Reduced‐scale test to assess the effect of fire barriers on the flaming combustion of cored composites: An upholstery‐material case study

Abstract

Herein, we describe a reduced-scale test ("Cube" test), measuring the fire performance of specimens including a fire barrier (FB) and a flammable core material, which acts as the main fuel load. The specimen is intended to reproduce a cross-section of a composite product where heat/mass transfer occurs primarily in a direction perpendicular to the FB. The Cube test procedure and benefits are discussed in this work by adopting residential upholstery furniture as an exemplary study. One flexible polyurethane foam, one polypropylene cover fabric, and 10 commercially available FBs were selected. They were used to compare the fire performance of FBs, measured in terms of peak of heat release rate, in the ASTM E1474-14 standard test and the newly developed Cube test. Edge effects severely affected the performance of FBs in the ASTM E1474-14 standard test but not in the Cube test. Furthermore, appropriate test conditions were determined in the Cube test to measure the so-called "wetting point," that is, the time and value of heat release rate measured when flammable liquid products were first observed on the bottom of the specimen. The relevance of the "wetting point" in terms of full-scale fire performance and failure mechanism of FBs is discussed.

Revisiting flexible polyurethane foam flammability in furniture and bedding in the United States

“…This will involve partnerships with industry, academia, and government to be successful, along with sustained funding at meaningful levels. Heat release rate testing is recommended by the author of this article, and the “NIST cube test” designed to be compatible with the cone calorimeter would be a good starting point to consider 34 Fire Safe Recyclable Flexible Polyurethane Foam: As mentioned toward the beginning of this section, there is a need to understand the long‐term durability of flame retardant flexible polyurethane foam, and related to this need is also the need to understand the end‐of‐life for that foam.…”

“…A visual example of this is shown in Figure 2, 33 but other examples exist. Indeed, recent studies at NIST have focused on apparatus that can capture how the flexible polyurethane foam liquefies and pools under furniture items, which in turn percolates and/or breaks through fabrics and results in rapid flare‐ups of burning liquid polyurethane decomposition products 34 . This technique further measures heat release via use of a cone calorimeter (ASTM E1354/ISO 5660) to understand how the molten polyurethane decomposition products contribute to heat release/fire growth in fire events involving furniture and mattresses.…”

Fire performance of upholstery materials :

“…Based on their mechanisms of action, barriers can be classified as "passive" barriers and "active" barriers. Passive barriers operate by physical mechanisms of action including heat/mass transfer reduction, endothermic decomposition and dilution effects associated to the release of non-flammable gases (e.g., water vapor) during the decomposition of the barrier [27,28]. Active barriers operate by both physical and chemical mechanisms.…”

“…However, the ability of the CBUF-based tests to predict the performance of a barrier in full-scale products is affected by edge effects (associated to leak of pyrolyzates, flame spread and heat transfer), and lack of information about the mass transfer of LPs through the barrier. This is a major limitation because mass transfer controls bottom ignition and pool fire formation [27].…”

Solving the soft furnishings fire problem (without incurring collateral damage)

“…Cushions on a solid support, rather than a web, reduced the PHRR by hindering the formation of pool fires under the chair. Two relatively simple models showed promise at predicting the PHRR and the total heat released.The fuel in the pool fire is the liquid from the decomposed cushion materials dripping through the bottom of the seat cushion.Zammarano and co-workers developed a test for the ability of a GANN barrier layer at the underside of a seat cushion to contain this liquid and keep it from becoming ignited 14. The test uses the cone calorimeter with a special holder that eliminates edge effects during the burning of a fabric/barrier/FPUF composite while simplifying the composite preparation relative to the CBUF procedure.…”