Revision Sept. 06 Safe Use of Hydrogen and Hydrogen Systems NASA Safety Training Center https://ntrs.nasa.gov/search.jsp?R=20070018005 2018-07-03T21:10:57+00:00Z
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Rev
isio
n Se
pt. 0
6
Saf
e U
se o
f Hyd
roge
nan
d H
ydro
gen
Sys
tem
s
NA
SA
Saf
ety
Trai
ning
Cen
ter
https://ntrs.nasa.gov/search.jsp?R=20070018005 2018-07-03T21:10:57+00:00Z
Cou
rse
Out
line
Cou
rse
Out
line
•In
trodu
ctio
n•
Why
Stu
dy H
ydro
gen
Saf
ety?
•Th
e H
ydro
gen
Haz
ard
•A
ddre
ssin
g th
e H
ydro
gen
Haz
ard
•C
ompo
nent
Des
ign
•P
EM
Fue
l Cel
l/Ele
ctro
lyze
r Iss
ues
•H
ydro
gen
Faci
lity
Des
ign
•H
ydro
gen
Haz
ards
Ana
lysi
s A
ppro
ach
•S
umm
ary
Intro
duct
ion
Intro
duct
ion
•A
ttend
ees
–N
ame
–W
hat d
o yo
u do
with
hy
drog
en?
•In
stru
ctor
s–
Har
old
Bee
son
–K
evin
Far
rah
–M
ax L
euen
berg
er–
Mig
uel M
aes
–La
rry
Sta
rritt
–S
teph
en W
oods
Adm
inis
trativ
e D
etai
lsA
dmin
istra
tive
Det
ails
•Fa
cilit
y sa
fety
con
side
ratio
ns•
Res
troom
s•
Bre
aks
•Q
uest
ions
and
ans
wer
s•
Cou
rse
eval
uatio
ns
Cou
rse
Obj
ectiv
esC
ours
e O
bjec
tives
•To
fam
iliariz
e yo
u w
ith H
2sa
fety
pr
oper
ties
•To
ena
ble
you
to id
entif
y, e
valu
ate,
and
ad
dres
s H
2sy
stem
haz
ards
•To
teac
h yo
u –
Saf
e pr
actic
es fo
r•
Des
ign
•M
ater
ials
sel
ectio
n•
H2
syst
em o
pera
tion
Cou
rse
Obj
ectiv
es (c
ont.)
Cou
rse
Obj
ectiv
es (c
ont.)
–P
hysi
cal p
rinci
ples
and
em
piric
al
obse
rvat
ions
on
whi
ch th
ese
safe
pra
ctic
es
are
base
d–
How
to re
spon
d to
em
erge
ncy
situ
atio
ns
invo
lvin
g H
2
–H
ow to
vis
ualiz
e sa
fety
con
cept
s th
roug
h in
-cla
ss e
xerc
ises
–Id
entif
y nu
mer
ous
para
met
ers
impo
rtant
to
H2
safe
ty
Hyd
roge
n ca
n be
han
dled
saf
ely…
…w
hile
stre
ssin
g ap
prop
riate
pre
caut
ions
We
Will
Sho
wW
e W
ill S
how
Cou
rse
Mat
eria
lsC
ours
e M
ater
ials
•C
ours
e sl
ides
•A
NS
I/AIA
A G
-095
-200
4, G
uide
toS
afet
y of
Hyd
roge
n an
d H
ydro
gen
Sys
tem
s*•
29C
FR19
10.1
03, H
ydro
gen
*Als
o av
aila
ble
on th
e N
AS
A T
echn
ical
Sta
ndar
ds
Pro
gram
[http
://st
anda
rds.
msf
c.na
sa.g
ov/]
Dis
clai
mer
Dis
clai
mer
•Th
e us
e, o
r mis
use,
of t
his
mat
eria
l is
the
resp
onsi
bilit
y of
the
atte
ndee
•If
you
have
an
inci
dent
–D
o no
t bla
me
the
cour
se in
stru
ctor
s–
Do
not b
lam
e an
yone
els
e–
Get
goo
d vi
deo
Cou
rse
inst
ruct
ors
assu
me
no re
spon
sibi
lity
Cou
rse
Lim
itatio
nsC
ours
e Li
mita
tions
•Im
prec
ise
quan
tific
atio
n •
Tech
nica
l jud
gmen
t req
uire
d•
No
uniq
ue s
olut
ions
giv
en•
No
endo
rsem
ents
impl
ied
•E
xam
ples
are
illu
stra
tions
onl
y
Tech
nica
l Jud
gmen
tTe
chni
cal J
udgm
ent
•O
verla
ppin
g ro
les
–W
hat m
ust y
ou k
now
?–
Wha
t mus
t oth
ers
know
?•
How
doe
s th
is in
form
atio
n af
fect
me?
Bot
tom
line
: Yo
u m
ust t
hink
Wha
t is
Judg
men
t?W
hat i
s Ju
dgm
ent?
•R
ecog
nitio
n of
–N
eed
–Li
mita
tions
–Im
plic
atio
ns a
nd c
onse
quen
ces
of a
ctio
ns•
Con
serv
ativ
e ap
proa
ch•
Sea
rchi
ng fo
r haz
ards
•E
very
situ
atio
n is
uni
que
•Y
ou a
re re
spon
sibl
e
Rem
embe
r…R
emem
ber…
Bat
tery
Box
Exp
losi
onO
ld J
SC
Wat
er Im
mer
sion
Fac
ility
(Jan
uary
29,
197
2)
Bat
tery
Box
Exp
losi
onO
ld J
SC
Wat
er Im
mer
sion
Fac
ility
(Jan
uary
29,
197
2)
•W
ater
tight
por
tabl
e ba
ttery
sup
ply
with
2
lead
-aci
d ce
lls h
ad b
een
char
ged
over
nigh
t•
H2
gas
vent
val
ve c
lose
d, n
ot o
pen
•V
alve
inst
alle
d to
pur
ge H
2at
dire
ctio
n of
pre
viou
s ha
zard
s an
alys
is•
Man
ually
ope
rate
d sw
itch
on li
d (m
agne
tic s
witc
h co
ntac
ts in
tern
al to
bo
x)
In a
see
min
gly
conv
entio
nal a
pplic
atio
n su
ch a
s th
is s
eale
d ba
ttery
box
…
…th
e bo
x lid
kill
ed o
ne w
orke
r and
sev
erel
y in
jure
d an
othe
r bef
ore
punc
turin
g a
35-ft
-hig
h co
ncre
te c
eilin
g
Tube
Tra
iler A
ccid
ent
Tube
Tra
iler A
ccid
ent
O2
inad
verte
ntly
leak
ed in
to th
is H
2tu
be tr
aile
r (m
odifi
catio
ns m
ade
with
out r
evie
w)
Tube
Tra
iler A
ccid
ent (
cont
.)Tu
be T
raile
r Acc
iden
t (co
nt.)
The
mix
ture
det
onat
ed a
t ~55
0 ps
i
Tube
Tra
iler A
ccid
ent (
cont
.)Tu
be T
raile
r Acc
iden
t (co
nt.)
Tube
s an
d sh
rapn
el w
ere
hurle
d 12
50 ft
, an
d se
vera
l em
ploy
ees
wer
e bu
rned
Tube
Tra
iler A
ccid
ent (
cont
.)Tu
be T
raile
r Acc
iden
t (co
nt.)
H2
Ven
t Lin
e E
xplo
sion
LH V
ent L
ine
Inci
dent
Sur
vey
H2
Ven
t Lin
e E
xplo
sion
Duc
t Fai
ls A
long
W
eld
H2
Ven
t Lin
e E
xplo
sion
(con
t.)H
2V
ent L
ine
Exp
losi
on (c
ont.)
H2
Ven
t Lin
e E
xplo
sion
(con
t.)H
2V
ent L
ine
Exp
losi
on (c
ont.)
Hyd
roge
n fla
mes
do
not
take
co
rner
s w
ell
H2
Ven
t Lin
e E
xplo
sion
(con
t.)H
2V
ent L
ine
Exp
losi
on (c
ont.)
H2
Ven
t Lin
e E
xplo
sion
(con
t.)H
2V
ent L
ine
Exp
losi
on (c
ont.)
Hyd
roge
n B
allo
on A
ccid
ent
Hyd
roge
n B
allo
on A
ccid
ent
•C
arls
bad,
NM
200
2 fir
ewor
ks d
ispl
ay•
Poo
r jud
gmen
t use
d in
con
stru
ctin
g an
d de
ploy
ing
a ba
lloon
fil
led
with
hyd
roge
n an
d ox
ygen
•O
ne fi
refig
hter
in
jure
d, a
nd p
ublic
“u
nnec
essa
rily
put
at ri
sk”
Why
stu
dy h
ydro
gen
safe
ty?
Why
Stu
dy H
2S
afet
y?W
hy S
tudy
H2
Saf
ety?
•B
ecau
se a
ccid
ents
occ
ur!
–In
the
‘70s
Ove
r 400
indu
stry
acc
iden
ts (F
acto
ry M
utua
l 4A
7NO
.RG
)
–96
NA
SA
mis
haps
(‘74
-Ord
in, N
AS
A T
M X
-715
65)
–S
ee th
e D
OE
Hyd
roge
n In
cide
nts
Dat
abas
e [h
ttp://
ww
w.h
2inc
iden
ts.o
rg/]
•D
espi
te H
2’s s
afe
use
for o
ver 1
00 y
ears
–To
wn
gas
was
50%
H2
•P
ublic
per
cept
ion
is c
autio
n &
dan
ger
–H
igh
scho
ol c
hem
istry
cla
ss e
xper
imen
t–
Hyd
roge
nbo
mb
Hyd
roge
n U
ses
Hyd
roge
n U
ses
•C
hem
ical
s23
%–
Sor
bito
l pro
duct
ion
–G
ener
al p
harm
aceu
tical
•E
lect
roni
cs23
%–
Pol
ysili
con
prod
uctio
n–
Epi
taxi
al d
epos
ition
–Fi
ber o
ptic
s•
Met
als
19%
–A
nnea
ling/
heat
trea
ting
–P
owde
r met
allu
rgy
•P
ropu
lsio
n17
%•
Food
, flo
at g
lass
, oth
er18
%–
Fats
/fatty
aci
ds–
Bla
nket
ing
Hyd
roge
n P
rodu
ctio
nH
ydro
gen
Pro
duct
ion
•P
rimar
y so
urce
–Li
ght h
ydro
carb
ons
•G
H2
prod
uctio
n (U
SA
)–
35 b
illio
n S
CFD
(Air
Pro
duct
s 20
02)
•LH
2op
erat
ing
capa
city
–13
6 to
ns p
er d
ay (U
SA
198
6)•
LH2
dem
and
–82
tons
per
day
(US
A 1
986)
Acc
iden
ts o
ccur
…A
ccid
ents
occ
ur…
…bu
t loo
ks c
an b
e de
ceiv
ing
Tank
er T
ruck
Fire
Tank
er T
ruck
Fire
Tank
er T
ruck
Fire
(con
t.)Ta
nker
Tru
ck F
ire (c
ont.)
LH2
Trai
ler A
ccid
ents
LH2
Trai
ler A
ccid
ents
Mile
s dr
iven
87
,600
,000
Tr
ips
76,2
00D
eliv
erie
s 13
5,00
0H
ydro
gen
rele
ases
an
d ac
cide
nts
0
Air
Pro
duct
s da
ta (1
967-
1989
)
LH2
Tran
spor
tatio
n -R
ealit
yLH
2Tr
ansp
orta
tion
-Rea
lity
Less
ons
Lear
ned
from
P
revi
ous
Inci
dent
sLe
sson
s Le
arne
d fro
m
Pre
viou
s In
cide
nts
Gen
eral
Mis
hap
Cau
ses
Det
aile
dM
isha
pC
ause
s
Less
ons
Lear
ned
from
Pre
viou
s In
cide
nts
(con
t.)
Less
ons
Lear
ned
from
Pre
viou
s In
cide
nts
(con
t.)
Hin
denb
urg
Mis
conc
eptio
nH
inde
nbur
g M
isco
ncep
tion
Hin
denb
urg
Mis
conc
eptio
n (c
ont.)
Hin
denb
urg
Mis
conc
eptio
n (c
ont.)
Wha
t has
bee
n se
en
Theo
ryTh
eory
•R
esea
rche
rs c
oncl
uded
H2
not t
o bl
ame
–Fi
lm fo
otag
e an
alys
is s
how
s ex
plos
ion
to
be in
cons
iste
nt w
ith h
ydro
gen
fire,
whi
ch
only
bur
ns u
pwar
d, w
ith n
o vi
sibl
e fla
me
–G
asba
gs c
oate
d w
ith g
elat
in–
Al p
owde
r mix
ed w
ith d
opin
g so
lutio
n m
ade
to s
tretc
h an
d w
ater
proo
f out
er h
ull
•19
30s
fabr
ic s
ampl
es te
sted
in m
oder
n la
bora
torie
s pr
oved
to s
till b
e co
mbu
stib
le
The
Hyd
roge
n H
azar
d
Saf
ety-
rela
ted
Pro
perti
es and
Wha
t You
Nee
d to
Kno
w
The
Hyd
roge
n H
azar
dTh
e H
ydro
gen
Haz
ard
•G
ener
al p
rope
rties
•P
rimar
y hy
drog
en h
azar
ds–
Com
bust
ion
–P
ress
ure
haza
rds
–Lo
w te
mpe
ratu
re–
Hyd
roge
n em
britt
lem
ent
–E
xpos
ure
and
heal
th
Phys
ical
Pro
pert
ies
Hyd
ro (w
ater
) + g
enes
(for
min
g) =
Hyd
roge
nPh
ysic
al P
rope
rtie
sH
ydro
(wat
er) +
gen
es (f
orm
ing)
= H
ydro
gen
•Fo
rms:
Ato
mic
Hyd
roge
n, M
olec
ular
Hyd
roge
n•
Isot
opes
: Pro
tium
(1am
u),
Deu
teriu
m (2
am
u),
Triti
um (3
am
u)•
Mol
ecul
ar H
ydro
gen
Sta
tes
–O
rthoh
ydro
gen
–pr
oton
s ha
ve p
aral
lel s
pins
–P
arah
ydro
gen
–pr
oton
s ha
ve a
nti-p
aral
lel s
pins
–N
orm
al h
ydro
gen
–th
erm
al e
quili
briu
m m
ix o
f bot
h•
300
K:2
5% p
arah
ydro
gen
•77
K:
50%
par
ahyd
roge
n•
20 K
:99
.8%
par
ahyd
roge
n
•S
tate
s: G
as, L
iqui
d, S
lush
, and
Sol
id
Ene
rgy
Pro
perti
esE
nerg
y P
rope
rties
•H
eat o
f com
bust
ion
(mas
s)–
(HH
V) 6
1,06
2 B
tu/lb
–(L
HV
) 51,
560
Btu
/lb•
Vol
umet
ric e
nerg
y de
nsity
–(H
HV
) 318
.1 B
tu/s
cf•
1 kg
H2
~ 1
gallo
n of
gas
olin
e•
Hyd
roge
n m
ass
to v
olum
e co
nver
sion
s–
1 kg
H2
= 42
3 sc
f= 1
1.13
Nm
3(n
orm
al m
3 )
Gas
eous
Hyd
roge
n P
rope
rties
Gas
eous
Hyd
roge
n P
rope
rties
•D
escr
iptio
n–
Col
orle
ss, o
dorle
ss, t
aste
less
•G
ener
al P
rope
rties
–Fl
amm
able
,–
Non
-irrit
atin
g, n
onto
xic,
asp
hyxi
ant
–N
on-c
orro
sive
–Li
ghte
st g
as, b
uoya
nt, c
an e
scap
e ea
rth•
Phy
sica
l Pro
perti
es–
GH
2 de
nsity
@ N
TP0.
0838
kg/
m3
(1/1
5thai
r)–
GH
2 sp
ecifi
c gr
avity
0.06
96(A
ir =
1.0)
–V
isco
sity
33
.64
x 10
-3kg
/m h
r(1
/2 a
ir)–
Diff
usiv
ity1.
697
m2 /h
r(4
x N
G in
air)
–Th
erm
al C
ondu
ctiv
ity0.
157
kcal
/m h
r K(7
x a
ir)
Liqu
id H
ydro
gen
Pro
perti
esLi
quid
Hyd
roge
n P
rope
rties
Des
crip
tion
-Non
corr
osiv
e, c
olor
less
liqu
id
Nor
mal
boi
ling
poin
t20
.268
K, 1
01.3
25 k
Pa
Den
sity
@ N
BP
vapo
r 1.
338
kg/m
3 liq
uid
70
.78
kg/m
3LH
2 sp
ecifi
c gr
avity
, NB
P
0.07
10 (H
2O =
1.0
)E
quiv
alen
t vol
gas
@ N
TP84
5.1
(per
vol
liqui
d @
NB
P)
Pre
ssur
e to
mai
ntai
n N
BP
17
2 M
Pa
liqui
d de
nsity
in N
TP g
asTr
iple
poi
nt13
.8 K
, 7.0
4 kP
aTh
erm
al e
xpan
sion
0.01
64 K
-1
Ther
mal
Exp
ansi
on C
oeffi
cien
ts
of S
ome
Cry
ogen
saTh
erm
al E
xpan
sion
Coe
ffici
ents
of
Som
e C
ryog
ensa
Liqu
id
Ther
mal
Exp
ansi
on
Coe
ffici
ent
Wat
erb
0.00
07
Oxy
gen
0.00
44
Arg
on
0.00
44
Nitr
ogen
0.
0057
N
eon
0.01
44
Hyd
roge
n 0.
0164
c H
eliu
m
0.21
00
a Sou
rce:
Ede
skut
y an
d S
tew
art 1
996.
Dat
a fo
r NB
P.
b Incl
uded
for c
ompa
rativ
e pu
rpos
e.
c 23
.4 ti
mes
that
for w
ater
.
Hyd
roge
n C
ombu
stio
nR
equi
rem
ents
Hyd
roge
n C
ombu
stio
nR
equi
rem
ents
•H
ydro
gen
mix
ed w
ith a
n ox
idiz
er to
form
a
flam
mab
le m
ixtu
re•
Igni
tion
ener
gy s
ourc
e (b
ut m
ay n
ot b
e ne
cess
ary
for s
ensi
tive
mix
ture
s)•
Com
bust
ion
can
invo
lve
any
of th
ese
–Fi
re–
Def
lagr
atio
n–
Det
onat
ion
•C
onfin
emen
t can
lead
to fl
ame
acce
lera
tion
and
over
pres
sure
Not
e:B
oth
defla
grat
ion
and
deto
natio
n ca
n ap
pear
as
an
expl
osio
n to
the
hum
an s
ense
s
Fire
Fire
•R
apid
che
mic
al
reac
tion
that
pr
oduc
es h
eat a
nd
light
•S
tatio
nary
flam
e w
ith th
e fla
mm
able
m
ixtu
re fe
d in
to th
e re
actio
n zo
ne
(plu
me
or je
t)
•C
hara
cter
ized
by
sust
aine
d bu
rnin
g,
as m
anife
sted
by
any
or a
ll of
the
follo
win
g–
Ligh
t–
Flam
e–
Hea
t–
Sm
oke
Def
lagr
atio
nD
efla
grat
ion
•Fl
ame
mov
ing
thro
ugh
a fla
mm
able
mix
ture
as
a s
ubso
nic
wav
e, w
ith re
spec
t to
the
unbu
rned
mix
ture
–S
low
def
lagr
atio
n oc
curs
in th
e op
en o
r with
co
nfin
emen
ts th
at d
on’t
favo
r fla
me
acce
lera
tion
•La
min
ar b
urni
ng (2
–3
m/s
)•
Non
acc
eler
atin
g co
nfin
emen
ts (l
ess
than
100
m/s
)–
Flam
e ac
cele
ratio
n up
to c
hoke
d flo
w (a
ppro
ache
s so
und
spee
d in
unb
urne
d ga
ses,
400
–80
0 m
/s)
–D
efla
grat
ion-
to-d
eton
atio
n tra
nsiti
on (D
DT)
: ac
cele
rate
d fla
mes
trip
to d
eton
atio
n by
turb
ulen
ce
or re
flect
ion
of s
hock
wav
es.
