Generally
equipment manufactured in brass tends to offer the cheapest option,
then stainless steel, with Monel being the most expensive. When
choosing equipment it is important to give consideration to the metals
that will make up your equipment. Not all metals are compatible with
all gases and some may even prove dangerous if matched with the wrong
component. The list below identifies which equipment material you
should be using with your gas process. This is fairly straight forward
for pure gases, but what about mixtures of gases? As a rule you should
be selecting the equipment material by the most toxic, flammable or
corrosive component within the mixture.
|
Brass |
Stainless steel |
Monel® |
| Acetylene |
 |
 |
|
| Air (Synthetic) |
|
|
|
| Ammonia |
 |
|
|
| Argon |
|
|
|
| Butane-N |
|
|
|
| Butene-1 |
|
|
|
| Carbon dioxide |
|
|
|
| Carbon monoxide |
|
|
|
| Chlorine |
|
|
|
| Deuterium |
|
|
|
| Ethane |
|
|
|
| Ethylene |
|
|
|
| Halocarbon R14 |
|
|
|
| Halocarbon R22 |
|
|
|
| Halocarbon R23 |
|
|
|
| Halocarbon R116 |
|
|
|
| Halocarbon R134a |
|
|
|
| Helium |
|
|
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| Hydrogen |
|
|
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| Hydrogen bromide |
 |
|
|
| Hydrogen chloride |
|
|
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| Hydrogen Fluoride |
|
|
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| Hydrogen Sulphide |
|
|
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| Isobutane |
|
|
|
| Krypton |
|
|
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| Methane |
|
|
|
| Neon |
|
|
|
| Nitric Oxide |
|
|
 |
| Nitrogen |
|
|
|
| Nitrogen dioxide |
|
|
|
| Nitrogen trifluoride |
|
|
|
| Nitrous oxide |
|
|
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| Oxygen |
|
|
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| Propane |
|
|
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| Propylene |
|
|
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| Propylene oxide |
|
|
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| Sulphur dioxide |
|
|
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| Sulphur hexafluoride |
|
|
|
| Xenon |
|
|
|
| Key |
|
Recommended |
|
Not recommended |
|
Depends on conditions |
 |
Insufficient data available |
Example:
Mixture: 0.1% Sulphur Dioxide, 21% Oxygen in Nitrogen
Nitrogen and Oxygen make up 99.9% of the mixture and are compatible
with brass equipment, however although the Sulphur Dioxide only makes
up 0.1%, it has the greater influence on the metal used. Sulphur
Dioxide is toxic and corrosive so is not suitable for use with brass,
meaning you should opt for a stainless steel regulator.
Note:
Even though brass equipment can be used for inert gases e.g. nitrogen,
helium etc; many customers prefer to use stainless steel. There are a
number of reasons for this including, personal preference and the need
to attach the new equipment to existing components with stainless steel
threads. Stainless Steel of course being a harder wearing metal than
brass. The Experis® Equipment Selector will give you the option, if it
is available.
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