Tiêu chuẩn iso 18154 2017

© ISO 2017 Ships and marine technology — Safety valve for cargo tanks of LNG carriers — Design and testing requirements Navires et technologie maritime — Soupape de sûreté pour les réservoirs de carga[.]

Ships and marine technolog y — Safety

val ve for car g o tanks ofLNG carriers

Navi res et te h ologi e mari ti me — S u a e de s ûr té p ur les

rés ervoi rs de carg i s on des méth ni ers — Exi genc s de co cepti on

et d’es s ai

Fir t edition

2 17-0

Refer ence n mb r

COPYRIGHT PROTECTED DOCUMENT

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F reword v

1 Sc ope 1

2 Nor mati ve r eferenc es 1

3 Terms an definitions 1

4 Main val ve c ompo ents 2

4.1 Bod y 2

4.2 Noz le 2

4.3 Disk 2

4.4 Co e 2

4.5 Dia hrag m 2

5 Desig n 3

6 Materials 4

7 Productio testing and inspectio 4

7.1 Purp se 4

7.2 Impact es 4

7.3 Non-des ructive inspe tion 4

7.4 Pr es ur e tes 5

7.4.1 General r eq ir ement 5

7.4.2 Fluid 5

7.4.3 Duration 5

7.4.4 Tes eq ipment 5

7.5 Surfac inspe tion 5

7.6 Visual inspe tion 5

8 Perfor manc e test 6

8.1 Pe formanc tes in ambient temper atur e 6

8.1.1 P rp se 6

8.1.2 Numbe of tes times 6

8.1.3 Fluid 6

8.1.4 A cc ptanc c ite ia 6

8.2 Leakag e tes in ambient emperatur e 6

8.2.1 P rp se 6

8.2.2 Fluid 6

8.2.3 Tes pr es ure 6

8.2.4 Duration 6

8.2.5 A cc ptanc leakag e rate 6

8.2.6 Tes eq ipment 7

8.3 Pe formanc tes in low temperatur e 7

8.3.1 P rp se 7

8.3.2 Numbe of tes times 7

8.3.3 Fluid 7

8.3.4 A cc ptanc c ite ia 7

8.4 Pr eparation for the pe formanc tes in low temperatur e 7

8.4.1 Start temperatur e for thetes 7

8.4.2 Safety req ir ement 7

8.4.3 Tes sys em 7

8.5 Leakag e tes in low temperatur e 8

8.5.1 P rp se 8

8.5.2 Fluid 8

8.5.3 Tes pr es ure 8

8.5.4 Duration 8

9 Vacuum test 9

9.1 Purp se 9

9.2 Vacu m con ition 9

9.2.1 Tes temperatur e 9

9.2.2 Vacu m set tes 9

9.2.3 Numbe of tes times 9

9.2.4 Fluid 9

10 T ype test 9

11 Deter minatio of piot oper ated safety val ve per formanc e 9

12 Sizing of pi ot o erated safety val ves 10

13 Mar king and se lng 10

Biblog raph y 11

ISO (he Int ernational Org nization for Stan ardization) is a worldwide fede ation of national s an ards

b dies (ISO membe b dies) The work of pr p ring Int ernational Standards is normaly car ied out

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org nizations, g ove nmental an non-g ove nmental, in laison with ISO, also take part in the work

ISO cola orat es closely with the Int ernational Ele trot ech ical C mmis ion (IEC) on al matt ers of

ele trot ech ical s an ardization

The proc d r s used t o develo this document an those int en ed for it furthe maint enanc ar

desc ibed in the ISO/IEC Dir ctives, Part 1 In p rticular the dife ent a pro al c it eria ne ded for the

dife ent ty es of ISO document should be not ed This document was draft ed in ac ordanc with the

edit orial rules of the ISO/IEC Dir ctives, Part 2 ( e www iso org dir ctives)

A tt ention is drawn t o the p s ibi ity that ome of the element of this document ma be the subje t of

p t ent right ISO shal not be held r sponsible for identifying any or al such pat ent right Detais of

any p t ent right identif ied d ring the develo ment of the document wi be in the Introd ction an / r

on the ISO ls of p t ent de larations r c ived ( e www iso org p t ent )

