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D100071X012

Material Guidelines for Gaseous Oxygen

Service

All organic and inorganic materials will react with

gaseous or liquid oxygen at certain pressures and

temperatures. The reaction that occurs can cause a

fire or an explosion. Because of these inherent

dangers, process system design and control valve

material selection are extremely important.

Oxygen service has many inherent hazards and

requires careful and knowledgeable design of

the process system. The information and

guidelines presented here are intended to help

the user; however, other factors such as service

conditions and process system design must be

considered to properly select materials that will

handle this gas in a safe manner.

Many of the materials commonly used in control

valves have ignition temperatures above the normal

flowing temperature of gaseous oxygen. Ignition of

these materials by normal flowing temperatures is

generally not the danger. The danger is in the

ignition of these materials by abnormal, localized

high temperatures. Listed below are some of the

common causes of localized high temperature. This

list has been compiled from the best information

available, but does not necessarily contain all the

hazardous conditions that might be encountered in

oxygen service applications.

Common Sources of Localized High

Temperature

Flow Velocity

All valve materials should be suitable for oxygen

service, and material selection should meet the

velocity criteria, such as set by the Compressed Gas

Association Pamphlet G-4.4 (copies can be obtained

from Compressed Gas Association, Inc., 500 Fifth

Avenue, New York, NY 10036). In general, if the

velocity through the port of the valve can exceed 61

meters per second (200 feet per second), only

copper-base alloy material should be used for valve

body and trim parts in contact with the flow stream.

Foreign Particle Impingement

A foreign particle, such as weld spatter, that is being

carried in the flow stream and that strikes the valve

trim or the valve body wall might have its kinetic

energy transformed into sufficient heat to raise the

impinging particle or the material it strikes to its

respective ignition temperature.

Ignition by Already-Burning Material

An organic valve disk, for example, that has already

been ignited by foreign particle impingement will

release sufficient heat to ignite surrounding metallic

materials, thus initiating a serious fire.

Vibration

A part that is caused to vibrate, usually by the

flowing velocity, might generate enough heat from

internal friction to raise its temperature to its ignition

point.

Adiabatic or Rapid Compression of Gas

Opening a valve to pressure the downstream system

will result in the compression of the gas in the

downstream system. If this is done rapidly, it can

result in abnormally high gas temperatures, which

might ignite material in the valve and piping system.

Static Electricity Discharge

The flow of gas across the trim of a ball, butterfly, or

eccentric disk valve might generate a static charge

on the trim. Because these valves inherently do not

have a good grounding path from the trim to the

valve body or from the valve body to the pipeline,

use proper provisions and care for their grounding.

Failure to do this might allow a discharge spark

between the trim and valve body or between the

Product Bulletin

59:045

October 2006

Gaseous Oxygen Service

Summary of content (4 pages)

PAGE 1
Product Bulletin 59:045 October 2006 Gaseous Oxygen Service Material Guidelines for Gaseous Oxygen Service All organic and inorganic materials will react with gaseous or liquid oxygen at certain pressures and temperatures. The reaction that occurs can cause a fire or an explosion. Because of these inherent dangers, process system design and control valve material selection are extremely important. Oxygen service has many inherent hazards and requires careful and knowledgeable design of the process system.
PAGE 2
Product Bulletin 59:045 October 2006 Gaseous Oxygen Service valve body and adjacent piping, igniting the surrounding material. Resistance to Ignition in Oxygen Conclusion D Copper, copper alloys, and nickel-copper alloys --most resistant Materials are listed in order from hardest to ignite to easiest to ignite. 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.
PAGE 3
Product Bulletin 59:045 October 2006 In general, diaphragm casings, diaphragm plates, springs, and other parts not in the main flow stream may be of ordinary materials such as carbon steel, stainless steel, or cast iron. It is suggested, however, that all valve body and trim parts in contact with the flow stream be made of copper, copper alloy, or nickel-copper alloys. 3. All diaphragms in contact with oxygen gas should be made of fluoroelastomer. 4.
PAGE 4
Product Bulletin Gaseous Oxygen Service 59:045 October 2006 Fisher is a mark owned by Fisher Controls International LLC, a member of the Emerson Process Management business division of Emerson Electric Co. Emerson Process Management, Emerson, and the Emerson logo are trademarks and service marks of Emerson Electric Co. All other marks are the property of their respective owners.