Current through Register Vol. 54, No. 50, December 14, 2024
(a) Each bulkhead in tunnels of 12 feet or more in diameter (or equivalent area) shall have at least two locks in perfect working condition, one of which shall be used as a man-lock.(b) The man-lock shall be large enough so that those using it are not compelled to be in a cramped position, and it shall not be less than 5 feet in height. The emergency lock shall be large enough to hold an entire heading shift.(c) All locks used for decompression shall be lighted by electricity and shall contain a pressure gauge, a time piece, a glass "bull's eye" in each door or in each end, and shall also have facilities for heating.(d) Valves shall be arranged so that the locks may be operated both within and without.