ONLINE SELF-STUDY Compressed Gas Safety

Objectives In accordance with OSHA's Hazardous Materials standard (29 CFR 1910 Subpart H) it is important:  To understand hazards associated with compressed gases.  To learn how to effectively manage these hazards.  To learn about University policies regarding compressed gas use.

About Compressed Gases A compressed gas cylinder is any cylinder specifically designed to contain gases under pressure of greater than one atmosphere, and having the capability of dispensing the gas by the means of a control valve mechanism to assure the safe and proper use of the gas at a point of operation.

About Compressed Gases Compressed gases are hazardous because they can cause fires, explosions, oxygen deficient atmospheres, and toxic gas exposures. In addition there are the innate physical hazards associated with cylinders under high pressure.

About Compressed Gases A variety of compressed gases exist, including flammables, non-flammables, explosives, corrosives, as well as toxic and oxidizing gases. Reference labeling, safety data sheets (SDS), and other safety literature for specific hazard information.

About Compressed Gases Special storage, usage, handling and disposal procedures are necessary to ensure the safety of employees using compressed gases. Also, compressed gases should be included in chemical inventories. For laboratories, their hazards should be indicated on lab entrance signs.chemical inventories lab entrance signs

Labels All compressed gas cylinders must bear labels that clearly identify the contents.

Labels No compressed gas cylinder should be accepted that does not have its contents identified by name. If labeling on a cylinder is not clear and the contents cannot be identified, the cylinder should be marked "contents unknown" and returned directly to the manufacturer.

Labels Do not use the color of a cylinder for identification. Color coding may vary between suppliers. Also, do not rely on labels on cylinder caps because these caps are interchangeable.

Storage Store cylinders in designated areas where they will not be knocked over or damaged by passing or falling objects. Where cylinders are stored in the open, they should be protected from accumulations of ice and snow and from the direct rays of the sun. Full cylinders should be used in rotation as received from the supplier.

Storage Cylinders should not be subjected to a temperature above 125°F, nor should a flame ever be permitted to come in contact with any part of a compressed gas cylinder. Tanks should not be stored in cold rooms due to the lack of exhaust in these spaces.

Storage Compressed gas cylinders must be in an upright position and supported at all times, whether full or empty. Be sure to secure the cylinder above its center of gravity (~2/3 up the cylinder). Do NOT secure cylinders by the valve. Do NOT attempt to catch a falling cylinder.

Storage Acceptable methods of support include:  wall-mounted or bench-mounted gas cylinder brackets  chains or belts anchored to walls or benches  dollies or carts designed for gas cylinders and equipped with safety chains or belts

Storage The picture to the right is an example of how NOT to secure a compressed gas cylinder. This does not provide sufficient support. Securing cylinders individually is ideal. If cylinders must be ganged together for storage, only gang two cylinders together at a time, if possible. If it is necessary to gang more cylinders together please contact EHS for advice.

Transporting Cylinders Valve caps must be securely fastened before cylinders are moved. Use appropriate dollies or hand trucks to move cylinders weighing more than 50 pounds. Cylinders should never be rolled or dragged.

Transporting Cylinders Improper handling can seriously weaken the cylinder and render it unfit for further use, or transform it into a rocket having sufficient thrust to drive it through walls. (You can watch the MythBusters make this happen.)You can watch the MythBusters make this happen.)

Regulators and Gauges Pressure regulators and gauges must be compatible with the cylinder valves. You may not use "cheaters" (adapters) instead of the correct regulator and gauge.

Regulators and Gauges The Compressed Gas Association has devised standard outlet connections to prevent mixing of incompatible gases. Outlet threads may vary in diameter. Some are internal, some are external; some are right-handed, some are left- handed. If a valve must be forced, it is a good sign that the wrong valve is being used.

Regulators and Gauges All the connections should be checked with a soap solution for leaks (except for oxygen tanks). Never use oil or grease. Threads on cylinder valves, regulators and other fittings should be inspected regularly to ensure they are correct and undamaged.

