# ASTM E1591-13

Designation: E1591 − 13 An American National StandardStandard Guide forObtaining Data for Fire Growth Models1This standard is issued under the fixed designation E1591; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (´) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide describes data required as input for math-ematical fire growth models.1.2 Guidelines are presented on how the data can beobtained.1.3 The emphasis in this guide is on ignition, pyrolysis andflame spread models for solid materials.1.4 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.6 This fire standard cannot be used to provide quantitativemeasures.2. Referenced Documents2.1 ASTM Standards:2C177 Test Method for Steady-State Heat Flux Measure-ments and Thermal Transmission Properties by Means ofthe Guarded-Hot-Plate ApparatusC518 Test Method for Steady-State Thermal TransmissionProperties by Means of the Heat Flow Meter ApparatusC835 Test Method for Total Hemispherical Emittance ofSurfaces up to 1400°CC1371 Test Method for Determination of Emittance ofMaterials Near Room Temperature Using Portable Emis-sometersD2395 Test Methods for Specific Gravity of Wood andWood-Based MaterialsD3417 Test Method for Enthalpies of Fusion and Crystalli-zation of Polymers by Differential Scanning Calorimetry(DSC) (Withdrawn 2004)3D5865 Test Method for Gross Calorific Value of Coal andCokeE176 Terminology of Fire StandardsE408 Test Methods for Total Normal Emittance of SurfacesUsing Inspection-Meter TechniquesE472 Practice for Reporting Thermoanalytical Data (With-drawn 1995)3E537 Test Method for The Thermal Stability of Chemicalsby Differential Scanning CalorimetryE793 Test Method for Enthalpies of Fusion and Crystalliza-tion by Differential Scanning CalorimetryE906 Test Method for Heat and Visible Smoke ReleaseRates for Materials and Products Using a ThermopileMethodE967 Test Method for Temperature Calibration of Differen-tial Scanning Calorimeters and Differential Thermal Ana-lyzersE968 Practice for Heat Flow Calibration of DifferentialScanning CalorimetersE1321 Test Method for Determining Material Ignition andFlame Spread PropertiesE1354 Test Method for Heat and Visible Smoke ReleaseRates for Materials and Products Using an Oxygen Con-sumption CalorimeterE1537 Test Method for Fire Testing of Upholstered Furni-tureE1623 Test Method for Determination of Fire and ThermalParameters of Materials, Products, and Systems Using anIntermediate Scale Calorimeter (ICAL)E2058 Test Methods for Measurement of Synthetic PolymerMaterial Flammability Using a Fire Propagation Appara-tus (FPA)E2257 Test Method for Room Fire Test of Wall and CeilingMaterials and Assemblies3. Terminology3.1 Definitions—For definitions of terms appearing in thisguide, refer to Terminology E176.1This guide is under the jurisdiction ofASTM Committee E05 on Fire Standardsand is the direct responsibility of Subcommittee E05.33 on Fire Safety Engineering.Current edition approved April 1, 2013. Published May 2013. Originallyapproved in 1994. Last previous edition approved in 2007 as E1591–07. DOI:10.1520/E1591-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at service@astm.org. For Annual Book of ASTMStandards volume information, refer to the standard’s Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Significance and Use4.1 This guide is intended primarily for users and develop-ers of mathematical fire growth models. It is also useful forpeople conducting fire tests, making them aware of someimportant applications and uses for small-scale fire test results.The guide thus contributes to increased accuracy in fire growthmodel calculations, which depend greatly on the quality of theinput data.4.2 The emphasis of this guide is on ignition, pyrolysis andflame spread models for solid materials.5. Summary of Guide5.1 This guide provides a compilation of material propertiesand other data that are needed as input for mathematical firegrowth models. For every input parameter, the guide includesa detailed description and information on how it can beobtained.5.2 The following input parameters are discussed: 6.1,combustion efficiency; 6.2, density; 6.3, emissivity; 6.4, flameextinction coefficient; 6.5, flame spread parameter; 6.6, heat ofcombustion; 6.7, heat of gasification; 6.8, heat of pyrolysis;6.9, heat release rate; 6.10, ignition temperature; 6.11, massloss rate; 6.12, production rate of species; 6.13, pyrolysistemperature; 6.14, specific heat; 6.15, thermal conductivity;and 6.16, thermal inertia.5.3 Some guidance is also provided on where to find valuesfor the various input parameters.6. Data for Fire Growth Models6.1 Combustion Effıciency:6.1.1 Introduction—The effective heat of combustion infires is smaller