Def
lagr
atio
n in
Ope
n A
ir Fo
llow
ing
5 G
allo
n LH
2 Sp
ill
Det
onat
ion
Det
onat
ion
•E
xoth
erm
ic c
hem
ical
reac
tion
coup
led
to s
hock
wav
e th
at p
ropa
gate
s th
roug
h a
deto
nabl
e m
ixtu
re–
Sho
ckw
ave
velo
city
is s
uper
soni
c w
ith
resp
ect t
o th
e un
burn
ed g
ases
–A
fter i
nitia
tion,
ther
mal
ene
rgy
of re
actio
n su
stai
ns s
hock
wav
e, w
hich
com
pres
ses
unre
acte
d m
ater
ial t
o su
stai
n re
actio
n
Exp
losi
onE
xplo
sion
•R
apid
equ
ilibra
tion
of p
ress
ure
betw
een
a sy
stem
and
the
surro
undi
ngs,
suc
h th
at a
sho
ckw
ave
is p
rodu
ced
•M
ay o
ccur
thro
ugh
–M
echa
nica
l fai
lure
of v
esse
ls c
onta
inin
g hi
gh-p
ress
ure
fluid
s–
Rap
id c
hem
ical
reac
tion
prod
ucin
g a
larg
e vo
lum
e of
hot
gas
es
Hyd
roge
n C
ombu
stio
nR
elat
ed P
rope
rties
Hyd
roge
n C
ombu
stio
nR
elat
ed P
rope
rties
•W
ide
flam
mab
ility
ra
nge
•Lo
w ig
nitio
n en
ergy
•S
mal
l que
nchi
ng
dist
ance
•R
apid
diff
usio
n•
Sm
all m
olec
ule
•B
uoya
nt in
air
(abo
ve 2
3 K
)•
Hig
h ig
nitio
n te
mpe
ratu
re•
Hig
h fla
me
velo
city
•Lo
w fl
ame
emis
sivi
ty
Rem
embe
r: H
ydro
gen
mus
t be
mix
ed w
ith a
n ox
idiz
er [a
ir, O
2, C
l, F,
N2O
4, et
c..]
to b
urn
Flam
mab
ility
lim
its in
NTP
air
3.9
-75.
0 vo
l%Fl
amm
abili
ty li
mits
in N
TP o
xyge
n3.
9 -9
5.8
vol%
Det
onab
ility
lim
its in
NTP
air
18.3
-59
.0 v
ol%
Det
onab
ility
lim
its in
NTP
oxy
gen
15 -
90 v
ol%
Min
imum
igni
tion
ener
gy in
air
0.01
7 m
JA
utoi
gniti
on te
mpe
ratu
re85
8 K
Que
nchi
ng g
ap in
NTP
air
0.06
4 cm
Diff
usio
n co
effic
ient
in N
TP a
ir0.
061
cm2 /s
Flam
e ve
loci
ty2.
70 m
/sFl
ame
emis
sivi
ty0.
10
* D
ata
is fo
r par
ahyd
roge
nbu
t is
appl
icab
le to
orth
oor
nor
mal
hyd
roge
n
Com
bust
ion
Pro
perti
es*
Com
bust
ion
Pro
perti
es*
Flam
mab
ility
Lim
its in
Air
Flam
mab
ility
Lim
its in
Air
010
2030
4050
6070
8090
100
Met
hane
Pro
pane
Hyd
roge
n
Flam
mab
le R
egio
n
% V
olum
e Fu
el in
Air
Fire
Fire
Tria
ngle
Tria
ngle
O X
I D
I Z
E R
F U E LI G N I T
I O N
Elec
tric
Spa
rk
Elec
tric
Arc
Hea
tH
ydro
gen
Oxy
gen
Air
Com
bust
ion
Haz
ards
Com
bust
ion
Haz
ards
Fire
Con
cern
sFi
re C
once
rns
•W
ithou
t Con
finem
ent:
–H
igh
flam
e te
mpe
ratu
re (i
n ai
r):
2045
ºC (3
713
ºF)
–D
iffic
ult t
o se
nse
exce
pt b
y di
rect
exp
osur
e,
unle
ss d
etec
tion
is u
sed
•W
ith C
onfin
emen
t–
Can
lead
to h
igh
pres
sure
s (fa
ctor
1 –
8x)
–M
echa
nica
l pre
ssur
e re
lief f
or c
onfin
ed
volu
mes
is a
dequ
ate
Def
lagr
atio
n C
once
rns
Def
lagr
atio
n C
once
rns
•S
low
Def
lagr
atio
n: th
e co
ncer
ns a
re th
e sa
me
as fo
r fir
e [c
once
ntra
tions
> 8
% v
/v]
•A
ccel
erat
ed fl
ames
and
cho
ked
prop
agat
ion:
–C
once
ntra
tions
> 1
2% v
/v–
Con
finem
ent c
hara
cter
ized
by
L/W
ratio
s >
8–
Rap
id p
ropa
gatio
n (4
00 –
800
m/s
)–
Pre
ssur
e pi
ling:
pre
ssur
izat
ion
of u
nbur
ned
gase
s–
Dyn
amic
pre
ssur
es ra
ngin
g fro
m th
ose
prod
uced
by
conf
ined
fire
to a
fact
or o
f 15x
initi
al p
ress
ure
•D
DT:
tran
sitio
n to
det
onat
ion
due
to tu
rbul
ence
and
su
perp
ositi
on o
f ref
lect
ed s
hock
wav
es [N
ote:
may
be
gin
with
pre
ssur
es fo
rmed
by
pres
sure
pili
ng]
•P
rote
ctio
n of
ves
sels
by
mec
hani
cal r
elie
f dev
ices
m
argi
nal f
or fu
lly a
ccel
erat
ed fl
ames
Def
lagr
atio
n Pr
essu
res
Vol
ume
%T
oP o
Tfa
P fa
To
P oT
fP f
H2
(K)
(kPa
)(K
)(k
Pa)
(K)
(kPa
)(K
)(k
Pa)
Hyd
roge
n/A
ir
529
810
1.3
707.
923
4.7
273
101.
368
4.3
247.
625
298
101.
321
59.2
643.
827
310
1.3
2141
.969
7.0
5029
810
1.3
1937
.959
0.0
273
101.
319
17.7
637.
375
298
101.
311
65.7
375.
627
310
1.3
1142
.640
1.9
Hyd
roge
n/O
xyge
n
529
810
1.3
694.
223
0.1
273
101.
367
1.6
243.
025
298
101.
321
34.5
639.
127
310
1.3
2118
.369
2.2
5029
810
1.3
2913
.080
8.5
273
101.
329
08.3
880.
075
298
101.
330
03.4
837.
527
310
1.3
2999
.291
1.6
9029
810
1.3
1899
.258
1.4
273
101.
318
78.6
612.
295
298
101.
311
32.8
365.
927
310
1.3
1132
.839
9.4
a Tf a
nd P
f are
the
fina
l tem
pera
ture
and
pre
ssur
e th
at w
ould
occ
ur in
the
fixe
d vo
lum
e (2
m3 )
whe
n th
erm
odyn
amic
equi
libri
um o
ccur
red.
Det
onat
ion
Con
cern
sD
eton
atio
n C
once
rns
•A
det
onat
ion
is p
oten
tially
the
wor
st-
case
eve
nt re
sulti
ng fr
om ig
nitio
n of
a
com
bust
ible
H2/o
xidi
zer m
ixtu
re–
Hig
h ve
loci
ty15
00 m
/s–
Larg
e pr
essu
re ra
tio15
–12
0 x
–P
ress
ure
relie
fN
o
Det
onat
ion
Con
cern
s (c
ont.)
Fact
ors
that
Influ
ence
Det
onat
ion
Det
onat
ion
Con
cern
s (c
ont.)
Fact
ors
that
Influ
ence
Det
onat
ion
•P
erce
ntag
e of
H2
–D
eton
atio
n lim
its in
air*
: 18
.3-5
9 vo
l%–
Det
onat
ion
limit
in o
xyge
n*:
15-9
0 vo
l%•
Initi
al te
mpe
ratu
re, p
ress
ure,
com
posi
tion,
an
d pr
esen
ce o
f dilu
ents
or i
nhib
itors
•S
treng
th (e
nerg
y) o
f ign
ition
sou
rce
•D
egre
e of
con
finem
ent
* A
ppro
xim
ate
perc
enta
ges
are
base
d up
on m
oder
ate
initi
atio
n en
ergi
es, b
ette
r det
erm
inat
ions
are
bas
ed
on c
ell s
ize
info
rmat
ion
Det
onat
ion
Pres
sure
s an
d T
empe
ratu
res
Vol
ume
To
aP o
bT
oP o
% H
2(K
)(k
Pa)
T1/
To
P 1/P
o(K
)(k
Pa)
T1/
To
P 1/P
o
Hyd
roge
n/A
ir
18.3
298
101.
37.
657
12.1
5429
810
.17.
580
12.1
1125
298
101.
39.
257
14.6
0529
810
.18.
870
14.2
2350
298
101.
38.
706
13.7
1329
810
.18.
482
13.5
5559
298
101.
37.
678
12.1
4429
810
.17.
601
12.1
19
Hyd
roge
n/O
xyge
n
529
810
1.3
3.11
84.
880
298
10.1
3.11
94.
882
2529
810
1.3
9.03
414
.289
298
10.1
8.66
013
.896
5029
810
1.3
11.6
4617
.857
298
10.1
10.5
3716
.616
7529
810
1.3
12.1
1118
.671
298
10.1
10.8
3417
.250
9029
810
1.3
8.57
613
.584
298
10.1
8.32
713
.393
aT
= te
mpe
ratu
reb
P =
pre
ssur
e
Hyd
roge
n/G
asol
ine
Com
paris
onH
ydro
gen/
Gas
olin
e C
ompa
rison
Pro
perty
Hyd
roge
nG
asol
ine
Com
paris
on
MIE
(in a
ir)17
240
-
Flam
mab
ility
rang
e(v
ol %
in a
ir)4-
751.
5-7.
6+/
-
Diff
usio
n co
effic
ient
(cm
2 /s in
NTP
air)
0.61
0.05
+/-
Buo
yant
vel
ocity
(m/s
in N
TP a
ir)1-
2.9
nonb
uoya
nt+/
-
HY
DR
OG
EN
AN
D G
ASO
LIN
E C
OM
PAR
ISO
NPR
OPE
RT
YH
YD
RO
GE
NG
ASO
LIN
EC
OM
PAR
ISO
NM
inim
um Ig
nitio
n E
nerg
y in
air
, µJ
1724
0-
Aut
oign
ition
Tem
pera
ture
in a
ir, K
858
530
+Fl
amm
abili
ty R
ange
, vol
% in
air
4-75
1.5-
7.6
+/-
Det
onab
ility
Ran
ge, v
ol %
in a
ir18
.3-5
9.0
1.1-
3.3
+/-
Flam
e T
empe
ratu
re, K
2323
2470
=Fl
ame
Vel
ocity
, m/s
2.7-
3.5
0.4
+/-
Flam
e E
mis
sivi
ty0.
10+/
-T
herm
al E
nerg
y ra
diat
ed fr
omfl
ame
to s
urro
undi
ngs,
%17
-25
30-4
2+
Dif
fusi
on C
oeff
icie
nt in
NT
P ai
r,cm
2 /s0.
610.
05+/
-
Dif
fusi
on V
eloc
ity in
air
at N
TP,
cm/s
<2.0
<0.1
7+/
-
Buo
yant
vel
ocity
in N
TP
air,
m/s
1.2-
9no
nbuo
yant
+/-
Que
nchi
ng D
ista
nce
at 1
01.3
kPa
abso
lute
, mm
0.64
2-
Vap
oriz
atio
n ra
te (s
tead
y st
ate)
of
liqui
d po
ols
with
out b
urni
ng,
cm/m
in
2.5-
5.0
0.00
5-0.
02+/
-
Bur
ning
rate
s of
spi
lled
liqui
dpo
ols,
cm
/min
3.0-
6.6
0.2-
0.9
+/-
-
deno
tes
hydr
ogen
mor
e ha
zard
ous
than
gas
olin
e w
ith re
spec
t to
this
pro
pert
y+
de
note
s ga
solin
e m
ore
haza
rdou
s th
an h
ydro
gen
with
resp
ect t
o th
is p
rope
rty
=
deno
tes
haza
rd is
abo
ut e
qual
for h
ydro
gen
and
gaso
line
with
resp
ect t
o th
is p
rope
rty
+/- d
enot
es th
at th
e ha
zard
for h
ydro
gen
coul
d be
mor
e or
less
than
gas
olin
e w
ith re
spec
t to
this
pro
pert
y
de
pend
ing
on th
e ci
rcum
stan
ces
Sum
mar
y of
Pos
sibl
eC
ombu
stio
n C
onse
quen
ces
Sum
mar
y of
Pos
sibl
eC
ombu
stio
n C
onse
quen
ces
•Fi
re –H
eatin
g (th
erm
al &
UV
ene
rgy
radi
ated
from
fla
me)
–P
rom
oted
com
bust
ion
(dire
ct c
onta
ct w
ith fl
ame)
–B
urns
(the
rmal
& U
V)
•D
efla
grat
ion
and
Det
onat
ion
–E
ffect
s of
fire
–B
last
(ove
rpre
ssur
e)–
Frag
men
ts
Form
atio
n of
Com
bust
ible
Mix
ture
sFo
rmat
ion
of C
ombu
stib
le M
ixtu
res
•Id
entif
y so
urce
s of
hyd
roge
n an
d ox
idiz
ers
–B
oil-o
ff an
d ve
ntin
g–
Bat
terie
s, fu
el c
ells
, ele
ctro
lyze
rs–
Che
mic
al p
roce
sses
, rad
ioac
tive
deca
y•
Leak
s an
d sp
ills
–E
xter
nal l
eaka
ge–
In-le
akag
e–
Leak
age
betw
een
syst
em c
ompo
nent
s•
Sec
onda
ry a
ccum
ulat
ion
•In
tern
al c
onta
min
atio
n
Pos
sibl
e Le
ak/S
pill
Cau
ses
Pos
sibl
e Le
ak/S
pill
Cau
ses
•M
ater
ials
–D
iffus
ion/
perm
eatio
n–
Exp
ansi
on/c
ontra
ctio
n–
Em
britt
lem
ent
•H
ydro
gen
•Lo
w te
mpe
ratu
re
•C
orro
sion
, wea
r, da
mag
e
•M
echa
nica
l–
Mec
hani
cal s
tress
an
d vi
brat
ion
–D
efor
mat
ion
•P
ress
ure
•Te
mpe
ratu
re
•O
pera
tor e
rror
Inte
rnal
Con
tam
inat
ion
Cau
ses
Inte
rnal
Con
tam
inat
ion
Cau
ses
•Im
prop
er p
urgi
ng•
Con
tam
inat
ed fl
uids
–P
ress
uriz
atio
n ga
s–
Pum
p oi
ls–
Bui
ldup
of i
mpu
ritie
s•
In-le
akag
e–
Occ
urs
from
out
side
to in
side
of a
sys
tem
–C
ryop
umpi
ng•
Inte
rnal
leak
age
–O
ccur
s fro
m o
ne p
art o
f sys
tem
to a
noth
er
Igni
tion
Sou
rces
Igni
tion
Sou
rces
•E
lect
rical
•M
echa
nica
l•
Ther
mal
•C
hem
ical
Ele
ctric
al Ig
nitio
n S
ourc
esE
lect
rical
Igni
tion
Sou
rces
•S
tatic
dis
char
ge•
Sta
tic e
lect
ricity
(tw
o-ph
ase
flow
)•
Sta
tic e
lect
ricity
(fl
ow w
ith s
olid
pa
rticl
es)
•E
lect
ric a
rc•
Ligh
tnin
g
•C
harg
e ac
cum
ulat
ion
•E
lect
rical
cha
rge
gene
rate
d by
eq
uipm
ent o
pera
tion
•E
lect
rical
sho
rt ci
rcui
ts•
Ele
ctric
al s
park
s•
Clo
thin
g (s
tatic
el
ectri
city
)
Mec
hani
cal I
gniti
on S
ourc
esM
echa
nica
l Ign
ition
Sou
rces
•M
echa
nica
l im
pact
•Te
nsile
rupt
ure
•Fr
ictio
n an
d ga
lling
•M
echa
nica
l vib
ratio
n•
Met
al fr
actu
re
Ther
mal
Igni
tion
Sou
rces
Ther
mal
Igni
tion
Sou
rces
•O
pen
flam
e•
Hot
sur
face
•P
erso
nnel
sm
okin
g•
Wel
ding
•E
xhau
st fr
om
com
bust
ion
engi
ne•
Res
onan
ce ig
nitio
n
•E
xplo
sive
cha
rge
•H
igh-
velo
city
jet
heat
ing
•S
hock
wav
e fro
m
tank
rupt
ure
•Fr
agm
ent f
rom
bu
rstin
g ta
nk
Che
mic
al Ig
nitio
n S
ourc
esC
hem
ical
Igni
tion
Sou
rces
•C
atal
ysts
•R
eact
ants
Fire
Fire
Tria
ngle
Tria
ngle
O X
I D
I Z
E R
F U E LI G N I T
I O N
For m
ore
com
bust
ion
haza
rds
info
rmat
ion:
* (R
ivki
n, C
arl,
H.
The
NFP
A G
uide
to G
as S
afet
y. N
atio
nal F
ire P
rote
ctio
n A
ssoc
iatio
n, Q
uinc
y, M
A 2
005
* B
enz,
Fra
nk J
., C
raig
V. B
isho
p, M
icha
el P
edle
y. Ig
nitio
n an
d Th
erm
al
Haz
ards
of S
elec
ted
Aer
ospa
ce F
luid
s. R
D-W
STF
-000
1, J
ohns
on S
pace
C
ente
r Whi
te S
ands
Tes
t Fac
ility
, Las
Cru
ces
NM
880
04, O
ctob
er 1
4, 1
988.
Pre
ssur
e, lo
w-te
mpe
ratu
re,
and
hydr
ogen
em
britt
lem
ent i
mpl
icat
ions
H2
Pro
perti
es R
elat
ed to
O
verp
ress
ure
Haz
ards
H2
Pro
perti
es R
elat
ed to
O
verp
ress
ure
Haz
ards
•La
rge
liqui
d-to
-gas
exp
ansi
on ra
tio•
Low
hea
t of v
apor
izat
ion
•La
rge
ther
mal
diff
eren
ce•
Sig
nific
ant p
oten
tial e
nerg
y of
co
mpr
esse
d ga
s
Ove
rpre
ssur
e H
azar
d S
ourc
esO
verp
ress
ure
Haz
ard
Sou
rces
•P
ress
uriz
atio
n sy
stem
failu
re•
Pre
ssur
e re
lief s
yste
m fa
ilure
•Fi
re fr
om a
n ex
tern
al s
ourc
e•
Inad
equa
te v
entin
g•
Orth
o-to
par
ahyd
roge
n co
nver
sion
•O
verfi
lling
•Li
quid
-to-g
as p
hase
cha
nge
Phy
siol
ogic
al E
ffect
s of
B
last
Ove
rpre
ssur
eP
hysi
olog
ical
Effe
cts
of
Bla
st O
verp
ress
ure
Max
. Ove
rpre
ssur
eE
ffect
on
pers
onne
l(k
Pa)
(ps
i)7
1K
nock
per
sonn
el d
own
355
Ear
drum
dam
age
100
15Lu
ng d
amag
e24
035
Thre
shol
d fo
r fat
aliti
es34
550
50%
fata
litie
s45
065
99%
fata
litie
s
Low
-tem
pera
ture
Haz
ards
Low
-tem
pera
ture
Haz
ards
•C
old
fluid
s–
Con
tam
inan
t sol
idifi
catio
n •
Col
d su
rface
s–
Oxy
gen
enric
hmen
t of a
ir–
Cry
ogen
ic b
urn
(fros
tbite
)•
Low
-tem
pera
ture
em
britt
lem
ent
–C
onta
inm
ent m
ater
ials
–N
earb
y m
ater
ials
Atm
osph
eric
Com
posi
tion
Vapo
r
Dew
Lin
e
Boi
ling
or
Bub
ble
Line
•
AB
•
90 K
77 K
210
0% N
0% N
Liqu
id
Temperature (K)
222
100%
O0%
O2
21%
O22
50%
O2
2
2
N2/O
2P
hase
Dia
gram
Sho
win
g O
2E
nric
hmen
tN
2/O2
Pha
se D
iagr
amS
how
ing
O2
Enr
ichm
ent
020406080100 0
24
68
10Im
pact
Ene
rgy
(kg
m)
100%
LO
X
50%
LO
X
30%
LO
X
20%
LO
X
. .
