The use of compressed gases on campus is to be in accordance with recommendations published by the Compressed Gas Association. The following rules summarize basic guidelines for the use and storage of compressed gases:
- All compressed gas cylinders must bear labels that clearly identify the contents.
- Compressed gas cylinders must be supported at all times, whether full or empty (Figure 3.5). 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.
Make sure that any chains, belts, or wall anchors supporting multiple cylinders have the strength to support the weight of the entire potential load. Do not overload support systems.
- Gas cylinders must have the valve protection cap in place except when in use. A cylinder connected to a piece of equipment and properly supported is “in use”. Remove the pressure regulators and replace valve protection caps before moving cylinders, even if you have secured the cylinders to a dolly or hand truck. For example, do not transport acetylene and oxygen cylinders, used for cutting and brazing with regulators attached to the cylinders, except in the cylinder cart.
- Post all hydrogen and/or acetylene storage and usage locations with permanent placards that read: “HYDROGEN/ACETYLENE – FLAMMABLE GAS – NO SMOKING – NO OPEN FLAMES.”
- Gas cylinders must be in an upright position and clamped securely at all times. Because of the extreme hazards created by using certain cylinders in a horizontal position (e.g., acetylene), you must consult EHS before using cylinders in any position other than vertical, with the valve up.
- Use appropriate dollies or hand trucks to move cylinders weighing more than 50 pounds. Do not move cylinders by spinning, sliding, rolling, etc. For movement within shops and laboratories, one may carry cylinders weighing less than 50 pounds, if desired.
- Keep cylinders of all gases having a health hazard rating of three or four, such as ammonia, carbonyl sulfide, hydrogen cyanide, hydrogen sulfide, methylamine, and nitric oxide, in hoods or other enclosures that vent directly outside. Each hood or enclosure may not have more than three cylinders of this type. Provide appropriate and clearly marked first aid, antidote information, and supplies at room entrances. Safety data sheets must be available, either in hard copy or electronic format.
- Installed piping systems for flammable gases, toxic gases and oxygen must be in accordance with OSHA, NFPA, and ANSI standards and approved by EHS.
- Pressure regulators and gauges must be compatible with the cylinder valves. You may not use “cheaters” (adapters) instead of the correct regulator and gauge.
- All oxygen valves, gauges, regulators, pipes and fittings must be scrupulously free of oil, grease, graphite or any other oxidizable substance. For this reason, do not use soap-based leak detectors on oxygen cylinder regulators or fittings. Oxygen pipes, gauges, fittings, etc., must not reach elevated temperatures due to proximate welding operations, burners or other heat sources. Although oxygen is quite safe under normal temperatures and pressures, elevated temperatures and/or pressures (or contamination) may result in the rapid and violent oxidation of normally non-reactive materials. For example, a regulator used in oil-pumped nitrogen could produce a serious explosion if subsequently used for oxygen, due to the oil residue.
- There are two general types of compressed gas cylinders: returnable (owned by the gas supplier, demurrage charged to the University) and non-returnable. Most suppliers will accept the return of their cylinders even if they are not empty (pressure approaching atmospheric). However, suppliers will not accept non-returnable cylinders under any circumstances. Disposal of non-returnable cylinders containing highly toxic or reactive gas can be very expensive. Therefore, purchase compressed gases in returnable cylinders if available.