INTERNATIONAL STANDARD ISO 16852 Second edition 2016-10-15 Flame arresters — Performance requirements, test methods and limits for use Arrête-flammes — Exigences de performance, méthodes d’essai et limites d’utilisation Reference number ISO 16852:2016(E) © ISO 2016 ISO 16852:2016(E) COPYRIGHT PROTECTED DOCUMENT © ISO 2016, Published in Switzerland All rights reserved Unless otherwise specified, no part o f this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission Permission can be requested from either ISO at the address below or ISO’s member body in the country o f the requester ISO copyright o ffice Ch de Blandonnet • CP 401 CH-1214 Vernier, Geneva, Switzerland Tel +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org ii © ISO 2016 – All rights reserved ISO 16852:2016(E) Contents Page Foreword v Introduction vii Scope Normative references Terms and definitions Abbreviated terms and symbols Hazards and flame arrester classifications 6 Flame trans mis s io n: deflagratio n, s tab le and uns tab le deto natio n 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 Measuring instruments Construction Housings Joints Pressure test Leak test Flow measurement (air) Flame transmission test 6.8.1 General 6.8.2 Test mixtures f 10 General requirements 6.9 tes ts to b e co nducted Construction 11 Design series 11 Flame transmission test 12 7.3.1 General 12 12 7.3.3 Detonation test 16 7.3.4 Short time burning test 21 7.3.5 Endurance burning test 23 Limits for use 25 7.4.1 General 25 26 26 26 26 7.3 D eflagratio n tes t I n- line flame arres ter Pre- vo lume flame arres ter 4 D eto natio n flame arres ter S ho rt time b urn flame arres ters Specific requirements for liquid product detonation flame arresters 27 8.1 8.2 8.3 8.4 Liquid seals 27 Foot valves 27 Flame transmission test 28 Limits for use 29 9.1 9.2 General 29 Flame transmission tests 30 30 31 32 9.2.4 Endurance burning test 32 Limits for use 33 Specific requirements for dynamic flame arresters (high velocity vent valves) 29 9.3 10 S ummary o Specific requirements for static flame arresters 11 7.1 7.2 7.3 7.4 Flame transmission: stabilized burning 5.2 9.2 Lo w flo w flame trans mis s io n tes t 9.2 Flame trans mis s io n tes t by o p ening and clo s ing 9.2 D eflagratio n tes t Specific requirements for hydraulic flame arresters 33 © ISO 2016 – All rights reserved iii ISO 16852:2016(E) 10.1 Equipment 33 10.2 Flame transmission test 33 10.2.1 General 33 10.2.2 Short time burning test 33 34 10.2.4 Detonation test 34 10.3 Limits for use 34 0.2 D eflagratio n tes t 37 11.1 General 37 11.2 Flame transmission test 37 11.2.1 General 37 f 39 f 39 12 Information for use 40 12.1 Instructions for use 40 12.2 Marking 41 12.2.1 Flame arrester 41 12.2.2 Flame arrester element 43 Annex A (normative) Flow measurement 44 Annex B (informative) f f 48 Annex C (informative) Best practice 49 50 1 T e s t o f f l a m e a r i iv b l i o g r a p h e s t e r s i n s t a l l e d o n o r w i t h i n g a s c o nv e y i n g e q u i p m e n t 1 2 Tes t p ro cedure o r gas co nveying equip ment with inlet p res s ure > 0 hPa 1 Tes t p ro cedure o r gas co nveying equip ment with inlet p res s ure ≤ 0 hPa B r I n o r m a t i o n o r s e l e c t i n g f l a m e a r r e s t e r s y © ISO 2016 – All rights reserved ISO 16852:2016(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies) The work o f preparing International Standards is normally carried out through ISO technical committees Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters o f electrotechnical standardization The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part In particular the different approval criteria needed for the di fferent types o f ISO documents should be noted This document was dra fted in accordance with the editorial rules of the ISO/IEC Directives, Part (see www.iso.org/directives) Attention is drawn to the possibility that some o f the elements o f this document may be the subject o f patent rights ISO shall not be held responsible for identi fying any or all such patent rights Details o f any patent rights identified during the development o f the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents) Any trade name used in this document is in formation given for the convenience o f users and does not constitute an endorsement For an explanation on the meaning o f ISO specific terms and expressions related to formity assessment, as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html The committee responsible for this document is ISO/TC 21, Equipment for fire protection and firefighting This second edition cancels and replaces the first edition (ISO 16852:2008), which has been technically revised with the following changes: — Clause 1: information concerning existing standard from IMO (International Maritime Organization) for maritime application added; — 3.18 : definition of dynamic flame arrester revised; — Clause 4: abbreviation for the time tPpeak added; — 6.5 : production test procedure for flame arresters of welded construction and of cast components revised; — 6.7: flow measurement (air) revised; — 7.3.3.2 and 7.3.3.4: in the flame transmission test for stable and unstable detonation without restriction the deflagration tests with Lu/D = deleted; — 7.3.3.2: formula for the calculation of the average value p md added; — Figure and Figure : figures for the test apparatus for deflagration tests of end-of-line flame arrester and o f pre-volume flame arresters revised; — Figure and Figure 7: figures for the test apparatus