Compressed Gas Cylinders

Labeling Physical Condition Procurement Regulators Safety Shipping Storage Requirements Transport Toxic Gases Disposal

Due to their unique properties and contents, gas cylinders require special handling and procurement procedures. This webpage describes how to handle, package, store, ship and dispose of gas cylinders properly.

Labeling

Any cylinder used on campus must be clearly labeled. The labeling must list contents, concentrations, hazard classifications, safety precautions and the manufacturer. Do not remove manufacturer applied labels.

Physical Condition

The cylinder must be in good condition with an operable valve or regulator. Cylinders without valves and regulators should be capped.

Procurement

All gas cylinders used on and off campus should be purchased or rented through eProcurement. This ensures the cylinders come from suppliers that have a return authorization program for empty and non-empty cylinders. Non-empty cylinders are expensive to dispose of. When purchasing your gas cylinder from another vendor, make sure that the manufacturer will take back any unused portion of gas to avoid having to dispose of the cylinder as hazardous waste, which is very expensive. Retain all return instructions, including the return agreement.

After an open competitive solicitation process and in consultation with several university departments, Praxair, Inc. was awarded a university-wide contract to provide compressed and liquid (cryogenic) gases.

Regulators

Pressure regulators lower the gas pressure to a useable level. There are two kinds of pressure regulator designs: single and two stage. They appear similar. Single stage regulators are used when precise control of delivery pressure is not required. Two-stage regulators give precise control.

Keep regulators clean. Regulators used for oxidant gases should especially be free of surface oil and grease.

Always use the proper regulator for the gas in the cylinder. Plaques and decals on the regulator indicate which gas the regulator is designed for.

Safety

Gas cylinders present two unique hazards:

1. Gases in cylinders are usually pressurized from 100 to 2,500 psig. A cylinder under pressure, if broken or punctured, can propel itself at great speeds. Even the smallest cylinder can cause serious injury and property damage. Cylinders should always be treated with great care.
   
2. Gases are often invisible and tasteless. However, some are very toxic, and some can form an explosive mixture with air. Treat these gases as chemicals; avoid exposures and prevent leaks. Some inert gases are heavier than air and can displace it. Release of a gas in a poorly ventilated room could cause asphyxiation.

Shipping

Pressurized gas cylinders are hazardous materials. You must be trained and certified to transport them on roads or ship them. See Shipping Hazardous Materials for more information about training. Any shipment of compressed gas cylinders from campus needs the following (as well as training):

• A return authorization from the gas manufacturer
• Material Safety Data Sheet for the product being shipped
• Hazardous Material Shipping Paper
• Emergency Response Information for the product being shipped
• If shipping a 2.3 Poison Gas cylinder, a 2.3 Poison Gas placard may be required for the transporter
• If shipping a 2.3 Poison Gas cylinder, it may need to be certified as shippable.
• Contact EH&S’s Hazardous Materials Shipping Coordinator for advice at 206.616.5835.
• Cylinders that meet DOT specifications, but that are packed in additional outer packaging, must have a notice attached reading "Inside container(s) comply with prescribed regulations" as per 49 CFR 173.306

Storage Requirements

Compressed gas cylinders should be stored in an organized, ventilated, well-lit place away from combustible materials. Gas types should be separated from incompatibles and the areas marked. No manufacturer applied labels, decals, or cylinder content information should be damaged or removed from the cylinder. Any storage area must be protected from excessive heat, open flame, or ignition sources. Storage outside should be above grade, dry, and protected from weather conditions. Store cylinders so oldest products get used first.

Compressed gas containers, cylinders and tanks must be stored in the upright position. There are two exceptions:

1. Containers designed for use in the horizontal position
2. Compressed gas containers with a water volume less than 5 litres are allowed to be stored in the horizontal position

Incompatible materials in storage must be segregated by one of the following methods:

• Keeping them a distance away of not less than 20 feet
• Using noncombustible partitions extending not less than 18 inches above and to the sides of the containers, cylinders, or tanks
• Using approved storage cabinets or exhausted enclosures

Securing of compressed gas containers, cylinders and tanks must be by one of the following methods:

• Secure with a bracket, chain, strap or other approved restraint to a fixed object such as a wall or bench. It is recommended that the cylinder be secured by two straps or chains located at 1/3 and 2/3 of the cylinder height above the floor, because cylinders secured by a single strap have been found to escape the strap during an earthquake.
• When being moved and when routine mobility is necessary, secure to a cart, hand truck or other mobile device designed for the movement of compressed gas containers, cylinders, or tanks
• Secured to or within a rack, framework, cabinet, or similar assembly designed for such use

Transport

Always cap a cylinder before you move it. Cylinders must always be transported using a hand truck or cart designed for that purpose. Safety glasses and closed toe shoes should be worn when handling cylinders.

Toxic Compressed Gases

The UW Toxic Gas Program requires specific authorization to procure and specifies minimum requirements for safe storage, use, and handling of toxic gas. See our UW Toxic Gas Program page for more information.

Disposal

Normally cylinders are owned by a vendor and are returned to them, full or empty. Cylinders of toxic or flammable gas that are not empty and cannot be returned to a vendor must be disposed of as hazardous waste at the cost of your department. Cylinders of oxygen, nitrogen, helium, argon or other normal constituents of air may be vented. To dispose of empty cylinders, do the following:

• Remove or deface all labels
• Punch a hole in the cylinder (if cylinder contained flammable gas, leave open in well-ventilated area for 24 hours prior)
• Draw a circle around hole and write the word “empty” next to it
• Dispose of as scrap metal. (At UW Seattle, contact UW Recycling & Solid Waste at recycle@uw.edu to arrange pickup.)