Covering of access openings in heating, ventilating or air-conditioning systems through which a person could enter, where there is a possibility of the opening being accidentally closed while the system or equipment is being serviced, in buildings described in Sentence 1.3.3.2.(1) of Division A.

This also applies to buildings to which Part 9 applies [see Sentence 1.3.3.3.(1) of Division A for application of Part 9], with respect to:

• mechanical ventilating systems other than self-contained systems serving single dwelling units, as stated in Sentence 9.32.1.2.(2),
• the ventilation of all occupancies other than residential occupancies, as stated in Sentence 9.32.1.1.(2),
• heating systems, including requirements for combustion air, and air-conditioning systems other than those serving individual dwelling units, as stated in Sentence 9.33.1.1.(2), and
• air duct distribution systems serving heating systems in which the rated heat input exceeds 120 kW, as stated in Sentence 9.33.6.1.(2).