Ulvac CRYOPUMP CRYO-U Series Instruction Manual page 15

For handling toxic gases, specific safety measures to the gas may have to be taken as
well as the safety precautions for flammable or explosive gases. For example, purge of
pump or dilution of exhaust duct with inert gas corresponds to it.
Customers are requested to take safety measures for cryopump operation
appropriate for the equipment or processes.
Table 1 Combustion range and detonation range of major gases
Gas
Hydrogen H
Carbon CO
Monoxide
Hydrogen H
Sulfide
Silane* SiH
Arsine* AsH
Phosphine* PH
Diborane* B
2
Ammonium NH
Methane CH
Ethane C
2
Propane C
3
Etylene C
2
Acetylene C
2
(*): Hikaru Harada; "Handotai-gas Anzen-ka Souran 1st Edition" (The 1st edition of
Semiconductor gas safing comprehensive manual) published by Science Forum Inc.
1984Except (*): The high pressure gas safety institute of Japan; "Koatsu-gas Kogyo Gijyutu"
(High pressure gas industrial technology) published by Kyoritsu Shuppan Co., Ltd. 1977
Table 2 Combustion range and detonation range of
Gas
Hydrogen
Acetylene
Methane
Propane
Carbon Monoxide
Ammonium
The high pressure gas safety institute of Japan; "Koatsu-gas Kogyo Gijyutu" (High pressure gas industrial
technology) published by Kyoritsu Shuppan Co., Ltd. 1977
(Volume percentage against air)
Molecular Specific
Weight
0℃, 1atm
2.016
2
28.01
S 34.08
2
32.14
4
77.94
3
34.00
3
H 27.67
6
17.03
3
16.04
4
H 30.07
6
H 44.10
8
H 28.05
4
H 26.04
2
mixture of oxygen and flammable gas
Combustion Range
(Vol. %)
4 - 94
2.3 - 94.5
5.1 - 61
2.3 - 55
15.5 - 94
15 - 79
ULVAC CRYOGENICS INCORPORATED
Boiling
Gravity Point
K
0.070 20.3
0.970 81.7
1.190 213.6
1.107 161.2
2.692 210.7
1.146 185.5
0.955 180.7
0.590 239.8
0.555 111.6
1.040 184.6
1.550 231.1
0.978 169.5
0.907 198.2
Detonation Range
Combustion Detonation
Range Range
Vol. % Vol. %
4.0-75.0 18.3- 59
12.5-74.0
4.3-45.0
0.8-98
0.8-98
1.3-98
0.8-98
15-28
5.3-14
3.0-12.5
2.2-9.5
3.1-32
2.5-100 4.2- 50
(Vol. %)
15 - 90
3.5 - 93
-
3.7 - 37
38 - 90
25.4 - 75
S-3