Polyurethane foam can be used in buildings as an interior wall or ceiling finish or trim but only after the product has been shown to meet relevant building code requirements and has been approved by the Authority Having Jurisdiction (AHJ) - typically the local building code inspector.
Generally, a code-prescribed thermal barrier (1/2-inch thickness gypsum wall board or equivalent) is required (2012 IBC, Sec. 2603.4) over installed polyurethane foam, but, at times, it may be more practical to install another type of barrier, or in certain circumstances, no barrier. In such a situation, the model building codes have provisions that allow, via large scale fire tests, the demonstration of acceptable performance of assemblies without the prescriptive thermal barrier, as described in 2012 IBC, Sec. 2603.10. This guidance document addresses some of the model building code flammability requirements when using polyurethane foam as an interior finish or trim. It does not address all of the model building code requirements.