Smoke Evolution Research Articles

ULTEM 2100, 2200, 2300 and 2400

Abstract ULTEM 2100, 2200, 2300 and 2400 resins have high heat resistance, inherent flame resistance with low smoke evolution, broad chemical resistance and outstanding processability. Glass reinforcment provides increased rigidity and dimensional stability while maintaining good processing features. The ULTEM 2000 series is available in both low viscosity and mold release grades in addition to the standard grades. This datasheet provides information on physical properties, hardness, tensile properties, and compressive and shear strength as well as fracture toughness. Filing Code: Cp-5. Producer or source: G. E. Plastics.

Toxic Gases and Smoke Evolution from Foam Plastic Building Materials Burning in Fire Environments

Foam plastic building materials were exposed to practical fire en vironments. Toxic gases evolution from various foam plastic boards burning under fire conditions involving plywood combustion was determined. A foam plastic board as a specimen lined on one of the inside walls of a "plywood box shape" was combusted in a semi-full-scale fire test room under different air sup ply rates. CO was the most important toxicant, followed by HCN and acrolein. The difference in maximum total toxicity according to the fire test was rather small, probably because the toxicity from plywood accounted for a large portion of the total toxicity. However, the maximum total toxicity indexes of combus tion gases involving rigid urethane and polyisocyanurate foams were higher than when phenolic and polystyrene foams were involved in fire tests, because a considerably great amount of HCN was produced from the above nitrogen- containing materials.

Smoke and CO Evolution from Cotton and Flame Retarded Cotton. Part 1: Behaviour of Single Layer Fabrics under LOI Conditions

The limiting oxygen indices of two different area densities of untreated and phosphorus-containing flame retardant cotton fabrics (Proban CC, Amgard TR, Amgard CD) have been determined at 20 and 100°C. Simultaneous smoke and CO evolutions from all the fabrics have been determined at respective LOI and (LOI + 0.010) oxygen concentration conditions at 20 and 100°C. At 20 ° C, flame retardants present greatly increased smoke generation whilst little if any change in CO generation (except for the bromine-containing Amgard CD) occurred. Whilst increase in temperature to 100°C reduced fabric LOI and increased apparent and specific smoke optical densities its effect on CO generation was not straightforward. Lightweight, bromine-free flame retarded fabrics showed increased CO formation whilst for the heavier fabrics, increased area density and/or presence of bromine stabilised or reduced CO evolution.

Quantification of Smoke Production during ICBO Type Room Corner Tests

A method was developed to quantify smoke evolution during an ICBO type room corner fire test using temperature and smoke density measurements taken at the room doorway. This method eliminates the need for an overhead canopy hood/ex haust duct system to collect and quantify the smoke emitted from the doorway. The method was established by examining various combinations of room-doorway mea surements as candidate smoke prediction techniques. These included the in-doorway vertical profile of measured temperature or velocity, coupled with averaged smoke density measured across the doorway width or height, or horizontally outward from the doorway top. The basis for assessing the utility of each candidate method was its ability to predict, from doorway measurements, the smoke production measured by a hood/exhaust duct system. The data used in this evaluation were from four ICBO type room corner fire tests conducted by Underwriters Laboratories, Inc. (ULI) for SPI under a previous contract. The recommended prediction technique estimates volumetric outflow of combus tion products from the doorway from the vertical temperature profile in the door way. The temperature profile is truncated to include only data above the inflow- outflow interface. The "best" estimate of smoke density (concentration) in the outflow was obtained from instrumentation oriented horizontally outward from the top of the doorway. The authors presented a paper, "Quantification of Smoke Production During ICBO Type Room Corner Tests—An SPI Report," to the 30th Annual Technical/ Marketing Conference in October 1986. Although the described research was near ing completion at the time of that presentation, significant factors, particularly on matters related to data truncation, became evident only shortly before the presenta tion, and long after submitting the paper for pre-print in the conference proceedings. The purpose of this presentation is to briefly summarize previously reported materi als, address new research findings, present conclusions, and make recommendations both for implementation of the analysis technique and for data collection in future ICBO type room fire testing.

