Konrad Wilkens Flecknoe-Brown, DBI (Danish Institute of Fire & Security Technology), presented fire tests of polyurethane slabs (1.2m x 0.6m x 50mm), showing that flame spread, time to peak heat release, and peak heat release rate are all very variable and dependent on the point of ignition (edge and corner effects). Flame spread rate varied from 3 to 7 mm/second and peak heat release rate varied from 100 to 250 kW.
Karolina Storesund, RISE Fire Research, Norway, summarised an ongoing project looking at fire safe and sustainable loose furnishings (CircleSafe, funded by Brandforsk, Sweden) Objectives are to ensure repairability and durability (circular economy) and to optimise the life cycle assessment. Wool and cotton show much higher overall energy input in production. Flame retardant selection should target non-toxic chemicals, compatible with recycling. The project report is expected Autumn 2019. She also presented results of life cycle analysis studies and model scale fire testing of different materials for upholstered furniture. She suggests that polyurethane shows relatively (our main comparison was latex) poor LCA results (on sustainability, mainly energy consumption in production and environmental impact (global warming, terrestrial ecotoxicity, mineral resource scarcity). In fire tests, barriers combining inherently flame-resistant fibres (e.g. Lenzing) and fibres such as cotton, wool or polyester provide some fire protection, but can increase smoke generation. A 3D-web of thermoplastic fibre material for filling was shown to have better fire performance that polyurethane foam for some material combinations. Cost aspects are not addressed, and tests did not assess conformity to specifications such as TB117.
Dow reactive polymer polyol solution for flexible PU foams
Paul Cookson, Global Innovation leader for Consumer Comfort at Dow, presented the Company’s non halogenated polymer polyol which reacts into the polyurethane during polymerisation reducing overall emissions. This polyol acts by preferentially degrading in fire (at ~200 C), absorbing heat energy and releasing CO2 to inhibit burning. It can be effectively combined with PIN flame retardants such as melamine, which inhibits burning by decomposing in heat to absorb energy, releasing nitrogen and forming char. The polyol is compatible with a wide latitude of foam processing conditions, using foamers’ existing equipment to produce conventional and high resilience combustion modified foams across the density and hardness range. Polyol – melamine (PIN FR) foam can achieve Crib 5 fire performance with compatibility with Oekotex emissions and chemical requirements.
“Combining fire safety and low emissions in bedding and furniture: an industry challenge or opportunity”, P. Cookson, poster at Interflam 2019
Dow (Dow Inc. and its subsidiaries) is a sustainable materials science company with a broad technology set. Dow’s portfolio includes performance materials, industrial intermediates and plastics for segments such as packaging, infrastructure and consumer care. Dow operates 113 manufacturing sites in 31 countries, employs approximately 37,000 people and delivered sales of approximately $50 billion in 2018. www.dow.com or @DowNewsroom on Twitter.
Mark Gratkowski, US Department of Justice, presented 108 full scale tests (27 configurations) of bedding, carried out to try to understand how fire had developed in a real motel fire. The bedding consisted of cotton/polyester sheet and quilted bedspread, and was placed on a non-flammable ceramic fibres mat on a frame (not a mattress). Bedding was cut to half or a quarter of real full bedding set, and the tests were terminated when flame transitioned to the top of the surrogate mattress. In nearly all the tests, the bedding was ignited from a fire source consisting of a burning ‘book’ of paper matches placed on or next to the bedding, and in three quarters of the tests ignition occurred within ten seconds. Heat release in the first two minutes reached up to 150 kW.
Andrew Lock, US Consumer Product Safety Commission (CPSC), summarised developments in the US on furniture fire safety. The US federal legislation (Flammable Fabrics Act) gives the CPSC authority to regulate fire safety hazards for domestic furniture, taking into account addressability, technically practicality, and cost effectiveness. Domestic furniture is the main cause of home fire deaths in the USA, and is a critical contributor to flashover. Most deaths are related to smouldering ignition, and this is decreasing. Small flame ignition is related to many fewer deaths, but is not significantly decreasing. Full scale tests of chairs, using non FR foam with different types of barrier, show that peak heat release can be reduced and delayed, but barriers can generate smouldering which can develop into flames. The CPSC recently granted a petition and began rulemaking to ban additive organohalogen flame retardants, and NAS (National Academy of Sciences) has recently concluded that these can be dealt with by subclasses (see pinfa Newsletter n°103). A proposed US federal bill (“SOFFA” = S.3551)l currently under discussion (since 2018) would if adopted require all sold in the US (but not mattresses or bedding) to respect the current California furniture fire safety standard (smouldering cigarette resistance, TB117 (2013).