A number of fuel gases are commonly used: propane, propylene, propylene-based mixtures, acetylene, natural gas, liquefied petroleum (LP) gases, and hydrogen. All but hydrogen are under low pressure.

All fuel gases are potentially hazardous. They will burn and can explode when mixed with air or oxygen. Following are general rules that apply to all fuel gases:

• Always call a gas by its proper name. Never refer only to "gas".

• Do not use a fuel gas for any purpose other than that for which it was intended.

• Treat fuel gases with respect. Follow the correct procedures for assembling and disassembling equipment (discussed in Chapter 1). Use only regulators and other equipment designed for the gas being used and always follow the manufacturer's instructions.

• Never let a fuel-gas cylinder reach a temperature above 130°F (54°C).

• Always keep fuel-gas cylinders upright. Never use them on their sides. Use, move, and secure them with the same care used for high-pressure cylinders.

• Close the cylinder valve of a leaking fuel-gas cylinder, take the cylinder to a safe place outside and away from ignition sources, mark it, and call the supplier or gas distributor.