The conditioner must not increase the engine back pressure above 18 inches of water or 1 1/2 inches of mercury when the diesel equipment is developing its rated horsepower. The conditioner must hold sufficient water for four hours of operation without replenishing and at the end of four hours of operation, the exhaust temperature again must not exceed (180°) Fahrenheit. Water to be completely drained and replenished once each shift. The conditioner must be checked, serviced, and cleaned once each week. Any other conditioner approved by the Arizona State Mine Inspector may be used.
Ariz. Admin. Code § R11-1-423