Illinois Statutes Chapter 820. Employment § 245/3. Rate of decompression

(a) Where the air pressure is greater than normal and not more than fifteen pounds per square inch, the time of decompression shall be at least two minutes;

(b) Where the air pressure is more than fifteen pounds per square inch, and not more than twenty-six pounds per square inch, decompression shall be at the average rate of not more than three pounds per minute;

(c) Where the air pressure is more than twenty-six pounds per square inch, and not more than thirty-three pounds per square inch, decompression shall be at the average rate of not more than two pounds per minute;

(d) Where the air pressure is more than thirty-three pounds per square inch, decompression shall be at the average rate of not more than one pound per minute;

(e) Where the air pressure is more than fifteen pounds per square inch, a stage decompression shall be used in which a drop of one-half of the maximum gauge pressure shall be at the rate of five 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;

(f) The time of decompression shall be posted in each man lock.