for short time burning test and for endurance burning test revised; — 7.3.4: short time burning test for inline flame arresters revised; — 7.3.5 : test pressure for the endurance burning test of inline flame arresters added; — 7.4.5 : limits for use of short time burn flame arresters added; — 8.3 : flame transmission test for liquid product detonation flame arresters revised; © ISO 2016 – All rights reserved v ISO 685 : 01 6(E) — — — — — — Clause : “Specific requirements for dynamic flame arresters (high velocity vent valves)” revised; Clause 11 : “Test of flame arresters installed on or within gas conveying equipment” added; 12.1 : “Instructions for use” revised; 12.2 : “Marking” revised; Figure A.1: pipe lengths revised; Annex C : “Best practice” revised; — Annex D: “Use o f in-line stable detonation flame arresters” deleted; — Bibliography: updated It also incorporates the Technical Corrigenda ISO 16852:2008/Cor 1:2008 and ISO 16852:2008/Cor 2:2009 vi © ISO 2016 – All rights reserved ISO 16852:2016(E) Introduction F la me a rre s ters are s a fe ty device s fitte d to op en i ngs o f enclo s u re s or to pip e work and are i ntende d to a l low flow but prevent fla me tra n s m i s s ion T hey h ave widely b e en u s e d for de c ade s i n the chem ic a l a nd oi l i ndu s tr y, and a varie ty o f nationa l s tandard s i s avai lable T h i s I nternationa l Standa rd was prep a re d b y an i nternationa l group o f e xp er ts , who s e a i m was to e s tabl i s h a n i nternationa l b a s i s b y harmon i z i ng and incorporating recent national developments and standards as far as reasonable This International Standard addresses manufacturers (performance requirements) and test institutes (test methods), as well as customers (limits for use) O n ly relatively genera l p er forma nce re qu i rements are s p e ci fie d a nd the s e a re kep t to a s tric t m i n i mu m E xp erience h as shown th at e xce s s ively s p e ci fic re qu i rements restrictions and prevent innovative solutions T he z ard identi fic ation o f com mon appl ic ation s fou nd in th i s field o ften cre ate unj u s ti fie d i n i ndu s tr y le ad s to the s p e c i fic ation o f the te s t me tho d s T he s e te s t me tho d s refle c t s tandard prac tic a l s ituation s and, a s s uch, form the he ar t o f th i s I nternationa l Sta nda rd b e c au s e they a l s o a l low cla s s i fic ation o f the variou s typ e s o f flame arre s ters and then determination of the limits of use A considerable number of test methods and test conditions had to be taken into account for two main reasons a) D i fferent typ e s o f fl ame arre s ters are covere d with re s p e c t to the op erati ng pri nciple (s tatic, hyd rau l ic, l iqu id , dyna m ic) a nd e ach typ e cle a rly ne e d s its s p e c i fic te s t s e t-up a nd te s t pro ce du re b) I t i s ne ce s s a r y to adap t fl ame arre s ters to the s p e ci a l cond ition s o f appl ic ation ( ga s , i n s ta l lation) b e c au s e o f the fl ic ti ng demand s o f h igh flame quench i ng cap abi l ity and low pre s s ure lo s s; th i s s ituation i s comple tely d i fferent from the o ther wi s e s i m i la r pri nc iple o f pro te c tion by flamepro o f enclo s u re (o f ele c tric a l e qu ipment) , where the i mp or ta nce o f pro ce s s gas flow th rough gap s i s ne gl igible; i mp or ta nce b ei ng place d on the flame quench i ng e ffe c t o f the gap C on s e quently, i n th i s I nternationa l Standard, the te s ti ng a nd cl as s i fication rel ate d to the ga s group s and the i n s ta l l ation cond ition s have b e en s ub d ivide d more than i s u s ua l ly the c a s e I n p a r tic u l ar, — explosion group IIA is subdivided into sub-groups IIA1 and IIA, — explosion group IIB is subdivided into sub-groups IIB1, IIB2, IIB3 and IIB, and — the typ e “de tonation arre s ter ” i s d i vide d i nto fou r s ub -typ e s , wh ich ta ke i nto accou nt s p e ci fic installation situations The test conditions lead to the limits for use which are most important for the customer This I nternationa l Sta nda rd s p e c i fie s th i s s a fe ty relevant i n formation and its d i s s em i nation th rough the manu fac tu rer ’s written i n s truc tion s T he l i m its for for u s e a nd the ma rki ng o f the flame a rre s ters u s e are a l s o a l i n k to more genera l (op erationa l) s a fe ty s ideration s and regu lation s , wh ich remai n the re s p on s ibi l ity o f nationa l or cor p orate authoritie s Annex B and Annex C offer some gu idance i n th i s field © ISO 2016 – All rights reserved vii INTERNATIONAL STANDARD ISO 16852:2016(E) Flame arresters — Performance requirements, test methods and limits for use Scope T hi s I nternational Standard s peci fies the requirements for flame arres ters that prevent flame transmission when explosive gas-air or vapour-air mixtures are present It establishes uniform principles for the clas s i fication, b as ic cons truc tion and in formation for us e, includi ng the marking o f flame arres ters , and s peci fies tes t metho ds to veri fy the s a fety requirements and determine s a fe limits o f us e This International Standard is valid for pressures ranging from 80 kPa to 160 kPa and temperatures rangi ng from −2 ° C to + ° C NO TE see 7.4 Fo r fl a me a r re s ters with o p eration a l cond itio n s i n s ide the s cop e , b ut outs ide atmo s p her ic cond itio n s , NO TE I n de s ign i ng a nd te s ti ng fl a me a r re s ters fo r o p eration u nder cond itio n s o ther th a n