e

e

d i s ta nc e (d B ) ;

(m) ;

a nd the m a x i mu m de te c ti o n d i s ta nc e (d B/m) .

Fo r e xa mp l e , s e e F i g u re E . 2 .

24

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

Key

A Ad Ae Ah An d x

k

amplitude detection threshold evaluation threshold amplitude of Hsu-Nielsen source at 0,02 m from centre of sensor peak background noise distance difference in decibels between the detection threshold and the peak background noise difference in decibels between the evaluation threshold and the detection threshold Figure E .1 — Determination of maximum sensor spacing from attenuation curve

© ISO 2016 – All rights reserved

25

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

Key

A Ac Am d α Δd

amplitude corrected source amplitude measured source amplitude distance attenuation coefficient between 20 e and the maximum detection distance

distance from AE source minus 20 e Figure E . 2 — E xample for compensation of distance- dependent losses

26

© ISO 2016 – All rights reserved

BS EN ISO 1 61 48:201 6 ISO 1 61 48: 2 01 6(E)

Bibliography

[1]

Un i te d N atio n s ,

Recommendations on the Transport of Dangerous Goods — Model Regulations

,

as

a m e nde d , G e ne va

[2 ]

I S O 10 2 8 6 ,

[3 ]

ISO

[4]

ISO

[5 ]

C G A C -1 8 ,

[6 ]

Gas cylinders — Terminology

1 2 71 3 ,

transducers

Non-destructive testing — Acoustic emission inspection — Primary calibration of

Non-destructive testing — Acoustic emission inspection — Secondary calibration of acoustic emission sensors

B

1 2 714 ,

Methods for Acoustic Emission Requalification of Seamless Steel Compressed Gas Tubes

lackburn

P. R .

Periodic AE re-tests of seamless steel gas cylinders,

in

Ac o u s tic

e m i s s io n :

standards and technology update, ASTM STP 1353, Vahaviolos, S. J. Ed

Non-destructive testing — Acoustic emission — Examination of metallic pressure equipment during proof testing — Planar location of AE sources

[7 ]

EN

[8]

K esten M., & S ager Cylinders and Pressure Vessels”, EIGA Symposium, Jan. 1996 (IGC Doc. 55/95)

[9 ]

145 8 4 ,

D.

“T he

Us e

o f A l te r n ati ve

Te s ti n g

P ro c e du re s

fo r

the

Re te s ti n g

of Gas

arth é l é my H.M. “Acoustic emission — current practice and future directions,” Periodic inspection of compressed gas cylinders and transport vessels by using AET. ASTM Spec. Tech. B

P ub l .

19 9 1 Fe b .

[10]

ASTM 2223, Standard Practice for Examination of Seamless, Gas-Filled, Steel Pressure Vessels Using

[11]

ASTM E543, Standard Specification for Agencies Performing Nondestructive Testing

[12]

ASTM E587, Standard Practice for Ultrasonic Angle-Beam Contact Testing

[13]

ASTM E2191/E2191M:2016, Standard Practice for Examination of Gas-Filled Filament-Wound

Angle Beam Ultrasonics

Composite Pressure Vessels Using Acoustic Emission

© I S O 2 0 1 6 – Al l ri gh ts re s e rve d

27

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