HANDLING OF COMPRESSED GASES
- A compressed gas is any
material or mixture having in the container an absolute pressure exceeding
40 psi (pounds per square inch) at 70° F or, regardless of pressure at 70°
F, having an absolute pressure exceeding 104 psi at 130° F, or any liquid
material having a vapor pressure exceeding 40 psi absolute at 100° F as determined
by ASTM (American Society for Testing and Materials) Test D-323.
- Carefully read the label
before using or storing compressed gases. The Safety Data Sheet
(SDS) will provide any special hazard information. Always use the minimum
size cylinder required to perform the work.
- All cylinders must be
marked as to content. Do not accept cylinders with unidentifiable contents.
- Dispose of or return gases for which there is no need.
- If a cylinder or valve becomes damaged, the tremendous pressure inside may suddenly be released, causing the cylilnder to become a dangerous and powerful missile. Cylinders of compressed gases must be handled as high energy sources.
- If cylinders topple over, they
can also take off like a missile. When storing or moving a cylinder,
have the cap securely in place to protect the stem. Use suitable racks,
straps, chains or stands to support cylinders. Compressed gas
cylinders also pose a crush hazard to hands and feet.
- Wear safety glasses or goggles when handling and using compressed gases.
- Promptly remove the regulators from empty cylinders and replace the protective caps at once. Label the cylinder to show that it is empty.
- Never bleed cylinders completely empty. Leave a slight pressure to keep contaminants out.
- Do not store full and
empty cylinders together. Serious "suckback" can occur when
an empty cylinder is mistakenly attached to a pressurized system. This
could possibly form an explosive mixture.
- Group cylinders by type
of gas. For example, store oxidizing gases at least 20 feet away from
- Monitor compressed gases for leaks.
- Bond and ground all cylinders,
lines, and equipment used with flammable compressed gases.
- Do not expose cylinders to temperatures higher than about 50 degrees. Some rupture devices on cylinders will release at about 65 degrees C. Some small cylinders, such as lecture bottles, are not fitted with rupture devices and may explode if exposed to high temperatures.
- Always use the correct
regulator. Do not use a regulator adapter.
- Cylinders of toxic, flammable
or reactive gases must be stored and used in a fume hood or with local ventilation (exhausted gas cabinet).
- Open the cylinder valve
slowly. (When practical, never turn main cylinder more than a quarter
- Close the main cylinder valves tightly when not in use.
- Avoid rolling or dragging
cylinders, even for short distances. Move cylinders only on a handtruck.
Use chains to secure them to the handtruck. Do not lift cylinders by
- When moving compressed gas cylinders, strap them to properly designed, wheeled carts to ensure stability.
- Never lubricate, modify, force, or tamper with cylinder valves.
- Never direct high-pressure gases at a person.
- Do not use compressed gas or compressed air to blow away dust or dirt, the resultant flying particles are dangerous.
- Be aware that rapid release of a compressed gas will cause an unsecured gas hose to whip dangerously and also may build up a static charge that could ignite a combustible or flammable gas.
- Do not extinguish a flame involving a highly combustible until the source of gas has been shut off; otherwise, it can re-ignite causing an explosion.
- Do not put oil or grease on the high-pressure side of an oxygen, chlorine, or other oxidizing agent cylinder. A fire or explosion can result.
- Wrenches should not be used on valves equipped with a handwheel. If the valve is difficult to operate or faulty, contact the Stockroom to arrange return of the cylinder.
- For more information, contact your Laboratory Supervisor or the EHRS Department.
Observe the following special rules when working with acetylene cylinders:
- Always store acetylene cylinders upright. They are partially filled with liquid acetone, which can be discharged instead of or along with acetylene.
- Do not use an acetylene cylinder that has been stored or handled in a non-upright position until it has remained in an upright position for at lease 30 minutes.
- Ensure that the outlet line of an acetylene cylinder is protected with a flash arrester.
- Never exceed the pressure limit indicated by the warning red band of an acetylene pressure gauge.
- Use the correct kind of tubing to transport the gaseous acetylene. Some tubing materials such as copper form explosive acetylides.
View additional information on Compressed Gas Storage in Section V, 3.f.