tho s e s p e c i fie d ab o ve , th i s I nter n ation a l S ta nd a rd c a n b e u s e d a s a gu ide H owever, add itio n a l te s ti ng rel ate d s p e c i fic a l l y to the i ntende d cond itio n s o f u s e i s advi s ab le T h i s i s p a r tic u l a rl y i mp o r ta nt when h igh temp eratu re s a nd p re s s u re s a re ap p l ie d T he te s t m i x tu re s m ight ne e d to b e mo d i fie d i n the s e c a s e s NOTE An additional standard IMO MSC/Circ 677 for maritime application from IMO (International Maritime Organization) exists This International Standard is not applicable to the following: — e xterna l s a fe ty-relate d me a s u rement and control e quipment th at m ight b e re qu i re d to ke ep the operational conditions within the established safe limits; NO TE I nte grate d me a s u rement a nd control e qu ipment, s uch a s i nte grate d temp eratu re a nd fl a me s en s ors a s wel l a s p a r ts wh ich , fo r e xa mp le , i ntention a l l y melt (re ta i n i ng pi n) , b u r n away (we ather ho o d s) (bimetallic strips), is within the scope of this International Standard — for fla me arre s ters u s e d or b end e xplo s ive m i x tu re s o f vap ou rs and gas e s , wh ich tend to s el f- de comp o s e (e g ace tylene) or wh ich are chem ic a l ly u n s table; — — fla me arre s ters u s e d for c a rb on d i s u lph ide, due to its s p e ci a l prop er tie s; fla me a rre s ters who s e i ntende d u s e i s for m i xtu re s o ther than ga s -a i r or vap ou r-a i r m i x tu re s (e g h igher ox ygen-n itro gen ratio , ch lori ne a s oxida nt, e tc ) ; — fla me arre s ter te s t pro ce du re s — fas t ac ti ng for i nterna l- combu s tion compre s s ion ign ition engi ne s; va lve s , e xti ngu i s h i ng s ys tem s and o ther e xplo s ion i s olati ng s ys tem s Normative references T he fol lowi ng c u ments , i n whole or i n p ar t, are normatively re ference d i n th i s c u ment a nd are indispensable for its application For undated references, the latest edition of the referenced document (i nclud i ng any amend ments) appl ie s IEC 60079-1, Explosive atmospheres — Part 1: Equipment protection by flameproof enclosures “d” Terms and definitions For the pu r p o s e s o f th i s c u ment, the © ISO 2016 – All rights reserved fol lowi ng term s and defi n ition s apply ISO 685 : 01 6(E) f l a m e a r r e s t e r device fitte d to the op en i ng o f an enclo s u re, or to the ne c ti ng pip e work o f a s ys tem o f enclo s u re s , and who s e i ntende d fu nc tion i s to a l low flow but prevent the tra n s m i s s ion o f flame 3.2 portion of a flame arrester (3.1) whose principal function is to provide a suitable enclosure for the flame arrester element (3.3 h o u s i n g ) a nd a l low me ch an ic a l ne c tion s to o ther s ys tem s 3.3 portion of a flame arrester (3.1 f l a m e a r r e s t e r e l e m e n t ) who s e pri nc ip a l fu nc tion i s to prevent flame tran s m i s s ion s t a b i l i z e d b u r n i n g s te ady bu rn i ng o f a fl ame s tabi l i ze d at, or clo s e to , the flame arrester element (3.3) 3.5 s h o r t t i m e b u r n i (3.4 n stabilized burning g ) for a s p e ci fie d ti me e n d u r a n c e b u r n i stabilized burning (3.4) for an unlimited time n g explosion abrupt oxidation or decomposition reaction producing an increase in temperature, pressure, or both s i mu ltane ou s ly [SOURCE: ISO 8421-1:1987, 1.13] 3.8 (3.7 [SOURCE: ISO 8421-1:1987, 1.11] d e f l a g r a t i o explosion n ) prop agati ng at s ub s on ic velo city detonation (3.7 [SOURCE: ISO 8421-1:1987, 1.12] explosion ) prop agati ng at s up ers on ic velo city and cha rac teri ze d b y a s ho ck wave 10 stable detonation (3.9 pressure characteristics detonation ) pro gre s s i ng th rough a fi ne d s ys tem without s ign i fic a nt vari ation o f velo city a nd N o te to entr y: For the atmo s p her ic co nd ition s , te s t m i x tu re s a nd te s t p ro ce du re s o f th i s I nter n ation a l S ta nd a rd , typ ic a l velo c itie s nge b e twe en 0 m/s a nd 2 0 m/s 11 uns table detonation detonation detonation (3.9) during the transition of a combustion process from a deflagration (3.8) into a stable No te to entr y: T he tran s ition o cc u rs i n a l i m ite d s p atia l z one, where the velo city o f the combu s tion wave i s no t s tant and where the e xplo s ion pre s s u re i s s ign i fic antly h igher than i n a s table de tonation T he p o s ition o f th i s tran s ition z one dep end s , amongs t o ther fac tors , on pip e diame ter, pip e figu ration , te s t gas and e xplo s ion group © ISO 2016 – All rights reserved ISO 16852:2016(E) Key f f D , length: L ), D1 D2 , length: L ), D2 throttle valve mixture inlet mixture outlet temperature sensor 10 11 12 f f 13 alternative ignition points close to the moved parts of the equipment gas co nveying equip ment flame arres ter inlet s ide, s ize o flange co nnectio n Ø flame arres ter o utlet s ide, s ize o flange co nnectio n Ø tes t p ip e flame arres ter inlet s ide – thro ttle valve (Ø: ≤ Ø1 tes t p ip e flame arres ter o utlet s ide – thro ttle valve (Ø : p re s s u re sensor (s tati c) ; in ad d i ti o n as an o p ti o n : p re s s u re ≤ Ø2 s enso r (dyn am i c) , fl am e d e te cto r an d p res s ure s ens o r (dynamic) flame detecto r temp erature s ens o r o n the flame arres ter s ur ace acing the tes t p ip e Figure 13 — Test apparatus for the flame transmission test o f flame arresters installed on or within gas conveying equipment The diameter of the