Reaction Frequency (%)
Oxy
gen
Enr
ichm
ent E
ffect
(Pol
yeth
ylen
e)O
xyge
n E
nric
hmen
t Effe
ct( P
olye
thyl
ene)
H2
Atta
ck o
f Met
als
H2
Atta
ck o
f Met
als
•M
echa
nica
l pro
perti
es c
an b
e si
gnifi
cant
ly
redu
ced
by H
2em
britt
lem
ent
–Te
nsile
stre
ngth
–D
uctil
ity–
Frac
ture
toug
hnes
s–
Cra
ck b
ehav
ior
•Fa
ilure
s ha
ve re
sulte
d•
Use
less
sus
cept
ible
mat
eria
ls
Type
s of
H2
Em
britt
lem
ent
Type
s of
H2
Em
britt
lem
ent
•E
nviro
nmen
tal e
mbr
ittle
men
t–
Obs
erve
d in
met
als
and
allo
ys p
last
ical
ly
defo
rmed
in H
2en
viro
nmen
t (es
peci
ally
hi
gh p
ress
ure)
–M
axim
um e
ffect
from
200
-30
0K•
Inte
rnal
em
britt
lem
ent
–C
ause
d by
abs
orbe
d H
2
–M
axim
um e
ffect
from
200
-30
0K
Type
s of
H2
Em
britt
lem
ent (
cont
.)Ty
pes
of H
2E
mbr
ittle
men
t (co
nt.)
•H
2re
actio
n em
britt
lem
ent
–A
bsor
bed
H2
chem
ical
ly c
ombi
nes
with
m
etal
to fo
rm a
brit
tle h
ydrid
e–
Low
ers
mat
eria
ls d
uctil
ity–
Occ
urs
read
ily a
t ele
vate
d te
mpe
ratu
re–
Met
hane
can
form
with
car
bon
in s
teel
s
H2
Exp
osur
e an
d U
ltim
ate
Stre
ngth
H2
Exp
osur
e an
d U
ltim
ate
Stre
ngth
-27.
199
3 (1
14,0
00)
724
(105
,000
)69
MPa
N2
69 M
PaH
2
K M
onel
(ann
eale
d)
-55.
017
31 (2
51,0
00)
779
(113
,000
)69
MPa
N2
69 M
PaH
2
K M
onel
PH
-24.
473
0 (1
06,0
00)
552
(80,
000)
69 M
PaN
2
69 M
PaH
2
C10
25
-66.
629
46 (3
62,0
00)
834
(121
,000
)69
MPa
N2
41 M
PaH
2
4140
(hig
h st
reng
th)
-15.
216
60 (2
41,0
00)
1407
(204
,000
)69
MPa
N2
69 M
PaH
2
4140
(low
str
engt
h)
Cha
nge
(%)
Stre
ngth
[MPa
(psi
)]Ex
posu
re(a
t 80
ºF)
Mat
eria
l(n
otch
ed s
ampl
e)
Fact
ors
& M
echa
nism
s In
volv
edFa
ctor
s &
Mec
hani
sms
Invo
lved
•O
pera
ting
envi
ronm
ent
–Te
mpe
ratu
re, p
ress
ure,
exp
osur
e tim
e•
Mat
eria
l –
Phy
sica
l and
mec
hani
cal p
rope
rties
, stre
ss
stat
e, s
tress
con
cent
ratio
ns, s
urfa
ce fi
nish
, m
icro
stru
ctur
e, c
rack
s•
Hyd
roge
n–
Pur
ity, c
once
ntra
tion
Fact
ors
& M
echa
nism
s In
volv
ed (c
ont.)
Fact
ors
& M
echa
nism
s In
volv
ed (c
ont.)
•S
usce
ptib
ility
to e
mbr
ittle
men
t gen
eral
ly
incr
ease
s w
ith in
crea
sing
–Te
nsile
stre
ss–
Allo
y ul
timat
e st
reng
th–
H2
purit
y•
Ele
ctric
al d
isch
arge
mac
hini
ng
incr
ease
s po
tent
ial f
or H
2em
britt
lem
ent
Hea
lth H
azar
dsH
ealth
Haz
ards
•B
urns
–D
irect
con
tact
with
flam
e–
Ther
mal
ene
rgy
radi
ated
from
flam
e–
UV
exp
osur
e•
Asp
hyxi
atio
n–
Hyd
roge
n–
Pur
ge g
as (N
2, H
e)•
Hyp
othe
rmia
Hea
lth H
azar
ds (c
ont.)
Hea
lth H
azar
ds (c
ont.)
•C
ryog
enic
bur
n (fr
ostb
ite)
–S
imila
r to
ther
mal
bur
ns p
rodu
ced
from
co
ntac
t with
cry
ogen
or c
old
surfa
ces
–C
an re
sult
in p
erm
anen
t eye
dam
age
–C
ryog
en v
apor
can
free
ze s
kin
or e
yes
fast
er th
an li
quid
con
tact
, eve
n fa
ster
than
m
etal
lic c
onta
ct
Third
-deg
ree
cryo
gen
burn
(fr
ostb
ite) t
o fin
gers
Seco
nd-d
egre
e th
erm
al b
urn
to h
and
Cry
ogen
ic B
urns
Cry
ogen
ic B
urns
Wha
t You
Nee
d to
Kno
wS
umm
ary
Wha
t You
Nee
d to
Kno
wS
umm
ary
•G
ener
al p
rope
rties
•P
rimar
y hy
drog
en h
azar
ds–
Com
bust
ion
–P
ress
ure
haza
rds
–Lo
w te
mpe
ratu
re–
Hyd
roge
n em
britt
lem
ent
–E
xpos
ure
and
heal
th
Add
ress
ing
the
H2
Haz
ard
Saf
ety
Man
agem
ent
and
Sta
ndar
ds
Sta
rt w
ith S
afet
y M
anag
emen
tS
tart
with
Saf
ety
Man
agem
ent
•M
inim
ize
cons
eque
nces
•U
se s
afe
prin
cipl
es a
nd p
ract
ices
•P
erfo
rm re
view
s•
Be
prep
ared
for e
mer
genc
y si
tuat
ions
Igno
re it
?
Con
trol i
t?E
limin
ate
it?
Avo
id it
?
Man
agin
g a
Haz
ard
Man
agin
g a
Haz
ard
Safe
Use
of H
ydro
gen
Follo
w p
rope
r prin
cipl
es,
prac
tices
, and
pro
cedu
res…
…by
pro
perly
trai
ned
and
mot
ivat
ed p
erso
nnel
Cor
ners
tone
sC
orne
rsto
nes
Fede
ral R
egul
atio
nsFe
dera
l Reg
ulat
ions
•29
CFR
1910
.103
, Hyd
roge
n•
29C
FR19
10.1
19, P
roce
ss S
afet
y M
anag
emen
t of H
ighl
y H
azar
dous
C
hem
ical
s•
49C
FR S
ubtit
le B
, Vol
2, C
h 1,
Par
ts
171-
180,
Tra
nspo
rtatio
n
* S
ee o
sha.
gov
for l
ates
t CFR
refe
renc
es
HY
DR
OG
EN C
FR IN
FOR
MA
TIO
N
Che
mic
al F
orm
ula
H2
Com
mon
nam
eH
ydro
gen
Haz
ard
mat
eria
l des
crip
tion
and
prop
ersh
ippi
ng n
amea
GH
2
LH2
Hyd
roge
n, c
ompr
esse
da
Hyd
roge
n, re
frig
erat
ed li
quid
(cry
ogen
ic li
quid
) a, b
Ship
ping
iden
tific
atio
n nu
mbe
raG
H2
LH2
UN
1049
a
UN
1966
a
Ship
ping
haz
ard
clas
s or
div
isio
naG
H2
LH2
2.1a
2.1a
Ship
ping
pac
king
gro
upa
Non
e gi
ven
a, c
Ship
ping
labe
ls re
quire
daG
H2
LH2
FLA
MM
AB
LE G
ASa
FLA
MM
AB
LE G
ASa
Ship
ping
spe
cial
pro
visi
onsa
Non
e gi
ven
a
Ship
ping
pac
kagi
ng a
utho
rizat
ion
exce
ptio
nsa
GH
2
LH2
See
49C
FR17
3.30
6a
See
49C
FR17
3.31
6a
Ship
ping
non
bul
k pa
ckag
ing
requ
irem
ents
aG
H2
LH2
See
49C
FR17
3.30
2a
See
49C
FR17
3.31
6a
Ship
ping
bul
k pa
ckag
ing
requ
irem
ents
aG
H2
LH2
(See
49C
FR17
3.30
2 an
d 17
3.31
4)a
(See
49C
FR17
3.31
8 an
d 17
3.31
9)a
Ship
ping
qua
ntity
lim
itatio
ns fo
rpa
ssen
ger a
ircra
ft or
railc
ara
GH
2
LH2
Forb
idde
na
Forb
idde
na
Ship
ping
qua
ntity
lim
itatio
ns fo
r car
goai
rcra
ft on
lya
GH
2
LH2
150
kg a
Forb
idde
na
Ves
sel s
hipp
ing
stow
age
requ
irem
ents
aG
H2
LH2
E a,
d
D a,
e
Ves
sel s
hipp
ing
stow
age
prov
isio
nsa
GH
2
LH2
40a,
f , 57a,
g
40 a,
f
Proc
ess
Safe
ty M
anag
emen
t Thr
esho
ldQ
uant
ityh , l
b≥1
0,00
0 lb
h
NO
TE
S:a 4
9CFR
172.
101
b Pun
ctua
tion
mar
ks a
nd w
ords
in it
alic
s are
not
par
t of t
he p
rope
r shi
ppin
g na
me,
but
may
be u
sed
in a
dditi
on to
the
prop
er sh
ippi
ng n
ame.
a
c Cla
ss 2
mat
eria
ls d
o no
t hav
e pa
ckin
g gr
oups
.a
d “E”
mea
ns th
e m
ater
ial m
ay b
e st
owed
“on
dec
k” o
r “un
der d
eck”
on
a ca
rgo
vess
el, b
utis
pro
hibi
ted
on a
pas
seng
er v
esse
l.a
e “D
” m
eans
the
mat
eria
l mus
t be
stow
ed “
on d
eck”
on
a ca
rgo
vess
el, b
ut is
pro
hibi
ted
ona
pass
enge
r ves
sel.a
f Sto
age
prov
isio
n “4
0” m
eans
: “St
ow ‘c
lear
of l
ivin
g qu
arte
rs’”
(49C
FR17
6.84
).g S
toag
e pr
ovis
ion
“57”
mea
ns: “
Stow
‘sep
arat
ed fr
om’ c
hlor
ine”
(49C
FR17
6.84
).h 2
9CFR
1910
.119
Gui
delin
es a
nd V
olun
tary
Con
sens
us S
tand
ards
*G
uide
lines
and
Vol
unta
ryC
onse
nsus
Sta
ndar
ds*
•S
tand
ards
–N
FPA
55,
Sta
ndar
d fo
r the
Sto
rage
, Use
, and
Han
dlin
g of
C
ompr
esse
d G
ases
and
Cry
ogen
ic F
luid
s in
Por
tabl
e an
d S
tatio
nary
Con
tain
ers,
Cyl
inde
rs, a
nd T
anks
. [S
uper
sede
s N
FPA
50
A a
nd 5
0 B
]•
NFP
A 5
0A, G
H2
Sys
tem
s at
Con
sum
er S
ites
•N
FPA
50B
, LH
2 S
yste
ms
at C
onsu
mer
Site
s•
Con
sens
us G
uide
s–
AN
SI/A
IAA
G-0
95-2
004
Gui
de to
Saf
ety
of H
ydro
gen
and
Hyd
roge
n S
yste
ms
[Req
uire
d by
NA
SA
]
* A
ppro
ved
stan
dard
s an
d gu
idel
ines
are
ava
ilabl
e th
roug
h th
e N
AS
A
Tech
nica
l Sta
ndar
ds P
rogr
am a
vaila
ble
on th
e w
eb
[http
://st
anda
rds.
msf
c.na
sa.g
ov/]
Indu
stry
Res
ourc
esIn
dust
ry R
esou
rces
•A
ccep
ted
indu
stry
pra
ctic
e–
CG
A G
-5, H
ydro
gen
–C
GA
G-5
.5, H
ydro
gen
Ven
t Sys
tem
s–
CG
A G
-5.4
, Sta
ndar
d fo
r Hyd
roge
n P
ipin
g S
yste
ms
at C
onsu
mer
Loc
atio
ns–
CG
A G
-5.6
, Hyd
roge
n P
ipel
ine
Sys
tem
s•
Indu
stry
reso
urce
doc
umen
ts–
CG
A H
-2 G
uide
lines
for t
he C
lass
ifica
tion
and
Labe
ling
of H
ydro
gen
Sto
rage
Sys
tem
s w
ith H
ydro
gen
Abs
orbe
d in
Rev
ersi
ble
Met
al H
ydrid
es–
CG
A H
-3 C
ryog
enic
Hyd
roge
n S
tora
ge–
CG
A H
-4 T
erm
inol
ogy
Ass
ocia
ted
with
Hyd
roge
n Fu
el T
echn
olog
ies
–C
GA
P-1
2 S
afe
Han
dlin
g of
Cry
ogen
ic L
iqui
ds–
CG
A P
-28
Ris
k M
anag
emen
t Pla
n G
uida
nce
Doc
umen
t for
Bul
k Li
quid
Hyd
roge
n S
yste
ms
•In
dust
ry p
ositi
ons
–C
GA
PS
-17
CG
A P
ositi
on S
tate
men
t on
Und
ergr
ound
Inst
alla
tion
of L
iqui
d H
ydro
gen
Sto
rage
Tan
ks–
CG
A P
S-2
0 C
GA
Pos
ition
Sta
tem
ent o
n th
e D
irect
Bur
ial o
f Gas
eous
Hyd
roge
n S
tora
ge T
anks
–C
GA
PS
-21
Pos
ition
Sta
tem
ent o
f Adj
acen
t Sto
rage
of C
ompr
esse
d H
ydro
gen
and
Oth
er F
lam
mab
le G
ases
–C
GA
PS
-25
Rec
omm
enda
tions
for a
eria
l sto
rage
–C
GA
PS
-26
The
Use
of C
arbo
n Fi
ber,
Fully
Wra
pped
Com
posi
te S
tora
ge V
esse
lsin
S
tatio
nary
Gas
eous
Hyd
roge
n Fu
elin
g S
yste
ms
(pro
pose
d)
Gui
delin
es a
nd V
olun
tary
C
onse
nsus
Sta
ndar
ds(c
ont.)
Gui
delin
es a
nd V
olun
tary
C
onse
nsus
Sta
ndar
ds(c
ont.)
•S
tora
ge v
esse
ls–
AS
ME
, Int
erna
tiona
l Boi
ler a
nd P
ress
ure
Ves
sel C
ode,
Sec
tion
VIII
, Pre
ssur
e V
esse
ls–
AP
I Sta
ndar
d 62
0, D
esig
n an
d C
onst
ruct
ion
of
Larg
e, W
elde
d, L
ow-p
ress
ure
Sto
rage
Tan
ks•
Pip
ing
–A
SM
E B
31.3
, Pro
cess
Pip
ing
–C
GA
G-5
.4, S
tand
ard
for H
ydro
gen
Pip
ing
Sys
tem
s at
Con
sum
er L
ocat
ions
–C
GA
G-5
.6, H
ydro
gen
Pip
elin
e S
yste
ms
Saf
ety
Res
pons
ibili
tyS
afet
y R
espo
nsib
ility
•M
anag
emen
t is
resp
onsi
ble
for
–E
stab
lishi
ng a
nd e
nfor
cing
saf
ety
polic
y–
Ens
urin
g th
at a
ll ap
plic
able
sta
tuto
ry a
nd
regu
lato
ry re
quire
men
ts a
re id
entif
ied,
do
cum
ente
d, a
nd a
dher
ed to
in H
2us
e•
Ulti
mat
ely,
eve
ryon
e in
volv
ed w
ith H
2sy
stem
or o
pera
tion
is re
spon
sibl
e fo
r sa
fety
Aut
horit
y H
avin
g Ju
risdi
ctio
nA
utho
rity
Hav
ing
Juris
dict
ion
•M
anag
emen
t sha
ll de
fine,
des
igna
te, a
nd
docu
men
t the
ent
ity
(AH
J) th
at is
em
pow
ered
to
impl
emen
t and
en
forc
e sa
fety
pol
icie
s an
d pr
oced
ures
•Th
e A
HJ
may
be
a pe
rson
, a g
roup
, an
offic
e, a
n or
gani
zatio
n,
or a
fede
ral,
stat
e, o
r lo
cal g
over
ning
bod
y
Org
aniz
atio
nal
Pol
icie
s an
d P
roce
dure
sO
rgan
izat
iona
l P
olic
ies
and
Pro
cedu
res
•R
equi
red
to c
ontro
l han
dlin
g/us
e of
H2
•S
houl
d be
–Fo
rmal
(writ
ten)
–A
ppro
ved
and
enfo
rced
by
uppe
r lev
el
man
agem
ent
–A
vaila
ble
to, a
nd u
nder
stoo
d by
, all
pers
onne
l inv
olve
d in
H2
activ
ities
–A
pplic
able
to a
ll ph
ases
of s
yste
m
oper
atio
ns
Hyd
roge
n S
afet
y A
chie
ved
byH
ydro
gen
Saf
ety
Ach
ieve
d by
•In
here
nt s
afet
y•
App
rove
d op
erat
ing
proc
edur
es
•Tr
aine
d pe
rson
nel
•D
esig
n, s
afet
y, h
azar
d, a
nd o
pera
tiona
l re
view
s•
App
rove
d qu
ality
con
trol a
nd
mai
nten
ance
pro
gram
s
Inhe
rent
Saf
ety
Inhe
rent
Saf
ety
•In
here
nt s
afet
y vs
. inh
eren
t haz
ards
•In
volv
es–
Fail-
safe
des
ign
–A
utom
atic
saf
ety
desi
gn–
Cau
tion
and
war
ning
dev
ices
–C
ontro
l of H
2qu
antit
y–
Siti
ng o
f H2
faci
litie
s
Del
ta C
lippe
rD
elta
Clip
per
App
rove
d O
pera
ting
Pro
cedu
res
App
rove
d O
pera
ting
Pro
cedu
res
•R
equi
red
for f
acili
ty
or s
yste
m o
pera
tion
and
for r
outin
e ta
sk
perfo
rman
ce
•P
repa
red/
revi
ewed
by
app
ropr
iate
pe
rson
nel
•P
erfo
rmed
by
train
ed p
erso
nnel
•R
evie
wed
ap
prop
riate
ly to
en
sure
that
cha
nges
to
pro
cess
es,
equi
pmen
t, an
d op
erat
ing
cond
ition
s ha
ve b
een
prop
erly
co
nsid
ered
App
rove
d O
pera
ting
Pro
cedu
res
(con
t.)A
ppro
ved
Ope
ratin
g P
roce
dure
s (c
ont.)
