Textiles used in the construction of structural firefighter turnout gear jackets and pants have been found to contain per- and polyfluoroalkyl substances (PFAS) as well as fluoropolymer membranes and treatments containing fluorinated polymers. Additionally, older and used turnout gear have been found to contain greater concentrations of PFAS compared with new gear, though the source of these elevated PFAS concentrations is still under investigation. To determine if the stressing turnout gear textiles encounter during typical use could contribute to the observation of higher PFAS concentrations, this Technical Note reports the concentrations of 51 PFAS in 20 firefighter turnout gear textiles following exposure to abrasion, elevated temperatures, laundering, or weathering by exposure to ultraviolet radiation and elevated humidity. Compared with corresponding concentrations in unstressed textiles, individual and summed PFAS concentrations were higher following exposure to abrasion, elevated temperature, and weathering, but were similar or slightly lower following laundering. For example, the median summed PFAS concentrations among durable water repellent treated outer shell textiles rose from 1,430 µg/kg when new to 3,500 µg/kg with abrasion, 4,420 µg/kg with exposure to elevated temperatures, and 3,540 µg/kg with weathering, while it fell to 963 µg/kg with laundering. These changes in summed PFAS concentrations with stressing largely reflected changes in the concentrations of PFAS that were present in the highest concentration in unstressed turnout gear textiles: 6:2 FTMAC and 6:2 FTOH. Consequently, while physical stressing may contribute to altered PFAS concentrations in stressed compared with unstressed turnout gear textiles, the mechanisms responsible for these changes cannot be authoritatively identified by the targeted analytical approach employed here. For example, the analytical approached used in this report cannot distinguish between PFAS production by the chemical transformation of PFAS that were excluded from the targeted analyte list from enhanced PFAS extraction due to degradation of firefighter gear textiles and their associated fluorinated polymer treatments.

This report provides an overview of quantitative measurement data and visual observations obtained from a series of 52 full-scale fire growth experiments conducted on 16 unique combustible solids including: natural and synthetic polymers, copolymers, fiberglass-reinforced composite materials, porous polymer foams, and electrical cables. Key measurement devices were incorporated into this test apparatus in order to measure the primary mechanism controlling fire growth (flame to surface heat transfer during upward flame spread over the surface of the combustible solids) and to measure global quantities characterizing fire behavior and development: heat release rate (HRR), soot and gaseous species (i.e., CO and CO2) yields. This information can be used to improve the analysis and determination of fuel loading in electrical enclosures, which in turn can be used to define peak fire size (HRR) for use in PRAs. Additionally, measurements obtained from these full-scale experiments provide a comprehensive source of reference data needed to validate numerical models that can predict ignitability, fire growth rate, and peak fire size of combustible solids (e.g., materials found in electrical enclosures).

Turnout gear is increasingly recognized as a potential source of per- and polyfluoroalkyl substance (PFAS) exposure to firefighters. To determine the type, concentration, and prevalence of PFAS potentially present in new firefighter turnout gear, fifty-three nonvolatile, semivolatile, and volatile PFAS were quantified in twenty textiles used in the construction of firefighter turnout gear. Between one and seventeen PFAS were observed and quantified in each textile, with higher numbers of detections and higher concentrations of PFAS present in moisture barrier and outer shell textiles compared with thermal liner textiles. Three fluorotelomerization-derived PFAS with six perfluorinated carbons, 6:2 fluorotelomer methacrylate, 6:2 fluorotelomer alcohol, and 6:2 fluorotelomer sulfonic acid, were quantified at the highest concentrations of any individual PFAS, up to 1,570 µg/kg ± 140 µg/kg (mean ± standard deviation of triplicate measurements), 613 µg/kg ± 15 µg/kg and 393 µg/kg ± 98 µg/kg, respectively. These three PFAS were not detected in outer shells that had not received fluoropolymer treatments which could indicate they were remnant raw materials from side-chain fluorinated polymer manufacturing. Also widely identified were two compounds with four perfluorinated carbons; perfluorobutane sulfonic acid and perfluorobutane sulfonamide. Perfluorocarboxylic acids, especially those with fewer than six perfluorinated carbons, were nearly universally identified, but entirely at concentrations below 40 µg/kg. In contrast, PFAS with eight or more perfluorinated carbons, such as perfluorooctanoic acid and perfluorooctane sulfonic acid, were present at summed concentrations below 2 µg/kg in all textiles. The wide variation in summed PFAS concentrations among each textile type suggests that the amount of PFAS present in new turnout gear could vary widely based on the specific textiles used in gear manufacturing.

