Smoke toxicity from combustion products based on polymers containing flame retardant additives (original) (raw)
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Toxic species and particulate emissions from synthetic polymer fires
2020
Overall fire statistics and residential and industrial fires in which there have been large number of fatalities demonstrate that the cause of most deaths can be attributed to effects of toxic smoke produced in these fires. Despite this fact there are no national or international legal requirements to determine the toxic emissions from materials used in construction, electrical cabling or the wide range of polymer based products used in house construction and industry. Many polymers used commercially are fire retarded and the materials used for this can add to the toxicity. The only indirect control comes through some test requirements for product classification based on the volume of smoke production. However, this is not an adequate approach to the problem. Fire smoke contents can cause death directly or can impair escape so that people die indirectly from the effects of toxic gases, and in the first we need to identify and quantify these emissions for different materials and unde...
Factors affecting the combustion toxicity of polymeric materials
Polymer Degradation and Stability, 2007
Fire gas toxicity is an essential component of any fire hazard analysis. However, fire toxicity, like flammability, is both scenario and material dependent. A number of different methods exist to assess the fire toxicity, but many of them fail to relate this to a particular fire scenario. Sample thickness alone, in a closed box test such as the NBS Smoke Chamber, is shown to change the fire scenario from well-ventilated to under-ventilated. Data from two flow-through tests, the static tube furnace (NF X 70-100) and the steady state tube furnace (the Purser furnace, BS 7990 and ISO TS 19700) show that there are different patterns of behaviour for different polymers (LDPE, polystyrene, rigid PVC and Nylon 6.6). The predicted toxicities show variation of up to two orders of magnitude with change in fire scenario. They also show change of at least one order of magnitude for different materials in the same fire scenario. Finally, they show that in many cases CO, which is often assumed to be the most, or even the only toxicologically significant fire gas, is of less importance than either HCl, or HCN, when present, and in some cases less important than organo-irritants. Nylon 6.6 shows the highest predicted toxicity, the greatest scenario dependence, and the least sensitivity to different apparatuses, while polystyrene shows the highest sensitivity to the different apparatuses, but the lowest to different fire scenarios. PVC shows high toxicity, mostly due to HCl in the fire effluent, under all fire conditions, and LDPE shows a more progressive increase in toxicity from wellventilated flaming to both smouldering and under-ventilated flaming.
Polymers in Fire Protection, 2023
In this entry, fire protection of polymeric materials has been discussed with respect to flameretardant polymers as well as additives employed. Flame retardants for polymer and their potential suitability for use in fire applications have been reviewed. Five principle types of flame retardants were discussed for inclusion in polymers, namely halogen, phosphorus, nitrogen, silicon, and organic flame retardants. In this regard, the choice of polymer matrix, additive, processing techniques and characterization method is important for the formulation of high-performance nonflammable system. The influence of polymers and modified flame retardant addition on flame retardation and smoke suppression features have been investigated using cone calorimetric methods, limiting oxygen index measurement, and thermogravimetric analysis. Consequently, it was observed that with increasing flame retardant content, significant enhancement in flame retardancy features may occur.
Smoke and hydrocarbon yields from fire retarded polymer nanocomposites
Polymer Degradation and Stability, 2011
Polypropylene (PP) and Polyamide 6 (PA6) samples, with and without fire retardants (FR) (ammonium polyphosphate in PP, and a mixture of organic aluminium phosphinate and melamine polyphosphate (OP 1311) in PA 6) and nanofillers (NC) were burned under different fire conditions in order to compare their toxic product yields. Fire effluents (CO, smoke and hydrocarbons) were generated using a steady state tube furnace (BS 7900, ISO TS 19700) for the separate materials and fire retarded and nanocomposite modifications of these materials under flaming conditions. Under well-ventilated conditions yields of carbon monoxide (CO) for all PP samples are similar, whereas for PA6 samples much higher yields of CO for PA6 þ FR and PA6 þ NC are observed. The highest yields of CO occur for both pure polymers in underventilated fire conditions when fire retardant and nanoclay are combined together. For PP the smoke is fairly independent of fire condition, but the PP þ FR þ NC shows less agglomeration. For PA6 the sample containing OP 1311 shows consistently higher smoke yields. For hydrocarbon yields similar effects are observed for both PP and PA6 polymers; the highest yields are for PA6 þ NC, except under-ventilated fires where PA6 þ FR produce the most; for PA6 þ FR þ NC samples the lowest yields are observed, compared to either NC or FR formulations.
