Compressed Gas Cylinders

Purpose

Compressed gas cylinders can be extremely hazardous when misused or abused. Certain precautions must be observed when storing, handling, and using compressed gas cylinders in order to keep the hazards to a minimum. The uncontrolled release of a compressed gas can result in serious consequences, not only because of possible toxicity and flammability, but also because a high pressure cylinder can become a lethal missile if the cylinder valve is broken off.

Storage Areas

Store cylinders in an upright position (valve end up), on a level fireproof floor.
Check to make sure that new cylinders received as well as cylinders stored over time have a hydrostatic test date that is less than 5 years.
Fasten cylinders securely at all times.

Proper Storage Methods:

Secure Cylinder Cylinder Racks

Improper Storage Methods:

Unsecured Cylinder Unsecured Cylinders

Keep storage area well ventilated and dry.
Ensure no flammable substances such as oil and volatile liquids are stored in the same area.
Separate oxygen cylinders from cylinders containing flammable gases or other combustible materials by 6m, or by a 1.5m high fire-resistant wall with a rating of at least 30 minutes.
Store out of direct sunlight and away from other sources of heat as cylinder temperatures must not exceed 122°F/50°C. Some cylinders will release their contents through a rupture device at 65°C, however small cylinders without these devices may explode if exposed to elevated temperatures.
Separate empty and full cylinders. Clearly mark the empties "MT and date" with chalk. The regulator must be removed and the valve cap replaced.
Remove all sources of ignition from the storage room.
Propane tanks greater than 5 lbs. in size must be stored outdoors.

Laboratory Storage:

Storage of cylinders in the laboratory should be restricted to those cylinders connected and in use.
As soon as possible remove empty, not in use, or unnecessary cylinders from the laboratory.
Toxic gases should be placed in ventilated storage cabinets.
Keep the MSDS for the cylinder accessible in the lab.

Compressed Gas Cylinder Storage

	Flammable or Oxidizing Gas	Liquefied Flammable Gas	Gases with Health Hazard Rating of 3 or 4 (LC₅₀<3000 PPM) (stored in ventilated cabinet)
Number of large cylinders per 500 ft²	3	2	3

Handling:

Numbers, marks, and paint colours on cylinders identify them and must not be removed or changed. Tags attached to the cap are not a satisfactory method of identification.
Because of their shape, smooth surface, and weight, cylinders must not be carried by hand. Cylinders are to be moved only with cylinder carts in which the cylinder is securely held by a chain.

Cylinder on Cart

Keep the metal valve cap securely in place to protect the valve whenever the cylinder is not connected for use. This includes during transport.
If necessary, cylinders may be rolled on their bottom edge while in a nearly vertical position, but never dragged.
Avoid dropping cylinders or allowing them to strike violently against other cylinders.
Handle empty cylinders as carefully as full ones; residual pressures can be dangerous.
Do not tamper with safety devices in valves or on cylinders.
Never refill a cylinder. This calls for specialized equipment and techniques.
Never mix gases in a cylinder. The next person who draws from it may unknowingly cause an explosion.
If an outlet valve becomes clogged with ice or frozen, thaw with warm (not boiling) water (if gas is not water reactive), applied only to the valve. Do not use a flame.

Use and Operation:

Use cylinders, particularly those containing liquefied gas, in an upright position and secure them firmly with chains or clamps.
Never use cylinders if their contents are not known.
Always wear safety goggles when handling or using compressed gases.
Reduce the pressure of a compressed gas through a manufacturers specified regulator attached to the cylinder valve.
Ensure the threads on a regulator or union correspond with those on the cylinder valve outlet. Do not force mismatched connections.
Use regulators and pressure gauges only with gases for which they are designed and intended. Do not use adapters or modify connectors.
Open cylinder valves slowly with valve outlet directed away from all personnel.
DO NOT EMPTY A CYLINDER COMPLETELY. Leaving ~25 psi in the cylinder will prevent backflow and a possibly explosive mixture.
Never use oil or grease on valves or attachments for oxygen cylinders and never handle oxygen cylinders and apparatus with oily hands, gloves, or clothing.
Test cylinders for leaks each time you use them. Use soapy water, approved leak - test solution or detection equipment to check for leaks, never use flame. Test each of the locations indicated below:
If leaks occur in cylinders of toxic or combustible gases, close the valve and remove the cylinder outdoors or place in fume hood and notify the Safety Office.
Purge oxygen and acetylene lines before lighting.
When bleeding off flammable gases, use a ground wire on cylinder valves.
Do not use recessed top of the tank cylinders for the storage of tools or other equipment. Do not hang clothing or materials on cylinders.
Never direct compressed air or other gases toward the body.
Exercise care to avoid injury to hands or feet. The use of safety shoes and heavy gloves is highly recommended while handling cylinders.
Do not use force to open or close cylinder valves; If there is a problem, notify the Safety Office.
Use the cylinder valve for turning the gas off, not the regulator valve.
Close the main cylinder valve as soon as it is no longer necessary to have it open.
Before you remove the regulator make sure that the cylinder valve is closed.
Place a trap between the regulator valve and the reactor vessel to prevent contamination when carrying out chemical reactions using pressurized gas.
Turn off the cylinder valve and then the regulator, when your work is finished. The pressure gauges should be brought back to zero.

Hoses and Connections

Do not use unnecessarily long hoses. If a long hose must be used, make sure it is free from kinks and away from high traffic areas.
Examine hoses periodically for leaks by submersing sections in water and looking for bubbling.
Repair leaks properly and promptly.
Store hoses in a cool place, and protect from hot objects, and sparks.
Do not use a single hose having more than one gas passage.