•H
elp
miti
gate
haz
ards
•Te
ach
how
to p
reve
nt, d
etec
t, an
d re
spon
d to
H2
leak
s•
Out
line
–A
dequ
ate
vent
ilatio
n gu
idel
ines
–S
uita
ble
mai
nten
ance
and
em
erge
ncy
proc
edur
es
Trai
ned
Per
sonn
elTr
aine
d P
erso
nnel
•Tr
aini
ng a
nd re
fresh
ers
are
man
dato
ry–
Taug
ht b
y ap
prov
ed in
stru
ctor
s–
Tailo
red
to s
peci
fic fa
cilit
y or
sys
tem
–C
ente
red
on H
2’s p
hysi
coch
emic
al
prop
ertie
s an
d th
eir s
afet
y im
plic
atio
ns•
Hum
an li
mita
tions
nec
essi
tate
feed
back
–S
tude
nt in
put i
mpr
ove
subs
eque
nt tr
aini
ng•
Cer
tify
for c
ritic
al o
pera
tions
Des
ign,
Saf
ety,
Haz
ard,
and
O
pera
tiona
l Rev
iew
sD
esig
n, S
afet
y, H
azar
d, a
nd
Ope
ratio
nal R
evie
ws
•S
houl
d be
mad
e of
a s
yste
m/fa
cilit
y be
fore
H2
wet
ting
•S
houl
d be
regu
larly
con
duct
ed to
en
sure
con
tinua
l saf
e us
e of
H2
QC
and
Mai
nten
ance
Pro
gram
sQ
C a
nd M
aint
enan
ce P
rogr
ams
•A
ll m
ater
ials
and
com
pone
nts
shou
ld b
e su
bjec
t to
a co
mpr
ehen
sive
insp
ectio
n an
d be
qua
lity-
cont
rolle
d•
Mai
nten
ance
pro
gram
mus
t be
appr
oved
and
sus
tain
ed a
s ne
eded
–
Insp
ecte
d at
leas
t ann
ually
–M
aint
aine
d by
qua
lifie
d pe
rson
nel
acco
rdin
g to
app
rove
d pr
oced
ures
•In
spec
tion
shou
ld b
e pe
rform
ed o
nly
if eq
uipm
ent i
s m
ade
safe
for s
uch
mai
nten
ance
Mai
nten
ance
Exa
mpl
esM
aint
enan
ce E
xam
ples
•Lu
bric
atio
n•
Inst
rum
enta
tion
calib
ratio
n•
Cle
anin
g an
d pa
intin
g•
Ope
ratio
nal
verif
icat
ion
of re
lief
and
chec
k va
lves
•R
epla
cem
ent o
f fil
ter e
lem
ents
•R
epai
r or
repl
acem
ent o
f–
Dam
aged
or f
aulty
co
mpo
nent
s–
Com
pone
nts
subj
ect
to w
ear (
seal
s, s
eats
, be
arin
gs)
Min
imiz
e co
nseq
uenc
es
Min
imiz
e S
ever
ity o
f Con
sequ
ence
sM
inim
ize
Sev
erity
of C
onse
quen
ces
•M
inim
ize
quan
tity
invo
lved
•C
ontro
l the
are
a •
Use
–
Goo
d ho
usek
eepi
ng p
ract
ices
–P
erso
nnel
pro
tect
ion
–O
pera
tiona
l req
uire
men
ts–
H2
and
H2
fire
dete
ctio
n–
Ala
rms
and
war
ning
dev
ices
Min
imiz
e Q
uant
ity In
volv
edM
inim
ize
Qua
ntity
Invo
lved
•M
inim
ize
stor
age,
tran
spor
t, tra
nsfe
r, an
d en
d-us
e qu
antit
y –
Miti
gate
s co
nseq
uenc
es o
f acc
iden
ts–
Red
uces
siti
ng re
quire
men
ts a
nd a
rea
cont
rol r
equi
rem
ents
•S
iting
requ
irem
ents
bas
ed o
n qu
antit
y in
volv
ed
and
type
of u
se
QU
AN
TIT
Y C
OV
ER
ED
BY
VA
RIO
US
STA
ND
AR
DS
AN
D C
OD
ES
CO
DE,
STA
ND
AR
DFL
UID
QU
AN
TITY
CO
VER
ED
29C
FR 1
910.
103
(HSS
.1-2
; A-5
3 - A
-54)
GH
2D
oes n
ot a
pply
to a
syst
em h
avin
g a
tota
lco
nten
t of l
ess t
han
11 m
3 (400
ft3 ).
No
max
imum
qua
ntity
spec
ified
.Q
D R
equi
rem
ents
app
ly to
any
qua
ntity
.N
FPA
50A
GH
2N
o m
in o
r max
qua
ntity
spec
ified
.D
oes n
ot a
pply
to si
ngle
syst
ems u
sing
cont
aine
rs h
avin
g a
tota
l con
tent
of l
ess t
han
11 m
3 (400
ft3 ) a
t 101
.3 k
Pa (1
4.7
psia
) and
294.
1 K
(70
ºF).
App
lies w
here
indi
vidu
al sy
stem
s, ea
ch h
avin
ga
tota
l con
tent
of l
ess t
han
11 m
3 (400
ft3 ) a
t10
1.3
kPa
(14.
7 ps
ia) a
nd 2
94.1
K (7
0 ºF
), ar
elo
cate
d le
ss th
an 1
.5 m
(5 ft
) fro
m e
ach
othe
r.Q
D re
quire
men
ts a
pply
to a
ny q
uant
ity.
29C
FR 1
910.
103
(HSS
.1-2
; A-5
5 - A
-56)
LH2
No
min
or m
ax q
uant
ity sp
ecifi
ed.
Doe
s not
app
ly to
por
tabl
e co
ntai
ners
hav
ing
ato
tal c
onte
nt le
ss th
an 1
50 L
(39.
63 g
al).
QD
requ
irem
ents
app
ly to
150
L (3
9.63
gal
) to
113,
550
L (3
0,00
0 ga
l).N
FPA
50B
LH2
No
min
or m
ax q
uant
ity sp
ecifi
ed.
Doe
s not
app
ly to
por
tabl
e co
ntai
ners
hav
ing
ato
tal c
onte
nt le
ss th
an 1
50 L
(39.
63 g
al).
QD
requ
irem
ents
app
ly to
150
L (3
9.63
gal
) to
283,
875
L (7
5,00
0 ga
l).29
CFR
191
0.11
9(H
SS.1
-2)
any
form
≥ 45
36 k
g (1
0,00
00 lb
m)
NSS
174
0.12
(NSS
.A-5
6 - A
-62)
LH2
0 - 4
.536
x 1
06 kg
(1 x
107 lb
m)
Con
trol t
he A
rea
Con
trol t
he A
rea
•D
eter
min
e–
Who
can
ent
er, a
nd fo
r how
long
–W
hat c
an e
nter
, esp
ecia
lly ig
nitio
n so
urce
s–
Wha
t kin
d of
act
iviti
es a
re a
llow
ed in
the
area
Goo
d H
ouse
keep
ing
Pra
ctic
esG
ood
Hou
seke
epin
g P
ract
ices
•W
eeds
or s
imila
r com
bust
ible
s ar
e no
t pe
rmitt
ed w
ithin
25
ft of
LH
2eq
uipm
ent
(29C
FR 1
910.
103,
Hyd
roge
n)•
Acc
ess
and
evac
uatio
n ro
utes
are
to b
e ke
pt c
lear
of e
quip
men
t•
Con
duct
ive
and
nons
park
ing
floor
s ar
e to
be
kept
cle
an o
f dirt
Per
sonn
el P
rote
ctio
nP
erso
nnel
Pro
tect
ion
•Li
mit
or, i
f pos
sibl
e, e
limin
ate
pers
onne
l ex
posu
re to
cry
ogen
ic o
r fla
me
tem
pera
ture
s•
Pro
tect
per
sonn
el fr
om e
xpos
ure
to–
Ther
mal
radi
atio
n fro
m H
2fir
e, in
clud
ing
inte
ntio
nally
flar
ed H
2
–O
xyge
n-de
ficie
nt a
tmos
pher
es o
f H2
or
iner
t pur
ge g
ases
(N2,
He)
Per
sonn
el P
rote
ctio
n (c
ont.)
Per
sonn
el P
rote
ctio
n (c
ont.)
•E
nsur
e pe
rson
nel w
ear p
rote
ctiv
e eq
uipm
ent t
o m
inim
ize
inju
ry if
exp
osed
–Q
uick
ly re
mov
e an
inju
red
pers
on fr
om a
da
nger
zon
e •
Insu
late
col
d su
rface
s
Per
sonn
el P
rote
ctio
n (c
ont.)
Per
sonn
el P
rote
ctio
n (c
ont.)
•O
pera
tions
invo
lvin
g a
cryo
geni
c flu
id
requ
ire e
ye a
nd h
and
prot
ectio
n•
Face
shi
eld
whe
n co
nnec
ting
and
disc
onne
ctin
g lin
es/c
ompo
nent
s•
Cot
ton/
Nom
ex c
loth
ing
•C
lose
d-to
e sh
oes
•H
earin
g pr
otec
tion
as a
ppro
pria
te•
Har
d ha
ts a
s ap
prop
riate
Ope
ratio
nal R
equi
rem
ents
Ope
ratio
nal R
equi
rem
ents
•B
uddy
sys
tem
•S
yste
m/fa
cilit
y tra
inin
g•
Hyd
roge
n tra
inin
g•
Em
erge
ncy
plan
ning
•D
on’t
inno
vate
!
H2
and
H2
Fire
Det
ectio
nH
2an
d H
2Fi
re D
etec
tion
•H
uman
sen
ses
cann
ot n
orm
ally
det
ect H
2–
Col
orle
ss a
nd o
dorle
ss•
Per
sonn
el s
houl
d us
e po
rtabl
e H
2de
tect
ors
•D
etec
tors
sho
uld
be p
erm
anen
tly in
stal
led
whe
re le
aks
can
occu
r–
Val
ves,
join
ts
H2
and
H2
Fire
Det
ectio
n (c
ont.)
H2
and
H2
Fire
Det
ectio
n (c
ont.)
•H
2fla
me
near
ly in
visi
ble
in d
aylig
ht•
H2
flam
e em
issi
vity
is lo
w–
Diff
icul
t to
feel
•P
erso
nnel
sho
uld
use
porta
ble
fire
dete
ctor
s
Ala
rms
and
War
ning
Dev
ices
Ala
rms
and
War
ning
Dev
ices
•W
arni
ng d
evic
es s
houl
d pr
ovid
e an
al
arm
for p
oten
tially
haz
ardo
us
situ
atio
n, p
refe
rabl
y be
fore
it h
appe
ns–
Abn
orm
al c
ondi
tion,
mal
func
tion,
inci
pien
t fa
ilure
•A
larm
can
be
audi
ble,
vis
ible
, or b
oth
War
ning
Sys
tem
Exa
mpl
esW
arni
ng S
yste
m E
xam
ples
•P
ress
ure
extre
mes
•H
ydro
gen
in b
uild
ing
vent
ilatio
n in
take
•Fl
are
flam
eout
•Lo
ss o
f vac
uum
in
sula
tion
•V
alve
pos
ition
•P
ump
spee
d ex
trem
es•
Hyd
roge
n le
ak•
Filte
r diff
eren
tial
pres
sure
•Fi
re
Use
saf
e pr
inci
ples
and
pra
ctic
es
Use
a S
afe,
Pro
ven
App
roac
h U
se a
Saf
e, P
rove
n A
ppro
ach
•P
rinci
ples
–E
limin
ate
igni
tion
sour
ces
–U
se fa
il-sa
fe d
esig
n–
Use
redu
ndan
cy in
cr
itica
l are
as
•P
ract
ices
–C
ontro
l sto
rage
and
tra
nsfe
r –
Pre
vent
unw
ante
d ai
r an
d fu
el m
ixtu
res
–P
reve
nt
over
pres
sure
s
Sto
rage
and
Tra
nsfe
r Ope
ratio
nsS
tora
ge a
nd T
rans
fer O
pera
tions
•B
e al
ert f
or le
aks
•K
eep
stor
age
and
trans
fer a
reas
cle
ar
of n
ones
sent
ial p
erso
nnel
–B
uddy
sys
tem
–E
stab
lish
area
con
trol
•C
ance
l or d
isco
ntin
ue o
pera
tions
in
elec
trica
l sto
rms
•Is
olat
e, v
ent,
and
purg
e to
rem
ove
H2
or
air
SO
UR
CE
: H
SS
.2-1
5, 4
-9
But
ass
ume
an ig
nitio
n so
urce
is p
rese
nt
Elim
inat
e Ig
nitio
n S
ourc
esE
limin
ate
Igni
tion
Sou
rces
•C
ontro
l sm
okin
g,
open
flam
es,
wel
ding
, use
of
mec
hani
cal t
ools
•
Bon
ding
and
gr
ound
ing
•W
ear p
rope
r cl
othi
ng
•U
se li
ghtn
ing
prot
ectio
n•
Use
con
duct
ive
mac
hine
ry b
elts
•U
se e
xplo
sion
-pro
of
or p
urge
d en
clos
ures
for
elec
trica
l equ
ipm
ent
Pre
vent
Unw
ante
d Fu
el/A
ir M
ixtu
res
Pre
vent
Unw
ante
d Fu
el/A
ir M
ixtu
res
•P
urgi
ng•
Leak
free
sys
tem
s•
Hyd
roge
n ve
ntin
g an
d di
spos
al•
Ven
tilat
ion
•M
aint
ain
posi
tive
pres
sure
s
Pre
vent
Unw
ante
d Fu
el/A
ir M
ixtu
res
Pre
vent
Unw
ante
d Fu
el/A
ir M
ixtu
res
Pur
ging
Pur
ging
•P
urge
equ
ipm
ent w
ith in
ert g
as b
efor
e an
d af
ter u
sing
H2
–P
urge
oxi
dize
r bef
ore
intro
duci
ng H
2
–P
urge
H2
befo
re in
trodu
cing
oxi
dize
r•
Use
GN
2if
tem
pera
ture
is >
80 K
; if
cold
er, u
se H
e•
Turn
off
N2
purg
e to
ven
t sta
ck b
efor
e ve
ntin
g co
ld H
2–
Oth
erw
ise,
N2
will
sol
idify
Pur
ge G
as S
yste
ms
Pur
ge G
as S
yste
ms
•N
eede
d fo
r pur
ge, p
ress
uriz
atio
n ga
ses
•H
2vo
lum
es s
houl
d be
cap
able
of b
eing
pu
rged
and
ven
ted
•In
ert g
as s
ubsy
stem
s sh
ould
be
prot
ecte
d fro
m H
2co
ntam
inat
ion
–U
se h
ighe
r pre
ssur
e, c
heck
val
ves,
or a
do
uble
blo
ck-a
nd-b
leed
arr
ange
men
t
Impr
oper
Pur
ging
Cau
ses
Mis
haps
Impr
oper
Pur
ging
Cau
ses
Mis
haps
Pur
ging
Mis
haps
No.
(%)
Mis
haps
iden
tifie
d w
ith p
urgi
ng p
robl
ems
24*
25E
ffect
s of
mis
haps
due
to p
urgi
ng p
robl
ems
rele
ase
into
atm
osph
ere
1458
Rel
ease
into
sys
tem
con
tain
ers
10
42E
ffect
s of
rele
ase
into
atm
osph
ere
igni
tion
1393
Non
-igni
tion
17
Effe
ct o
f rel
ease
into
sys
tem
con
tain
ers
igni
tion
1010
0*25
% o
f tot
al m
isha
ps
Pur
ging
Tec
hniq
ues
Pur
ging
Tec
hniq
ues
•E
vacu
atio
n an
d ba
ckfil
l•
Pre
ssur
izat
ion
and
vent
ing
•Fl
ow-th
roug
h
Leak
-free
Sys
tem
sLe
ak-fr
ee S
yste
ms
•M
inim
ize
num
ber o
f joi
nts
and
fittin
gs•
Thre
aded
fitti
ngs
disc
oura
ged
–B
ack-
braz
e or
sea
l wel
d•
Leak
-che
ck w
ith N
2, th
en H
e
Dis
pose
of H
ydro
gen
Pro
perly
Dis
pose
of H
ydro
gen
Pro
perly
•V
entin
g–
Low
flow
•Fl
arin
g–
Flar
e st
ack
–B
urn
pond
Ven
t Fire
sV
ent F
ires
•Li
ghtn
ing
a co
mm
on c
ause
of v
ent f
ires
•P
roce
dure
for e
xtin
guis
hing
ven
t fire
–A
dd in
ert g
as fl
ow, s
uch
as H
e–
Sto
p H
2flo
w–
Con
tinue
iner
t gas
flow
unt
il m
etal
coo
ls–
Res
tart
H2
vent
ing
–S
top
iner
t gas
flow
Ven
tilat
ion
Ven
tilat
ion
•V
entil
atio
n m
ust p
recl
ude
form
atio
n of
fla
mm
able
mix
ture
–V
entil
ate
to b
elow
1/4
of L
FL•
Nee
d to
cou
ple
with
H2
dete
ctio
n•
Lim
ited
effe
ctiv
enes
s on
com
plex
ge
omet
ries
Mai
ntai
n P
ositi
ve P
ress
ures
Mai
ntai
n P
ositi
ve P
ress
ures
•P
recl
ude
air i
nclu
sion
into
sys
tem
–C
ritic
al if
sys
tem
is n
ot p
urge
d w
hen
idle
•P
recl
ude
cont
amin
atio
n of
pur
ge a
nd
vent
sys
tem
s
Pre
vent
Ove
rpre
ssur
eP
reve
nt O
verp
ress
ure
Typi
cal v
olum
es
that
requ
ire
pres
sure
relie
f
Use
Red
unda
ncy
in C
ritic
al A
reas
Use
Red
unda
ncy
in C
ritic
al A
reas
•P
ress
ure
relie
f•
Isol
atio
n•
Det
ectio
n
Per
form
revi
ews
Rev
iew
sR
evie
ws
•D
esig
n•
Saf
ety
•H
azar
d–
Req
uire
men
ts–
Haz
ards
ana
lysi
s pr
otoc
ol•
Ope
ratio
nal
Des
ign
Rev
iew
Des
ign
Rev
iew
•Ty
pica
lly fo
ur ty
pes
–C
once
pt–
Pre
limin
ary
–Fi
nal
–C
ertif
icat
ion
•M
ade
for n
ew fa
cilit
y, o
r sig
nific
ant
mod
ifica
tion
of e
xist
ing
faci
lity
•S
houl
d be
mad
e by
qua
lifie
d pe
rson
nel
of v
ario
us fi
elds
of e
xper
tise
Saf
ety
Rev
iew
Saf
ety
Rev
iew
•Fa
cilit
y sa
fety
revi
ews
mad
e fo
r –
Con
stru
ctio
n–
Ope
ratio
n–
Mai
nten
ance
–Fi
nal d
ispo
sitio
n•
Incl
udes
–S
yste
m s
afet
y an
alys
es–
Failu
re m
odes
and
effe
cts
anal
yses
Haz
ard
Rev
iew
Haz
ard
Rev
iew
•C
over
s–
Com
pone
nt a
nd s
yste
m d
esig
n–
Ope
ratin
g co
nditi
ons
and
proc
edur
es–
Pro
tect
ive
mea
sure
s–
Em
erge
ncy
proc
edur
es
•P
erfo
rmed
–Fo
r com
pone
nts
and
syst
ems
–R
egul
arly
and
as
need
ed b
y qu
alifi
ed
tech
nica
l per
sonn
el
Haz
ard
Rev
iew
Req
uire
men
tsH
azar
d R
evie
w R
equi
rem
ents
•29
CFR
1910
.119
, Pro
cess
saf
ety
man
agem
ent o
f hig
hly
haza
rdou
s ch
emic
als
•29
CFR
1910
.103
, Hyd
roge
n•
Fede
ral C
lean
Air
Act
•E
mer
genc
y pr
epar
edne
ss
Haz
ard
Rev
iew
Req
uire
men
ts (c
ont.)
Haz
ard
Rev
iew
Req
uire
men
ts (c
ont.)
•Id
entif
y ha
zard
ous
oper
atio
ns•
Ass
ess/
anal
yze
risk
to p
erso
nnel
, eq
uipm
ent,
and
faci
litie
s•
Elim
inat
e or
con
trol h
azar
ds•
Follo
w a
n ap
prov
ed h
azar
dous
op
erat
ing
proc
edur
e or
per
mit
•C
ertif
y pe
rson
nel w
ho p
erfo
rm o
r con
trol
haza
rdou
s op
erat
ions
Haz
ard
Rev
iew
Req
uire
men
ts (c
ont.)
Haz
ard
Rev
iew
Req
uire
men
ts (c
ont.)