Any trade name used in this document is information given for the convenienc of use s an does not

cons itut e an en orsement

For an ex lanation on the meaning of ISO spe ific terms an ex r s ions r lated to conformity as es ment,

as wel as information a out ISO’s adhe enc to the Wor ld Trade Org nization (WTO) principles in the

Te h ical Bar ie s to Trade (TBT) se the folowing URL: www iso org / iso/ for word html

This document was pr p r d b ISO Te hnical Committ ee ISO/TC 8, S ips a d marine techn lo y,

Subcommitt ee SC3, Pipin a d machine y

Ships and marine technolog y — Safety val ve for car g o

This document spe ifies the r q ir ment of design, t es and inspe tion methods for dia hra m-ty e

piot o e at ed safety v lves, w hich ar used in carg o tanks of LNG car ie s in orde t o ke p the pr s ur

inside the tank below ma imum alowa le working pr s ur

2 Normati ve r eferences

The folowing document ar r fe r d t o in the t ext in such a wa that some or al of their cont ent

cons itut es r q ir ment of this document F or dat ed r fe enc s, only the edition cit ed a ples F or

un at ed r fe enc s, the lat es edition of the r fe enc d document ( inclu ing any amen ment ) a ples

ISO 41 6-4, S fet y dev ic es fr protec tio a ains t exc es s i ve pr s s ur — Part 4 : Pilot o e ated s afet y v lves

IMO, The Inte n tio al Code fr the Co s truc tio a d Eq ipment o S ips Carr y in Lique ied G as es in B ulk

(IG C Code)

API STD 5 7, Seat Tig tnes s o Pres s ur R elefValves

ASME B1 34, Valves-Fla ged, Thr aded a d Weldin End

3 Terms and definitions

F or the purpose of this document, the folowing t erms an def initions a ply

ISO an IEC maintain t erminolo ical data ases for use in s an ardization at the folowing ad r s es:

— IECEle tro edia: a aia le at ht p:/ www ele tro edia org

— ISO Onlne brow sing plat orm:a ai a le at ht p:/ www iso org o p

3.1

blowdown

dife enc betwe n theset an r seating pr s ur s

Note 1 t o entry: Blowdown is normal y stated as a per entag e of set pres ure, ex cept or pres ures of les than 3

b r, when the blowdown is e pres ed in b r

3.2

flow are

c os -se tional ar a (but not the curtain ar a) betwe n inlet an seat that is used t o calculat e the

theor tical flow ca acity of the main v lve, with no ded ction for any o s ruction

3.3

l f

actual tra el of the main v lve disk awa from the closed p sition

piot operated safety valve

a ut omatic, self-actuat ed devic comprising a main v lve an an at ached piot v lve

Not e 1 t o entry: T e pilot respon s to the pres ure of the fluid without an other energy sour e than the fluid

itself, an controls the operation of the main valve T e valve opens when the fluid pres ure inc e ses t o the pilot

valve set point T e valve re-closes when the fluid pres ure is red ced t o rese ting pres ure S e Figure 1

3.5

rese ting pres ure

v lue of the inlet s atic pr s ur at w hich the disk r -es a l shes contact with the seat or at w hich the

l f be omes z ro

3.6

set pres ure

tan pr s ur at w hich the main v lve of a piot o e at ed safety v lve un e o e ating con itions

begins t o o en

3.7

theoretical dis harg e capacity

calculat ed ca acity ex r s ed in mas or v lumetric u it of a theor ticaly pe fe t noz le ha ing a

c os -se tional flow ar a eq al t o theflow ar a of a main v lve

3.8

v acuum set

neg tive tank pr s ur v lue at w hich the v lve s art t o o en u de working con itions

4 Main val ve c omponents

4.1 Bod y

The b dy inlet is con e t ed dir ctly t o the tan , and the exit is conne t ed t o a discharg e pipe It keeps

the pr s ur contained an en ur s the r action of pr s uriz d fluid discharg ed from the sy st em