test pipe parts (D1 , D2 ) i n s ta l le d b e twe en the flame arre s ters a nd the th ro ttle va lve s sh a l l no t b e larger tha n the s i ze o f fl ange ne c tion o f the re s p e c tive fla me arre s ter Re duc tion s or en l argements o f the d i ame ters o f the te s t pip e p ar ts may b e c a rrie d out on ly a fter a leng th o f 10 × down s tre a m o f the flame a rre s ter on the i n le t s ide and 10 × D1 D2 down s tre am o f the flame arre s ter on the outlet side The nominal size of the throttle valve shall be the same or smaller than the diameter of the pipe (D1 or D2 ) Mixture inlets and outlets in the test pipe shall be arranged to be close to the throttle valve T he ignition s ou rce sha l l b e pl ace d a s ne ar as p o s s ible to the me ch an ic a l ly move d p ar ts o f the e qu ipment on the inlet side or on the outlet side 38 © ISO 2016 – All rights reserved ISO 685 : 01 6(E) The tests shall be carried out with a gas/air-test mixture as specified in Table The test apparatus with a closed throttle valve shall be purged with the test mixture until the mixture concentration at the outlet corresponds to the specifications o f Table 2, and then isolated from the gas filling system 11.2.2 Test procedure for gas conveying equipment with inlet pressure >600 hPa A fter su fficiently purging the test apparatus with the test mixture, the specified parameters in Table 8: — operating state of the equipment, — position of the throttle valve, and — test mixture pressure in the test apparatus shall be adjusted for the respective test 12 tests shall be carried out with working equipment (see Table 8) The mixture temperature and the equipment shall be warmed up that the temperature profile up to a steady-state temperature (60 °C or the maximum allowed temperature given by the manu facture at the inlet as a general rule) The maximum gas temperature shall be measured at the mixture outlet Six tests shall be carried out with switched-off equipment (see Table 8) The equipment and the test mixture shall be at ambient temperature when the test mixture is ignited Table — Number o f the individual tests and test parameters for the flame transmission test o f flame arresters installed on or within gas conveying equipment with inlet pressures >600 hPa Tes t p arameters Operating state M i xture pres sure Ignition point Max inlet pressure outlet pressure Rotating at max speed Max Max inlet pressure Max outlet pressure Stationary Max inlet pressure Po sition of the Numb er of tes ts throttle valve Inlet side Outlet side Inlet side Outlet side Open Approx 80 % closed a Open Approx 80 % closed a closed closed 3 3 3 a Valve closed so far (approx 80 %) so that the maximum outlet pressure is achieved in the equipment, but a su fficient air flow is remaining to avoid overheating o f the equipment In addition, the flame arrester on the inlet side shall be subjected to a short time burning flame transmission test according to 7.3.4 with connected pipe The external sur face temperature shall be taken into account when speci fying the temperature class o f the equipment 11.2.3 Test procedure for gas conveying equipment with inlet pressure ≤600 hPa A fter su fficiently purging the test apparatus with the test mixture, the specified parameters in Table 9: — operating state o f the gas conveying equipment, — position of the throttle valve and — test mixture pressure in the test apparatus shall be adjusted for the respective test © ISO 2016 – All rights reserved 39 ISO 685 : 01 6(E) Tests shall be carried out at the maximum operational temperatures at the flame arrester element according to Table T a f l b a l e m e — a r r N e u s t m e b r s e i r n o s f t t a h l l e e i d n d o i n v o i d r u w a i l t t h e i s n t s g a a s n c d o t n e s v e t y p i a n r g a e m q e u t i e p r s m f e o n r t t h w i e t f h l i a n m l e e t t p r r a e n s s s m u r i s e s s i o ≤ n t e s t h o P f a Tes t p arameters O p e r a t i n g s t a t e M i xture pres sure Po sition of the I g n i t i o n p o i n throttle valve Temperature at the flame arresters: Ambient temperature (≤60 °C) Rotation at max speed Max outlet pressure Stationary Max inlet pressure Stationary Max outlet pressure Max inlet pressure Open Closed Open Closed Closed 5 Outlet side Inlet side Outlet side Closed Closed Closed 3 Inlet side Inlet side Outlet side Open Closed Closed In addition, i f temperature at the flame arrester at inlet: >60 °C Rotation at max speed Stationary Max outlet pressure Max inlet pressure Numb er of tes ts Inlet side Outlet side Inlet side Outlet side In addition, i f temperature at the flame arresters at outlet: >60 °C Rotation at max speed t In addition, the flame arrester on the inlet side shall be subjected to a short time burning flame transmission test according to 7.3.4 with connected pipe The external sur face temperature shall be taken into account when speci fying the temperature class o f the equipment Information for use Instructions for use The manufacturer shall provide the following minimum written instructions and information: a) the in formation marked on the flame arrester and an explanation o f its meaning; b) in formation concerning the classification o f the flame arrester as outlined in Clause 5; c) all details o f the operational requirements, including the specific limits in accordance with 7.4, 8.4, 9.3 and 10.3, as appropriate; the maximum operational temperature and pressure shall be given; d) static flame arresters classified as sa fe for endurance