•M
itiga
te h
azar
ds in
ord
er o
f prio
rity
–D
esig
n co
mpo
nent
s an
d sy
stem
s ap
prop
riate
ly–
Inst
all s
afet
y, c
autio
n, a
nd w
arni
ng d
evic
es–
Dev
elop
adm
inis
trativ
e co
ntro
ls–
Pro
vide
pro
tect
ive
clot
hing
and
equ
ipm
ent
Haz
ards
Ana
lysi
s P
roto
col
Haz
ards
Ana
lysi
s P
roto
col
•S
yste
mat
ical
ly a
nd o
bjec
tivel
y*–
Iden
tify
haza
rds
–D
eter
min
e th
eir r
isk
leve
l–
Pro
vide
mec
hani
sm fo
r the
ir el
imin
atio
n or
co
ntro
l
* S
ee N
AS
A R
efer
ence
Pub
licat
ion
1358
, Sys
tem
Eng
inee
ring
“Too
lbox
”for
Des
ign-
Orie
nted
Eng
inee
rs*
See
NA
SA
TM
-200
3-21
2059
, Gui
de fo
r Hyd
roge
n H
azar
ds
Ana
lysi
s on
Com
pone
nts
and
Sys
tem
s
Def
ine
Scop
e of
Ana
lysi
sSe
lect
Haz
ards
Tea
m M
embe
rs
Com
pile
Com
pone
nt/S
yste
m In
form
atio
n
Dec
ide
on C
ompo
nent
Ana
lysi
s St
rate
gy
Det
erm
ine
Com
pone
nt H
azar
ds S
cena
rios
Asse
ss P
ossi
ble
Com
bust
ible
Mix
ture
Form
atio
n
Asse
ss P
ossi
ble
Igni
tion
Mec
hani
sms
Asse
ss P
ossi
ble
Com
bust
ion
Mec
hani
sms
Fire
Def
lagr
atio
n
D
eton
atio
n
Anal
yze
Poss
ible
Sec
onda
ry E
ffect
s
Asse
ss R
eact
ion
Effe
cts
Com
plet
e Re
port
Com
pone
ntBy
Com
pone
nt
Team
Ana
lysis
Hyd
roge
n H
azar
dsA
naly
sis
Pro
cess
Com
pone
nt H
azar
ds C
hart
Com
pone
nt H
azar
ds C
hart
Rat
ings
0 =
Alm
ost i
mpo
ssib
le1
= R
emot
e2
= U
nlik
ely
3 =
Pro
babl
e4
= H
ighl
y pr
obab
le
Rea
ctio
n E
ffect
sA
= N
eglig
ible
B =
Mar
gina
lC
= C
ritic
alD
= C
atas
troph
ic
As
sess
Pro
babi
lity
Rat
ing
for:
C
ompo
nent
/ O
pera
tiona
l M
ode
Failu
re
Mod
es
Flam
mab
le
Mix
ture
Fo
rmat
ion
Igni
tion
Fire
D
efla
grat
ion
Det
onat
ion
Seco
ndar
yEf
fect
s O
vera
llEf
fect
s
Valv
e #
---
Rat
ing
0 –
4 0
–4
0 –
40
–4
N/R
A -D
Ope
ratio
nal R
evie
ws
Ope
ratio
nal R
evie
ws
•O
pera
ting
proc
edur
es•
Ope
rato
r tra
inin
g•
Test
read
ines
s•
Ope
ratio
nal r
eadi
ness
insp
ectio
n•
Em
erge
ncy
proc
edur
es
Be
prep
ared
for e
mer
genc
y si
tuat
ions
Em
erge
ncy
Res
pons
eE
mer
genc
y R
espo
nse
•P
rimar
y ai
m is
to p
rote
ct li
fe a
nd
prev
ent i
njur
y•
Prin
cipa
l dan
ger f
rom
a le
ak o
r spi
ll is
fir
e•
H2
flam
e lim
its a
re d
iffic
ult t
o de
tect
–Fl
ame
may
be
invi
sibl
e in
day
light
•In
adve
rtent
flam
e en
try
Em
erge
ncy
Leak
Pro
cedu
res
Em
erge
ncy
Leak
Pro
cedu
res
•Is
olat
e so
urce
, ven
t, pu
rge,
and
repa
ir•
Avo
id ig
nitio
n so
urce
s•
Exc
lude
peo
ple
and
vehi
cles
from
leak
ar
ea
•D
o no
t del
iber
atel
y fla
re a
leak
Em
erge
ncy
Fire
Pro
cedu
res
Em
erge
ncy
Fire
Pro
cedu
res
•Le
t H2
burn
unt
il su
pply
can
be
cut o
ff •
Use
wat
er to
sto
p fir
e fro
m s
prea
ding
•D
o no
t spr
ay w
ater
on
vent
sys
tem
s or
re
lief v
alve
s•
Rem
ove
a bu
rnin
g ve
ssel
from
nea
rby
vess
els
if it
can
be d
one
safe
ly
Avo
id A
sphy
xiat
ion
Avo
id A
sphy
xiat
ion
•A
void
are
as n
ear s
pills
•O
xyge
n m
onito
ring
•Ta
nk e
ntry
(H2,
N2,
He)
–E
nsur
e fre
sh a
ir su
pply
–M
onito
r atm
osph
ere
in ta
nk–
Ent
ry p
lan,
with
em
erge
ncy
plan
s–
Saf
ety
prec
autio
ns
% O
2 at
1 a
tmto
tal p
ress
ure
At r
est s
ympt
oms
(vol
bas
is)
15 -
19D
ecre
ased
abi
lity
to p
erfo
rm ta
sks;
may
indu
ce e
arly
sy
mpt
oms
in p
erso
ns w
ith h
eart,
lung
, or c
ircul
ator
ypr
oble
ms
12 -
15R
espi
ratio
n de
eper
, pul
se fa
ster
, poo
r coo
rdin
atio
n10
-12
Gid
dine
ss, p
oor j
udge
men
t, lip
s sl
ight
ly b
lue
8 -1
0N
ause
a, v
omiti
ng, u
ncon
scio
usne
ss, a
shen
face
,fa
intin
g, m
enta
l fai
lure
6 -8
100%
die
in 8
min
; afte
r 6 m
in 5
0% d
ie a
nd 5
0%
reco
ver w
ith tr
eatm
ent,
100%
reco
ver w
ith tr
eatm
ent
in 4
-5 m
in
4C
oma
in 4
0 s,
con
vuls
ions
, res
pira
tion
ceas
es, d
eath
Ano
xia
Sym
ptom
sA
noxi
a S
ympt
oms
Sum
mar
yS
umm
ary
•S
afe
use
of H
2is
ach
ieva
ble
–C
ompl
y w
ith re
gula
tions
–M
anag
emen
t com
mitm
ent
–A
pply
pro
ven
prin
cipl
es a
nd p
ract
ices
•M
inim
ize
cons
eque
nces
•D
esig
n fo
r inh
eren
t saf
ety
•R
evie
w d
esig
ns, s
afet
y, a
nd o
pera
tions
•U
se a
ppro
ved
oper
atin
g pr
oced
ures
•P
rope
r mai
nten
ance
•U
se P
PE
and
app
ropr
iate
det
ectio
n•
Pre
pare
for e
mer
genc
y si
tuat
ions
–Tr
ain
and
mot
ivat
e pe
rson
nel
Com
pone
nt D
esig
n
Com
pone
nt a
nd M
ater
ial
Con
side
ratio
ns
Hyd
roge
n C
ompo
nent
Des
ign
Hyd
roge
n C
ompo
nent
Des
ign
•S
yste
m c
ompo
nent
s–
CG
A G
-5.4
, Sta
ndar
d fo
r Hyd
roge
n P
ipin
g S
yste
ms
at C
onsu
mer
Loc
atio
ns•
Mat
eria
ls s
elec
tion
•Li
quid
Hyd
roge
n C
ompo
nent
C
onsi
dera
tions
Sys
tem
Com
pone
nts
Sys
tem
Com
pone
nts
•Jo
ints
and
con
nect
ions
•V
alve
s•
Pre
ssur
e re
lief d
evic
es•
Inst
rum
enta
tion
and
cont
rols
•Fi
lters
•H
ydro
gen
dete
ctor
s•
Fire
det
ecto
rs
•Jo
ints
and
con
nect
ions
•V
alve
s•
Pre
ssur
e re
lief d
evic
es•
Inst
rum
enta
tion
and
cont
rols
•Fi
lters
•H
ydro
gen
dete
ctor
s•
Fire
det
ecto
rs
Mat
eria
l con
side
ratio
ns
Mat
eria
l Con
side
ratio
nsM
ater
ial C
onsi
dera
tions
•U
se p
rope
r mat
eria
ls–
Met
als
–N
onm
etal
s•
Und
erst
and
tem
pera
ture
effe
cts
–H
ydro
gen
embr
ittle
men
t•
Dis
sim
ilar m
ater
ials
use
d to
geth
er•
Per
mea
bilit
y an
d po
rosi
ty
Se
rvic
e
Mat
eria
l G
H 2
LH2
SLH 2
Re
mar
ks
A
lum
inum
and
its a
lloys
Y
es
Yes
Y
es
A
uste
nitic
stai
nles
s ste
els w
ith >
7%
ni
ckel
(suc
h as
, 304
, 304
L, 3
08, 3
16,
321,
347
)
Yes
Y
es
Yes
So
me m
ake m
arte
nsiti
c con
vers
ion
if str
esse
d ab
ove y
ield
poi
nt a
t low
te
mpe
ratu
re.
Car
bon
steel
s Y
es
No
No
Too
britt
le fo
r cry
ogen
ic se
rvic
e. C
oppe
r and
its a
lloys
(suc
h as
, bra
ss,
bron
ze, a
nd co
pper
-nic
kel)
Yes
Y
es
Yes
Gra
y, d
uctil
e, or
cast
iron
No
No
No
Not
per
mitt
ed fo
r hyd
roge
n se
rvic
e. L
ow-a
llow
steel
s Y
es
No
No
Too
britt
le fo
r cry
ogen
ic se
rvic
e. N
icke
l and
its a
lloys
(suc
h as
, Inc
onel
® a
nd M
onel
®)
No
Yes
Y
es
Susc
eptib
le to
hyd
roge
n em
britt
lem
ent
Nic
kel s
teel
s (su
ch a
s, 2.
25, 3
.5, 5
, and
9
% N
i) N
o N
o N
o D
uctil
ity lo
st at
LH 2
and
SLH
2 te
mpe
ratu
res.
Tita
nium
and
its a
lloys
N
o Y
es
Yes
Su
scep
tible
to h
ydro
gen
embr
ittle
men
t
Asb
esto
s im
preg
nate
d wi
th T
eflo
n®
Yes
Y
es
Yes
A
void
use
bec
ause
of c
arci
noge
nic
haza
rd.
Chl
orop
rene
rubb
er (N
eopr
ene®
) Y
es
No
No
Too
britt
le fo
r cry
ogen
ic se
rvic
e. D
acro
n®
Yes
N
o N
o To
o br
ittle
for c
ryog
enic
serv
ice.
Flu
oroc
arbo
n ru
bber
(Vito
n®)
Yes
N
o N
o To
o br
ittle
for c
ryog
enic
serv
ice.
Myl
ar®
Y
es
No
No
Too
britt
le fo
r cry
ogen
ic se
rvic
e. N
itrile
(Bun
a-N
®)
Yes
N
o N
o To
o br
ittle
for c
ryog
enic
serv
ice.
Pol
yam
ides
(Nyl
on®
) Y
es
No
No
Too
britt
le fo
r cry
ogen
ic se
rvic
e. P
olyc
hlor
otrif
luor
ethy
lene
(Kel
-F®
) Y
es
Yes
Y
es
P
olyt
etra
fluor
ethy
lene
(Tef
lon®
) Y
es
Yes
Y
es
Und
erst
and
H2
Em
britt
lem
entE
ffect
sU
nder
stan
d H
2E
mbr
ittle
men
tEffe
cts
•E
xtre
mel
y em
britt
led
–41
0 S
S, 1
042
stee
l, 17
-7 P
H S
S, 4
140,
44
0C, I
ncon
el 7
18•
Sev
erel
y em
britt
led
–Ti
-6A
l-4V
, Ti-5
Al-
2.5S
n, A
ISI 1
020,
43
0F, N
i 270
, A51
5
•S
light
ly e
mbr
ittle
d–
304
ELC
SS
, 305
S
S, B
e-C
u A
lloy
25,
Ti•
Neg
ligib
ly e
mbr
ittle
d–
310
SS
, 316
SS
, 11
00 A
l, 60
61-T
6 A
l, 70
75-T
73 A
l, O
FHC
C
u, A
286
Add
ress
H2
Em
britt
lem
ent
Add
ress
H2
Em
britt
lem
ent
•In
crea
sed
mat
eria
l thi
ckne
ss•
Sur
face
fini
sh•
Wel
ding
tech
niqu
e•
Mat
eria
l sel
ectio
n•
Con
serv
ativ
e de
sign
stre
ss (a
void
yi
eldi
ng)
Typi
cal m
ater
ials
App
licat
ion
LH2 o
r SLH
2G
H2
Val
ves
Forg
ed, m
achi
ned,
and
cas
t val
ve b
odie
s (30
4 or
316
stai
nles
s ste
el, o
r bra
ss) w
ithex
tend
ed b
onne
t, an
d w
ith o
ther
mat
eria
ls in
side
App
ropr
iate
indu
stria
l pro
duct
sb
Fitti
ngs
Stai
nles
s ste
el b
ayon
et ty
pe fo
r vac
uum
jack
ets
App
ropr
iate
indu
stria
l pro
duct
sb
O-r
ings
Stai
nles
s ste
elc , K
el-F®
, or T
eflo
n ®A
ppro
pria
te in
dust
rial p
rodu
ctsb
Gas
kets
Soft
Alu
min
um, l
ead,
or a
nnea
led
copp
er b
etw
een
serra
ted
flang
es; K
el-F®
; Tef
lon ®
;gl
ass-
fille
d Te
flon ®
App
ropr
iate
indu
stria
l pro
duct
sb
Flex
ible
hos
esC
onvo
lute
d va
cuum
jack
eted
316
or
321
stai
nles
s ste
elSt
ainl
ess s
teel
bra
ided
with
Tef
lon-
linin
g
Rup
ture
disk
asse
mbl
y30
4, 3
04L,
316
, or 3
16L
stai
nles
s ste
el30
4, 3
04L,
316
, or 3
16L
stai
nles
s ste
el
Pipi
ng30
4, 3
04L,
316
, or 3
16L
stai
nles
s ste
el30
0 se
ries s
tain
less
stee
l (31
6 pr
efer
redh )
Car
bon
stee
lg
Dew
ars
304,
304
L, 3
16, o
r 316
L st
ainl
ess s
teel
Not
app
licab
leLu
bric
ants
No
lubr
ican
ts u
sed
in so
me
appl
icat
ions
.h Lub
rican
ts li
sted
for G
H2
are
com
patib
le b
ut w
illbe
com
e so
lid a
t low
tem
pera
ture
s. D
ry lu
bric
ants
, suc
h as
PTF
E, P
TFE
carb
on, P
TFE
bron
ze, f
iber
glas
s-PF
TE g
raph
ite.e G
raph
ite a
nd m
olyb
denu
m d
isulfi
de p
erm
it on
ly v
ery
limite
d se
rvic
e lif
e fo
r bea
rings
. f
Dup
ont K
ryto
x 24
0AC
, Flu
oram
ics O
XY
-8, D
ow C
orni
ng D
C-3
3, D
owC
orni
ng F
S-34
52, B
ray
Oil
Bra
ycot
e 60
1, G
ener
al E
lect
ric V
ersi
lube
,H
ough
ton
Cosm
olub
e 51
00, B
rayc
ote
640
AC
, Dup
ont G
PL 2
06,
Hal
ocar
bon
Serie
s 6.
3 oi
l, an
d K
el-F®
oil
aA
dapt
ed fr
om T
able
6.1
, Rec
omm
ende
d M
ater
ials
for H
ydro
gen
Syst
ems,
in “
Hyd
roge
n Pr
opel
lant
,” C
hapt
er 6
in L
ewis
Saf
ety
Man
ual,
NA
SA T
echn
ical
Mem
oran
dum
104
438,
Nov
embe
r (19
92):
pp.
6-7
0.b
A n
umbe
r of s
tand
ard
indu
stria
l pro
duct
s ar
e av
aila
ble
cove
ring
a w
ide
rang
e of
tem
pera
ture
s an
d pr
essu
res
in a
var
iety
of c
ompa
tible
mat
eria
ls.
cM
etal
O-ri
ngs
have
pro
ven
satis
fact
ory
whe
n co
ated
with
a s
oft m
ater
ial a
nd w
hen
used
on
smoo
th s
urfa
ces.
Typ
e 32
1 st
ainl
ess
stee
l, w
ith a
coa
ting
of te
flon
or s
ilver
, sho
uld
be u
sed
in s
tain
less
ste
el fl
ange
sw
ith s
tain
less
bol
ting.
Tef
lon ®
coa
ted
alum
inum
sho
uld
be u
sed
in a
lum
inum
flan
ges
with
alu
min
um b
oltin
g. U
sing
sim
ilar m
ater
ials
avo
ids
the
leak
age
poss
ibili
ty fr
om u
nequ
al c
ontra
ctio
n of
dis
sim
ilar
met
als.
(Le
wis
Hyd
roge
n Sa
fety
Man
ual,
Dec
embe
r 10,
(195
9) p
p. 3
-18)
dTh
read
ed jo
ints
sho
uld
be a
void
ed in
LH
2 or S
LH2 s
yste
ms.
If t
hey
mus
t be
used
, the
mal
e an
d fe
mal
e th
read
s sh
ould
be
tinne
d w
ith a
60%
lead
-40%
tin
sold
er, t
hen
heat
ed to
pro
vide
a s
olde
red
join
t with
pip
eth
read
stre
ngth
. (L
ewis
Hyd
roge
n Sa
fety
Man
ual,
Dec
embe
r 10,
(195
9) p
p. 3
-15)
e W
. Pes
chka
, Liq
uid
Hyd
roge
n, F
uel o
f the
Fut
ure,
Spr
inge
r-V
erla
g W
ien,
New
Yor
k, (1
992)
: pp
. 197
.f
D. A
. Wig
ley,
“Th
e Pr
oper
ties
of N
onm
etal
s,” In
Mec
hani
cal P
rope
rtie
s of
Mat
eria
ls a
t Low
Tem
pera
ture
, Cha
pter
4, p
p. 2
25,
Plen
um P
ress
, New
Yor
k 19
71g
Car
bon
stee
l mee
ting
AN
SI/A
SME
B31
.3 s
tand
ards
may
be
used
for G
H2 s
ervi
ce a
bove
244
K (-
20 °
F.)
(Lew
is S
afet
y M
anua
l, C
hapt
er 6
“H
ydro
gen
Prop
ella
nt,”
NA
SA T
echn
ical
Mem
oran
dum
104
438,
Nov
embe
r (19
92):
pp.
6-3
5.)
h M
cPhe
rson
, B.,
Priv
ate
com
mun
icat
ion
(199
6).
LH2 C
ompo
nent
Con
side
ratio
nsLH
2 C
ompo
nent
Con
side
ratio
ns
Line
s an
d Fi
tting
sLi
nes
and
Fitti
ngs
•U
se v
acuu
m ja
cket
ed li
nes
•D
o no
t use
thre
ad s
eala
nt in
LH
2sy
stem
s•
“Col
d sh
ock”
and
retig
hten
line
s an
d fit
tings
•U
se m
etal
con
volu
ted
flexi
ble
hose
s
Ther
mal
Insu
latio
nTh
erm
al In
sula
tion
•LH
2sy
stem
s no
rmal
ly in
sula
ted
–R
educ
e he
at in
put
and
boilo
ff–
Pre
vent
liqu
id a
ir fo
rmat
ion
–P
reve
nt c
old
surfa
ce
cont
act b
y pe
rson
nel
•C
old
GH
2sy
stem
s m
ay n
eed
to b
e in
sula
ted
Ther
mal
Insu
latio
nTh
erm
al In
sula
tion
•In
sula
tion
shou
ld h
ave
selfe
xtin
guis
hing
fir
e ra
ting
•C
once
rn w
ith fo
am in
sula
tion
over
air
cond
ensa
tion
with
oxy
gen
enric
hmen
t–
Invo
lves
fact
ors
such
as
open
cel
l vs
clos
ed
cell,
cel
l siz
e, in
ters
titia
l gas
, joi
nts
and
gaps
Ven
tsV
ents
•V
ents
mus
t be
size
d to
allo
w fo
r flo
w
unde
r all
cond
ition
s–
Nor
mal
flow
–
Coo
l dow
n•
Ven
ts s
houl
d be
at l
east
rate
d fo
r 150
ps
ig p
er C
GA
G5-
5•
Pre
caut
ions
mus
t be
take
n to
pre
vent
cr
yopu
mpi
ng a
nd m
oist
ure
colle
ctio
n
Rel
ief D
evic
esR
elie
f Dev
ices
•B
oth
norm
al fl
ow a
nd c
oold
own
need
pr
otec
tion
–S
udde
n pr
essu
re d
ecre
ase
on re
lief v
alve
ac
tuat
ion
will
cau
se s
udde
n bo
iling
•A
void
ther
mal
cyc
ling
on ru
ptur
e di
scs
•M
oist
ure
colle
cted
in re
lief v
alve
will
freez
e an
d pr
even
t val
ve fr
om o
pera
ting
Vac
uum
Sub
syst
emV
acuu
m S
ubsy
stem
•M
aint
ain
insu
latin
g va
cuum
•R
emov
e un
wan
ted
H2
or o
ther
gas
es b
y pu
rgin
g–
Bew
are
that
vac
uum
pum
p w
ith b
alla
st
valv
e co
uld
deve
lop
com
bust
ible
mix
ture
w
ithin
the
pum
p or
its
exha
ust
Vac
uum
Sub
syst
em (c
ont.)