It jets out pr s uriz d fluid to the discharg e pipe

It works with the seat t o pro ide sealng function t o pr vent leakag e w hen it is closed It is in dir ct

contact with the working fluid, an ma be damag ed p rt if the fluid contains solds or for ign mat erial

4.4 Cover

It is con e ted to the b dy an makes a pr s ur spac whe e flow can oc ur

It is a main component as embled betwe n the main v lve body an the co e It delve s the fluid

pr s ur t o the disk

8 sense diap rag m

Figure 1 — Main compo ents of piot operated safety valve (Diaphra m ty e)

5.1 The desig n shal incorp rate g uiding arr ang ement ne es ary to ensur e consis ent o eration an

seat tig htnes

5.2 The noz le of the main v lve, othe than when it is an integ r al p rt of the v lve b d y, shal be

fas ened se urely to pr event the seat fr om be oming lo se in se vic

5.3 Valve o eration shal be desig ned to provide consis ent , pr ope fu ction in ve y low pres ur e an

c y g enic se vic s

5.4 Means shal be pr ovided to lock an / r to seal al exte nal adjustment to pr event u authoriz d

adjus ment of the piot o erated safety v lve

5.5 In thecase of main v lves with r es ricted lft , the lf restricting devic shal lmit the main v lve lf

but shal not othe wise inte fer e w ith the o er ation of the main v lve The lf r es ricting devic shal be

desig ned, ins aled an sealed b the v lve man factur er

5.6 Piot o er ated safety v lves for flamma le fluids shal dischar g e to a non-hazar dous location

5.7 Valves shal be desig ned so that tear or damag e to the dia hrag m can be che ked without

disas embly

5.8 It shal be desig ned that fluid can be fuly r eleased un e 1,1 times of the max imum alowa le

pr es ure of the pr ote tion sys em

5.9 The fitting of any ad itional devic to a piot an v lve combination shal not pr event the

pr es uriz d sys em fr om being pr ote ted u de any circumstanc s

6.1 Mate ials of the v lve used near slppe y surfac s, such as disk, disk g uide an holde /spindle,

shal be corrosion r esis ant an wear r esis ant These mate ials shal also ha ve d r abi ty in ve y low

temperatur e envir onments

6.2 Gasket that ha ve sealng fu ctions shal be cons ructed of mate ials ha ving d rabi ty in – 6 °C

envir onment

6.3 Mate ials of the b dy an noz le that ar e directly ex posed to ve y low temperatur e envir onment

shal be eq al to C 3M

6.4 The spring mate ials shal be eq al to C 3M for d rabi ty in ve y low temperatur es

6.5 The mate ials of al othe comp nent shal ha ve d rabi ty in ve y low temperatur es

7 Production testing and inspection

The purp se of these t es s is t o ensur that pr s ur r taining component , espe ial y cas ings, me t

the r q ir ment for w hich they ha e be n designed an man factur d without exhibiting any form of

q alty defe t

7.2 Impact test

Cas ings, such as b dy an noz le et c shal satis y the V-not ch c it eria of Charp imp ct t es ing in

ac ordanc with IGC code 6.1.4

7.3 Non-destructi ve inspection

If the mat erial is cas ing, the inside or out ide of the mat erial shal be t est ed b non-des ructive

inspe tion Normaly, a radio ra hic t es (RT) is con uct ed, but alt ernative non-des ructiveinspe tion

can be con uct ed b r q ir ment of the pur hase s

7.4 Pres ur e test

7.4.1 General r equirement

It is con uct ed on cas ings such as the noz le, b dy an co e These component shal not ha e

deformation, leakag e or any othe un sual con ition w hen 1,5 times of set pr s ur is a pled ac ording

t o ASME B1 34

7.4.2 Fluid

Pr s ur t es shal be con uct ed b wat er or air pr s ur The working fluid shal be fr sh wat er an

con uct ed in ambient t empe atur

7.4.3 Duration

It shal be for 1 min aft er a plying t es pr s ur

7.4.4 Test eq ipment

An ex mple of the eq ipment is shown in Figur 2

Key

1 b d an cover

2 noz le

Figure 2 — Water pres ure test eq ipment

7.5 Surface inspection

It shal be che ked an ve if ied that the e ar no shrin ag e ca ities, bur s, san inclusions or c acks on

the inside an out ide of thecas ing surfac If the ear c acks, the de ision shal satis y ISO 41 6-4