The development of fire prevention and mitigation technologies with a benign toxicological and environmental profile has become of particular interest in the USA due to the recent adoption of state regulations that severely restrict the use of flame retardants in certain products, like residential upholstered furniture (RUF). Herein, the effectiveness of a backcoating technology in RUF is demonstrated. The backcoating is a silicone-based elastomer, filled with vinyl-silane modified aluminum-hydroxide that was applied to the back side of an upholstery fabric to generate a flexible and effective fire barrier. Chair mock-ups were assembled using either an uncoated cotton fabric (UCF) or a backcoated cotton fabric (BCF) as cover fabric. The fire performance of the chair mock-ups incorporating the UCF and BCF was compared in an open-burning calorimeter after exposure to either a flaming ignition source or a smoldering ignition source. In the flaming ignition tests, the chair mock-ups with BCF showed a reduction in the peak heat release rate and the total heat released by factors of about 6 and 45, respectively, as compared to the chair mock-ups with UCF. In the smoldering ignition tests, the chair mock-ups with UCF showed intense smoldering, which eventually transitioned to open flaming, whereas, the BCF chair mock-ups showed no sign of foam or fabric smoldering. The backcoating also offered a durable fire protection solution, with an abrasion resistance of BCF roughly doubled compared to UCF. Ultimately, the backcoating provided an unusual combination of smoldering and flaming ignition resistance while complying with several recently enacted or pending U.S. state regulations.

Ignitability of structural components due to ember accumulation is a common cause of structural fires in wildland urban interface (WUI) communities. To fire harden structures in WUI communities, it is important to quantitatively predict the ember ignitability of wooden substrates. To commence this effort, past studies have been compiled and analyzed to identify knowledge gaps. Key topics including ignition of structures in WUI fires, measurement of thermal response of solid wood products used in residential structures, controlling mechanisms in ignition and sustained smoldering of wood, measurement of ember properties, real-scale and bench-scale experiments on assessing ember ignitability of structural components, and surrogate ignition sources for assessing smoldering propensity of the wooden substrate have been reviewed. Existing test methods have also been reviewed in the light of common exposures seen WUI environment.

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.

Regulations for cigarette ignition resistance (CIR) of soft furnishings (beds and upholstered furniture) and less fire-prone cigarettes have contributed substantially to the decrease in losses from cigarette-initiated fires over time. Two standard reference cigarettes play key roles in mitigating these losses and in sustaining the effectiveness of the fire safety regulations as exogenous changes occur. SRM 1082 provides a uniform, durable supply of cigarettes for use in ASTM E2187 that assures manufacturers and regulators of compliance with regulations for reduced ignition propensity cigarettes; enables quality control of cigarette fire test performance; enables assurance of uniform interlaboratory test results; obviates effects on fire safety as tobacco crops and smokers change over time; and, when the original ASTM E2187 substrate material was no longer available, enabled adding a new, equivalent substrate. SRM 1196 provides a uniform, durable supply of cigarettes for assurance of consistent interlaboratory evaluation of the ignition resistance of soft furnishings using the mandated test methods; obviates possible unknown changes in soft furnishings' CIR due to the evolving ignition strength of the original test cigarette over time; and provided a test cigarette that was stronger than most cigarettes being smoked after manufacture of the original commercial test cigarette ceased.

Beds are a prevalent combustible in fatal fires in the United States effective 1 July 2007, the US Consumer Product Safety Commission promulgated a standard to severely reduce the heat release rate and the early heat output from mattresses and foundations when ignited by a flaming ignition source. This study estimates the Standard's success over its first decade using fire incidence, US population, and mattress sales data. The technique mitigates the influence of some exogenous factors that might have changed during this decade. The Standard is accomplishing its purpose, preventing approximately 65 fatalities (out of an estimated 95 fatalities in 2002-2005) from bed fires annually during 2015-2016, although not all pre-Standard mattresses had yet been replaced. Compared to residential upholstered furniture fires, which were not affected by the Standard, the numbers of bed fires decreased by 12%, injuries by 34%, and deaths by 82% between 2005-2006 and 2015-2016. Per bed fire, injuries decreased by 25% and fatalities decreased by 67%, indicating that the severity of bed fires is being reduced.