Vac
uum
Sub
syst
em (c
ont.)
•V
acuu
m p
ump
exha
ust m
ust b
e co
nnec
ted
to a
pro
per v
ent
–To
ven
t H2
gas
–To
ven
t oil
vapo
rs (m
echa
nica
l pum
p)•
Leak
in a
n ev
acua
ting
syst
em c
an re
sult
in s
yste
m b
eing
con
tam
inat
ed w
ith a
ir
Sum
mar
yS
umm
ary
•C
aref
ul c
onsi
dera
tion
shou
ld b
e gi
ven
to–
Eac
h pa
rt of
eve
ry c
ompo
nent
–O
pera
ting
cond
ition
s–
How
eac
h co
mpo
nent
is u
sed
in a
n H
2sy
stem
•S
peci
al c
onsi
dera
tions
are
requ
ired
for
LH2
syst
ems
PE
M*
Fuel
C
ell/E
lect
roly
zer
Issu
es
Initi
al T
houg
hts
on
Hyd
roge
n C
ombu
stio
n Is
sues
for F
uel C
ell/E
lect
roly
zer
Sys
tem
Des
ign
* P
roto
n E
xcha
nge
Mem
bran
e
M e m b r a n e
Pre
vent
s th
e hy
drog
en
and
oxyg
en fr
om
mix
ing.
DC
Ele
ctric
Pow
er
+(-
)E
lect
rons
Ele
ctro
ns tr
avel
from
Ano
de
to C
atho
de th
roug
h ex
tern
al
load
.
Hyd
roge
n(H
2)O
xyge
n(O
2)C
oola
nt
Wat
er S
tora
ge
O2 / W
ater
Sep
arat
or
Ano
de (C
atal
ytic
Ele
ctro
de)
2H2
-> 4
H+
+ 4e
-
Ove
rall
Rea
ctio
n:2H
2 + O
2 ->
2H2O
Oxy
gen
Circ
ulat
ion
Pum
p
Cat
hode
(Cat
alyt
ic E
lect
rode
)4H
+ +
O2 +
4e-
->
2H2O
Tran
sfer
s pr
oton
s (H
+ )
from
Ano
de to
Cat
hode
.
PE
M F
uel C
ell C
once
ptP
EM
Fue
l Cel
l Con
cept
Fuel
Cel
l Sta
ck
H2
in
O2
in
Eje
ctor
Eje
ctor
Ext
erna
l sen
se
Ext
erna
l sen
se
Sec
onda
ry C
oola
nt L
oop
Pur
ge C
ontro
l Val
ve
Ext
erna
l Sen
se R
egul
ator
sP
assi
ve
Wat
er
Sep
arat
or
Prim
ary
Coo
lant
Loo
p
Coo
lant
Pum
p
Pro
duct
W
ater
Pur
ge C
ontro
l Val
ve
Sys
tem
Sch
emat
icS
yste
m S
chem
atic
Und
erst
and
Com
bust
ion
Pot
entia
lU
nder
stan
d C
ombu
stio
n P
oten
tial
•U
nder
stan
d po
ssib
ilitie
s–
H2
+ O
2
–H
2+
air
–H
2+
othe
r oxi
dize
rs•
Prim
ary
focu
s on
H2-
wet
ted
volu
mes
–In
ters
tack
spa
ces
& s
tack
hea
ders
–G
as s
epar
ator
s–
Filte
rs, h
eat e
xcha
nger
s, p
umps
–Li
nes
and
fittin
gs
Sec
onda
ry A
naly
sis
Req
uire
dS
econ
dary
Ana
lysi
s R
equi
red
•S
econ
dary
focu
s on
regi
ons
expo
sed
follo
win
g ex
posu
re–
Ext
erna
l to
com
pone
nts
and
syst
em–
Inte
rnal
to g
auge
s•
Sep
arat
e O
2ha
zard
s an
alys
is re
quire
d–
Pos
sibi
lity
of O
2/mat
eria
l com
bust
ion
–“K
indl
ing
chai
n”pr
oces
ses
–R
equi
res
addi
tiona
l exp
ertis
e
App
roac
hes
to C
ombu
stio
n C
ontro
lA
ppro
ache
s to
Com
bust
ion
Con
trol
•E
xplo
it ph
ysic
al c
ombu
stio
n lim
its–
Fire
and
def
lagr
atio
n•
Cho
ose
dim
ensi
ons
<que
nchi
ng g
ap•
Avo
id fl
amm
able
mix
ture
com
posi
tions
–D
eton
atio
n•
Cho
ose
dim
ensi
ons
<crit
ical
cel
l siz
e•
Avo
id d
eton
able
mix
ture
com
posi
tions
–D
efla
grat
ion-
to-d
eton
atio
n tra
nsiti
on•
Des
ign
chan
nel l
engt
hs <
~0.5
m•
Avo
id d
eton
able
mix
ture
com
posi
tions
App
roac
hes
to C
ombu
stio
n C
ontro
l (c
ont.)
App
roac
hes
to C
ombu
stio
n C
ontro
l (c
ont.)
•C
ontro
l com
bust
ible
atm
osph
ere
form
atio
n–
Com
posi
tion
<1%
H2
–D
etec
tion
•H
2se
nsor
s in
air,
or O
2se
nsor
s in
H2
–M
ultip
le fa
ult t
oler
ance
•B
uffe
r H2
from
oxi
dize
rs w
ith p
urge
s•
Pos
tfailu
re s
afin
g•
Mon
itor c
ell p
erfo
rman
ce fo
r pin
hole
s
App
roac
hes
to C
ombu
stio
n C
ontro
l (c
ont.)
App
roac
hes
to C
ombu
stio
n C
ontro
l (c
ont.)
•M
inim
ize
igni
tion
sour
ces
–B
ewar
e of
com
pone
nt p
ower
use
•In
dica
tes
igni
tion
pote
ntia
l–
Red
uce
cond
uctiv
e de
bris
–Is
olat
e po
tent
ial s
urfa
ces
–C
ontro
l acc
umul
atio
n of
cat
alyt
ic fi
nes
Oth
er C
onsi
dera
tions
Oth
er C
onsi
dera
tions
•C
onsi
der m
ater
ial
com
patib
ility
•H
2em
britt
lem
ent
•C
onsi
der H
2in
so
lutio
n•
Cho
ose
SS
line
s ov
er p
last
ic•
Avo
id c
ombu
stib
le
seal
mat
eria
ls
•D
esig
n fo
r wor
st-
case
con
tain
men
t–
Det
onat
ion
p ini
tialx
~(
15 to
20)
x 3
(r
efle
ctio
n) x
saf
ety
fact
or–
Def
lagr
atio
n p i
nitia
lx
~(1
to 8
) x s
afet
y fa
ctor
Hyd
roge
n Fa
cilit
y D
esig
n
Gen
eral
Des
ign,
S
uppo
rt In
frast
ruct
ure,
an
d S
afet
y S
ubsy
stem
s
Gen
eral
Fac
ility
Des
ign
Gen
eral
Fac
ility
Des
ign
•G
ener
al c
onsi
dera
tions
•Fa
cilit
y si
ting
•P
ipin
g an
d st
orag
e•
Ven
ting,
flar
ing,
and
dis
pers
ion
•B
uild
ings
and
test
cha
mbe
rs
Gen
eral
con
side
ratio
ns
Gen
eral
Con
side
ratio
ns
Goa
ls o
f Fac
ility
Saf
ety
Goa
ls o
f Fac
ility
Saf
ety
•P
rote
ctio
n of
the
publ
ic a
nd w
orke
rs
mos
t im
porta
nt•
Val
ue o
f equ
ipm
ent
•Im
porta
nce
of m
issi
on•
Pub
lic p
erce
ptio
n•
Env
ironm
ent
Gen
eral
Con
side
ratio
ns
A S
afe
Faci
lity
A S
afe
Faci
lity
•S
afet
y co
nsid
ered
in d
esig
n an
d co
nstru
ctio
n–
As
fool
proo
f as
poss
ible
•S
afet
y an
d ha
zard
ana
lyse
s–
Inpu
ts fr
om d
esig
ners
, ope
rato
rs, s
afet
y en
gine
ers
•G
ood
mai
nten
ance
•S
afet
y co
mm
ittee
ove
rsig
ht
Gen
eral
Con
side
ratio
ns Saf
e O
pera
tion
Saf
e O
pera
tion
•Tr
aini
ng–
Initi
al a
nd p
erio
dic
•S
OP
s an
d ch
eckl
ists
Faci
lity
sitin
g
Faci
lity
Siti
ng, S
tora
ge a
nd P
ipin
g
Faci
lity
Siti
ngFa
cilit
y S
iting
•S
ite lo
catio
n pr
efer
ence
s•
Qua
ntity
-dis
tanc
e re
quire
men
ts•
Exc
lusi
on a
reas
•B
arric
ades
, dik
es a
nd
impo
undm
ents
Site
Loc
atio
n P
refe
renc
esS
ite L
ocat
ion
Pre
fere
nces
•D
riven
by
appl
icat
ion
and
quan
tity
–La
bora
tory
sca
le o
pera
tions
(sm
all q
uant
ities
)–
Non
-pro
pella
nt–
Pro
pella
nt•
Labo
rato
ry s
cale
–D
eter
min
ed b
y si
te A
HJ
–O
SH
A r
egul
atio
n: G
H2
< 11
.3 m
3 (4
00 ft
3), L
H2
< 15
0 L
(39.
6 ga
l)•
Non
-pro
pella
nt–
Indu
stry
like
app
licat
ions
for G
H2
or L
H2
–P
rimar
y ha
zard
is in
adve
rtent
rele
ase
into
air
and
subs
eque
nt fi
re–
Mus
t con
side
r sta
ndar
d ex
posu
res
[pow
erlin
es, d
rain
s, e
tc..]
Sim
ulat
ed S
pill
1500
Gal
LH
2 in
30
seco
nds
Sim
ulat
ed S
pill
1500
Gal
LH
2 in
30
seco
nds
Pre
ferr
ed O
rder
for
Loca
ting
GH
2S
tora
ge S
yste
ms
Pre
ferr
ed O
rder
for
Loca
ting
GH
2S
tora
ge S
yste
ms
G
H2 V
olum
e N
atur
e of
Loc
atio
n <3
K ft
3
(85
m3 )
3 to
15K
ft3
(85
to 4
25 m
3 )>1
5K ft
3
(425
m3 )
Out
door
s I
I I
In s
epar
ate
build
ing
II II
II In
spe
cial
room
III
III
N
ot p
erm
itted
Insi
de b
uild
ings
, ex
pose
d to
oth
er
occu
panc
ies,
but
no
t in
spec
ial r
oom
IV
Not
per
mitt
ed
Not
per
mitt
ed
NFP
A G
aseo
us H
ydro
gen
Sep
arat
ion
Dis
tanc
esN
FPA
Gas
eous
Hyd
roge
nS
epar
atio
n D
ista
nces
•Id
entif
ies
expo
sure
s,–
Wal
ls b
y m
ater
ial,
open
ings
, fire
ratin
gs–
Pre
senc
e of
flam
mab
le/c
ombu
stib
le li
quid
s (a
bove
and
be
low
gro
und)
, com
bust
ible
mat
eria
ls–
Pla
ces
of p
ublic
ass
embl
y, s
idew
alks
, par
king
, pro
perty
line
s•
Pro
vide
s a
brea
kdow
n by
qua
ntity
: <30
00 ft
3(8
5 m
3 ), 3
000
ft3
(85
m3 )
–15
,000
ft3
(425
m3)
, >15
,000
ft3
(425
m3 )
•Fo
r exa
mpl
e: >
15,0
00 ft
3(4
25 m
3 )–
25 ft
to u
nspr
inkl
ered
build
ing
–50
ft to
flam
mab
le g
ases
oth
er th
an h
ydro
gen
–50
ft to
pla
ces
of p
ublic
ass
embl
y •
See
NFP
A 5
5, S
tand
ard
for t
he S
tora
ge, U
se, a
nd H
andl
ing
of
Com
pres
sed
Gas
es a
nd C
ryog
enic
Flu
ids
in P
orta
ble
and
Sta
tiona
ry C
onta
iner
s, C
ylin
ders
, and
Tan
ks [s
uper
sede
s N
FPA
50
A]
Pre
ferr
ed O
rder
for
Loca
ting
LH2
Sto
rage
Sys
tem
sP
refe
rred
Ord
er fo
r Lo
catin
g LH
2 S
tora
ge S
yste
ms
LH
2 Vol
ume,
L (g
al)
Nat
ure
of L
ocat
ion
150-
189
(40-
50)
190-
1136
(5
1-30
0)
1137
-227
1
(301
-500
) >2
271
(>60
0)
Out
door
s I
I I
I In
sep
arat
e bu
ildin
gII
II II
Not
pe
rmitt
edIn
spe
cial
room
III
III
N
ot
perm
itted
N
ot
perm
itted
Insi
de b
uild
ings
, ex
pose
d to
oth
er
occu
panc
ies,
but
no
t in
spec
ial r
oom
IV
Not
pe
rmitt
ed
Not
pe
rmitt
ed
Not
pe
rmitt
ed
NFP
A L
iqui
d H
ydro
gen
Sep
arat
ion
Dis
tanc
esN
FPA
Liq
uid
Hyd
roge
nS
epar
atio
n D
ista
nces
•Id
entif
ies
expo
sure
s,–
Wal
ls b
y m
ater
ial,
open
ings
, fire
ratin
gs–
Inta
kes
for c
ompr
esso
rs, A
C, o
r ven
tilat
ion
–P
rese
nce
of fl
amm
able
/com
bust
ible
liqu
ids
(abo
ve a
nd b
elow
gr
ound
), co
mbu
stib
le m
ater
ials
–P
lace
s of
pub
lic a
ssem
bly,
sid
ewal
ks, p
arki
ng, p
rope
rty li
nes
•P
rovi
des
a br
eakd
own
by q
uant
ity 7
5 ft
(gal
lons
): 39
.65
–3,
500,
35
01 –
15,0
00, 1
5,00
1 –
75,0
00.
•Fo
r exa
mpl
e: 1
5,00
1 –
75,0
00 g
allo
ns–
100
ft to
uns
prin
kler
edbu
ildin
g–
75 ft
to li
quid
oxy
gen
–10
0 ft
to a
ll cl
asse
s of
flam
mab
le &
com
bust
ible
liqu
ids
–75
ft to
pla
ces
of p
ublic
ass
embl
y•
See
NFP
A 5
5, S
tand
ard
for t
he S
tora
ge, U
se, a
nd H
andl
ing
of
Com
pres
sed
Gas
es a
nd C
ryog
enic
Flu
ids
in P
orta
ble
and
Sta
tiona
ry C
onta
iner
s, C
ylin
ders
, and
Tan
ks [s
uper
sede
s N
FPA
50
B]
Siti
ngfo
r Pro
pella
nt A
pplic
atio
nsS
iting
for P
rope
llant
App
licat
ions
•P
rope
llant
app
licat
ions
are
det
erm
ined
by
the
pote
ntia
l for
mix
ing
fuel
and
oxi
dize
r•
Typi
cal a
pplic
atio
ns in
clud
e:–
Laun
ch p
ads
–S
tatic
test
sta
nds,
col
d-flo
w te
st o
pera
tions
–B
ulk
stor
age,
rest
sto
rage
, & ru
n ta
nkag
e–
Pip
elin
es•
Am
ount
s <
45 k
g (1
00 lb
s) e
xplo
sive
eq
uiva
lent
(fue
l + o
xidi
zer)
are
con
trolle
d by
th
e A
HJ
LH2-
LOX
Ran
ge S
afet
y Te
stLH
2-LO
X R
ange
Saf
ety
Test
Siti
ngfo
r Pro
pella
nt A
pplic
atio
nsS
iting
for P
rope
llant
App
licat
ions
•D
ista
nces
are
muc
h la
rger
than
NFP
A–
75,0
00 lb
~10
0,00
0 ga
l–
1200
ft to
inha
bite
d bu
ildin
gs–
1200
ft to
pub
lic tr
affic
–13
0 ft
to in
tragr
oup
stor
age
•N
AS
A a
dher
es to
DO
D A
mm
uniti
on a
nd
Exp
losi
ve S
afet
y S
tand
ard
[605
5.9]
–[h
ttp://
ww
w.d
desb
.pen
tago
n.m
il/D
oD60
55.9
-S
TD%
205%
20O
ct%
2020
04.p
df]
•La
test
rang
e sa
fety
test
dat
a: C
orre
latio
n of
Li
quid
Pro
pella
nts
NA
SA
Hea
dqua
rters
R
TOP
,WS
TF-T
R-0
01-0
1-02
Faci
lity
Siti
ngE
xclu
sion
Are
asFa
cilit
y S
iting
Exc
lusi
on A
reas
•C
reat
e an
exc
lusi
on a
rea
with
con
trols
–Li
mit
acce
ss to
per
sonn
el w
ith re
quire
d tra
inin
g an
d pr
oper
pro
tect
ive
equi
pmen
t–
Ens
ure
equi
pmen
t is
not a
n ig
nitio
n so
urce
–O
pera
te a
ccor
ding
to a
ppro
ved
proc
edur
es
•P
ost k
now
n ha
zard
s–
Min
imum
exc
lusi
on a
rea
= Q
-D re
quire
men
ts
Faci
lity
Siti
ngB
arric
ades
Faci
lity
Siti
ngB
arric
ades
•U
se b
arric
ades
to p
rote
ct–
From
shr
apne
l and
frag
men
ts–
H2
faci
lity
from
oth
er h
azar
ds–
Nea
rby
faci
lity
from
H2
faci
lity
•U
se e
arth
mou
nds
and
blas
t mat
s•
Ens
ure
it do
es n
ot p
rovi
de c
onfin
emen
t su
ffici
ent f
or d
eton
atio
n
Faci
lity
Siti
ngD
ikes
and
Impo
undm
ents
Faci
lity
Siti
ngD
ikes
and
Impo
undm
ents
•U
se to
con
tain
spi
lls•
Can
lim
it va
poriz
atio
n ra
te–
Pos
sibl
y sm
alle
r com
bust
ion
clou
d, b
ut
long
er ti
me
to v
apor
ize
•U
se c
rush
ed s
tone
for a
dded
sur
face
ar
ea to
incr
ease
vap
oriz
atio
n ra
te in
an
impo
undm
ent c
an•
Ens
ure
they
do
not p
rovi
de c
onfin
emen
t su
ffici
ent f
or d
eton
atio
n
Pip
ing
and
stor
age
Sto
rage
Ves
sels
Sto
rage
Ves
sels
•D
esig
n–
AS
ME
, Int
erna
tiona
l Boi
ler a
nd P
ress
ure
Ves
sel C
ode,
Sec
tion
VIII
, Pre
ssur
e V
esse
ls•
Des
ign
and
sitin
g–
29C
FR19
10.1
03, H
ydro
gen
–N
FPA
50A
, GH
2S
yste
ms
at C
onsu
mer
Site
s–
NFP
A 5
0B, L
H2
Sys
tem
s at
Con
sum
er S
ites
•H
azar
ds a
naly
sis
–29
CFR
1910
.119
, Pro
cess
saf
ety
man
agem
ent
of h
ighl
y ha
zard
ous
chem
ical
s(≥
10,0
00 lb
)
Sto
rage
Ves
sel D
esig
nS
tora
ge V
esse
l Des
ign
•E
quip
with
shu
toff
valv
e –
Aut
omat
ic o
pera
tion
pref
erre
d•
Pro
vide
for a
ppro
ved
vent
and
pre
ssur
e re
lief s
yste
ms
•P
rovi
de b
arrie
rs to
pot
entia
l fai
lure
of
rota
ting
equi
pmen
t, su
ch a
s pu
mps
Sto
rage
Ves
sel I
nsta
llatio
nS
tora
ge V
esse
l Ins
talla
tion
•E
nsur
e th
at L
H2
vess
els
are
–In
sula
ted
•Li
mits
vap
oriz
atio
n an
d co
nden
satio
n of
air
•S
houl
d be
sel
f-ext
ingu
ishi
ng–
Per
iodi
cally
war
med
to re
mov
e so
lid
cont
amin
ants
–
Ele
ctric
ally
bon
ded
at a
ll jo
ints
–G
roun
ded
and
prop
erly
labe
led
•C
onte
nts,
cap
acity
, MA
WP
–S
urro
unde
d by
a 1
5-ft
clea
r spa
ce
Faci
lity
Siti
ng, S
tora
ge a
nd P
ipin
g
Pip
ing
Siti
ngP
ipin
g S
iting
•B
e lo
cate
d in
acc
orda
nce
with
ap
prop
riate
sta
ndar
ds–
29C
FR19
10.1
03, N
FPA
55
[Sup
erse
des
NFP
A 5
0 A
and
B]
•N
ot lo
cate
d be
neat
h el
ectri
c po
wer
line
s•
New
pip
ing
shou
ld n
ot b
e bu
ried
•P
rote
ct fr
om p
oten
tial f
ailu
re o
f rot
atin
g eq
uipm
ent a
nd fr
om v
ehic
les
Faci
lity
Siti
ng, S
tora
ge a
nd P
ipin
g
Pip
ing
Des
ign
and
Fabr
icat
ion
Pip
ing
Des
ign
and
Fabr
icat
ion
•D
esig
n, fa
bric
ate,
and
test
to A
SM
E
B31
.3 a
nd C
GA
G-5
.4•
Pro
vide
app
ropr
iate
–
Flex
ibili
ty (e
xpan
sion
join
ts, l
oops
, offs
ets)
–S
uppo
rts, g
uide
s, a
nd a
ncho
rs
–R
elie
f dev
ices
–
Ele
ctric
al b
ondi
ng a
cros
s al
l joi
nts
–G
roun
ding
–La
belin
g (c
onte
nts,
flow
dire
ctio
n)
Ven
ting,
flar
ing,
and
dis
pers
ion
Ven
t/Fla
re a
nd D
ispe
rsio
nV
ent/F
lare
and
Dis
pers
ion
•V
ent o
r fla
re a
ccor
ding
to a
ppro
ved
met
hods
•E
nsur
e H
2ve
nt s
yste
m v
eloc
ity is
in
satis
fact
ory
rang
e•
Pro
vide
pur
ge c
apab
ility
–U
se N
2or
He,
dep
endi
ng o
n te
mpe
ratu
re
Ven
t/Fla
re a
nd D
ispe
rsio
n (c
ont.)