Thermal properties of composites with bismaleimide‐vinyl poly(styrylpyridine) blends

AbstractFlammability, thermal properties, and selected mechanical properties of composites fabricated with epoxy and other thermally stable resin matrices are described. Properties measured included limiting‐oxygen index, smoke evolution, thermal degradation products, total‐heat release, heat‐release rates, mass loss, flame spread, ignition resistance, thermogravimetric analysis, and selected mechanical properties. This paper describes the properties of eight different graphite composite panels fabricated using four different resin matrices and two types of graphite reinforcement. The resin matrices included: XU71775/H795, a blend of vinyl poly(styrylpyridine) and bismaleimide; H795, a bismaleimide; Cycom 6162, a phenolic; and PSP 6022M, a poly(styrylpyridine). The graphite fiber used was AS‐4 in the form of either tape or fabric. The properties of these composites were compared with those of epoxy composites. It was determined that the blend of vinyl poly(styrylpyridine) and bismaleimide (XU71775/H795) with the graphite tape was the optimum design giving the lowest heat release rate.

An assessment of PVC smoke

AbstractThe conventional test method for evaluating the potential of a material to produce smoke in a real fire is the NBS Smoke Density Chamber. However there are major problems with this approach. These include foremost the fact that its results do not correlate with those of real fires. Furthermore, materials that melt and drip are able to achieve a favorable, but misleading, evaluation because a significant fraction of the sample escapes the burning process. Another problem is that the test takes no account of the role the rate or extent of material burning plays in controlling the smoke density in a real fire situation. The physical problems are solved by material smoke production evaluation techniques based on measurements from the Cone Calorimeter rate of heat release apparatus, which has been developed by the National Bureau of Standards. A smoke parameter has been developed, calculated from cone calorimeter measurements, which reflects the smoke hazard of a real fire. The smoke evolution characteristics for a series of rigid thermoplastic materials have been measured using the cone calorimeter and the smoke parameter concept. The results demonstrate that due to its tendency to resist ignition and to burn very slowly, PVC would produce very little smoke in a real fire situation. Of the 15 materials tested, the expected real fire smoke performance characteristics of PVC were superior to those of all other materials except one.

Bismaleimide-Vinylpolystyrylpyridine Graphite Composites

Flammability, thermal, and selected mechanical properties of composites fabricated with epoxy and other thermally stable resin matrices are described. Properties which were measured included limiting-oxygen index, smoke evolution, thermal degradation products, total-heat release, heat-release rates, mass loss, flame spread, ignition resistance, thermogravimetric analysis and selected mechanical properties. This paper describes the properties of eight different graphite composite panels fabricated using four different resin matrices and two types of graphite reinforcement. The resin matrices included: XU71775/H795, a blend of vinylpolystyrylpyridine and bismaleimide; H795, a bismaleimide; Cycom 6162, a phenolic; and PSP 6022M, a polystyrylpyridine. The graphite fiber used was AS-4 in the form of either tape or fabric. The properties of these composites were compared with epoxy composites. It was determined that the blend of vinylpolystyrylpyridine and bismaleimide (XU71775/H795) with the graphite tape was the optimum design giving the lowest heat release rate.

An iron–organic polymeric smoke suppressant for poly(vinyl chloride)

AbstractThe incorporation of a poly[ferrocene‐1, 2 (1, 3: 1, 1′)diylmethylene] fraction with M̄n=2100 as a smoke suppressant additive into both unplasticized and di(2‐ethylhexyl)phthalate‐plasticized, calcium carbonate‐filled poly(vinyl chloride) (PVC) compositions entails appreciable reductions in smoke evolution during combustion tests relative to unmodified formulations. Best results, with smoke density reductions in the range 25‐80%, are obtained at the 3% loading level, with higher additive concentrations causing no further improvements. The findings of this study may have implications on the design of other polymeric engineering materials exposed to potential fire hazards.

Thermal and Flammability Characterization of Graphite Composites

Flammability, thermal, and selected mechanical properties of composites fabricated with epoxy and other thermally stable resin matrices are described. Properties which were measured included limiting-oxygen index, smoke evolu tion, thermal degradation products, total-heat release, heat-release rates, mass loss, flame spread, ignition resistance, thermogravimetric analysis and selected mechanical properties. This paper describes the properties of eight dif ferent graphite composite panels fabricated using four different resin matrices and two types of graphite reinforcement. The resin matrices included: XU71775/H795, a blend of vinylpolystyrylpyridine and bismaleimide; H795, a bismaleimide; Cycom 6162, a phenolic; and PSP 6022M, a polystyrylpyridine. The graphite fiber used was AS-4 in the form of either tape or fabric. The prop erties of these composites were compared with epoxy composites. It was deter mined that the blend of vinylpolystyrylpyridine and bismaleimide (XU71775/ H795) with the graphite tape was the optimum design giving the lowest heat release rate.

