Fire performance evaluation of cladding wall assemblies using the 16‐ft high parallel panel test method of ANSI/FM 4880

Abstract

SummaryCladding assemblies are façade systems made of cladding panels such as aluminum composite materials (ACMs) and high‐pressure laminates (HPLs), and layers of continuous insulation (CI) and weather resistive barrier (WRB). Recent incidents of catastrophic fires involving cladding assemblies have warranted efforts to understand their fire hazards and develop engineering risk mitigation guidelines for existing constructions. This research provides a comprehensive fire performance evaluation of cladding assemblies exposed to realistic fire scenarios. Twelve cladding assemblies, with a combination of four types of claddings, four types of CIs, and two WRBs are selected. The tests are conducted using the 16‐ft (4.9 m) high parallel panel test (16‐ft PPT) method of ANSI/FM 4880 standard; the method imparts realistic >100 kW/m2 heat flux to the wall assemblies. The results show that the chemical heat release rate (HRR) based evaluation criterion used in the 16‐ft PPT provides an objective and robust assessment of fire performance. The wall assemblies comprising of thermoplastic‐core ACMs demonstrated accelerated flame spread within a matter of a few minutes, regardless of the combustibility of the CI used. At low heat flux exposures, unlike severe fire scenarios of the 16‐ft PPT, it is shown that the thermoplastic‐core ACMs appear to perform favorably. The fire‐retardant ACM and HPL assemblies reveal limited flame spread, regardless of whether the CI used in the assembly was charring combustible or noncombustible. Lastly, for the assemblies evaluated, the flammability of claddings exhibits greater influence on the overall performance of the wall system, while the CI and WRB affect the system performance in a secondary manner.