Ven
t/Fla
re a
nd D
ispe
rsio
n (c
ont.)
•P
reve
nt a
ir an
d pr
ecip
itatio
n fro
m
ente
ring
vent
/flar
e sy
stem
–U
se m
olec
ular
sea
l or f
lapp
er•
Ens
ure
relie
f dev
ice
conn
ectio
n to
m
anifo
ld d
oes
not a
ffect
relie
f pre
ssur
e
Igni
ter
H2
flare
sta
ck
with
gas
(m
olec
ular
) sea
l
Ven
ting,
Fla
ring
and
Dis
pers
ion
Siti
ngS
iting
•Lo
cate
roof
ven
ts s
o th
at H
2do
es n
ot
get i
nto
build
ing
air i
ntak
es–
Roo
f ven
t loc
ated
16
ft ab
ove
roof
can
be
used
to v
ent u
p to
0.5
lb/s
•D
ispo
se o
f lar
ge q
uant
ities
of H
2by
fla
ring
–Fl
are
stac
k or
bur
n po
nd
Dis
posa
l Fac
tors
Dis
posa
l Fac
tors
•H
2qu
antit
y/ex
tent
in c
ombu
stib
le c
loud
•Th
erm
al ra
diat
ion
from
flam
e•
Site
con
ditio
ns–
Siz
e of
exc
lusi
on a
rea
–B
uild
ing
loca
tions
–P
erso
nnel
con
trol
–W
eath
er
Dis
pers
ion
Test
Res
ults
Dis
pers
ion
Test
Res
ults
Flam
mab
le M
ixtu
re
and
Vis
ible
Clo
udFl
amm
able
Mix
ture
an
d V
isib
le C
loud
0
20406080
050
100
150
200
Combustible Cloud Length (m)
Hyd
roge
n R
elea
se R
ate
(g/s
)
A C DB
NIG
HT
, 1 m
/s
NIG
HT
, 3 m
/s
DA
Y, 1
m/s
DA
Y, 3
m/s
Com
bust
ible
Clo
ud L
engt
hC
ombu
stib
le C
loud
Len
gth
020406080100 0
5010
015
020
0
Hydrogen Mass in Combustible Cloud (kg)
Hyd
roge
n R
elea
se R
ate
(g/s
)
A B C D
NIG
HT
, 1 m
/s
NIG
HT
, 3 m
/s
DA
Y, 1
m/s
DA
Y, 3
m/s
H2
Mas
s in
Com
bust
ible
Clo
udH
2M
ass
in C
ombu
stib
le C
loud
0246810
050
100
150
200
Combustible Cloud Maximum Rise (m)
Hyd
roge
n R
elea
se R
ate
(g/s
)
A BC D
Nig
ht, 1
m/s
Nig
ht, 3
m/s
Day
, 1 m
/sD
ay, 3
m/s
Com
bust
ible
Clo
ud M
ixtu
reC
ombu
stib
le C
loud
Mix
ture
Tim
e 0:
04
Tim
e 0:
08
Tim
e 0:
17
Tim
e 0:
26
Tim
e 0:
26
Tim
e 0:
38Ti
me
0:38
Tim
e 1:
14Ti
me
1:14
Bui
ldin
gs a
nd te
st c
ham
bers
Bui
ldin
gs a
nd T
est C
ham
bers
Bui
ldin
gs a
nd T
est C
ham
bers
•M
inim
ize
pers
onne
l inj
ury
and
faci
lity
dam
age
in c
ase
of H
2fir
e or
exp
losi
on•
Con
stru
ct w
ith li
ghtw
eigh
t, no
ncom
bust
ible
m
ater
ials
acc
ordi
ng to
29C
FR19
10.1
03,
Hyd
roge
n
Bui
ldin
g D
esig
nB
uild
ing
Des
ign
•A
void
pea
ks in
cei
lings
•U
se s
hatte
rpro
of g
lass
or p
last
ic in
w
indo
w fr
ames
•E
nsur
e a
2-h
fire
resi
stan
ce ra
ting
for
wal
ls, f
loor
s, a
nd c
eilin
gs•
Pro
vide
exp
losi
on v
entin
g in
ext
erio
r w
alls
or r
oof
•P
rovi
de h
eat b
y st
eam
, hot
wat
er, o
r ot
her i
ndire
ct m
eans
Bui
ldin
g V
entil
atio
nB
uild
ing
Ven
tilat
ion
•E
nsur
e st
ruct
ures
con
tain
ing
H2-
wet
ted
syst
ems
are
vent
ilate
d –
Ven
tilat
ion
rate
sho
uld
dilu
te H
2le
ak to
25
% o
f LFL
(1%
by
volu
me)
or l
ess
•E
stab
lish
vent
ilatio
n be
fore
intro
duci
ng
H2
into
the
syst
em•
Ens
ure
vent
ilatio
n do
es n
ot s
hut d
own
durin
g em
erge
ncy
shut
dow
n pr
oced
ure
Bui
ldin
g V
entil
atio
n (c
ont.)
Bui
ldin
g V
entil
atio
n (c
ont.)
•E
nsur
e bu
ildin
g ai
r int
ake
is in
stal
led
if H
2ve
nted
nea
rby
–S
enso
rs a
ctiv
ate
alar
ms
and
auto
mat
ic a
ir sh
utof
f if H
2de
tect
ed•
Inst
all H
2 se
nsor
s in
bui
ldin
g ou
tlet v
ents
if
H2
used
insi
de•
Avo
id s
uspe
nded
cei
lings
and
inve
rted
pock
ets
or e
nsur
e ad
equa
te v
entil
atio
n
Faci
lity
supp
ort i
nfra
stru
ctur
e
Faci
lity
Sup
port
Infra
stru
ctur
eFa
cilit
y S
uppo
rt In
frast
ruct
ure
•In
ert g
as s
ubsy
stem
•E
lect
rical
sub
syst
em•
Coo
ldow
n•
Tran
spor
tatio
n
Iner
t Gas
Sub
syst
emIn
ert G
as S
ubsy
stem
•U
sed
to p
rovi
de p
urge
and
pr
essu
rizat
ion
gase
s•
Ens
ure
that
all
H2-
cont
aini
ng v
olum
es
are
capa
ble
of b
eing
pur
ged
and
that
pu
rge
gas
is v
ente
d•
Pro
tect
iner
t gas
sub
syst
ems
from
H2
cont
amin
atio
n–
Hig
her p
ress
ure,
che
ck v
alve
, dou
ble
bloc
k an
d bl
eed
arra
ngem
ent
To a
tmos
pher
e
Pos
itive
GH
2S
huto
ff S
yste
ms
Pos
itive
GH
2S
huto
ff S
yste
ms
Ele
ctric
al R
equi
rem
ents
Ele
ctric
al R
equi
rem
ents
•M
ust c
onfo
rm to
NFP
A 7
0, N
atio
nal
Ele
ctric
al C
ode
–If
with
in 3
ft o
f whe
re c
onne
ctio
ns a
re
regu
larly
mad
e an
d di
scon
nect
ed
•N
FPA
70,
“Cla
ss I,
Gro
up B
, Div
isio
n 1”
loca
tions
, w
hich
rely
hea
vily
on
expl
osio
n-pr
oof o
r an
iner
t-ga
s-pu
rged
enc
losu
res
–If
with
in 2
5 ft
of w
here
con
nect
ions
are
re
gula
rly m
ade
and
disc
onne
cted
, or w
ithin
25
ft o
f an
LH2
stor
age
cont
aine
r•
NFP
A 7
0 “C
lass
I, G
roup
B, D
ivis
ion
2”lo
catio
ns
Def
initi
on o
f Exp
losi
on-p
roof
Def
initi
on o
f Exp
losi
on-p
roof
•E
nclo
sure
mus
t be
stro
ng e
noug
h to
w
ithst
and
any
inte
rnal
pre
ssur
es c
ause
d by
an
expl
osio
n an
d tig
ht e
noug
h to
pr
even
t the
issu
ance
of f
lam
es•
Doe
s no
t mea
n th
at e
quip
men
t has
to
be g
as-ti
ght
•E
xplo
sion
-pro
of e
lect
rical
equ
ipm
ent i
s re
quire
d in
“Cla
ss I”
haza
rdou
s lo
catio
ns p
er N
EC
NE
C D
efin
ition
sN
EC
Def
initi
ons
•C
lass
I: L
ocat
ion
in w
hich
flam
mab
le
gase
s or
vap
ors
exis
t in
quan
titie
s su
ffici
ent t
o re
nder
the
resu
ltant
at
mos
pher
e ex
plos
ive
or ig
nita
ble
•G
roup
B:
Atm
osph
eres
con
tain
ing
hydr
ogen
or g
ases
or v
apor
s of
eq
uiva
lent
haz
ards
suc
h as
m
anuf
actu
red
gas
NE
C D
efin
ition
sN
EC
Def
initi
ons
•D
ivis
ion
1: L
ocat
ions
whe
re h
azar
dous
co
ncen
tratio
ns o
f fla
mm
able
gas
es o
r va
pors
exi
st–
Con
tinuo
usly
, int
erm
itten
tly o
r per
iodi
cally
un
der n
orm
al c
ondi
tions
–Fr
eque
ntly
bec
ause
of r
epai
r/mai
nten
ance
op
erat
ion
or b
ecau
se o
f lea
kage
–D
ue to
bre
akdo
wn
or fa
ulty
ope
ratio
n of
eq
uipm
ent o
r pro
cess
es, w
hich
mig
ht a
lso
caus
e el
ectri
cal e
quip
men
t fai
lure
NE
C D
efin
ition
sN
EC
Def
initi
ons
•D
ivis
ion
2: L
ocat
ions
in w
hich
fla
mm
able
vol
atile
liqu
ids
or g
ases
are
ha
ndle
d, p
roce
ssed
, or u
sed
–N
orm
ally
con
fined
to c
lose
d co
ntai
ners
or
syst
ems
from
whi
ch th
ey c
an e
scap
e on
ly
by a
ccid
enta
l rup
ture
or b
reak
dow
n of
suc
h co
ntai
ners
or s
yste
ms
or b
y ab
norm
al
equi
pmen
t ope
ratio
n
Ele
ctric
al C
onsi
dera
tions
Ele
ctric
al C
onsi
dera
tions
•U
se a
pur
ged
encl
osur
e as
an
alte
rnat
ive
to e
xplo
sion
-pro
ofin
g•
Pro
vide
ligh
tnin
g pr
otec
tion
in a
ll ar
eas
whe
re th
ere
is H
2
•B
ond
and
grou
nd m
obile
H2
supp
ly u
nits
be
fore
dis
char
ge
Per
sonn
el E
lect
rical
Pro
tect
ion
Per
sonn
el E
lect
rical
Pro
tect
ion
•E
nsur
e pe
rson
nel a
re g
roun
ded
befo
re
wor
king
on
an H
2sy
stem
–U
se a
ntis
tatic
clo
thin
g•
Ens
ure
pers
onne
l use
con
duct
ive
mac
hine
ry b
elts
•P
rovi
de a
dequ
ate
illum
inat
ion
for a
ll H
2ar
eas
LH2
GH
2
FLO
W
300
20T (K)
L
Coo
ldow
n M
odel
Coo
ldow
n M
odel
Plug
Stra
tifie
d
Slug
Annu
lar
Dis
pers
ed
(Alm
ost a
ll liq
uid)
Wav
e
Bubb
le
Two-
phas
e Fl
ow R
egim
esTw
o-ph
ase
Flow
Reg
imes
Coo
ldow
n Is
sues
Coo
ldow
n Is
sues
•La
rge
stre
sses
can
resu
lt fro
m
–La
rge
circ
umfe
rent
ial a
nd ra
dial
te
mpe
ratu
re g
radi
ents
–La
rge
ther
mal
con
tract
ion,
esp
ecia
lly in
lo
ng li
nes
•Tw
o-ph
ase
flow
can
cau
se ra
ndom
co
olin
g –
Liqu
id fl
ow w
ill c
ool f
aste
r tha
n co
mpa
rabl
e ga
s flo
w
Coo
ldow
n Is
sues
(con
t.)C
oold
own
Issu
es (c
ont.)
•S
tratif
ied
flow
can
cau
se h
igh
stre
ss
from
larg
e ci
rcum
fere
ntia
l tem
pera
ture
gr
adie
nts
•M
aint
ain
min
imum
flow
dur
ing
cool
-do
wn
to a
void
pip
e bo
win
g•
Ven
t app
ropr
iate
ly th
e re
sulta
nt g
ases
•D
esig
n pi
pe p
rope
rly to
acc
omm
odat
e re
quire
d ga
s flo
w-th
roug
h
Coo
ldow
n Is
sues
(con
t.)C
oold
own
Issu
es (c
ont.)
•E
stab
lish
min
/max
coo
l-dow
n lim
its–
Too
slow
can
resu
lt in
stra
tifie
d, 2
-pha
se
flow
and
pip
e bo
win
g–
Too
fast
can
resu
lt in
larg
e ra
dial
te
mpe
ratu
re g
radi
ents
•
Flan
ge:
inne
r wal
l is
cool
ed q
uick
ly w
hile
the
oute
r wal
l rem
ains
nea
r am
bien
t tem
pera
ture
Max
imum
H2
Flow
Rat
eM
axim
um H
2Fl
ow R
ate
Min
imum
H2
Flow
Rat
eM
inim
um H
2Fl
ow R
ate
Tran
spor
tatio
nTr
ansp
orta
tion
•Tr
ansp
ort H
2ac
cord
ing
to 4
9CFR
–H
2tra
nspo
rtatio
n ab
oard
a p
asse
nger
ai
rcra
ft, ra
ilcar
, or s
hip
is p
rohi
bite
d–
Up
to 1
50 k
g (G
H2
only
) per
mitt
ed o
n a
carg
o ai
rcra
ft –
On
carg
o sh
ips,
GH
2m
ay b
e st
owed
on
or
belo
w d
eck,
but
LH
2m
ay o
nly
be s
tow
ed
on d
eck
Faci
lity
safe
ty s
ubsy
stem
s
Faci
lity
Saf
ety
Sub
syst
emFa
cilit
y S
afet
y S
ubsy
stem
•U
se le
ak-a
nd fi
re-d
etec
tion
elem
ents
•In
clud
e –
Fire
pro
tect
ion
–Fi
re fi
ghtin
g
Faci
lity
Fire
Pro
tect
ion
Faci
lity
Fire
Pro
tect
ion
•U
se –A
utom
atic
or m
anua
l pr
oces
s sh
utdo
wn
syst
ems
–S
prin
kler
s–
Del
uge
syst
ems
–W
ater
spr
ay s
yste
ms
–D
ry-c
hem
ical
ex
tingu
ishi
ng s
yste
ms
–H
alon
sys
tem
s
•La
rge
H2
syst
ems
–S
tora
ge, g
roup
ed
pipi
ng, a
nd p
umps
sha
ll be
com
plet
ely
cove
red
by a
wat
er-s
pray
sy
stem
acc
ordi
ng to
29
CFR
1910
.163
, Fix
ed
extin
guis
hing
sys
tem
s,
wat
er s
pray
and
foam
Faci
lity
Fire
Pro
tect
ion
(con
t.)Fa
cilit
y Fi
re P
rote
ctio
n (c
ont.)
•C
onsi
der i
nsta
lling
delu
ge s
yste
ms
alon
g th
e to
p of
sto
rage
are
as,
espe
cial
ly L
H2
•P
rovi
de fi
re h
ydra
nt o
r 2 in
. dia
hos
e bi
b ad
jace
nt to
all
LH2
stor
age
area
s–
Als
o us
ed fo
r was
h do
wn
•K
eep
wat
er fr
om e
nter
ing
H2
vent
s
Faci
lity
Fire
Fig
htin
gFa
cilit
y Fi
re F
ight
ing
•S
hut o
ff H
2su
pply
bef
ore
atte
mpt
ing
to
extin
guis
h an
H2
fire
–P
recl
ude
reig
nitio
n of
com
bust
ible
clo
ud•
Spr
ay w
ater
on
adja
cent
equ
ipm
ent t
o ke
ep it
coo
l•
Ext
ingu
ish
smal
l H2
fires
with
–D
ry c
hem
ical
or C
O2
extin
guis
hers
, N2,
or
stea
m
Sum
mar
yS
umm
ary
•K
eep
safe
ty a
s th
e pr
imar
y H
2fa
cilit
y co
nsid
erat
ion,
from
con
cept
thro
ugh
disp
osal
•A
dher
e to
pro
ven
prac
tices
and
pr
inci
ples
•Fo
llow
app
rove
d pr
oced
ures
follo
wed
fo
r all
oper
atio
ns
Sum
mar
y (c
ont.)
Sum
mar
y (c
ont.)
•C
ontro
l –
Igni
tion
sour
ces
–Fo
rmat
ion
of c
ombu
stib
le m
ixtu
re•
Min
imiz
e ex
posu
re to
the
haza
rd–
Siti
ng, q
uant
ity o
f H2
invo
lved
, num
ber o
f pe
ople
exp
osed
•B
e al
ert t
o ch
ange
s in
ope
ratin
g co
nditi
ons
Hyd
roge
n H
azar
ds A
naly
sis
Pre
requ
isite
s an
d A
ppro
ach
Ove
rvie
wO
verv
iew
•W
hy p
erfo
rm h
azar
ds a
naly
sis?
