Data Sheet

Gaseous Oxygen Service
Product Bulletin
59:045
October 2006
2
valve body and adjacent piping, igniting the
surrounding material.
Conclusion
This list shows that many of the hazards arise from
the velocity of the flowing gas. For this reason, it is
imperative that the system be designed such that
flowing velocities will be low.
Organic Materials
Organic materials have ignition temperatures below
those of metals. Use of organic materials in contact
with oxygen should be avoided, particularly when the
material is directly in the flow stream. When an organic
material must be used for parts such as valve seats,
diaphragms, or packing, it is preferable to select a
material with the highest ignition temperature, the
lowest specific heat, and the necessary mechanical
properties.
Lubricants and sealing compounds should be used
only if they are suitable for oxygen service and then
used sparingly. Ordinary petroleum lubricants are
not satisfactory and are particularly hazardous
because of their high heat of combustion and high
rate of reaction.
The approximate ignition temperatures in 138 bar
(2000 psig) oxygen for a few organic materials are
shown in table 1.
Table 1. Typical Ignition Temperatures
MATERIAL
TYPICAL IGNITION
TEMPERATURE
IN 138 BAR (2000 PSIG) OXYGEN
_C _F
PTFE and PCTFE
70% Bronze-filled PTFE
Fluoroelastomer
Nylon
Polyethylene
Chloroprene and Nitrile
468
468
316
210
182
149
875
875
600
410
360
300
Metals
The selection of metals should be based on their
resistance to ignition and rate of reaction. Following
is a comparison of these two properties for some
commonly used valve materials.
Resistance to Ignition in Oxygen
Materials are listed in order from hardest to ignite to
easiest to ignite.
D Copper, copper alloys, and nickel-copper alloys
--most resistant
D Stainless steel (300 series)
D Carbon steel
D Aluminum--least resistant
Rate of Reaction
Materials are listed in order from slowest rate of
combustion to most rapid rate of combustion.
D Copper, copper alloys, and nickel-copper alloys
--do not normally propagate combustion
D Carbon steel
D Stainless steel (300 series)
D Aluminum--burns very rapidly
Note that stainless steel, once ignited, burns more
rapidly than carbon steel. Nevertheless, the
austenitic grades (300 series) of stainless steel are
considered to be much better than carbon steel
because of their high resistance to ignition.
Suggested Guidelines
Consider the following guidelines when selecting
process equipment for gaseous oxygen service.
These guidelines are for customer use in selecting
appropriate equipment for oxygen service, and
neither Emerson, Emerson Process Management,
nor any of their affiliated entities assumes
responsibility for material selection.
1. All regulators and control valves should be
degreased and processed for oxygen service in
accordance with current Emerson Process
Managementt or customer specifications. Suitable
lubricants, anti-seizing compounds, gaskets, and
packing are included in Fisherr Specification FGS
8A11, Cleaning, Processing, and Handling
Equipment for Oxygen Service.
2. All metals in contact with oxygen in the main flow
stream should be of appropriate materials suitable
for the given oxygen service.