Synthesis and characterization of nadimidized 1‐[(dialkoxyphosphinyl)methyl1]‐2,4‐ and ‐2,6‐ diaminobenzenes and their polymerization to fire‐resistant laminating resins

AbstractA series of nadimidized 1‐[(dialkoxyphosphinyl1)methyl]‐2,4‐ and ‐2,6‐diaminobenzenes was prepared and polymerized thermally to yield highly crosslinked fire‐resistant laminating resins. Bisnadimides were characterized by elemental analysis and Fourier‐transform‐infrared (FT–IR) and proton nuclear magnetic resonance (1H‐NMR) spectroscopy. Curing behavior of the polymer precursors was studied by differential scanning calorimetry (DSC). Char yield of polymers at 700°C was 64–69% and 30–60% in nitrogen and air atmospheres, respectively. The pyrolysis behavior of some bisnadimides was investigated by gas chromatography–mass spectroscopy (GC–MS). Cyclopentadiene was evolved by retrograde Diels–Alder reaction during processing, but most was captured by copolymerization. The fire‐resistance of some polymers was evaluated by determining their limiting oxygen index and smoke evolution.

Fire‐ and heat‐resistant adhesive resins based on maleimido and citraconimido substituted 1‐[(dialkoxyphosphinyl)methyl]‐2,4‐ and ‐2,6‐diaminobenzenes

AbstractA novel class of fire‐ and heat‐resistant bisimide resins was prepared by thermal polymerization of maleimido or citraconimido derivatives of 1‐[(dialkoxyphosphinyl)methyl]‐2,4‐ and ‐2,6‐diaminobenzenes (1). The neat bisimide resin prepared by curing 1‐[di(2‐chloroethoxyphosphinyl)methyl]‐2,4‐ and ‐2,6‐bismaleimidobenzene exhibited a limiting oxygen index 75% higher and smoke evolution about 30 times lower compared with the parent polymer obtained by curing m‐phenylenebismaleimide. The char yield of cured bisimide resins at 700°C was 58–70% in a nitrogen atmosphere and 35–60% in air. An increase in formula weight between the imide groups slightly reduced the char yield. The polymer precursors were synthesized by reacting the phosphorus‐containing diamines (1) (1 mol) with maleic anhydride/citraconic anhydride (2 mol) or by reacting the monomaleimido derivative of (1) with benzophenone tetracarboxylic dianhydride/methylenebis(4‐phenylisocyanate) in a 2:1 mole ratio. The monomers were characterized by elemental analysis, Fourier‐transform–infrared (FT‐IR), proton nuclear magnetic resonance (1H‐NMR) spectroscopy, and gas chromatography–mass spectroscopy (GC‐MS). Direct cleavage of the PC bond and inversion of the synthesis reaction may occur during their pyrolysis. The thermal polymerization of the monomers was investigated by differential scanning calorimetry (DSC). Biscitraconimides are thermally polymerized at a relatively lower temperature than the corresponding bismaleimides.

Phosphorus‐containing polyurethanes and copolyurethanes based on 1,2‐dihydroxy‐1,2‐bis(diethoxyphosphinyl)ethane

AbstractThe reactions of 1,2‐dihydroxy‐1,2‐bis(diethoxyphosphinyl)ethane (DBE) with various diisocyanates, such as tolylene diisocyanate, methylenebis(4‐phenylisocyanate), and hexamethylene‐1,6‐diisocyanate, were studied for the synthesis of phosphorus‐containing polyurethanes. In addition, DBE and ethyleneglycol or butanediol‐1,4 were copolymerized with the diisocyanates. The synthesized poyurethanes were characterized by Fourier transform‐infrared (FT‐IR), proton nuclear magnetic resonance spectroscopy (1H‐NMR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). Their thermal properties were compared with those of the corresponding common polyurethanes. The fire resistance of the copolyurethanes was evaluated by determining their limiting oxygen index and smoke evolution.

Combustibility, smoke evolution, and thermal stability of modified oksalon fibres

A connection has been found between the bromine content of a polymer and its thermal stability, combustibility, and smoke evolution of oksalon fibres. At a bromine content of 4–5% by wt., a sharp increase in heat stability and smoke evolution is observed, plus a decrease in combustibility, which is caused by the formation of network structures.

