(a) Mattress. Sleeper berths shall be equipped with springs and a mattress at least 4 in. thick (unless the mattress is innerspring, air, or foam rubber) and adequate bedding. Sleeper berths shall be constructed to permit ready removal of mattress and bedding for cleaning.

(b) Ventilation. Sleeper berths shall be provided with louvers or other means of ventilation that are reasonably dust proof and rain proof.

(c) Location. Sleeper berths shall be located to prevent entrance of gases from the exhaust system, overheating or damage by the exhaust system, and leakage from the fuel system. Sleeper berths shall not be located in the cargo space unless completely and securely compartmentalized. No sleeper berth shall be installed in or on any trailer or semitrailer other than a house trailer.

(d) Communication With Driver. Unless the sleeper berth is inside the driver's compartment or has a direct entrance thereto, means shall be provided to enable the occupant of the berth to communicate with the driver. Such means may be a telephone, speaker tube, buzzer, pull cord, or other mechanical or electrical device.

(e) Entrance and Exit. Sleeper berths shall be constructed and maintained so that the occupant has at least two means of exiting without assistance. The two exits shall be on opposite sides of the vehicle and shall be not less than 18 in. high and 21 in. wide. However, if the berth is part of the cab and between the berth and the driving seat, has a doorway or opening at least 18 in. high and 36 in. wide, the requirement for two exits does not apply.

(f) Size. Sleeper berths shall be not less than 75 in. long, measured on the centerline of the longitudinal axis; 21 in. wide at the center; and 21 in. high at the center, measured from the top of the mattress. Sleeper berths shall be constructed so as not to hinder the ready entrance or exit of the occupant.

(g) Federal Requirements. Carriers subject to and in compliance with sleeper berth requirements of the U.S. Department of Transportation shall be deemed in compliance with this section.