Flammability, physical factors

Butylenes are not toxic. The effect of long-term exposure is not known, hence, they should be handled with care. Reference 96 Hsts air and water pollution factors and biological effects. They are volatile and asphyxiants. Care should be taken to avoid spills because they are extremely flammable. Physical handling requires adequate ventilation to prevent high concentrations of butylenes in the air. Explosive limits in air are 1.6 to 9.7% of butylenes. Their flash points range from —80 to —73° C. Their autoignition is around 324 to 465°C (Table 2). Water and carbon dioxide extinguishers can be used in case of fire. 

Fuels such as diesel and kerosene readily absorb hydrocarbon vapors, the total uptake and absorption rate depending on both chemical and physical factors. If a soluble test gas is introduced above a charged test oil the concentration of flammable test gas therefore decreases with time. Liquid mist and spray produced by charged liquid increase the absorption rate relative to a quiescent liquid surface. As discussed in A-5-4, absorption could lead to an underestimation of test gas MIE near the liquid surface unless the rate of test gas introduction is sufficiently high to offset the rate of removal. Table 3-8.1.2 shows solubilities of a selection of gases in a mineral-based transformer oil at ambient temperature and pressure [200]. 

Criteria and ciassification of flammability depending upon physical factors ... 

Hilado, C. J. The effect of chemical and physical factors on smoke evolution from polymers. J. Fire and Flammability, 1, 217 (1970)... 

Most of the basic commercial polymers are flammable [1]. Burning of plastics is a complicated phenomenon depending mainly on the chemical structure of polymers and on some physical factors [2]. The flammability of plastics is particularly severe when the basic polymers undergo depolymerization to form flammable monomers or active products. Such is the case for PS, PMMA, polyoxymethylene (POM), NR, etc. 

Flash point see Flammability Flattening factor for the earth, 14-1 Fluorescent Indicators, 8-18 to 19 Fluorine see also Elements critical constants, 6-39 to 58 electron configuration, 1-18 to 19 heat capacity, 4-135 history, occurrence, uses, 4-1 to 42 ionization energy, 10-203 to 205 isotopes and their properties, 11-56 to 253 physical properties, 4-133 to 134 thermodynamic properties, 5-1 to 3 thermodynamic properties at high temperature, 5-43 to 65 vapor pressure, 6-61 to 90,6-91 to 98 Fluorocarbon refrigerants, 6-133 to 135 Foods... 

An overview of some basic mathematical techniques for data correlation is to be found herein together with background on several types of physical property correlating techniques and a road map for the use of selected methods. Methods are presented for the correlation of observed experimental data to physical properties such as critical properties, normal boiling point, molar volume, vapor pressure, heats of vaporization and fusion, heat capacity, surface tension, viscosity, thermal conductivity, acentric factor, flammability limits, enthalpy of formation, Gibbs energy, entropy, activity coefficients, Henry s constant, octanol—water partition coefficients, diffusion coefficients, virial coefficients, chemical reactivity, and toxicological parameters. 

G. Quantity of flammable material the potential loss will be greater the greater the quantity of hazardous material in the process or in storage. The factor to apply depends on the physical state and hazardous nature of the process material, and the quantity of material. It varies from 0.1 to 3.0, and is determined from Figures 3, 4 and 5 in the Dow Guide. 

The authors proposed a mechanism that accounts for the reduction in flammability properties, which depends on physical processes in the condensed phase rather than chemical reactions. Three factors are critical in determining the silica behavior during the combustion process the density and surface area of the additive, the melt viscosity of the polymer. The interplay between these factors can determine whether the silica will accumulate near the surface or sink through the polymer melt. Fumed silica and silica gel provide examples for the first case where the silica particles accumulated on the surface and formed an insulating layer that provide protection to the underlying polymer. This is in contrast to the other case where the fused silica particles sank through the polymer melt. 

The leading mechanisms of flame retardance of polymers may be related to physical or chemical effects at any stage of the combustion. As a rule, the chemical influences (characterized by the rate constants of the respective reactions) are closely interrelated with the physical ones (characterized by heat- and mass-transfer parameters). Establishing the role of each factor and estimating its individual contribution to the overall effect is important for the development of ways of reducing the flammability of polymeric materials. 

The combustion is an extremely complex process including many chemical and physical phenomena of transformation of matter. The need and desire to know and control this process urges man to study its various aspects. Organic polymers are but one example of the multitude of materials used by man. They possess peculiar features and properties which individually affect the material behavior in a critical fire situation. It is, therefore, important to study the flammability characteristics of polymeric materials and the factors affecting them. 

The nature and composition of the volatile products, and the quantity of the char, determine the flammability of the cellulosic material and the rate of combustion or propagation of the fire, which is highly sensitive to the effect of the physical and environmental conditions prevailing, as well as to the chemical factors, such as the minor components and inorganic compounds present. 

Some of the important factors to consider in the development of alternative physical blowing agents are solubility, permeability, boiling point, vapor pressure, flammability, toxicity, VOC, ODP, GWP, availability, and cost. Similarly, the key important factors to be considered in the selection of CBAs for a given polymer are decomposition temperature, gas yield, rate of gas release, environmentally acceptable decomposition products, toxicity, and dispersability in the polymer matrix. 

Table 3.1 represents the maximum amount of various classes of materials representing physical hazards allowed in a controlled area, e.g.., laboratories, for a Hazard Class 2 facility. Note that few laboratories will be considered Hazard C lass 2 occupancies. Mo st wiU beconsideredBusinessoccupancies, and the limits on flammables in these facilities will be governed by OSHA regulations. The limits for laboratories will be discussed in detail in a later section dedicated to flammable solvents. Similarly, Table 3.2 does the same for materials which represent health risks for a Hazard Class 4. One factor must be borne in mind, no flammable materials may be stored orused in a space that is below grade, i.e., in major part below ground level. 

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