Let’s get right to it: Usually, no. Simply specifying a “fire-resistant paint” is not enough to protect exposed spray polyurethane foam (SPF) or satisfy code requirements.
The term fire-resistant paint has no consistent code definition. It is often used as a marketing term for products that may improve flame spread on certain substrates, but that does not mean they have been tested as ignition barriers or thermal barriers over SPF. For contractors, that’s an important distinction. If a coating hasn’t been evaluated for use over spray foam, it shouldn’t be assumed to provide the required level of fire protection. Before ordering materials, verify that the coating has been tested for the specific foam product and assembly being installed.
Not All Fire Protection Coatings Are Created Equal
Spray polyurethane foam cannot be left exposed in most occupiable spaces because it must be separated from the interior by a code-compliant thermal barrier or, where permitted, an approved ignition barrier.
Many coatings marketed as fire-resistant paints are designed for wood, steel or other construction materials. While they may slow flame spread on those substrates, they have not necessarily undergone the testing required for application over SPF.
An approved intumescent coating expands when exposed to heat, creating an insulating char that delays heat transfer to the foam beneath. More importantly, products intended for spray foam applications are tested as complete assemblies using recognized fire test methods. That testing evaluates how the coating performs with specific foam products, application thicknesses and installation conditions.
Without that documentation, there is no assurance that the coating will satisfy the applicable code requirements or the expectations of the authority having jurisdiction (AHJ).
Documentation Matters During Inspection
Contractors should avoid specifying coatings based solely on product descriptions or sales literature. Instead, request the evaluation reports, tested assemblies and installation requirements before work begins.
Equally important is following the published application requirements. Wet film thickness, dry film thickness and coverage rates all form part of the tested assembly. Deviating from those requirements may invalidate the installation, even when the correct product has been selected.
If your specification simply calls for “fire-resistant paint,” it’s worth revisiting the project documents before work begins. Contractors should specify an approved intumescent coating that has been tested for use over SPF, rather than relying on generic fire-resistant products that may not meet the required performance criteria.
IFTI helps contractors select compliant DC315 systems and provides the technical documentation needed to support successful inspections.