7.6 Visual inspection

7.6.1 F r g ing s shal be che ked for evidenc of cracks

7.6.2 T er e shal not be any defe t on machined surfac s directly contacting the gasket C rne s or

edg es shal be r ou ded out an chamfer ed

8 P erformanc e test

8.1 Perfor manc e test in ambient temperatur e

8.1.1 Purpose

The purp se is t o che k that the v lve is working wel un e set pr s ur an t ole anc in ambient

t empe atur

The set pr s ur an t ole anc shal satis y Ta le 1

Table 1 — Tolerance of set pres ure

a

± 0% of set pres ure

a

Actual set pres ure shal satis y p rchaser ’ spe ific tion

b

Toleranc for negative pres ure is ±2 %

8.1.2 Number of test times

The man factur rs an the pur hase s ma r ach an a r ement for the n mbe of pe formanc t es

times, but he t es shal be con uct ed at leas 5 times for pe formanc consist ency

8.1.3 Fluid

Ine t g s an air shal be used

8.1.4 Ac c eptanc e c iter ia

The v lve shal be o en u de the t ole anc of set pr s ur

8.2 Le kag e test in ambient temperature

8.2.1 Purpose

The purp se of this t es is t o ve ify the air tightnes on the seat w hen the v lve is closed in ambient

t empe atur

8.2.2 Fluid

Air or N

2

shal be used

8.2.3 Test pres ur e

It shal be s art ed at 90 % of the set pr s ur

8.2.4 Duration

It shal be r tained for at leas 5 min

8.2.5 Ac c eptanc e le kag e rate

Leakag e rat e of the safety v lve between the disk an seat shal be les than 0,0 ml/min/mm

(1,5 cm

3

/min/inch diamet er)

8.2.6 Test eq ipment

Inspe tion method is shown in Figur 3 Leakag e measur ment shal be con uct ed using 1,0 mm wal

thicknes an 8,0 mm out er diamet er pipe ac ording t o API STD 5 7

Figure 3 — Le kag e inspection metho

8.3 P erformanc e test in low temperature

8.3.1 Pur pose

The purp se of this t es is t o che k that the v lve is working ac urat ely u de the set pr s ur an the

t ole anc The set pr s ur an t ole anc shal satis y Ta le 1

8.3.2 Numbe of test times

The man factur rs an the pur hase s ma r ach an a r ement for the n mbe of pe formanc t es

times, but thet es shal be con uct ed at leas thr e times

8.3.3 Fluid

Hel um g s shal beused

8.3.4 Ac c eptanc e c iteria

The v lve shal o en u de the t ole anc of set pr s ur

8.4 Preparation for the perfor mance test in low temperatur e

8.4.1 Star t temperature for the test

The tes shal be s arted after the inside of the noz le tempe atur r aches – 6 °C; the t empe atur shal

be measur d b a the mocouple Also, the tempe atur shal be dro ped b LN

2

or simi ar lq id to LN

2

8.4.2 S fety r equir ement

Prot ectiveg ear mus be used d ring the t es

8.4.3 Test system

1 pres ur e gaug e

2 thermocou le

3 dig ital manometer

4 temperatur e sensor

Figure 4 — Sy stem for performance test in low t emperature (example)

8.5 Le kag e test in low temperatur e

8.5.1 Purpose

The purp se of this t es is t o ve ify the air tightnes on the seat w hen the v lve is closed in low

t empe atur s

8.5.2 Fluid

Helum g s, w hich is below – 6 °C, shal be used

8.5.3 Test pres ur e

It shal be s art ed at 90 % of the set pr s ur

8.5.4 Duration

It shal be r tained for at leas 5 min