Tiêu chuẩn iso 06184 2 1985 scan

ignitio of th rea c ta nts... It is imp orta nt tha t th c orec t- quiesc ent... Up n c omp le- tio of ea ch test, purge th ex p losio cha mb r with air.

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INT RATIO AL O G NIZA TIO FO STADR IZATIO W4 I(nY HAOnHR O rAHJA MR I-IO CTA~ATI4Al@4W*O GA NlSTlO INTR ATIOAL DE N RMALISTIO

Sy thmes d protectio co tre les explosio s - Pa rtie 2: D&termina tio d s in ices & explosio d s gaz combu tibles d ns la ir

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is

F oreword

IS0 (h Interna tio a l O rga niza tio for Sta nda rdiza tio ) is a worldwid fe era tio of

na tio a l sta nda rds b dies (IS0 memb r b dies) T he work of pre a ring Interna tio a l

b dy intereste in a s bjec t for which a tec hnic a l com ite h s b e esta b lish d ha s

me ta l a d n n-gov ernme ta l, in laiso with ISO , a lso ta ke pa rt in th work

Dra ft Interna tio a l Sta nda rds a do te by th tec hnica l com ite s a re c irc ula te to

th memb r b dies for a pprov a l b fore th ir a cce ta nce a s interna tio a l Sta nda rds by

lea st 7 % a pprov a l by th memb r b dies voting

Interna tio a l Sta nda rd IS0 616 /2 was pre a re by Tech ica l Com ite ISO /TC 21,

Equipme t for fire protectio a d fire fighting

Users sh uld n te tha t al Interna tio a l Sta nda rds un ergo revisio from time to time

a d tha t a ny refere ce ma e h rein to a y oth r Interna tio a l Sta nda rd imp lies its

la test e itio , unles oth rwise sta te

0 Interna tio a l O rga niza tio for Sta nda rdiza tio , 19 5 0

Printe In Switzerla nd

Ex p losion p r otection systems -

0.1 The a sses me t of mea sures re uir ed to p rovid p rotec -

tio a ga inst ex p losio ha za rds involving c omb ustib le ga s/ a ir

mix tures re uires p r ior d termina tio of th p ote tia l ex p losio

p rforma nce of ex p losio p rotec tio s stems re uires tha t th y

sh uld b teste a ga inst ex plosio s of known severity

The severity of a c omb ustib le ga s ex p losio is a func tio of th

folowing :

a) th c hemica l p rop erties of th c omb ustib le ga s;

b ) th c once tra tio of th c omb ustib le ga s in th ga s/ a ir

mix ture;

ga s/ air mix ture;

ga s/ air mix ture

0.2 This p a rt of IS0 616 is o e of a series d a ling with ex -

p losio p rotec tio s stems The oth r p a rts a re a s folows :

P a rt 1: Determina tio of ex p losio in ic es of c omb ustible

du ts in air

P a rt 3: D etermina tio of ex p losio in ic es of fue l/ air mix -

tures oth r tha n du t/ air a nd ga s/ a ir mix tures

P a rt 4 : Determina tio of efic a cy of ex p losio s p res io

s stems

0.3 The interp reta tio of ex p losio in ic es d termin d by th

meth d sp ec ifie in this p a rt of IS0 616 a nd th ir relatio to

p losio ha za rds sh uld b recognize In p ar tic ular , th d gre

of turbule c e ca n influe c e th ha za rd signific antly In p ra c tic e,

th ln b twe n a given d gre of turb ule c e a nd a sp ec ific

ty pe of ha za rd is th r esp onsib ilty of sp ec ialists in th fields of

ex p losio s a nd ex p losio p rotec tio

du fr ial p la nts a re :

a) quiesc ent c on itio s p r evailng in stora ge ves els;

b ) high turb ule c e c on itio s p r evailng in th regio of a n

ex tra c tio fa n

It sh uld b r ealize tha t turb ule c e ca n arise in two way :

op era ting c on itio s, a s a co se ue ce of p erturb a tio s to

th air-low;