•P
rere
quis
ites
for h
azar
ds a
naly
sis
•H
azar
ds a
naly
sis
appr
oach
•S
ampl
e an
alys
is•
Sum
mar
y
Why
Per
form
a H
azar
ds A
naly
sis?
Why
Per
form
a H
azar
ds A
naly
sis?
•S
yste
mat
ical
ly a
nd
obje
ctiv
ely
–Id
entif
y ha
zard
s–
Det
erm
ine
thei
r ris
k le
vel
–P
rovi
de m
echa
nism
to
eva
luat
e fo
r the
el
imin
atio
n or
con
trol
of h
azar
ds
•U
se to
–
Impr
ove
desi
gns
–E
valu
ate
safe
ty o
f op
erat
ions
–A
naly
ze fa
ilure
s•
Form
al h
azar
ds
anal
ysis
spe
cifie
s pr
otoc
ol fo
r ev
alua
tion
and
docu
men
tatio
n
Haz
ards
Ana
lysi
s P
rere
quis
ites
Haz
ards
Ana
lysi
s P
rere
quis
ites
•U
nder
stan
d an
alys
is
scop
e•
Hav
e de
taile
d de
sign
info
rmat
ion
–U
p-to
-dat
e sc
hem
atic
s–
All
vend
or
info
rmat
ion
–Id
entif
y al
l mat
eria
ls
expo
sed
to H
2
•A
ssem
ble
nece
ssar
y ex
perti
se•
Hav
e in
form
atio
n ne
cess
ary
to
eval
uate
all
leak
pa
ths
Haz
ards
Ana
lysi
s O
verv
iew
Haz
ards
Ana
lysi
s O
verv
iew
•H
2ha
zard
s an
alys
is
base
d on
NA
SA
W
STF
pro
toco
l•
Bef
ore
team
ana
lysi
s–
Sys
tem
ow
ners
set
ag
enda
/sco
pe–
Faci
litat
ors
com
pile
sy
stem
info
rmat
ion
•S
eque
ster
team
fro
m d
istra
ctio
ns•
Dec
ide
on a
naly
sis
stra
tegy
–C
ompo
nent
sim
ilarit
y–
Mat
eria
ls s
imila
rity
–A
ccor
ding
to s
yste
m
sequ
ence
Haz
ards
Ana
lysi
s O
verv
iew
(con
t.)H
azar
ds A
naly
sis
Ove
rvie
w (c
ont.)
•C
ondu
ct c
ompo
nent
-le
vel a
sses
smen
t–
Det
erm
ine
failu
re m
odes
an
d ca
uses
–C
lass
ify fa
ilure
mod
es
•D
eter
min
e fa
ilure
ef
fect
s on
com
pone
nts
and
syst
ems
Defin
e Sc
ope
of A
naly
sis
Sele
ct H
azar
ds T
eam
Mem
bers
Com
pile
Com
pone
nt/S
yste
m In
form
atio
n
Deci
de o
n Co
mpo
nent
Ana
lysi
s St
rate
gy
Dete
rmin
e Co
mpo
nent
Haz
ards
Sce
nario
s
Asse
ss P
ossi
ble
Com
bust
ible
Mix
ture
Form
atio
n
Asse
ss P
ossi
ble
Igni
tion
Mec
hani
sms
Asse
ss P
ossi
ble
Com
bust
ion
Mec
hani
sms
Fire
Def
lagr
atio
n
D
eton
atio
n
Anal
yze
Poss
ible
Sec
onda
ry E
ffect
s
Asse
ss R
eact
ion
Effe
cts
Com
plet
e Re
port
Com
pone
ntBy
Com
pone
nt
Team
Ana
lysis
•E
valu
ate
prob
abili
ty–
Com
bust
ible
mix
ture
fo
rmat
ion
–Ig
nitio
n so
urce
s–
Type
s of
com
bust
ion
even
ts [f
ire, d
efla
grat
ion,
de
tona
tion]
•E
valu
ate
seco
ndar
y ef
fect
s•
Eva
luat
e to
tal r
eact
ion
effe
cts
Failu
re E
ffect
s C
onsi
dera
tion
Failu
re E
ffect
s C
onsi
dera
tion
Def
ine
Scop
e of
Ana
lysi
sSe
lect
Haz
ards
Tea
m M
embe
rs
Com
pile
Com
pone
nt/S
yste
m In
form
atio
n
Deci
de o
n Co
mpo
nent
Ana
lysi
s St
rate
gy
Det
erm
ine
Com
pone
nt H
azar
ds S
cena
rios
Asse
ss P
ossi
ble
Com
bust
ible
Mix
ture
Form
atio
n
Asse
ss P
ossi
ble
Igni
tion
Mec
hani
sms
Asse
ss P
ossi
ble
Com
bust
ion
Mec
hani
sms
Fire
Def
lagr
atio
n
D
eton
atio
n
Ana
lyze
Pos
sibl
e Se
cond
ary
Effe
cts
Asse
ss R
eact
ion
Effe
cts
Com
plet
e Re
port
Com
pone
ntB
yCo
mpo
nent
Team
Ana
lysis
Que
stio
ns to
Con
side
rQ
uest
ions
to C
onsi
der
•W
hat f
ailu
re m
odes
invo
lve
H2?
•W
here
can
com
bust
ible
mix
ture
s fo
rm?
•W
hat i
gniti
on s
ourc
es e
xist
?•
Wha
t com
bust
ion
mec
hani
sms
are
activ
e?•
Wha
t are
the
com
bust
ion
effe
cts?
•W
hat a
re th
e ov
eral
l ris
ks to
sys
tem
, us
ers,
mis
sion
, or b
usin
ess?
Sam
ple
Ana
lysi
sS
ampl
e A
naly
sis
•Th
e fo
llow
ing
circ
uit d
epic
ts p
art o
f a
syst
em u
sed
to re
cove
r wat
er fr
om a
hy
drog
en g
as –
wat
er m
ixtu
re e
xitin
g fro
m a
n el
ectro
lyze
r–
The
wat
er is
crit
ical
for s
pace
craf
t op
erat
ions
–Th
e hy
drog
en is
ven
ted
over
boar
d.•
The
focu
s of
the
sam
ple
anal
ysis
is o
n th
e ba
ck-p
ress
ure
regu
lato
r com
pone
nt
Sys
tem
Sch
emat
ic
Com
pone
ntS
chem
atic
STEP
1ST
EP 2
STEP
3ST
EP 4
STEP
5ST
EP 6
STEP
71
23
45
67
89
1011
1213
1415
1617
18Pr
obab
ility
of F
ailu
re in
Thes
eM
odes
Prob
abili
ty o
f Com
bust
ible
Mix
ture
Fro
m T
hese
Eve
nts
Prob
abili
ty o
f Ign
ition
From
The
se S
ourc
es
Prob
abili
ty o
fTh
ese
Con
sequ
ence
s
Com
pone
nt
Noncatastrophic
Catastrophic
Other
External Leakage
In leakage
Contamination
Other
Electrical
Mechanical
Thermal
Other
Fire
Deflagration
Detonation
Other
Secondary Effect
Reaction Effect
Diff
eren
tial -
back
pres
sure
regu
lato
r int
o re
circ
ulat
ion
loop
110
032
00
01
30
00
014
00
ND
5
Diff
eren
tial-b
ackp
ress
ure
regu
lato
r int
o th
e va
cuum
encl
osur
e16
00
370
00
1 8
00
00
190
0N
D10
Haz
ards
Ana
lysi
s C
hart
Haz
ards
Ana
lysi
s C
hart
1. T
he fo
llow
ing
leak
pat
hs a
re c
onsi
dere
d:
A) A
sm
all i
nter
nal l
eak
acro
ss th
e va
lve
whi
ch d
oes
not d
rop
the
sepa
rato
r out
let
pres
sure
will
not
cre
ate
an H
2ha
zard
in th
e w
ater
line
.B
) A le
ak a
cros
s th
e be
llow
s w
ill c
ause
gas
eous
H2
to fl
ow in
to th
e w
ater
reci
rcul
atio
n lo
op a
nd w
ill b
e an
alyz
ed s
epar
atel
y.C
) Lea
ks e
xter
nally
into
the
vacu
um e
nclo
sure
can
occ
ur a
t the
man
ifold
sea
l or
adju
stin
g ca
p se
al.
D) A
larg
e in
tern
al le
ak w
hich
is n
ot s
ense
d by
the
delta
P s
enso
r, or
whe
n se
nsed
so
leno
id v
alve
fai
ls o
pen
(bot
h se
cond
poi
nt fa
ilure
) cou
ld c
ause
H2
from
the
phas
e se
para
tor t
o en
ter t
he re
circ
ulat
ion
loop
. Tw
o fa
ilure
s to
be
cons
ider
ed a
re 1
) if a
larg
e in
tern
al le
ak a
cros
s th
is v
alve
whi
ch d
oes
drop
the
sepa
rato
r out
let p
ress
ure
and
caus
e H
2to
ent
er th
e w
ater
line
or 2
) if t
he v
alve
fails
ope
n. B
oth
failu
res
will
be
dete
cted
by
eith
er th
e se
para
tor d
iffer
entia
l pre
ssur
e se
nsor
or t
he g
as d
etec
tor.
Hyd
roge
n ga
s w
ill
be is
olat
ed b
y a
sole
noid
val
ve b
efor
e a
com
bust
ible
mix
ture
is fo
rmed
. If
a se
cond
fa
ilure
occ
urs
whe
re th
e so
leno
id v
alve
fails
ope
n or
leak
s in
tern
ally
, the
n a
com
bust
ible
m
ixtu
re c
ould
form
in th
e re
circ
ulat
ion
loop
or d
owns
tream
.
Bec
ause
of t
he H
2em
britt
lem
ent p
rope
rties
of I
ncon
el 1
7-4a
nd 1
7-7P
H a
nd th
e 30
4L,
and
the
fact
that
thes
e m
ater
ials
are
use
d in
bel
low
s an
d sp
rings
, it i
s re
com
men
ded
that
a
fatig
ue a
naly
sis
be c
ondu
cted
to d
eter
min
e th
e lif
e of
the
parts
. A
fter a
ssem
bly
the
com
pone
nt a
ttach
ed to
the
man
ifold
is p
roof
ed to
1.5
tim
es M
DP
and
then
test
ed fo
r le
aks
at M
DP
usi
ng h
eliu
m.
2. C
ap le
akag
e fro
m th
e ex
terio
r can
resu
lt in
pre
ssur
izin
g th
e va
cuum
enc
losu
re to
0.2
5 ps
ia.
If th
is is
follo
wed
by
a co
mpo
nent
failu
re re
sulti
ng in
H2
leak
ing
into
the
vacu
um
encl
osur
e, th
is w
ill re
sult
in a
pot
entia
lly c
ombu
stib
le m
ixtu
re. T
he s
hutd
own
pres
sure
in
side
the
vacu
um e
nclo
sure
is 0
.25
psia
.
It is
reco
mm
ende
d th
at u
nder
thes
e co
nditi
ons
the
vacu
um e
nclo
sure
is v
ente
d w
hen
pres
sure
>0.
25 p
sia
so th
at to
tal p
ress
ure
rem
ains
<0.
43 p
sia
whi
ch is
whe
re H
2 an
d O
2 ar
e no
t fla
mm
able
for s
park
ene
rgie
s si
mila
r to
thos
e in
side
the
vacu
um e
nclo
sure
(see
Fu
els
Han
dboo
k).
3. E
lect
rical
igni
tion
sour
ces
are
pres
ent b
ut in
sula
tion,
gro
undi
ng, a
nd o
ther
pro
tect
ive
mea
sure
s ar
e de
sign
ed in
to re
duce
the
risk
of a
rcin
g or
spa
rkin
g. A
t 0.2
5 ps
ia, t
he
syst
em is
shu
t dow
n. B
leed
resi
ster
s ar
e pr
esen
t to
drai
n an
y re
sidu
al c
harg
e. In
the
abse
nce
of e
lect
rical
com
pone
nt fa
ilure
ther
e is
insu
ffici
ent e
nerg
y to
igni
te th
is m
ixtu
re.
4. G
iven
the
pres
ence
of t
wo
failu
res
to g
ive
a fla
mm
able
mix
ture
and
the
smal
l ign
ition
so
urce
s, th
e pr
obab
ility
of d
efla
grat
ion
insi
de th
e va
cuum
enc
losu
re is
rem
ote.
5. C
atas
troph
ic fa
ilure
of t
he s
yste
m is
def
ined
as
loss
of s
yste
m fu
nctio
n. C
ompo
nent
fa
ilure
resu
lts in
sys
tem
func
tion
loss
. 6.
A la
rge
inte
rnal
leak
(ini
tial f
ailu
re) n
ot s
ense
d by
the ∆
P s
enso
r or w
hen
the
sole
noid
va
lve
fails
ope
n (b
oth
seco
nd p
oint
failu
res)
cou
ld c
ause
H2
from
the
phas
e se
para
tor t
o en
ter t
he re
circ
ulat
ion
loop
. A le
ak a
cros
s th
e be
llow
s w
ill c
ause
GH
2 to
flow
into
the
wat
er re
circ
ulat
ion
loop
. The
effe
ct o
f the
se fa
ilure
s w
ill b
e an
alyz
ed s
epar
atel
y. L
eaks
ex
tern
ally
into
the
vacu
um e
nclo
sure
can
occ
ur a
t the
man
ifold
sea
l or a
djus
ting
cap
seal
. Afte
r ass
embl
y th
e co
mpo
nent
atta
ched
to th
e m
anifo
ld is
pro
ofed
to 1
.5 ti
mes
M
DP
and
then
test
ed fo
r lea
ks a
t MD
P u
sing
hel
ium
.
7. L
eaka
ge fr
om th
e ex
terio
r can
resu
lt in
pre
ssur
izin
g th
e va
cuum
enc
losu
re to
a
pres
sure
of 0
.25
psia
. If
this
is fo
llow
ed b
y a
failu
re o
f th
eco
mpo
nent
re
sulti
ng in
le
akin
g of
H2
into
the
vacu
um e
nclo
sure
, thi
s w
ill re
sult
in a
pot
entia
lly c
ombu
stib
le
mix
ture
. Th
e sh
ut d
own
pres
sure
insi
de th
e va
cuum
enc
losu
re is
0.2
5 ps
ia.
It is
reco
mm
ende
d th
at u
nder
thes
e co
nditi
ons
that
the
vacu
um e
nclo
sure
is v
ente
d w
hen
the
pres
sure
exc
eeds
0.2
5 ps
ia s
o th
at th
e to
tal p
ress
ure
rem
ains
bel
ow 3
kP
a (0
.43
psia
) w
hich
is w
here
dro
p ha
s sh
own
that
H2
and
O2
are
not f
lam
mab
le fo
r spa
rk
ener
gies
sim
ilar t
o th
ose
insi
de th
e va
cuum
enc
losu
re (S
ee F
uels
Han
dboo
k).
8. E
lect
rical
igni
tion
sour
ces
are
pres
ent b
ut in
sula
tion,
gro
undi
ng a
nd o
ther
pro
tect
ive
mea
sure
s ar
e de
sign
ed in
to re
duce
the
risk
of a
rcin
g or
spa
rkin
g. A
t 0.2
5 ps
ia th
e sy
stem
is s
hut d
own
. B
leed
resi
ster
s ar
e pr
esen
t to
drai
n an
y re
sidu
al c
harg
e.
Ther
efor
e, in
the
abse
nce
of fa
ilure
of e
lect
rical
com
pone
nts
ther
e is
insu
ffici
ent i
gniti
on
ener
gy to
igni
te a
0.2
5 ps
ia m
ixtu
re.
9. G
iven
the
pres
ence
of
two
failu
res
to g
ive
a fla
mm
able
mix
ture
and
the
smal
l ign
ition
so
urce
s, th
e pr
obab
ility
of d
efla
grat
ion
insi
de th
e va
cuum
enc
losu
re is
rem
ote.
10. C
atas
troph
ic fa
ilure
of t
he s
yste
m is
def
ined
as
loss
of s
yste
m fu
nctio
n. F
ailu
re o
f th
e co
mpo
nent
resu
lts in
loss
in fu
nctio
n of
the
syst
em.
Cla
ss E
xerc
ise
Ana
lysi
s R
esul
tsA
naly
sis
Res
ults
•S
ingl
e fa
ilure
re
quire
d fo
r fo
rmat
ion
of
com
bust
ible
mix
ture
in
firs
t ins
tanc
e–
Enc
losu
re (n
orm
al)
and
com
pone
nt
leak
age
–S
yste
m is
con
trolle
d w
ith p
ress
ure
sens
or
•E
lect
rical
igni
tion
sour
ces
pres
ent b
ut
smal
l•
Def
lagr
atio
n w
ill o
ccur
, bu
t lik
elih
ood
is lo
w•
Rea
ctio
n ef
fect
is a
fu
nctio
n of
app
licat
ion
and
is c
atas
troph
ic a
s de
fined
by
user
Cla
ss E
xerc
ise A
naly
sis
Res
ults
(con
t.)A
naly
sis
Res
ults
(con
t.)
•Tw
o fa
ilure
s re
quire
d fo
r fo
rmat
ion
of
com
bust
ible
mix
ture
–
Larg
e in
tern
al le
ak
not s
ense
d by
del
ta
pres
sure
sen
sor,
or
sens
ed b
ut s
olen
oid
valv
e fa
ils o
pen
•E
lect
rical
igni
tion
sour
ces
pres
ent,
but
smal
l
•D
efla
grat
ion
will
oc
cur,
but l
ikel
ihoo
d is
low
–pr
opag
atio
n in
bu
bbly
flow
•R
eact
ion
effe
ct is
a
func
tion
of
appl
icat
ion
and
is
cata
stro
phic
as
defin
ed b
y us
er
Sum
mar
yS
umm
ary
•H
azar
ds a
naly
sis
appr
oach
–
Sys
tem
atic
ally
and
ob
ject
ivel
y id
entif
y ha
zard
s an
d ev
alua
te ri
sk–
Tool
to h
elp
cont
rol
haza
rds,
impr
ove
desi
gns
•R
equi
res
–U
nder
stan
ding
the
scop
e of
the
anal
ysis
–C
ompl
ete
info
rmat
ion
–N
eces
sary
exp
ertis
e•
Suc
cess
fully
app
lied
to
seve
ral k
ey s
yste
ms
Cou
rse
Sum
mar
y
Fact
s an
d R
emin
ders
Cou
rse
Sum
mar
yC
ours
e S
umm
ary
•H
2us
e is
impo
rtant
•H
2us
e in
volv
es h
azar
ds/ri
sks
•H
2ca
n be
use
d sa
fely
–Th
inki
ng–
Pla
nnin
g–
Trai
ning
–B
eing
pre
pare
d
We
Hav
e S
tudi
edW
e H
ave
Stu
died
•H
ydro
gen’
s sa
fety
rela
ted
prop
ertie
s•
Haz
ards
ass
ocia
ted
with
H2
use
•H
ow to
dea
l with
haz
ards
and
em
erge
ncy
situ
atio
ns•
Typi
cal c
ompo
nent
s an
d m
ater
ials
for
use
with
H2
•H
2fa
cilit
y gu
idel
ines
•H
azar
ds a
naly
sis
appr
oach
Saf
ety
in th
e U
se o
f Hyd
roge
nS
afet
y in
the
Use
of H
ydro
gen
•P
rope
r sys
tem
des
ign
–C
ritic
al c
ompo
nent
re
dund
ancy
–Fa
il-sa
fe p
olic
y•
Pro
ven
prac
tices
and
pr
inci
ples
•P
erso
nnel
trai
ning
and
ce
rtific
atio
n•
Des
ign,
saf
ety,
haz
ard,
an
d op
erat
iona
l re
view
s
•C
aref
ul s
yste
m
oper
atio
n•
App
rove
d op
erat
ing
proc
edur
es a
nd
chec
klis
ts•
Per
sona
l pro
tect
ive
equi
pmen
t•
Qua
lity
cont
rol a
nd
mai
nten
ance
pr
ogra
ms
THA
NK
S
In S
umm
ary
In S
umm
ary
•A
cor
e bo
dy o
f kno
wle
dge
exis
ts•
It ha
s be
en u
sed
to p
rovi
de s
afe
H2
uses
•U
se c
onse
rvat
ive
appr
oach
•R
ecog
nize
haz
ards
and
lim
itatio
ns•
Sea
rch
for h
azar
ds•
Don
’t ta
ke c
hanc
es o
r sho
rtcut
s
Related Documents
