(1) LPG containers must not be installed, nor stored temporarily, inside any commercial coach.

(2)(a) Containers, control valves and regulating equipment, when installed, must be mounted on the "A" frame of the commercial coach or installed in a compartment that is vapor-tight to the inside of the commercial coach and accessible only from the outside.

(b) The compartment must be ventilated at top and bottom to diffuse vapors. The compartment must be ventilated with two vents having an aggregate area of not less than two percent of the floor area of the compartment and must open without restriction to the outside. The required vents must be equally distributed between the floor and ceiling of the compartment. If the lower vent is located in the access door or wall, the bottom edge of the vent shall be flush with the floor level of the compartment. The top vent must be located in the access door or wall with the bottom of the vent not more than twelve inches below the ceiling level of the compartment. All vents must have an unrestricted discharge to the outside atmosphere. Access doors or panels of compartments must not be equipped with locks or require special tools or knowledge to open.

(3) Doors, hoods, domes, or portions of housings and enclosures required to be removed or opened for container replacement must incorporate means for clamping them firmly in place and preventing them from working loose during transit. Provisions must be incorporated in the assembly to hold the containers firmly in position and prevent their movement during transit.

(4) LPG containers must be mounted on a substantial support or a base secured firmly to the commercial coach chassis. Neither the container nor its support can extend below the commercial coach frame.