b ) turb ule ce in u e by ob struc tio s within a n instal-

latio o a ga s which expa nds a s th res lt of a n ex p losio

This p a r t of IS0 616 sp ec ifies a meth d for th d termina tio

of th ex p losio in ic es of comb ustib le ga ses with air in a n

e close spa ce It giv es th cr ite r ia by which res lts ob ta in d

u ing oth r test proc edures ca n b c orelate to y ield ex p losio

in ic es a s d termin d by th meth d sp ec ifie in this p art of

IS0 616

2 Field of ap p lic atio

This p a rt of IS0 616 is a p p lic ab le o ly to th d termina tio of

ex p losio in ic es p ertaining to th d v elo me t of c onta in d

ga s/ air ex p losio s a fter ignitio of rea c ta nts It d es n t a pp ly

1

ignitio of th rea c ta nts If th sp ec ifie ex p erime ta l p ro-

res lt in ignitio of th ga s/ air mix ture, it sh uld n t b co -

c lud d that th ga s in questio ca nn t ex plo e The inter p r et

atio of s ch ca ses sh uld b le ft to sp ec ialists in th field of

exp losio s a nd exp losio p rotec tio

F or th purp se of this p a rt of IS0 616 th folowing de fini-

tio s a p p ly

3.1 ex p losio : Prop a ga tio of a fla me in a p re-mix ture of

c omb ustib le ga ses, s sp n e du ts), comb ustib le va p ourfs),

m ists), or mix tures th re f, in a ga se u ox ida nt s ch a s air , in

a c lose , or s b stantia lly close , v es el

a nce with th test meth ds sp ec ifie in this p a rt of IS0 616 ,

which cha ra c terizes th c onta in d ex p losio of a sp ec ifie co -

c entra tio of rea c ta nts in a ves el ha ving a v olume of 1 m3

NOT E - Fig re 1 s ows the p re s r e/ time c urv , ex p re s d in b ars1

an s c on s re p ec tivly , o f a ty p ic al ex p loio

th pres ure in th v es ela t th time of ignitio a tta in d during

a n ex p losio

3.2.2 ex p losio in ex p ,,

Ma ximum v a lue of th exp losio

in e pm d termin d by tests ov er a wid ra nge of rea c ta nt

co c entra tio s

rate of pres ure r i e with time tdp ldt, of a n ex p losio in a

v olume V, a cc ording to th e ua tio

NOT E - Un er cer tain c irc umstanc es, this e quatio n is no t valid fo r

ves els with a le ngth to diameter ratio gre ate r than 2 : 1 o r with a

v lume o f le s than 1-rn3

sio in ex K d termin d by tests over a wid ra nge of rea cta nt

c once tra tio s The viole c e of a n exp losio is ev a lua te from

th v a lue of Kma x

3.3 turb ule c e in ex : Numeric a l term which c ha ra cterizes

p a ra meter d fin d a s th time inter va l b twe n th initiatio n of

a ga s/air injec tio p roc edure in a n ex p erime ta l a pp a ra tu , a nd

th a c tiva tio of th ignitio n sourc e It cha ra c terizes th d gre

of turb ule c e p r evailng a t th mome t of ignitio

K ma x,Wrbule t d termin d a s sp ec ifie in this p a rt of IS0 616 to

th ex p losio in e K, , q iescent of th quies e t rea c ta nts It

is giv en by th e ua tio

K

T, =

ma x, tur b ulent

K

ma x, q ie c ent

c

Ti e, t

F ig r e 1

1) 1 br = 10 5 Pa

4 Test meth d

The ex p erime ta l a ppa ra tu d sc rib ed in this p a rt of IS0 616

is ch se a s a n exa mple, a nd is s ita b le for th evalua tio of

ex p losio in ic es of c omb ustib le ga ses in air

4 2 App a r a tu

The a pp a ra tu co sists es e tia lly of a c y lin ric al exp losio

cha mb r with a v olume of 1 m3 a nd a n a sp ct r atio n mina lly of

1 : 1, a s sh wn in fig r e 2

A c onta in r of a p p rox im ely 5 I ca pa city is a tta ch d to th ex-

p losio cha mb r a nd is c a p a ble of b eing pres urize with air to

2 b ar This c onta in r is fite with a 19 mm (3/ 4 in) quic k-

c onta in r within 10 ms of op ening th v a lve The c onta in r is

(3/4 in) inter na l dia meter tub which is forme into a p erfor-

a te (4 to 6 mm h le dia meter) semic irc ula r spra y p ip e The

numb r of h les in th p ip e shall b ch se s ch tha t th ir total

c ros -sec tio a l a re is a p prox im ely 3 0 m 2

C omb ustible ga s/ a ir mix tures, quies e t or turb ule t, shall b

F or ex a mple, a s ita b le ignitio source is a series of in uc tio

spa rks s sta in d for 0,5 s

NOT E - A s itab le ignitio source is pro u e by u ing a igh v olta ge

tra nsfor mer (a p p rox im ely 3 0 VA) with a n output of 15 kV (efec tive

va lue)