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Cone calorimetry experiments of on flexible polyurethane foam and flexible polyurethane foam covered with a variety of fire-blocking barrier fabrics were used to characterize and rank the effectiveness of barrier fabrics with the ultimate goal being an ability to predict the effectiveness of barrier fabrics for reducing the flammability of residential upholstered furniture. The primary measure used to characterize the burning behavior was heat release rate. The effect of the underlying sample substrate was shown to have a large effect on the burning behavior of flexible polyurethane foam samples, and a thermally insulating substrate was used during composite experiments. At times, rapid heat release rate fluctuations were observed, and in such cases approximate corrections were applied to correct for finite cone calorimeter time response. Measurements using thermocouples placed within the flexible polyurethane foam provided insights on flexible polyurethane foam pyrolysis behavior, the collapse rate of flexible polyurethane foam, and the thermal protective properties of barrier materials. Heat release rate temporal profiles for flexible polyurethane foam showed two distinct burning stages with peak values which have been attributed to sequential burning of species (primarily) derived from the diamine ( PHRR 1 ) and polyol components ( PHRR 2 ) used to manufacture the flexible polyurethane foam. When a barrier fabric was added, many of the composites displayed a three-stage burning behavior which was attributed to an initial short, intense burning (termed flash burning) stage associated with the barrier fabric covering followed by the two flexible polyurethane foam stages. Seven out of 16 flexible polyurethane foam/barrier fabric composites exhibited flame extinction prior to fuel burn out. Five out of the seven composites reignited when the spark ignition source was reapplied. Reignition allowed barrier fabric effectiveness to be assessed even for cases with flame extinction. Barrier fabric performance was shown to be consistent with four properties that were previously identified as important barrier fabric properties: barrier fabric flammability, gas permeability, thermal protection, and physical integrity. In addition, the current experiments indicate the presence and effectiveness of gas-phase active flame retardants in the barrier fabric can also play an important role. A limited number of tests were conducted to de-couple the effects of flame-retardant chemicals and physical effects of barrier fabrics on flexible polyurethane foam burning behavior. These tests showed that while flame-retardant chemicals can be effective in quenching and extinguishing the flames, the presence of effective barrier fabric shells is also very important in lowering the heat release rate of burning flexible polyurethane foam. In general, the presence of a barrier fabric was shown to reduce the heat release rate peak values during both flexible polyurethane foam burning stages. The magnitude of the peak associated with second-stage flexible polyurethane foam burning was deemed the most appropriate for characterizing the thermal protection provided by a barrier fabric. Since the times for PHRR 2 also varied between composites, a measurement referred to as the peak fire growth rate (PFIGRA) parameter was calculated by dividing the heat release rate by time since time to ignition and PFIGRA 2 was also considered for characterizing the barrier fabrics. Three possible classification schemes, each consisting of three classes, were introduced based on composite flame extinction and reignition behavior, PHRR 2 values, and PFIGRA 2 values. Each scheme provided differentiation between barrier fabric effectiveness. While the schemes were able to assess whether the barrier fabrics were particularly effective or ineffective, there were variations among classes of barrier fabrics having intermediate levels of effectiveness. Further work will be required to assess which, if any, of the classification schemes are most appropriate for predicting barrier fabric performance in residential upholstered furniture.

This study reports on the change in flammability of cotton fabrics caused by water-insoluble gel coatings applied from a single bath solution formulated with polymeric micelles and flame retardant amphiphiles.The flame resistant coatings are made from low concentration aqueous formulations of polyethylene oxide-polypropylene oxide-polyethylene oxide, and 5 % to 15 % mass fraction melamine and sodium hexametaphosphate.The coated cotton fabrics were tested and characterized by a variety of bench-scale tools, such as vertical flame testing, micro-scale combustion calorimetry, and thermogravimetric analysis.Properties such as increased ignition resistance, self-extinguishment, and higher decomposition temperatures were measured, relative to the uncoated cotton.

An overview of the facilitated process for the workshop is shown in Figure 1.1The workshop opened with presentations and panel discussions by experts in each field (Innovative Construction Materials, Advanced Polymers and Composites, Next Generation Fire Retardants, and Transportation and Infrastructure).As a single group, participants took part in a series of brainstorming and discussion sessions to develop a list of potentially significant applications and approaches, focused on fire-resistant materials.Then, as individual experts, each suggested a few applications and approaches they believed to have the highest priority (most critical and urgent applications and approaches in terms of overall impact on the fire problem).The workshop organizers compiled the expert's responses into a prioritized list of applications and approaches.Three breakout groups were formed, and each assigned to a) complete a discussion and review of the top four applications/approaches, and b) identify additional applications and approaches from a reduced list of the remaining ones.The intent was for all three breakout groups to only review these top four applications/approaches.Since the groups went through the assignment at different rates, we ended up with more than four applications/approaches reviewed.However, since the groups independently selected these topics, not all the applications/approaches were reviewed by all three breakout groups.

A durable and flexible silicone-based backcoating (halogen free) is applied to the backside of an otherwise smoldering-prone and flammable fabric. When exposed to fire, cyclic siloxanes (produced by thermal decomposition of the backcoating) diffuse through the fabric in the gas phase. The following oxidation of the cyclic siloxanes forms a highly conformal and thermally stable coating that fully embeds all individual fibers and shields them from heat and oxidation. As a result, the combustion of the fabric is prevented. This is a novel fire retardant mechanism that discloses a powerful approach towards textiles and multifunctional flexible materials with combined smoldering/flaming ignition resistance and fire-barrier properties.

