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Subchapter 7. General Industry Safety Orders



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§6105. Compressor Plant, Air Supply and Telephone Communication.

(a) There shall at all times be a qualified gauge tender on duty at the air control valves to regulate the pressure in the working areas. During tunneling operations, one gauge tender may regulate the pressure in not more than two headings provided that the gauges and controls are all in one location. In caisson work there shall be a gauge tender for each caisson.

(b) The low air compressor plant shall be of sufficient capacity to not only permit the work to be done safely, but shall provide a margin to meet anticipated emergencies and repairs.

(c) Low air compressor units shall have at least two independent and separate sources of power supply. Each independent and separate source of power supply shall be capable of operating the entire low air plant and its accessory systems.

(d) The capacity, arrangement, and number of compressors shall be sufficient to maintain the necessary pressure without overloading the equipment and to assure maintenance of such pressure in the working chamber during periods of breakdown, repair, or emergency.

(e) Switching from one independent source of power supply to the other shall be done periodically to ensure the workability of the apparatus in an emergency.

(f) Duplicate low pressure air feed lines and regulating valves shall be provided between the source of air supply and a point beyond the locks with one of the lines extending to within 100 feet of the working face.

(g) To prevent rapid decompression all air supply lines shall be equipped with check valves.

(h) Low pressure air shall be regulated automatically. In addition, manually operated valves shall be provided for emergency conditions.

(i) The air intakes for all air compressors shall be located at a place where fumes, exhaust gases, and other air contaminants will be at a minimum.

(j) Gauges indicating the pressure in the working chamber shall be installed in the compressor building, the lock attendant's station, and at the Field Office of the employer's representative.

(k) There shall be effective communication at all times between the following:

(1) The working chamber face;

(2) The working chamber side of the air lock near the door;

(3) The interior of the air lock;

(4) Lock attendants station;

(5) The compressor plant;

(6) The first-aid station;

(7) The emergency lock (if one is required);

(8) The special decompression chamber (if one is required).

Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.


1. New section filed 4-4-2006; operative 5-4-2006 (Register 2006, No. 14).

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