ASTM E1591-2007 Standard Guide for Obtaining Data for Deterministic Fire Models《确定性火灾模型的获取数据用标准指南》.pdf

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1、Designation: E 1591 07An American National StandardStandard Guide forObtaining Data for Deterministic Fire Models1This standard is issued under the fixed designation E 1591; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year

2、of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide describes data required as input for math-ematical fire models.1.2 Guidelines are presented on how the

3、data can beobtained.1.3 The emphasis in this guide is on compartment zone firemodels.1.4 The values stated in SI units are to be regarded as thestandard.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 th

4、is 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:2C 177 Test Method for Steady-State Heat Flux Meas

5、ure-ments and Thermal Transmission Properties by Means ofthe Guarded-Hot-Plate ApparatusC 518 Test Method for Steady-State Thermal TransmissionProperties by Means of the Heat Flow Meter ApparatusD 835 Specification for Refined Benzene-4853D 2395 Test Methods for Specific Gravity of Wood andWood-Base

6、d MaterialsD 3417 Test Method for Enthalpies of Fusion and Crystal-lization of Polymers by Differential Scanning Calorimetry(DSC)4D 5865 Test Method for Gross Calorific Value of Coal andCokeE 176 Terminology of Fire StandardsE 408 Test Methods for Total Normal Emittance of SurfacesUsing Inspection-M

7、eter TechniquesE 472 Practice for Reporting Thermoanalytical DataE 537 Test Method for The Thermal Stability Of ChemicalsBy Differential Scanning CalorimetryE 793 Test Method for Enthalpies of Fusion and Crystalli-zation by Differential Scanning CalorimetryE 906 Test Method for Heat and Visible Smok

8、e ReleaseRates for Materials and Products Using a ThermopileMethodE 967 Test Method for Temperature Calibration of Differ-ential Scanning Calorimeters and Differential ThermalAnalyzersE 968 Practice for Heat Flow Calibration of DifferentialScanning CalorimetersE 1321 Test Method for Determining Mate

9、rial Ignition andFlame Spread PropertiesE 1354 Test Method for Heat and Visible Smoke ReleaseRates for Materials and Products Using an Oxygen Con-sumption CalorimeterE 1623 Test Method for Determination of Fire and ThermalParameters of Materials, Products, and Systems Using anIntermediate Scale Calo

10、rimeter (ICAL)E 2058 Test Methods for Measurement of Synthetic Poly-mer Material Flammability Using a Fire PropagationApparatus (FPA)E 2257 Test Method for Room Fire Test of Wall and CeilingMaterials and Assemblies3. Terminology3.1 DefinitionsFor definitions of terms appearing in thisguide, refer to

11、 Terminology E 176.4. Significance and Use4.1 This guide is intended primarily for users and develop-ers of mathematical fire models. It is also useful for peopleconducting fire tests, making them aware of some importantapplications and uses for small-scale fire test results. The guidethus contribut

12、es to increased accuracy in fire model calcula-tions, which depend greatly on the quality of the input data.4.2 The emphasis of this guide is on zone models ofcompartment fires. However, other types of mathematical firemodels need many of the same input variables.1This guide is under the jurisdictio

13、n ofASTM Committee E05 on Fire Standardsand is the direct responsibility of Subcommittee E05.33 on Fire Safety Engineering.Current edition approved Jan. 1, 2007. Published February 2007. Originallyapproved in 1994. Last previous edition approved in 2000 as E 159100e1.2For referenced ASTM standards,

14、visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West

15、 Conshohocken, PA 19428-2959, United States.NOTE 1Mathematical fire models in this guide are referred to by theiracronyms (see 5.4).5. Summary of Guide5.1 This guide provides a compilation of material propertiesand other data that are needed as input for mathematical firemodels. For every input vari

