BCAB #1044 - Prefabricated Roof Vent Flashings, Article 9.27.4.1.

December 15, 1988

BCAB #1044

Re: Prefabricated Roof Vent Flashings, Article 9.27.4.1.

With reference to your letter of October 31, 1988 regarding prefabricated plastic vent flashings. The flashings in question are self-sealing, designed to accommodate a vent pipe penetration while remaining weathertight.

Article 9.27.4.1. of the Code deals with site manufactured vent flashings, and while permitting a reduced thickness for prefabricated lead units does not address such units if manufactured from other materials. The specific flashings under review have been tested to CSA B272, "Prefabricated Self-Sealing Vent Flashings", and comply with the standard except with respect to the base size, for which it complies with the provisions of Article 9.27.4.10. in the Building Code.

On the basis of the certification provided by CSA or Warnock Hersey, flashings designated as 11908-NC1 (11/4 to 11/2 in.), 11909-NC2 (2 in.), 11910-NC3 (3 in.), and 11911-NC4 (4 in.) are acceptable under the B.C. Building Code for use with PVC and ABS drain waste and vent pipes on sloping roofs. This is conditional on the plumbing system being designed as indicated in Article 3.3.9., with the means to accommodate expansion and contraction of the piping system, or movement of the structure.

J.C. Currie, Chair