Factors Influencing the Smoldering Performance of Polyurethane Foam

Abstract

The objective of this study was to evaluate whether polyurethane foam (PUF) could be produced as a Standard Reference Material for ultimate use in a standard test intended to ensure the smoldering performance of commercially available upholstered furniture. For this purpose, PUF was produced by a commercial manufacturer and its smoldering propensity was evaluated. The experimental design was organized into four parts or "Iterations". In Iteration 1, the results showed that smoldering intensity was dominated by foam morphology (cell size, strut thickness and length, open vs. closed cell structure, etc.), which overrode effects of chemical composition for the range of polyols and surfactants studied. In Iteration 2, the morphology of the foam was controlled by varying the processing parameters, that is, the tin catalyst content, water content and mixing head pressure. The results showed that smoldering increased with air permeability but that a better morphological descriptor of the foam structure was required to fully characterize smoldering in the high permeability range (i.e., in PUF with a dominantly open-cell structure). In Iteration 3, it was determined that for these PUFs, smoldering was controlled by cell size. The feasibility of a reference material with well-characterized and reproducible smoldering is linked to the ability to manufacture an open-cell PUF with a well-defined cell size and density. Preliminary data from Iteration 4 indicates that PUFs with consistent smoldering can be produced on a commercial scale manufacturing line.

Evaluating fire blocking performance of barrier fabrics

“…Correlation between total heat transferred and area density of the barrier fabrics (BFs). Uncertainties are reported as Type A uncertainties with experimental standard deviations.…”

“…A lower amount of heat was transferred (30 ± 8 MJ/m 2 ) through BF-18, compared to BF-15, which was 75 ± 7 MJ/m 2 . The higher heat transfer though BF-15 could be due to its higher porosity and hence higher Uncertainties are reported as Type A uncertainties [21,22] with experimental standard deviations. permeability of the woven structure.…”

Evaluating Smoldering Behavior of Fire-Blocking Barrier Fabrics

“…32 The FPUF foam used in this study was a well characterized flexible polyurethane foam 32 especially developed for evaluating upholstery materials and their tendency to support smoldering or limit flaming combustion. 33 The masses of the vertical (203 × 203 × 76) mm³ and horizontal (127 × 203 × 76) mm³ FPUF sections were recorded and used later to calculate the fraction that smoldered. The FPUF was covered with the BF, and, in turn, by the cover fabric (Indigo Buckaroo Denim purchased from Jo Ann Fabrics was used in this study), and the entire ensemble was placed in the wooden frame.…”

Investigation of surrogate smoldering ignition sources for testing soft furnishings

“…Both for obtaining reference data and for subsequent screening of alternate ignition sources, there needed to be a sufficient amount of uniformly ignition-susceptible material for a large number of tests. Variations in the properties of FPUF can affect its smoldering performance [35], so the specimens were cut from a block of foam whose ignition uniformity had been previously examined. It was also necessary that an SRM 1196 cigarette ignite the fabric/foam substrate some, but not all, of the time in a series of replicate tests.…”

“…Fortunately, recent research has identified properties of FPU foams that affect the extent of smoldering [35] and, probably, the foam's contribution to smoldering ignition. Thus, large, relatively uniform batches of FPUF can be ordered.…”