(1) Except as permitted in Sentences (2) to (6), combustible piping shall not be used where any part of a piping system partly or wholly penetrates a fire separation required to have a fire-resistance rating or penetrates a membrane that contributes to the required fire-resistance rating of an assembly.
(2) Combustible piping not located in a vertical shaft is permitted to penetrate a fire separation required to have a fire-resistance rating or a membrane that forms part of an assembly required to have a fire-resistance rating, provided the piping is sealed at the penetration by a fire stop that has an F rating not less than the fire-resistance rating required for the fire separation.
(3) The rating referred to in Sentence (2) shall be based on CAN/ULC-S115, “Fire Tests of Firestop Systems”, with a pressure differential of 50 Pa between the exposed and unexposed sides, with the higher pressure on the exposed side.
(4) Combustible drain piping is permitted to penetrate a horizontal fire separation or a membrane that contributes to the required fire-resistance rating of a horizontal fire separation, provided it leads directly from a noncombustible water closet through a concrete floor slab.
(5) Combustible piping is permitted,
(a) on one side of a vertical fire separation provided it is not located in a vertical shaft, and
(b) to penetrate a vertical or horizontal fire separation when the fire compartment on each side of the fire separation is sprinklered.
(6) In a house containing two dwelling units, combustible piping is permitted on one side of a horizontal fire separation.