8
Corrosive gas
Sources
fuel, auto emissions, ore smelting, and sulfuric acid manufacture.
Sulfur dioxide (SO
2
) and sulfur trioxide
(SO
3
)
Combustion of fossil fuel, auto emissions, ore smelting, sulfuric
acid manufacture, and tobacco smoke.
Sulphur (S)
Foundries and sulfur manufacture.
Hydrogen Fluoride (HF)
Fertilizer manufacture, aluminum manufacture, ceramics
manufacture, steel manufacture, electronics device manufacture,
and fossil fuel.
Nitrogen Oxide (NO
x
)
Automobile emissions, fossil fuel combustion, microbes, and
chemical industry.
Ammonia (NH
3
)
Microbes, sewage, fertilizer manufacture, geothermal steam,
refrigeration equipment, cleaning products, and reproduction
(blueprint) machines.
Carbonic oxide (CO)
Combustion, automobile emissions, microbes, trees, and wood
pulping.
Chlorine (Cl
2
) and chlorine dioxide
(ClO
2
)
Chlorine manufacture, aluminum manufacture, papermills, refuse
decomposition, and cleaning products.
Hydrochloric acid (HCl)
Automobile emissions, combustion, oceanic processes, and
polymer combustion.
Hydrobromic acid (HBr) and hydroiodic
acid (HI)
Automobile emissions.
Ozone (O
3
)
Atmospheric photochemical processes mainly involving nitrogen
oxides and oxygenated hydrocarbons, automotive emissions, and
electrostatic filters.
Hydrocarbons (C
n
H
n
)
Automobile emissions, fossil fuel processing, tobacco smoke,
water treatment, microbes, paper mill, and many other sources,
both natural and industrial.
Requirements of corrosive gas concentration vary by server model. For information about the
requirements, see the installation guide of the server.
Requirements for the data center equipment room
As a best practice, make sure the corrosive gas concentration for the data center equipment room
meets the requirements of severity level G1 of ANSI/ISA 71.04-1985. The rate of copper corrosion
product thickness growth must be less than 300 Å/month, and the rate of silver corrosion product
thickness growth must be less than 200 Å/month. Angstrom (Å) is a metric unit of length equal to one
ten-billionth of a meter.
To meet the copper and silver corrosion rates stated in severity level G1, make sure the corrosive
gases in the equipment room do not exceed the concentration limits as shown in
Table 4 Corrosive gas concentration limits in the data center equipment room
Corrosive gas
Concentration (ppb)
Remarks
H
2
S
< 3
CAUTION:
The concentration limits are
calculated based on the reaction
results of the gases in the
equipment room with a relative
humidity less than 50%. If the
relative humidity of the equipment
room increases by 10%, the
severity level of ANSI/ISA
SO
2
, SO
3
< 10
Cl
2
< 1
NO
x
< 50
HF
< 1
NH
3
< 500