Crosslinking of unsaturated polyester resins by combinations of vinyl esters and methacrylates

AbstractThe replacement of styrene by other crosslinking monomers in unsaturated polyester resins has been investigated because of the possible toxicity of this monomer and the strong smoke evolution of burning polyester materials. A theoretical study has been carried out to provide criteria for the applicability of classes of monomers in polyester curing. From this study it appeared that vinyl esters, vinyl ethers, N‐vinyl lactams, and styrenes are suitable, whereas acrylic and methacrylic esters and allylic or olefinic compounds are not. Combinations of vinyl esters and (meth)acrylic esters of polyols should generate IPN‐like structures. Polyesters cured by this combination of monomers gave materials with increased stiffness and strength relative to those obtained with the separate monomers and on the same level as styrene‐cured polyesters.

Flammability and thermal properties of rigid polyurethane foams with additionally introduced cyclic structures

Flammability, smoke evolution, thermal, and thermomechanical properties of low-density rigid polyurethane foams obtained from different aromatic polyols were investigated. The foams were prepared according to a standard formulation ensuring the same foam phosphorus content. Cellular polyurethanes with the best fire resistance were obtained from polyols containing disubstituted naphthalene and biphenyl rings. A linear equation was proposed to describe the influence of various structural units of the polyurethane (the content of cyclic structures Cc, nitrogen content CN, and crosslinking equivalent Mc) upon its flammability, expressed in terms of its oxygen index (OI) Thermal stability of crosslinked polyurethanes was not found to influence significantly their thermomechanical properties, while crosslink density and the type and quantity of cyclic structures additionally introduced did have a pronounced effect upon these properties.

A new approach to testing materials in the NBS smoke chamber

AbstractThe standard NBS/Aminco smoke test chamber is critically examined from the point of view of repeatability and reproducibility of the apparatus itself. Individual components contributing to the overall determination are examined and suggested lines for improvement are made which should result in more consistent results. Problems associated with the presentation of results are discussed and a new approach which includes time‐weighted data is proposed. This attempts to consider the rate dependence of smoke production in one calculated figure rather than isolated observations such as maximum optical density. Utilizing the NBS/Aminco chamber, a novel procedure for determining the smoke evolution characteristics of materials has been developed which can be considered to simulate more closely the progress of thermal degradation that a material undergoes in a real fire.

The effect of test conditions on apparent smoke density from various materials

Four samples of thermoplastics and nine samples of wood were evaluated for smoke evolution in the Aminco-NBS smoke chamber under piloted (flaming) conditions, using two different types of pilot burners, and in the Arapahoe chamber.

The effect of formulation variables on smoke evolution of plasticized PVC during combustion

AbstractUsing an NBS smoke test chamber, smoke evolution of a variety of plasticized and filled PVC formulations is studied. The lowest smoke evolution was provided by the joint use of alkylaryl phosphates and magnesium carbonate. Partial replacement of triaryl phosphates by chlorinated paraffins reduces significantly smoke evolution in the flaming mode without effect from antimony oxide.

Experiments on the Diffusion of Smoke in Isotropic Turbulent Flow

Detailed properties of the downstream evolution of smoke released in an isotropic turbulent flowfield are reported. Effects of turbulence on the mass-transfer characteristics of the flow, which in turn affect such things as the spread of pollution and the rate of chemical reactions, are studied. Smoke is released a short distance downstream of a uniform grid placed perpendicular to a uniform stream of air in a wind tunnel. A laser Doppler velocimeter is used to make the desired velocity field measurements, and a laser light-scatttering technique provides the instantaneous11 mass fraction c of smoke at the same point in the flowfield. One-point statistical properties of the velocity and concentration fields are obtained. The one-point cross correlations cu and cv are also reported.

Flammability Aspects of Foams

Abstract The growth of both flexible and rigid foams in the last decade has been very spectacular due to a combination of factors such as light weight, excellent physical properties and relatively low costs. The wide acceptance of foams in many diversified industries has led to the necessity of developing foams of low combustibility, often combined with low smoke evolution in case of fire, particularly in industries such as building and construction, transportation, bedding, etc. This paper deals with commonly used methods to impart varying degrees of flame retardance to foams and discusses effects of elemental constituents, synergism, fillers as well as some more recent approaches in changing the chemical structure to yield foams with inherent low combustibility and low smoke. Methods for incorporating flame retardants are reviewed. Finally, some aspects of government and code regulations concerning plastic foams are briefly discussed.