Division B
Acceptable Solutions

Part 5 — Environmental Separation

Section 5.6. Precipitation

(See Appendix A and Part 10.)

5.6.1. Protection from Precipitation

5.6.1.1. Required Protection from Precipitation
(See Appendix A.)
1) Intent StatementExcept as provided in Sentence (2), where a building component or assembly is exposed to precipitation, the component or assembly shall
a) minimize ingress of precipitation into the component or assembly, and
b) prevent ingress of precipitation into interior space.
2) Intent StatementProtection from ingress of precipitation is not required where it can be shown that such ingress will not adversely affect any of
a) the health or safety of building users,
b) the intended use of the building, or
c) the operation of building services.
5.6.1.2. Installation of Protective Materials
1) Intent StatementWhere a material applied to a sloped or horizontal assembly is installed to provide required protection from precipitation and its installation is covered in the scope of one of the standards listed below, installation shall conform to the requirements of the respective standard:
a) CAN/CGSB-37.51-M, “Application for Hot-Applied Rubberized Asphalt for Roofing and Waterproofing,”
b) CGSB 37-GP-55M, “Application of Sheet Applied Flexible Polyvinyl Chloride Roofing Membrane,”
c) CAN3-A123.51-M, “Asphalt Shingle Application on Roof Slopes 1:3 and Steeper,” or
d) CAN3-A123.52-M, “Asphalt Shingle Application on Roof Slopes 1:6 to Less Than 1:3.”
2) Intent StatementWhere masonry applied to vertical assemblies is installed to provide required protection from precipitation, installation shall conform to the requirements of CAN/CSA-A371, “Masonry Construction for Buildings.”
3) Intent StatementWhere protective materials are applied to assemblies to provide the required protection from precipitation, they shall be installed so as to shed precipitation or otherwise minimize its entry into the assembly and prevent its penetration through the assembly. (See Appendix A.) (See also Clause 5.3.1.2.(1)(d).)

5.6.2. Sealing, Drainage, Accumulation and Disposal

5.6.2.1. Sealing and Drainage
(See Appendix A.)
1) Intent StatementExcept as provided in Sentence (2), materials, components, assemblies, joints in materials, junctions between components and junctions between assemblies exposed to precipitation shall be
a) sealed to prevent ingress of precipitation, or
b) drained to direct precipitation to the exterior.
2) Intent StatementSealing or drainage are not required where it can be shown that the omission of sealing and drainage will not adversely affect any of
a) the health or safety of building users,
b) the intended use of the building, or
c) the operation of building services.
5.6.2.2. Accumulation and Disposal
1) Intent StatementWhere water, snow or ice can accumulate on a building, provision shall be made to minimize the likelihood of hazardous conditions arising from such accumulation.
2) Where precipitation can accumulate on sloped or horizontal assemblies, provision shall be made for drainage conforming with Article 2.4.10.4. of Division B of Book II (Plumbing Systems) of this Code.

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3) Intent StatementWhere downspouts are provided and are not connected to a sewer, provisions shall be made to
a) divert the water from the building, and
b) prevent soil erosion.
4) Intent StatementJunctions between vertical assemblies, and sloped or horizontal assemblies, shall be designed and constructed to minimize the flow of water from the sloped or horizontal assembly onto the vertical assembly.