The components of wood, especially lignin and cellulose, have great potential for improving the properties of polymer composites. In this chapter, we discuss some of the latest developments from our lab on incorporating wood-based materials into epoxy composites. Lignosulfonate was used as a flame retardant and cellulose nanocrystals were used as reinforcing materials. Lignosulfonate will disperse well in epoxy, but phase separates during curing. An epoxidation reaction was developed to immobilize the lignosulfonate during curing. The lignosulfonate–epoxy composites were characterized using microcombustion and cone calorimetry tests. Cellulose also has poor interfacial adhesion to hydrophobic polymer matrices. Cellulose fibers and nanocrystals aggregate when placed in epoxy resin, resulting in very poor dispersion. The cellulose nanocrystal surface was modified with phenyl containing materials to disrupt cellulose interchain hydrogen bonding and improve dispersion in the epoxy resin. The cellulose nanocrystal – epoxy composites were characterized for mechanical strength using tensile tests, water barrier properties using standardized water absorption, glass transition temperatures using differential calorimetry, and aggregation and dispersion using microscopic techniques. The observed peeling of the char layer during combustion in the cone calorimeter suggested the lignin migrated and separated from the epoxy matrix during curing. The migration was verified using microcombustion calorimetry. Microcombustion calorimetry is a small scale (3 mg to 10 mg samples) test, where a sample is heated in nitrogen, similar to thermogravimetric analysis, and the pyrolyzed gases are mixed with oxygen and combusted in a separate chamber. The amount of oxygen consumed can be correlated to heat released. The heat release capacity (HRC) and heat of combustion (H c ) measured by the MCC are correlated to several flammability parameters obtained from other measurements, including peak heat release rate (PHRR) and total heat released (THR) from cone calorimetry experiments. As , ethoxylated lignosulfonate has a lower flammability and higher char yield than alkali lignin, which is why it was chosen as the primary flame retardant in this study. Lignin and ethoxylated lignosulfonate have much lower flammabilities than epoxy. The use of these materials in epoxy significantly reduces the HRC by up to 45 % and the H c by up to 20 %. A 5 mg sample was taken from the top and the bottom of an 8 mm thick epoxy + 10 % REAX825E sample. The results show that the lignosulfonate migrates to the top surface of the epoxy during the curing process. The higher char yield and lower apparent heat capacity are likely due almost entirely to the lignin, rather than uncombusted epoxy. The low H c and char yield for AT verifies that it has potential as a gas-forming agent in intumescent formulations.

The main objective of the work reported here is to assess factors that could affect the outcome of a proposed open flame test for barrier fabrics (BF-open flame test). The BF-open flame test characterizes barrier effectiveness by monitoring the ignition of a flexible polyurethane foam (FPUF) layer placed in contact with the upper side of the barrier fabric, exposed to a burner flame from below. Particular attention is given to the factors that influence the ignitibility of the FPUF, including thermal resistance, permeability, and structural integrity of the barrier fabrics (BFs). A number of barrier fabrics, displaying a wide range of the properties, are tested with the BF-open flame test. Visual observations of the FPUF burning behavior and BF char patterns, in addition to heat flux measurements on the unexposed side of the barrier fabrics, are used to assess the protective performance of the BF specimen under the open flame test conditions. The temperature and heat transfer measurements on the unexposed side of the BF and subsequent ranking of BFs for their thermal protective performance suggest that the BF-open flame test does not differentiate barrier fabrics based on their heat transfer properties. A similar conclusion is reached with regard to BF permeability characterized at room temperature. However, the outcome of this BF-open flame test is found to be heavily influenced by the structural integrity of thermally degraded BF. The BF-open flame test, in its current form, only ignited FPUF when structural failure of the barrier was observed.

Certain engineered nanoparticles (ENP) reduce the flammability of components used in soft furnishings (mattresses and upholstered furniture). However, because of the ENP's small size and ability to interact with biological molecules, these fire retardant ENPs may pose a health and environmental risks, if they are released sometime during the life cycle of the soft furnishing. Quantifying the released amount of these ENPs under normal end-use circumstances provides a basis for assessing their potential health and environmental impact. In this article, we report on efforts to identify suitable methodologies for quantifying the release of carbon nanofibers, carbon nanotubes, and sodium montmorillonites from coatings applied to the surfaces of barrier fabric and polyurethane foam. The ENPs released in simulated chewing and mechanical stressing experiments were collected in aqueous solution and quantified using Ultraviolet-Visible and inductively coupled plasma-optical emission spectroscopy. The microstructures of the released ENPs were characterized using scanning electron microscopy. The reported methodology and results provide important milestones to estimate the impact and toxicity of the ENP release during the life cycle of the nanocomposites. To our knowledge, this is the first study of ENP release from the soft furnishing coating, something that can be important application area for fire safety.