Failing to use or store compressed gases properly invites disaster. Improper handling can cause serious fires, explosions or releases due to pressure buildup in cylinders or reactions with other materials. All employees should understand and follow proper procedures for handling and using acetylene gas.

ACETYLENE DANGERS

Acetylene is a widely used fuel gas in gas welding. Although common, it is extremely dangerous. Acetylene is highly reactive and should never come into contact with certain metals, such as unalloyed copper. It also should not be stored or used at pressures above 15 psi. (Cylinder pressures are rated for 250 psi, but this is safe because the gas is dissolved in acetone.)

SPECIAL ELECTRICAL CODE DESIGNATION

Acetylene is extremely flammable. The National Electrical Code gives it a special, most stringent designation for using electrical equipment around the gas—no other substance falls into this classification. Even small acetylene leaks can have serious consequences. Its explosive range in air is 2.5% to 82%, the widest of any commonly used gas.

OBSERVE THESE PROCEDURES

• Close the cylinder valve before shutting off the regulator to allow gas to bleed from the regulator.

• When returning empty cylinders to storage or for refill, close the valves. Even when the acetylene gas is used up, the flammable acetone in the cylinder can still evaporate and create hazards.

• Acetylene gas is lighter than air, so any leaks should rise. However, it is only slightly lighter, and certain atmospheric conditions can prevent this.

• Acetylene cylinders are not hollow. They are packed with porous rock saturated with acetone. Cylinders should be used and stored only in an upright position to prevent acetone from leaking. If this is not possible, place the cylinder upright and let it stand for 30 minutes before use to prevent liquid acetone from entering the regulator.

• Cylinders containing acetylene must not be taken into confined spaces.

• Always use acetylene in a well-ventilated area. Never store cylinders near open flames or electrical equipment, where a leak could allow gas to reach a flame or spark.

• Never store acetylene or any other fuel gas within 25 feet of oxygen cylinders. If this separation is not possible, erect a noncombustible, half-hour fire-rated partition at least five feet high between the two types of gas in storage.

• Always cap and secure stored cylinders upright to prevent them from falling and damaging the valve or cylinder.