43 Pa. Stat. § 451
No person shall be permitted to pass from any tunnel, caisson, compartment, or place where he has been employed in compressed air to atmosphere or normal pressure, without passing through an intermediate lock or stage of decompression. When the employe is passing from a tunnel to atmosphere of normal pressure, the rate of decompression shall be three pounds every two minutes, except when the air pressure in the tunnel exceeds thirty-six pounds, in which case the rate of decompression shall be one pound every minute. When the employe is passing from a caisson, compartment, or place to atmosphere of normal pressure, the time of decompression shall be as follows:
When the pressure in a caisson, compartment, or place exceeds normal, but does not exceed ten pounds, time of decompression one minute.
When the pressure in a caisson, compartment, or place exceeds ten but does not exceed fifteen pounds, time of decompression two minutes.
When the pressure in a caisson, compartment, or place exceeds fifteen but does not exceed twenty pounds, time of decompression five minutes.
When the pressure in a caisson, compartment, or place exceeds twenty pounds but does not exceed twenty-five pounds, time of decompression ten minutes.
When the pressure in a caisson, compartment, or place exceeds twenty-five pounds but does not exceed thirty pounds, time of decompression twelve minutes.
When the pressure in a caisson, compartment, or place exceeds thirty but does not exceed thirty-six pounds, time of decompression fifteen minutes.
When the pressure in a caisson, compartment, or place exceeds thirty-six but does not exceed forty pounds, time of decompression twenty minutes.
When the pressure in a caisson, compartment, or place exceeds forty but does not exceed fifty pounds, time of decompression twenty-five minutes.
43 P.S. § 451