burning shall include a warning that sa fe use is limited to hydrocarbons, and that extension to other chemicals may require testing with these specific chemicals; e) short time burning flame arresters and hydraulic flame arresters shall include a warning that additional external sa fety equipment is required; all data that are necessary to characterize the integrated temperature sensor used for the stabilized burning test shall be documented; if the user equips the flame arrester with any other temperature sensor, this sensor shall fulfil these requirements as a minimum; f ) the specific burn time and that this burn time was determined under atmospheric pressure; 40 © ISO 2016 – All rights reserved ISO 16852:2016(E) g) the a l lo we d i n s ta l l atio n d i re c tio n o f the fl a me a r re s ter wi th re ga rd to flo w d i re c tio n a nd protected side; h) a full description of installation and maintenance procedures; maintenance shall include cleaning f f conditions have taken place; i n s tr uc tion s and the pro ce du re to b e ol lowe d a ter deflagration, de tonation or s tabi l i z e d bu rn i ng i) fu l l de s crip tion o f the ne c tion s o f the fla me arre s ter; j) fla me arre s ters may b e u s e d i n combi nation with add itiona l pro te c tion me a s u re s , the overa l l s a fe ty o f the combi ne d i n s ta l lation s l l b e as s e s s e d , ta ki ng accou nt o f any h a z a rdou s are a cla s s i fic ation (zones) and of the likelihood of possible ignition sources; for k) end- o f-l i ne deflagration a rre s ters , a m i n i mu m d i s ta nce s l l be given for a ny ex terna l i n s ta l lation that m ight i mp r fla me or flow M a r k i n g 12.2.1 Flame arrester 12.2.1.1 General information T he fl ame arre s ter sh a l l b e marke d with the fol lowi ng i n formation: a) the name and address of the manufacturer; b) the designation of series; c) the serial number; the ye ar o f s tr uc tion [i f no t i ncor p orate d i n p oi nt c) ] ; d) e) the number of this International Standard, i.e ISO 16852; f) s e t pre s s u re and/or s e t vac uu m or for for flame arre s ters with i ntegrate d pre s s u re and/or vac uu m va lve, dynam ic flame a rre s ters; g) pro te c te d s ide (d i re c tiona l typ e s on ly) ; h) ma xi mu m flow rate ( hyd rau l ic fl ame arre s ters) ; i) explosion group M a nu fac turers and u s ers sha l l en s u re th at any marki ng i s le gible and l ab el s and attach ment device s are durable and resistant to environmental corrosion under operating conditions W a r n i n g i n f o r m a t i o n Flame arresters shall have a hazard sign with the following information: a) warning; b) fla me arre s ters h ave i n s ta l lation a nd app l ic ation l i m its; c) typ e de s ignation i n accorda nce with th i s I nternationa l Stand ard; d) for deflagration fla me a rre s ters , the s ign “DE F ” a nd the ratio e) for de tonation fla me arre s ters , the s ign “D E T ” i n combi nation with the typ e nu mb er: / L u D i s no t appl ic able (“n/a” ) ; — “1” – te s te d for / Lu D; for end- o f-l i ne fla me a rre s ters , un s table de tonation with re s tric tion; © ISO 2016 – All rights reserved 41 ISO 685 : 01 6(E) — “2” – tested for unstable detonation without restriction; — “3” – tested for stable detonation with restriction; — “4” – tested for stable detonation without restriction; f ) pre-volume flame arresters , the sign “VDEF” and the relevant limits (i.e pressure, temperature g) and volume) according to the test report, see 7.4.3; or burn rating, the sign “BC” plus the classification “a”, “b” or “c” (as specified below), together with f the burn time tBT (in min) for class “b”, i.e.: — “a” – endurance burn (no time limit); — “b” – short time burn according to 7.3.4; — “c” – no burn time; NOTE When a flame arrester has been tested against short-time burning, this will be marked with “Burning Class: b” and “Burning Time: tBT = ” (irrespective o f the fact i f the temperature sensors are installed or not) because this is a tested property o f the sa fety system h) explosion group; i) maximum operational temperature T0 ; j) maximum operational pressure p (absolute pressure) NOTE For end-o f-line flame arresters, the maximum operational pressure is not applicable Examples of marking plates are shown in Figures 14 and 15 below Figure 14 shows an example of a marking plate for an end-of-line deflagration arrester sa fe for burn classification “a” for explosion group (Ex Gp) IIA, for an operational temperature, T0 , o f 60 °C Warning Flame arresters have installation and application limits Type designation in accordance with ISO 16852 DEF F i L u/ D = n/a BC: a Ex Gp IIA T0 = 60° g u r e — E x a m p l e o f m a r k i — n g p l a t e , b u r n r a t i n g “ a ” Figure 15 shows an example of a marking plate for a detonation arrester of Type 2, for explosion group (Ex Gp) IIB3, for a burn classification “b” o f 15 min, an operational temperature, T0 , o f 120 °C and a maximum operational pressure, p0 , of 0,16 MPa NOTE 42 bar = 0,1 MPa © ISO 2016 – All rights reserved ISO 16852:2016(E) Warning Flame arresters have installation and application limits Type designation in accordance with ISO 16852 DET L u/ D = n/a BC: b; tBT = 15 Ex Gp IIB3 T0 = 120° p = 0,16 MPa abs F i g u r e — E x a m p l e o f m a r k i n g p l a t e , b u r n r a t i n g “ b ” 12.2.2 Flame arrester element T he fl ame arre s ter element sh a l l b e ma rke d with the ab ove, or a s a m i n i mu m with the information: a) the name of