than the net heat of combustion because of theincomplete combustion of fuel vapors. The combustionefficiency, χ, accounts for incomplete combustion.6.1.2 Procedures to Obtain Combustion Effıciency—Theratio between the effective heat of combustion and net heat ofcombustion is the combustion efficiency. Thus,χ 5∆hc,eff∆hnet(1)where:∆hc,eff= effective heat of combustion, kJ/kg, and∆hc,net= net heat of combustion, kJ/kg.The combustion efficiency for most hydrocarbons rangesfrom 0.4 to 0.9.6.1.3 Apparatus to Be Used:6.1.3.1 Test Method D5865 for ∆hc,net(with adjustment forwater vapor; see 6.6); and6.1.3.2 Cone Calorimeter (Test Method E1354), ICAL Ap-paratus (Test Method E1623), or the Fire Propagation Appa-ratus (Test Method E2058) for ∆hc,eff(see 6.6).6.2 Density:6.2.1 Introduction:6.2.1.1 The density of a material is the mass of material perunit volume. In fire models, density is usually expressed askg/m3.6.2.1.2 There are two reasons for density to change as amaterial is heated: volatile (flammable or nonflammable, orboth) may be lost and dimensional changes (expansion orcontraction) may occur. Although corrections for temperaturedependence can be made (1), many models use constant (room)temperature values.6.2.2 Procedures to Obtain Density:6.2.2.1 The density of a material is determined by measur-ing the mass and physical dimensions (volume) of a sample ofthe material. There are detailed ASTM guidelines for certaintypes of building materials, for example, Test Methods D2395for wood and wood-base materials.6.2.2.2 When the temperature dependence of density issought, changes in mass with temperature can be determinedusing thermogravimetric analysis and changes in dimensionswith temperature using dilatometric analysis (1,2).46.2.3 Apparatus to Be Used:6.2.3.1 Mass Balance (or equivalent).6.2.3.2 Caliper, Ruler (or equivalent).6.2.3.3 Dilatometric Apparatus.6.2.3.4 Thermogravimetric Analyzer.6.3 Emissivity:6.3.1 Introduction—The emissivity of a material is the ratioof the power per unit area radiated from its surface to thatradiated from a black body at the same temperature. Amaterial’s emissivity represents its thermal radiative behaviorintegrated over all wavelengths. Emissivity is a dimensionlessquantity with an upper limit of unity for a black body.6.3.2 Procedures to Obtain Emissivity— Several standardtest methods have been developed to measure the emissivity ofmaterials. A specimen of the material is usually placed in anevacuated chamber and heated (often with an electric current)to the temperature of interest. The power dissipated by thematerial is determined and equated to the radiative heat transferto the surroundings. The emissivity of the material is computedusing this power and the Stefan-Boltzman equation.6.3.3 Apparatus to Be Used:6.3.3.1 Vacuum Emittance Test Apparatus (Test MethodC835).6.3.3.2 Portable Emissometer (Test Methods C1371).6.3.3.3 Inspection Meter (Test Methods E408).6.4 Flame Extinction Coeffıcient:6.4.1 Introduction—The flame extinction coefficient interre-lates average radiation parameters such as emissivity, flameintensity, and temperature over the entire spectrum of wave-lengths. It is used in the following equation to calculate theemissive power of a flame:E˙5 AσTfA~1 2 e2kl! (2)where:E = emissive power of the flame, W,A = enveloping area of the flame, m2,σ = Boltzman constant, 5.67·10−8W/m2·K4,Tf= flame temperature, K,4The boldface numbers in parentheses refer to a list of references at the end ofthis standard.E1591 − 132k = flame extinction coefficient, m−1, andl = path length, m.k is also called the absorption coefficient, absorption-emission coefficient, or effective emission coefficient.6.4.2 Procedures to Obtain Flame Extinction Coeffıcient—The coefficient k can be estimated from measurement of theemissivity ε and path length l, assuming emissivity can beexpressed as ε =1−e−kl.6.4.3 Apparatus to Be Used—There is no apparatus formeasuring the flame extinction coefficient. The extinctioncoefficient can be determined by measuring all flame param-eters in the equation for Ė except k. Fire models include manyof such empirical equations, but the documentation usuallydoes not specify what the parameters mean and how they are tobe determined. It must be stressed that the equation for Ė ishighly empirical. This makes it essential that the flame area,flame temperature, and extinction coefficient be determined ina self-consistent manner.6.5 Flame Spread Parameter:6.5.1 Introduction:6.5.1.1 The opposed-flow (against the direction of the sur-rounding flow or against gravity) flame spread rate over asurface can be predicted via the equation originally developedby deRis (3):Vp5φkρc~Tig2 Ts!2(3)where:Vp= flame travel rate, m/s,φ = flame spread parameter, W2/m3,k = thermal conductivity, W/m·K,ρ = density, kg/m3,c = heat capacity, J/kg·K,Tig= surface temperature at ignition, K, andTs= surface temperature just prior to arrival of the flamefront, K.6.5.1.2 The flame spread parameter, φ, for specific orienta-tions and in standard air environments is a characteristic for theheat transfer from the flame to the fuel ahead of the flame frontin the vicinity of the flame foot. It is a material propertyexpressed in W2/m3.6.5.2 Procedures to Obtain the Flame Spread Parameter—The flame spread parameter can be obtained from a correlationof opposed-flow flame spread data, that is, flame spread rateover a range of irradiance levels (or surface temperatures). Thetest method described in Test Method E1321 was developedspecifically to measure the flame spread parameter. It must bestressed that the equation for Vpis highly empirical. Thismakes it essential that Vp,kρ c, and Tigbe determined in aself-consistent manner. Further details on consistent methodsto determine Tigand kρc can be found in 6.10 and 6.16,respectively.6.5.3 Apparatus to Be Used:6.5.3.1 LIFT Apparatus (Test Method E1321).6.6 Heat of Combustion:6.6.1 Introduction—All combustion reactions generateenergy, which may be expressed as heat. The heat of combus-tion is defined as the amount of heat generated when a unitquantity of fuel is oxidized completely. SI units for heat ofcombustion, ∆hc, is kJ/kg.6.6.2 Procedures to Obtain Heat of Combustion:6.6.2.1 Heats of combustion are measured by combustionbomb calorimetry. A known mass of fuel is burned completelyin an adiabatic apparatus containing pure oxygen. This methodyields the gross heat of combustion. The net heat of combus-tion can be determined by subtracting the latent heat ofevaporation (2.26 kJ/kg of water) from the gross heat ofcombustion.6.6.2.2 An effective heat of combustion can be obtainedfrom other tests that use oxygen calorimetry. For example, thecone calorimeter (Test Method E1354) measures the mass lossrate and heat release rate. Incomplete combustion may occur inthis environment. The effective heat of combustion, ∆hc,eff,isthe ratio between heat release rate and mass loss rate.∆hc,eff5q˙m˙(4)where:q˙ = heat release rate, kW, andm˙ = mass loss rate of the sample, kg/s.6.6.3 Apparatus to Be Used:6.6.3.1 Oxygen Bomb Calorimetry (Test Method D5865).6.6.3.2 Cone Calorimeter (Test Method E1354).6.6.3.3 ICAL Apparatus (Test Method E1623).6.6.3.4 Furniture calorimeter. (Test Method E1537).6.7 Heat of Gasification:6.7.1 Introduction—The heat of gasification of a material isequal to the net amount of heat that must be supplied throughits exposed surface to convert a mass unit to gaseous volatiles.∆hg5q˙net“m˙ “(5)where:q˙“net= net heat flux into the material, kW/m2, andm˙ “ = mass loss rate of the material, kg/m2·s.∆hg= heat of gasification, kJ/kg.6.7.2 Procedures to Obtain Heat of Gasification:6.7.2.1 For a flaming sample, the net heat flux conductedinto the material is equal to the sum of radiation and convectionfrom the flame and the external heat flux (from the radiantheater in a small-scale test), minus the (radiant) heat lossesfrom the surface. The flame flux and heat losses depend on thesurface temperature, which is very difficult to measure. Thecone calorimeter (Test Method E1354) has been used, inconjunction with surface temperature measurements, to deter-mine ∆hgfor wood products and PMMA.6.7.2.2 For some materials, the surface temperature is rea-sonably constant and independent of exposure conditions. Aplot of (mean or peak) mass loss rates as a function of externalirradiance yields a fairly linear relationship for such materials.Values of ∆ hgcan then be estimated from the inverse of theslope of the regression line through the data points. Tewarsonand Petrella have used this technique to obtain ∆hgvalues fora wide range of plastics (4,5).E1591 − 1336.7.2.3 Unfortunately, surface temperatures are not constantfor many materials, in particular charring materials and mate-rials with a high smoke yield. The method by Tewarson andPetrella can still be used, but it yields results that have littlephysical meaning. Various investigators have used the versionof the equation for ∆hgand have obtained a time-dependentheat of gasification curve instead of a single value (6-8)6.7.3 Apparatus to Be Used:6.7.3.1 Cone Calorimeter (Test Method E1354).6.7.3.2 ICAL Apparatus (Test Method E1623).6.7.3.3 Fire Propagation Apparatus (Test Method E2058).6.8 Heat of Pyrolysis (Heat of Reaction):6.8.1 Introduction:6.8.1.1 Chemical reactions generally involve the generationor absorption of energy. The heat of pyrolysis is the energyemitted or lost during the pyrolysis or thermal degradati