Regulators and Gauges Cylinders should be visually inspected to ensure that they are in safe condition. If a leaking cylinder is discovered, move it to a safe place (if it is safe to do so) and contact EHS for precautionary advice and disposal assistance. You should also call the vendor as soon as possible. Do NOT attempt to repair a cylinder or valve.

Special Notes Lecture Bottles Lecture bottles are small compressed gas cylinders, typically inches long and 2-3 inches in diameter. Lecture bottles should be secured during use. All lecture bottles containing hazardous gases should be used in a chemical fume hood. These cylinders are typically non-returnable.

Special Notes Hydrogen and Acetylene Hydrogen is a colorless, odorless and tasteless gas. Acetylene is a colorless gas with a distinctive garlic-like odor. These are both flammable gases. A mixture of either gas with oxygen or air in a confined area will explode if ignited by spark, flame or other source of ignition.

Special Notes Hydrogen and Acetylene Post all hydrogen and/or acetylene storage and usage locations with permanent placards that read: HYDROGEN/ACETYLENE - FLAMMABLE GAS - - NO SMOKING - - NO OPEN FLAMES -

Special Notes Oxygen Oxygen is a colorless, odorless, and tasteless gas. It can greatly accelerate combustion. These cylinders should never be stored near flammable gases. Greasy or oily material should never be stored around oxygen. Also, do not use soap based leak detector compounds on the connection threads of an oxygen cylinder.

Special Notes Corrosive Gases Corrosive gases can burn and destroy body tissues on contact. Corrosive gases can also attack and corrode metals. Common corrosive gases include ammonia, hydrogen chloride, chlorine and methylamine.

Special Notes Cryogenic Gases Cryogenic gases are extremely cold and accidental contact with eyes or skin may cause severe frostbite. Personal protective equipment (PPE) must be worn by employees who handle and use cryogenic gas cylinders. This includes gloves constructed of insulating materials, rubber aprons, safety glasses or goggles and a complete face shield.

Special Notes Cryogenic Gases Proper PPE:

Special Notes Cryogenic Gases Tremendous pressures can result in enclosed spaces as the liquid converts to gas. For example, one cubic centimeter of liquid nitrogen will expand to 700 times this volume as it converts to its gaseous state. For this reason, asphyxiation can be an issue. Depending on the size of a room and volume of gas, an oxygen monitor may be needed.

Special Notes Dangerous Gases Any gases that may cause significant acute health effects at a low concentration are considered dangerous gases. Cylinders of dangerous gases, such as ammonia, carbonyl sulfide, hydrogen cyanide, hydrogen sulfide, methylamine, and nitric oxide, must follow the University's Dangerous Gas Policy.Dangerous Gas Policy

Disposal There are two general types of compressed gas cylinders:  returnable (owned by the gas supplier, rental fee charged to the University)  non-returnable Most suppliers will accept the return of their cylinders even if they are not empty. However, suppliers will not accept non- returnable cylinders under any circumstances. Lecture bottles are typically non-returnable.

Disposal Disposal of non-returnable cylinders containing highly toxic or reactive gas can be very expensive. Therefore, purchase compressed gases in returnable cylinders if available. If non-returnable cylinders are the only alternative, be prepared to pay for the cost of disposal. To dispose of these cylinders request a waste pickup online through EHS.

Review  All compressed gas cylinders must bear labels that clearly identify the contents.  Compressed gas cylinders must be in an upright position and supported at all times, whether full or empty. Acceptable methods of support include:  wall-mounted or bench-mounted gas cylinder brackets;  chains or belts anchored to walls or benches; and,  free-standing dollies or carts designed for gas cylinders and equipped with safety chains or belts.

Review  Gas cylinders must have the valve protection cap in place except when in use.  Use appropriate dollies or hand trucks to move cylinders weighing more than 50 pounds.

Review  Pressure regulators and gauges must be compatible with the cylinder valves. You may not use "cheaters" (adapters) instead of the correct regulator and gauge.  Reference labeling, safety data sheets (SDS), and other safety literature for specific hazard information.