16、able, the guide includes a detaileddescription and information on how it can be obtained.5.2 The following input variables are discussed: 6.1, air/fuelratio; 6.2, combustion efficiency; 6.3, convective heat transfercoefficient; 6.4, density; 6.5, emissivity; 6.6, entrainmentcoefficient; 6.7, flame e

17、xtinction coefficient; 6.8, flame spreadparameter; 6.9, heat of combustion; 6.10, heat of gasification;6.11, heat of pyrolysis; 6.12, rate of heat release; 6.13, ignitiontemperature; 6.14, mass loss rate; 6.15, production rate ofspecies; 6.16, pyrolysis temperature; 6.17, specific heat; 6.18,thermal

18、 conductivity; and 6.19, thermal inertia.5.3 Some guidance is also provided on where to find valuesfor the various input variables.5.4 Ageneral commentary on zone models for compartmentfires and a list of acronyms and data requirements for somemodels are included in Appendix X1.6. Data for Zone Fire

19、 Models6.1 Air/Fuel Ratio:6.1.1 Introduction:6.1.1.1 Flames can be characterized as being either pre-mixed or diffusion. Premixed flames can be defined as thoseflames that result from the ignition of intimately mixed fuelsand oxidizers. Diffusion flames can be defined as those flamesthat result from

20、 the ignition of the fuel within the region inwhich the originally separate fuel and oxidizer meet and mix.Diffusion flames are by far the more common type of flame tobe encountered in hostile fire situations. A burning upholsteredfurniture item is an example of diffusion flame burning.6.1.1.2 The s

21、ource of the oxidizer in most fires is the oxygencontained in normal air. If a flame receives insufficient oxygento burn all of the fuel vapors present completely, the flame isconsidered to be “oxygen limited” or “oxygen starved.” Sto-ichiometric burning refers to conditions in which the amount ofox

22、ygen available in the combustion region exactly equals theamount required for complete combustion.Afuel-limited flameis one for which the amount of oxygen available is greater thanthat required for complete combustion of the available fuelvapors. Fuel-limited flame is sometimes also referred to as“f

23、ree burn fire.”6.1.1.3 The air/fuel ratio, g, of a fuel is a measure of themass of air required per unit mass of fuel being burned. Theeffective air/fuel ratio required in some mathematical firemodels is greater than or equal to the stoichiometric air/fuelratio since it reflects the excessive air en

24、trainment associatedwith free burning fires.6.1.1.4 The air/fuel ratio is used in the fire models tocalculate mass burning rates and hence heat release rate. Theair/fuel ratio is unique to each fuel and is dimensionless thatis, mass/mass.6.1.2 Procedures to Obtain Air/Fuel Ratios:6.1.2.1 As mentione

25、d above, the stoichiometric air/fuel ratiois derived easily from the chemical balance equation describingthe complete combustion of the fuel in normal air. Forexample, consider the burning of propane (C3Hg) gas in air.Here, air is described simply as containing oxygen andnitrogen.airC3H81 5O21 3.76N

26、2!3 CO21 4H2O 1 18.8N2reactants products (1)The mass ratio of air to fuel is found to be 686.4/44 = 15.6.Thus, the stoichiometric air to fuel ratio, gs, for propane isfound to be 15.6.6.1.2.2 Some models use an “effective” air/fuel ratio; forexample, see Ref (1).5The main purpose of using an effecti

27、veratio different from the stoichiometric ratio is to prevent fullutilization of oxygen entrained from the lower layer. However,this ad hoc approach is not generally accepted and validated.Aphysically correct method of preventing full utilization of theentrained oxygen requires the inclusion of an o

28、xygen massbalance in the set of model conservation equations. Only thestoichiometric air/fuel ratio is needed in this case, while thecombustion submodel accounts for the effects of vitiation andoxygen starvation.6.1.3 Apparatus to Be UsedThere is no direct need for anapparatus to determine the stoic

