Exit door(s) on self-propelled medical units must meet the following requirements:

(1) Exterior doors must be constructed for exterior use.

(2) The exterior door must be at least a twenty-eight inches wide clear opening by seventy-two inches high.

(3) Locks must be operable from the interior of the unit without use of a key.

(4) Exit doors may either be hinged or sliding. Roll-up doors may not be used to meet the requirements of this section.

(5) Exit doors where the threshold of the door is more than fourteen inches above the adjacent grade or road surface must have landings, stairs, handrail, and guardrails meeting the requirements of IBC chapter 10 as referenced in chapter 51-50 WAC.