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3.1.14.1. Fire-Retardant-Treated Wood Roof Systems
- If a fire-retardant-treated wood roof system is used to comply with the requirements of Subsection 3.2.2., the roof deck assembly shall meet the conditions of acceptance of CAN/ULC-S126, "Test for Fire Spread Under Roof-Deck Assemblies."
- Supports for the roof deck assembly referred to in Sentence (1) shall consist of
- fire-retardant-treated wood,
- heavy timber construction,
- noncombustible construction, or
- a combination thereof.
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| 3.1.14.2. |
Metal Roof Deck Assemblies
- Except as permitted by Sentence (2), a metal roof deck assembly shall meet the conditions of acceptance of CAN/ULC-S126, "Test for Fire Spread Under Roof-Deck Assemblies," if
- it supports a combustible material above the deck that could propagate a fire beneath the roof deck assembly, and
- the deck is used to comply with the requirements of Sentences 3.2.2.25.(2), 3.2.2.32.(2), 3.2.2.60.(2), 3.2.2.66.(2), 3.2.2.76.(2) and 3.2.2.83.(2) for noncombustible construction.
- The requirements of Sentence (1) are waived provided
- the combustible material above the roof deck is protected by not less than 12.7 mm thick gypsum board, mechanically fastened to a supporting assembly if located beneath the roof deck, or by a thermal barrier conforming to one of Clauses 3.1.5.15.(2)(c) to (e) that is located
- on the underside of the combustible material, or
- beneath the roof deck,
- the building is sprinklered throughout, or
- the roof assembly has a fire-resistance rating not less than 45 min.
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