Fire and Materials, 2014
This is part of a project considering whether flame retardants affect polymer heat release, a critical issue to assess whether adding flame retardants decreases fire hazard. The work investigated the following. (1) Fire properties affecting fire hazard, confirming that heat release rate is the key fire property most strongly influencing fire hazard. (2) Ways to assess heat release and whether full-scale fire heat release rate can be predicted from small-scale test results, confirming that cone calorimeter and Ohio State University data are adequate to predict full-scale heat release. (3) Analysis of key 1988 NBS/NIST study comparing the fire hazard of flame retarded products versus non-flame retarded products for the same application. This confirmed that the study demonstrated that flame retardants lower fire hazard and that the levels of additives in the flame retarded products used were not excessive. (4) Review of studies investigating effects of flame retardants on various polymeric systems. The overall conclusion is that flame retardants does indeed improve fire safety (when used appropriately) primarily because they decrease heat release. Part 2 of the project (separately) considers the key polymers that need to be potentially flame retarded and reviews recent studies on effects of flame retardants on heat released by such polymers.
Flame retardants and heat release: review of data on individual polymers
Fire and Materials, 2014
This work is the second of two parts that considered the following issue: do flame retardants affect heat release of polymers? The reason for investigating the issue is because it is important to assess whether the addition of flame retardants positively decreases fire hazard. This part of the work considered the two following issues. (1) Analysis of the individual polymeric materials that need to be studied. (2) Analysis of the data found on heat release (particularly peak heat release rate), ignitability (if available), and other thermal properties (as available) of polymers in small-scale test data in recent years. The effects are being presented in terms of the percentage of improvement. The work demonstrated that, almost without exception, when adequately compounded systems were developed, the peak heat release rate of the flame retarded system was lower than that of the non-flame retarded system. The overall conclusion of the two-part study was that flame retardants does indeed improve fire safety (when used appropriately) and that a key reason for the beneficial effect of flame retardants is that they decrease heat release.
Journal of Civil Engineering and Management, 2013
In order to investigate the impact of some inorganic additive flame retardants on the selected fire properties of the materials based on polyester resin Polimal 1033 APy, small-scale fire testing techniques have been used. Seven samples have been studied: unmodified PES, PES modified with MoO3 (7, 14 and 21 wt%) and PES modified with Sb2O3 (7, 14 and 21 wt%). The following flammable properties of materials have been determined: the heat of combustion (HOC), the ignition temperature of volatile thermal decomposition products (Tig), self-ignition temperature and oxygen index. A cone calorimeter method has been used for determining heat release rate (HRR), mass loss, specific extinction area (SEA) and other combustion parameters. The toxicological analysis of combustion products has been conducted. Based on the obtained results, the following conclusions have been made: (1) MoO3 and Sb2O3 added to the studied material change its flammable properties and fire parameters. It can be indic...
Fire and Materials, 2014
Thermal analysis is widely used for the investigation of the thermal decomposition of polymeric/lignocellulosic materials. Differential thermogravimetry (DTG) curves have been used for the assessment of fire retardants employing a mathematical technique, based on the observation that the DTG profile peaks become less pronounced and are shifted to lower temperatures when a fire retardant is added. The efficiency of a fire retardant is proposed to be assessed from a formula comprising of the following: (i) the depth of the main peak; (ii) the main decomposition peak temperature; (iii) the temperature range of the DTG curve; and (iv) the area above the curve. Initially, four well-known fire retardants have been assessed for their efficiency on a lignocellulosic matrix (Olea europaea). All the results deriving from the mathematical technique have been compared with the mass residue criterion and a limiting oxygen index test (Relative Limiting Oxygen Index). Both are commonly used as reliable tools for the assessment of a fire retardant. Secondly, the impact of fire retardant concentration on efficiency was investigated. In addition, using mathematical routines, an optimum concentration zone was proposed; further, an optimum concentration value (%) has been estimated.
Journal of Civil Engineering and Management, 2013
To investigate the influence of special additives – fire retardants – on the selected fire properties of materials based on polyester resin Polimal 1033 APy produced in the chemical plant ‘Organika-Sarzyna’ in Poland, a full scale of fire methods has been used. Three samples have been studied during combustion in a closed compartment: an unmodified sample, a sample containing 14% of MoO3 (molybdenum trioxide) and a sample containing 14% of antimony trioxide (Sb2O3). Several important parameters related to the combustion of tested polyester materials have been obtained as a result of the undertaken studies such as temperature and carbon monoxide (CO) concentration. This paper discusses the outcome of the conducted full-scale studies. Special emphasis is placed on analysis showing variation in time of these parameters during the combustion of three different polyester materials with and without fire retardant additives. One of the most important parameters taking into account evacuati...