manufacturer or trade mark; b) fol lowi ng the identi fic ation co de; c) the serial number or code; d) the pro te c te d s ide (d i re c tiona l flame a rre s ter elements on ly) Compliance with item e) in 12.2.1.1 shall not be stated unless all appropriate requirements of this International Standard are met M a nu fac turers and u s ers sha l l en s u re th at any marki ng i s le gible and l ab el s and attach ment device s are durable and resistant to environmental corrosion under operating conditions © ISO 2016 – All rights reserved 43 ISO 16852:2016(E) Annex A (normative) Flow measurement A.1 General The pipes, as well as the connections between the pipes and the flame arrester, shall be smooth and without obstructions causing additional turbulence The nominal size, D, of the test pipes (L1 , L2 , L3 and L 4) shall be the same size as the flame arrester or dynamic flame arrester connection All pressure measuring points shall be arranged normal to the pipe axis and shall not influence the flow The test medium shall be air at ambient conditions Ambient pressure and temperature shall be recorded to convert flow rate to normal conditions A mass flow meter may be used to obtain a flow rate/pressure drop curve with a minimum o f 10 suitably spaced readings from stationary flow conditions Separate flame arresters and pressure and/or vacuum valves that are combined and used together shall be flow tested together as a single unit A I n - l i n e f l a m e a r r e s t e r s The test apparatus is shown in Figure A.1 The test pipes shall have the following lengths: — L1 ≥ 10 × D; — L2 = × D ; — L3 ≥ 10 × D; — L = × D The flow rate shall be increased in suitable steps up to the maximum requested by the manu facturer or user The pressure drop for each step shall be recorded (see item in Figure A.1) The pressure or vacuum side o f the blower may be used for in-line flame arresters 44 © ISO 2016 – All rights reserved ISO 685 : 01 6(E) Key blower or fan flow detector for recording in-line flame arrester pressure sensor for recording L , L , L , L length of apparatus pipes Figure A.1 — Test apparatus for recording the pressure drop/flow rate curve for in-line flame arres ters A.3 End-o f-line flame arrester A.3 General The test apparatus is shown in Figure A.2 The diameter of the tank (3) shall be su fficient to allow a mean flow velocity o f less than 0,5 m/s in the tank All tank pressure data ( p T ) shall be recorded under these conditions The test pipe shall have a length L1 ≤ 10 × D (see Figure A.2 ) I f reduction pipes are used, they shall not cause additional turbulence or restriction to flow The flow rate shall be increased in suitable steps up to the maximum requested by the manu facturer The pressure drop, pT, for each step shall be recorded (see item in Figure A.2) End-o f-line flame arresters combined with, or integrated into, pressure and/or vacuum valves (see Figure A.2 ) shall have the flow rate/pressure drop curve start at the set pressure (opening pressure) with increases in suitable steps up to the maximum flow rate requested by the manu facturer Vacuum valves shall have the direction o f flow reversed A.3.2 Special flow measurement for dynamic flame arresters Flow measurements for dynamic flame arresters shall be made using the lowest possible setting for the specific model without changing its characteristics, as defined in 9.2 The flow measurement shall consist o f three phases: — phase (opening phase): the capacity from shut to fully open; — phase (working area): the capacity from fully open and upward; — phase (closing phase): the capacity from fully open to shut © ISO 2016 – All rights reserved 45 ISO 685 : 01 6(E) The flow measurement for phase is carried out to establish pressure surges and/or pressure reductions The flow rate to be used for this purpose is determined as the flow at which the dynamic flame arrester is fully open Ten equally spaced measurements (10 % o f the flow rate, 20 % o f the flow rate, etc.) shall be recorded in the interval from shut to fully open I f the dynamic flame arrester features a system that makes it change its dynamic characteristics from modulating to full li fting, 10 additional and equally spaced measurements shall be made at this point within a span o f 10 % to each side The flow measurement for phase is carried out to establish the pressure increase from when the dynamic flame arrester is fully open and upward The capacity shall be measured at the pressure at which the dynamic flame arrester is fully open, and at five or more increments o f 10 % above this pressure The flow measurement for phase is carried out to establish the blow-down value o f the dynamic flame arrester The flow rate to be used is the least capacity at which the dynamic flame arrester remains fully open The pressure shall then be recorded for 10 equally spaced capacities between this flow and when the dynamic flame arrester is shut A flow chart shall be drawn based on the above measurements Key blower or fan flow detector for recording explosion-pressure-resistant containment pressure sensor for recording end-o f-line flame arrester L length of connecting pipe pressure in the flow test o f an end-o f-line flame arrester pT F i g u r e A f A U n d a l — a m m p T e e e s a d t r a r o p e s s p t c a e i l r r l a s a t u w t i i s t o f o h n r o r r t e e c w s i t s o t r h o d o f i n u t d g i t n y n h t e e a g p r m r a i e t c s e s d f l u a r p e r m e d s e r s o u a r p / r e r e f l a s o n w d t e r / o r a r ( t e v