Every employer of persons for work in compressed air shall:

(1) Connect at least two air pipes with the working chamber and keep such pipes in perfect working condition;

(2) Attach to the working chamber in accessible positions all instruments necessary to show its pressure and keep such instruments in charge of competent persons, with a period of duty for each such person not exceeding six hours in any twenty-four;

(3) Place in each shaft a safe ladder extending its entire length;

(4) Light properly and keep clear such passageway;

(5) Provide independent lighting systems for the working chamber and shaft leading to it, when electricity is used for lighting;

(6) Guard lights other than electric lights;

(7) Protect workers by a shield erected in the working chamber when such chamber is less than ten feet long and is suspended with more than nine feet space between its deck and the bottom of the excavation;

(8) Provide for and keep accessible to employees working in compressed air a dressing room heated, lighted and ventilated properly and supplied with benches, lockers, sanitary waterclosets, bathing facilities, and hot and cold water;

(9) Establish and maintain a medical lock properly heated, lighted, ventilated, and supplied with medicines and surgical implements, when the maximum air pressure exceeds seventeen pounds.