(1) General. As used herein confined space is intended to mean a relatively small or restricted space such as a tank, boiler, pressure vessel, or small compartment of a ship.

(2) Ventilation. Ventilation is a prerequisite to work in confined spaces. For ventilation requirements see WAC 296-24-71501 through 296-24-71525.

(3) Securing cylinders and machinery. When welding or cutting is being performed in any confined spaces you must leave the gas cylinders and welding machines on the outside. Before operations are started, you must securely block heavy portable equipment mounted on wheels to prevent accidental movement.

(4) Lifelines. Where a welder must enter a confined space through a manhole or other small opening, you must provide means for quickly removing the welder in case of emergency. When safety belts and lifelines are used for this purpose you must attach them in a manner so that the welder's body cannot be jammed in a small exit opening. An attendant with a preplanned rescue procedure must be stationed outside to observe the welder at all times and be capable of putting rescue operations into effect.

(5) Electrode removal. When arc welding is to be suspended for any substantial period of time, such as during lunch or overnight, you must remove all electrodes from the holders and carefully locate the holders so that accidental contact cannot occur and the machine disconnected from the power source.

(6) Gas cylinder shutoff. In order to eliminate the possibility of gas escaping through leaks or improperly closed valves, when gas welding or cutting, you must close the torch valves and positively shut off the fuel-gas and oxygen supply to the torch at some point outside the confined area whenever the torch is not to be used for a substantial period of time, such as during lunch hour or overnight. Where practicable you must also remove the torch and hose from the confined space.

(7) Warning sign. After welding operations are completed, the welder must mark the hot metal or provide some other means of warning other workers.