820 ILCS 245/2
The working period of any person under compressed air in any compartment, caisson, tunnel or places shall be divided into two periods under compressed air with an interval of rest between the two periods. If the air pressure exceeds fifteen pounds per square inch, the said interval of rest must be spent in the open air. Persons who have not previously worked in compressed air, when the air pressure exceeds fifteen pounds per square inch, shall work therein only one of the two said periods during the first twenty-four hours of their employment. Except in cases of extreme emergency no person shall be employed or subjected to pressure exceeding fifty pounds per square inch. The maximum number of hours to each period and the minimum rest intervals between the periods during any twenty-four hours for any pressure as given in columns one and two of the following table shall be set opposite such pressure in columns three, four, five, six and seven of said table:
........................................................................ PERIODS AND INTERVALS OF WORK FOR EACH TWENTY-FOUR HOUR PERIOD ........................................................................ Pressure Hours More Not More Minimum than than inter- mini- maxi- val Minimum Maximum mum mum First of rest inter- second number number Maximum period in in open val of period in of of total compressed air- rest- compressed pounds pounds hours air-hours hours hours air-hours ........................................................................ Column Column Column Column Column Column Column 1 2 3 4 5 6 7 ........................................................................ Normal 15 8 * 1/3 * 15 26 6 3 1 3 26 33 4 2 2 2 33 38 3 1 1/2 3 1 1/2 38 43 2 1 4 1 43 48 1 1/2 3/4 5 3/4 48 or over 1 1/2 6 1/2 ........................................................................ *The employer may determine the time of each period when the pressure is not more than fifteen pounds per square inch, provided that the total for the periods does not exceed eight hours. The limits or hours as specified in said table shall apply according to the maximum pressure attained at any time during the period.
820 ILCS 245/2