The sp a rk ga p sh uld n rma lly b 3 to 5 mm a nd shall b

loc a te in th ge metric ce tre of th test a p pa ra tu

The a p pa ra tu is a rra nge so tha t th ignitio n d la y (urb ule c e

in ex &I ca n b va rie if n ces a ry from test to test

A p res ure tra nsdu er is fite to mea sure ex p losio cha mb r

p res ure, this b eing ln e to a rec ord r

NO T E - If a very high ignitio n e erg is ch se , it is p os ib le tha t th

res lts wi d via te from th se ob ta in d u in a low e ner gy ig itio

surc e, sc h as d sc r ib ed ab o ve

ex a mp le, th meth d of p ar tial p res ures, th res lta nt mix ture

b eing a t a tmosp heric p res ure It is imp orta nt tha t th c orec t-

quiesc ent S ta rt th pres ure rec ord r a nd th n a c tiv a te th

p losio cha mb r with air

/- Contain r

Pres re tr ans ducer

C omb ustib le

sp ray p ipe

F ig re 2

3

R ep a t this proce ure over a wid ra nge of ga s co c entra tio s

to ob ta in c rv es of pm, in b a rs, a nd K, in b a r metres p er

seco d, v ers s ga s co c entra tio , a s p rce ta ges by v olume

fig re 3)

It sh uld b n te tha t in c erta in ca ses c omb ustio instab ilties

ca n oc ur a s a r es lt of ge metric a nd ignitio fa c tors These

instab iltie s r es lt in p res ure/ime c rv es which a re n t th

sy mmetric a l s-sha pe sh wn in fig r e 1 In s ch ca ses, inter -

p reta tio of res lts sh uld b lef to sp ec ia lists in th fie ld of ex -

p losio s a nd ex p losio p rotec tio

a ccorda nce with th meth d d sc rib ed in 4.3.1 Pres urize th

5 I c onta in r with air to 2 b ar Sta r t th pres ure rec ord r a nd

ignitio sourc e

Ignitio of th turb ule t gas/ a ir mix ture a t a ch se ignitio

d lay , turb ule c e in e t, a fter th injec tio of th compres e

air cha rge res lts in a turb ule t ga s ex p losio (se fig r e 4 )

NO T E - The influe c e of th compres e air charge o th fin l ex-

p losive ga s c once tra tio sh uld b ta ke into a ccount Up n c omp le-

tio of ea ch test, purge th ex p losio cha mb r with air

Re ea t th p roc edure ov er a wid ra nge of ga s c once tra tio s

(se fig r e 3) to ob ta in c rv es of pm a nd K to ob ta in pmx a nd

Kmx resp ec tively

A

C omb ustib le gas c o ncentratio n

Comb ustib le gas c onc enta&n

F ig re 3

C onta in r

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High turb ule c e

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L w turb ule c e

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Tur b ule ce In e tv

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Turb ule c e in e tv

F ig r e 4

4.4 Alte r native te st meth d

The ex p losio in ic es of c omb ustib le gas/ a ir mix tures ca n b

d termin d u ing a lternative test e uipme t a nd/or test p ro-

meth d logy giv es res lts com e s ra te with res lts o ta in d

4 3.1)

The test meth ds d s rib d in cla use 4 a llow th ex p losio

in ic es pma x a nd

Kma x of quies e t a nd turb ule t ga s/ a ir mix -

a cc ra cy of a pma x d terminatio is zk 4 % The a cc ra cy of a

K ma x d termina tio is d p n e t up n th c on itio s of tur -

b ule c e of th mix ture a t th time of ignitio

The test rep ort sha ll inc lud th folowing infor matio :

a ) typ of c ombu tible ga s;

pma w a nd Kma x mea sureme ts;

e) ex p losio in e Kma x, in b a r metres p er seco d;

cla use 4; s ch d via tio s a r e p er mis ib le, prov id d th y a re

re orte ex a c tly ;

g) da te of test

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