H i c a u c r u g h v e u m v e f o l v o r a c l e n d - o f - l i n e v e i t y v e n t valves) Dynamic flame arresters shall be tested in order to determine the maximum pipe length, LM , that does not lead to undamped oscillations The test apparatus is shown in Figure A.3 The test set-up shall incorporate a valve disc location monitor (e.g video camera, position meter) to trace the position of the valve disc during the test runs The initial pipe length, L2 , (Figure A.3), the volume, VM , and the pipe diameter, DM , shall comply with the specifications by the manu facturer DM , VM and LM are also basic parameters for the flame transmission test (9.2) and the resulting limits for use (9.3 ) For valves which (due to their characteristics) may perform periodic open/close cycles 46 © ISO 2016 – All rights reserved ISO 16852:2016(E) at certain flow rates, it is recommended to comply with the following condition: The tank volume, VM , should be large enough to ensure that tank volume has no e ffect on oscillations in any o f the tests For any dynamic flame arrester type, the following tests shall be carried out at the lowest setting intended for approval The flow rate into the containment shall be increased in 10 steps The span and step width o f the 10 flow rates shall be chosen depending on the valve characteristic, as specified below — For valves with VCL > , the lowest flow rate shall be × VCL and the highest shall be × VCL (step width × VCL ) — For valves with VCL = the lowest flow rate shall be 10 % of the rate at which the valve is fully open This value shall also be taken as step width , , At each flow rate, an opening o f the valve shall be awaited (i f initially closed) and the flow shall then be maintained for additional I f the disc location monitor indicates periodic contact with seat or upper stop with a frequency o f more than 0,5 Hz (undamped oscillation), the pipe length (L2 ) shall be shortened until this frequency value is not exceeded or the contacting ceases That length shall be recorded as LM Key blower or fan flow detector for recording containment pressure sensor for recording dynamic flame arrester pressure sensor L length of vent pipe Figure A.3 — Test apparatus for determining the non-oscillating conditions for dynamic flame arresters © ISO 2016 – All rights reserved 47 ISO 16852:2016(E) Annex B (informative) I n f o r m a t i o n f o r s e l e c t i n g f l a m e a r r e s t e r s To help manu facturers and users decide which flame arrester is the most suitable for their application, the information outlined in Table B.1 should be considered T a b l e Characteristic Service Analysis o f gases or vapours Molecular weight or density o f gas or vapour Flow rate Temperature ranges Pressure ranges Allowable pressure drop Type B — I n f o r m a t i o n f o r s e l e c t i n g f l a m e a r r e s t e r s Aspect to be considered Provide a brie f description o f the intended use for the flame arrester Provide full details o f flammable and non-flammable components, which will allow the correct flame arrester design, explosion group and choice o f materi- als to be made This will allow an equivalent air flow rate to be calculated for pressure drop determination This should be in volumetric terms, or su fficient in formation should be provided to allow a volumetric flow rate to be calculated For storage tank applications, the inbreathing and outbreathing requirements should be given, or su fficient in formation on the tank type, pressure resistance shape, dimensions, fill and empty rates should be provided to enable these parameters to be calculated For both design and operating conditions, the maximum and minimum temperatures will allow the correct element and mechanical design o f the flame arrester housing to be made For both design and operating conditions, the maximum and minimum pressures will allow the correct flame arrester element and mechanical design o f the flame arrester housing to be made The maximum pressure at which an explosive mixture can ignite in the process should be highlighted if this is different to the normal operating pressure For storage tank applications, the pressure and vacuum requirements should be given This will enable the correct flame arrester configuration to be provided and is determined from the volumetric flow rate Speci fy in-line, end-o f-line, pre-volume, short time or endurance burning sa fe and stable/unstable detonation, as required For in-line types, details o f the piping between the flame arrester and possible source o f ignition should be supplied in the form of a dimensioned sketch or isometric drawing Orientation 10 Pipe size 11 Connection type 12 Housing material State the intended orientation o f the flame arrester 13 Element material State the pre ferred material o f construction; this may be checked by the 14 Construction 15 Documentation 16 Regulations 48 The nominal size of the connecting pipe work should be stated Provide details o f the flanged or screwed connections State the pre ferred material o f construction; this may be checked by the manufacturer from an evaluation of the mixture composition and operating conditions manufacturer from an evaluation of the mixture composition and operating conditions Care should be taken when using materials, such as aluminium or plastics, which can cause incentive sparking or electrostatic charging State documentation requirements Applicable corporate and/or statutory regulations should be identified © ISO 2016 – All rights reserved ISO 