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BOCA can facilitate acceptance of jobsite installation substitutions and extension of fire tested/classified roof assembly options through sealed professional engineering evaluation reports.
Architects and builders use published assembly details by the roofing component manufacturer to design and install fire-classified roof assemblies to meet building code requirements. When designs or installations call for modifications to the published component specifications, a variance is created with the need for an engineered solution to maintain code compliance. BOCA provides solutions.
The fire classification of roof assemblies tested in accordance with ASTM E108 or CAN/ULC-S107 is fundamentally system-dependent. The test evaluates the performance of a complete assembly under exposure conditions including intermittent flame, spread of flame, and burning brand tests. The resulting classification (Class A, B, or C) is directly tied to the specific configuration of materials tested.
A test assembly for steep-slope roofs typically includes the roof covering, underlayment, and the deck substrate. Low-slope roofs have multiple layers which may include a membrane (e.g., TPO, PVC, or EPDM), insulation (polyiso, EPS, etc.), cover boards, and attachment method (mechanically fastened, adhered, or ballasted), or a built-up roof that has multiple plies of bitumen and reinforcing felts and surfacing layer (gravel or cap sheet).
Any modification to the tested components has the potential to influence fire performance by altering heat transfer, spread of flame, or ignition susceptibility within the system. Given the impracticality of testing all permutations of roof assemblies, engineering analysis is used to extend tested results to alternate configurations. Engineering judgments must remain bounded by tested conditions and established fire performance principles. Overextension beyond comparable materials or configurations can invalidate the classification and introduce compliance risks. Effective extension of ASTM E108 test results requires direct experience with fire testing, failure modes, and assembly behavior under exposure conditions. This enables a rigorous assessment of whether alternate components will maintain, improve, or degrade fire performance.
Engineering extensions of ASTM E108 classified assemblies require careful evaluation of flame spread pathways, thermal gradients through the assembly, combustibility and fuel contribution of individual layers, potential for concealed fire propagation within insulation or interstitial spaces, deck type influence on heat penetration, and resistance to burning brand penetration under modified configurations.
BOCA’s engineering extensions are developed with a detailed understanding of material behavior, system interactions, and fire performance allowing manufacturers to qualify alternate components, reduce redundant testing, and bring solutions to market more efficiently while maintaining code compliance.
To conduct an assessment, BOCA engineers compare the original tested assembly component specifications against the proposed substitutions, use an engineered substitution model based on fire testing of the substituted components, and prepare a solution assembly detail.
Contact BOCA Engineering to discuss how we can support your fire classified roof assembly extensions and broader compliance strategy.
