Interruption of combustible coverings and linings of ducts, including associated adhesives and insulation:

• where the duct penetrates a fire separation, and
• at the immediate area of operation of heat sources in a duct system, including electric resistance heaters or fuel-burning heaters or furnaces.

This applies to buildings described in Sentence 1.3.3.2.(1) of Division A.

This also applies to:

• the fire safety characteristics of heating, ventilating and air-conditioning systems, as stated in Article 6.2.1.2., and
• 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 ventilation systems other than self-contained systems serving single dwelling units, as stated in Sentence 9.32.1.1.(2),
  • the ventilation of storage garages for more than 5 motor vehicles in residential occupancies, as stated in Sentence 9.32.1.1.(3),
  • mechanical ventilation systems used for the ventilation of rooms and spaces in dwelling units during the non-heating season, where natural ventilation is not provided in accordance with Article 9.32.2.2., as stated in Clause 9.32.2.1.(1)(b),
  • heating 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 in which the rated heat input exceeds 120 kW, as stated in Sentence 9.33.6.1.(2).

To limit the probability that fire will spread from one fire compartment to another fire compartment by means of the combustible coverings and linings of ducts, which could lead to harm to persons in the other fire compartment.

To limit the probability that fire will spread from one fire compartment to another fire compartment through gaps between a duct and the fire separation through which it passes if the combustible material were to be burnt in a fire occurring on one side of the fire separation, which could lead to harm to persons in the other fire compartment.

To limit the probability that combustible coverings and linings of ducts will be ignited from nearby heat sources, which could lead to the spread of fire along the ducts to other parts of the building, which could lead to harm to persons.