16852:2016(E) Annex C (informative) Best practice Manufacturers and users should be aware of the aspects listed below a) F lame velo citie s and pre s s u re s o f e xplo s ive m i xtu re s c a n b e en h ance d by up s tre am turbu lence, wh ich ca n be c au s e d b y b end s , va lve s o f c ro s s or any ch ange s e c tion in the pip e For i n-l i ne defl agration fla me a rre s ters , the pip el i ne s on the u npro te c te d s ide, i e the pip el i ne b e twe en ign ition s ou rce and p o s ition o f the fl ame arre s ter, shou ld b e a s s traight a s p o s s ib le without ob s truc tion s b) D ynam ic flame arre s ters a re s en s itive to tu rbu lence and pre s s u re d rop c au s e d b y ob s truc tion s a nd longer pip el i ne s on the pro te c te d s ide b e twe en the tan k and the dyna m ic fla me a rre s ter T h i s m ight c au s e “ha m meri ng” or u nda mp e d o s ci l lation s c) F lame a rre s ters or/and fla me arre s ter p ar ts shou ld be i nclude d in an exi s ti ng e qu ip o tentia l b ond i ng arrangement, i f ne ce s s ar y d) F lame arre s ters shou ld no t b e p o s itione d ne a r ho t e qu ipment u n le s s cer ti fie d for the elevate d temp eratu re, as he at tra n s fer to the fla me a rre s ter wi l l re duce its p er formance and may c au s e it to fail Therefore, in addition, the distance between neighbouring endurance burning end-of-line fla me arre s ters s hou ld b e more than five ti me s the ma xi mum d i ame ter o f the flame a rre s ter e) Continuous monitoring of pressure drop is advised if the process is known to contain particulates or s ub s tance s wh ich may blo ck the element a nd over-pre s s uri z e the s ys tem f) g) S hut- o ff device s shou ld b e fu l ly op en du ri ng norma l op eration T he s u itabi l ity o f a fl ame a rre s ter s hou ld b e che cke d i f the pro ce s s cond ition s or the pip e work figu ration h as b e en cha nge d h) S ep arate flow te s ti ng o f fla me a rre s ters and pre s s u re and/or vac uu m va lve s us e d a s combi ne d but s ep arate device s i s no t covere d b y th i s I nternationa l Standard i) T he u s e o f M E S G as a n u ne qu ivo c a l me a s u re o f fla me arre s ter e ffe c tivene s s h as no t b e en va l idate d for all gas mixtures MESG is also a function of p s p e ci fic gas or combi nation o f ga s e s , j) fur ther I f there i s any doub t as to the prop er tie s o f any s p e ci al i s t advice s hou ld b e s ought (s e e B ibl io graphy) Po s s ible c ata lytic re ac tion c an b e avoide d b y prop erly cho o s i ng the materi a l o f the fla me arre s ter k) Flame arresters should be installed in accordance with the manufacturer’s operation manual and s hou ld b e mai ntai ne d regu larly, dep end i ng on the exi s ti ng op eration cond ition s I f it i s de te c te d that a fl as h b ack (deflagration or de tonation) or a s tabi l i z e d burn i ng s o cc u rre d at the device, the complete device needs to be checked l) F lame arre s ters may b e u s e d i n combi nation with add itiona l pro te c tion me as u re s T he overa l l s a fe ty o f the combi ne d i n s ta l lation s l l be as s e s s e d, ta ki ng accou nt o f any z ardou s are a cla s s i fic ation (zone s) a nd o f the l i kel i ho o d o f p o s s ible ign ition s ou rce s m) H igh s tre s s e s c a n b e exer te d on the fi xi ng p oi nts o f the fl ame arre s ter and on the u npro te c te d s ide o f the pipi ng e s p e ci a l ly i n the c a s e o f a de tonation ( h igh pre s s u re s ho ck wave) ; s tre s s e s b e twe en the flame arre s ter and the adj oi n i ng pip e work s hal l b e l i m ite d to accep table level s b y appropri ate installation, selection of material and construction © ISO 2016 – All rights reserved 49 ISO 685 : 01 6(E) Bibliography [1] ISO 3511-1, Process measurement control functions and instrumentation — Symbolic representation — Part 1: Basic requirements [2] [3] [4] ISO 8421-1:1987, Fire protection — Vocabulary — Part 1: General terms and phenomena of fire ISO 14617-7, Graphical symbols for diagrams — Part 7: Basic mechanical components IEC 60079-4, Electrical apparatus for explosive gas atmospheres — Part 4: Method of test for [5] [6] [7] [8] [9] ignition temperature IEC 60079-20-1:2010, Explosive atmospheres — Part 20-1: Material characteristics for gas and vapour classification — Test methods and data IMO MSC/Circ 677 Revised standards for the design, testing and locating of devices to prevent the passage o f flame into cargo tanks in tankers B randes E., & Redeker T “Maximum experimental safe gap of binary and ternary mixtures” in The fourth international symposium on hazards, prevention and mitigation o f industrial explosions, IV ISHPMIE October 2002, pp 207-213, ISBN 2-86883-616-X B randes E März; G., Redeker, T Normspaltweiten von Mehr-Brennstoffkomponenten-Gemischen in Abhängigkeit der Brennsto ffzusammensetzung , Braunschweig, June 1997, ISBN 3-89429-994-0 NFPA 69, Standard on Explosion Prevention Systems, 2014 edition, NFPA, Batterymarch Park, Quincy, MA 02169-7471 USA [10] NFPA 497, Recommended practice for the classification of flammable liquids, gases or vapours and o f hazardous (classified) locations for electrical installations in chemical process areas, 2012 edition , NFPA, Batterymarch Park, Quincy, MA 02169-7471 USA [11] P erry R.H., & Green D.W Perry’s chemical engineer’s handbook Eighth Edition, 2007 50 © ISO 2016 – All rights reserved ISO 685 : 01 6(E) ICS 13.220.10 Price based on pages © ISO 2016 – All rights reserved