When is a permanent approved means of access required for mechanical equipment and appliances installed on roofs or elevated structures?
In accordance with Section 306.5 of the International Mechanical Code (IMC), access must be provided to the roof by permanent means (access hatch or permanent ladder) if the roof is greater than 16 feet above grade. The 16 foot measurement is from grade to the roof level and not to the height of the RTU from grade as shown in the following excerpt from the IMC Code and Commentary. In the case of mechanical equipment and appliances installed on a penthouse roof, the 16 foot measurement is from the building’s roof level to the penthouse roof level. As such, the technician may be required to bring equipment to the roof to provide access to all portions of the mechanical equipment and appliances in order to perform service.
It should be noted that such access may not require climbing over obstructions greater than 30-inches high or walking on roofs having a slope greater than four units vertical in 12 units horizontal (33-percent slope). Additionally, where access involves climbing over parapet walls, the height shall be measured to the top of the parapet wall.
