34 Pa. Code § 43.53 – Decompression.

(a) A stage decompression shall be used in which a drop of 1/2 of the maximum gauge pressure shall be at the rate of 5 pounds per minute. The remaining decompression shall be at a uniform rate and the total time of decompression shall equal the time specified for the original maximum pressure.
(b) No person employed in compressed air shall be permitted to pass from the place in which the work is being done to normal air, except after decompression in the intermediate lock as follows:
1. (1) If the air pressure is greater than normal and less than 15 pounds per square inch, decompression shall be at the maximum rate of 3 pounds per minute.
2. (2) If the air pressure is 15 pounds or more and less than 20 pounds per square inch, decompression shall be at the maximum rate of 2 pounds per minute.
3. (3) If the air pressure is 20 pounds or more and less than 30 pounds per square inch, decompression shall be at the maximum rate of 3 pounds every 2 minutes.
4. (4) If the air pressure is 30 pounds or more per square inch, decompression shall be at the maximum rate of 1 pound per minute.
(c) The time of decompression shall be posted in each man-lock as provided in § 43.54 (relating to pressure gauges).
(d) If air pressure reaches 17 pounds or more, a record of all men working in the air chamber shall be kept by a man detailed for that purpose who shall remain outside the lock near the entrance. This record shall show the period of stay in the air chamber of each person and the time taken for decompression.