29、hiometric air/fuel ratio. Theratio can be calculated from the stoichiometry of the combus-tion reactions, but this is often not possible since the elementalcomposition of the fuel is seldom known. The most commonway of determining the stoichiometric air/fuel ratio in actualfires or experiments is by

30、 calculating the ratio between theamount of energy released by combustion per mass unit of airfully depleted of its oxygen and the heat of combustion. Theformer is nearly identical for a wide range of materials andequal to 3 MJ/kg of air 6 5 %. Methods of determining thelatter are discussed in 6.9.6

31、.2 Combustion Effciency:6.2.1 IntroductionThe effective heat of combustion infires is smaller than the net heat of combustion because of theincomplete combustion of fuel vapors. The combustion effi-ciency, x, accounts for incomplete combustion.6.2.2 Procedures to Obtain Combustion EffciencyTheratio

32、between the effective heat of combustion and net heat ofcombustion is the combustion efficiency. Thus,x5Dhc,effDhnet(2)where:Dhc,eff= effective heat of combustion, kJ/kg, andDhc,net= net heat of combustion, kJ/kg.The combustion efficiency for most hydrocarbons rangesfrom 0.4 to 0.9.6.2.3 Apparatus t

33、o Be Used:6.2.3.1 Test Method D 5865 for Dhc,net(with adjustment forwater vapor; see 6.9); and6.2.3.2 Cone Calorimeter (Test Method E 1354), ICALApparatus (Test Method E 1623), or the Fire PropagationApparatus (Test Method E 2058) for Dhc,eff(see 6.9).5The boldface numbers in parentheses refer to th

34、e list of references at the end ofthis standard.E15910726.3 Convective Heat Transfer Coeffcient:6.3.1 Introduction:6.3.1.1 Convective heat transfer refers to the movement ofheat (energy) between a solid surface and a contacting fluid dueto a temperature difference between the two. The modeling ofcon

35、vective heat transfer requires the use of a convective heattransfer coefficient, commonly referred to as h, which can bedefined as follows:h q9DT(3)where:q9 = energy transferred per unit area, W/m2, andDT = temperature difference between the surface and mov-ing fluid, K.6.3.1.2 The convective heat t

36、ransfer coefficient commonlyhas SI units of W/m2K; it is a function of the fluid properties(thermal conductivity, density, and viscosity), nature of thefluid flow (velocity and turbulence), and geometry of the solidsurface.6.3.2 Procedures to Obtain the Convective Heat TransferCoeffcient:6.3.2.1 Gen

37、eral Method:(1) The selection of a proper heat transfer coefficient can bedifficult due to the extremely large number of variables thatmust be included in its derivation, even for the relatively smallnumber of practical situations encountered in mathematical firemodeling.(2) One wishing to obtain va

38、lues for heat transfer coeffi-cients generally searches compilations of previously derivedvalues for those that best apply to a problem or situation.Examples of these sources include heat transfer texts (forexample, see Ref (2). The situation can be further simplifiedwhen the fluid is air, which of

39、course is the situation generallyencountered in fire modeling. Most fire models assume thatsmoke behaves like and has physical characteristics similar tothose of air.(3) For example, the convective heat transfer coefficient forexchange between a turbulent air flow and a vertical plane canbe approxim

40、ated as follows:h 5 0.95DT!1/3(4)where:h =W/m2K, andDT = temperature difference between the vertical surfaceand the air, K.6.3.2.2 Default Values in Some Existing Fire Models:(1) Some models currently have fixed heat transfer coeffi-cients. Regardless of the conditions within the hot layer, thecoeff

41、icient is set at a constant value of approximately 10W/m2K.(2) Other models, such as CFC V (3) and FIRST (4) use aslightly more complex approach wherein the heat transfercoefficient is expressed as a function of the hot layer tempera-ture. A lower limit of 5 W/m2K and an upper limit of 50W/m2K were

42、selected in this approach. The expression forcalculating h in this method is as follows:h 5 minimum of 50 W/m2K and 5 1 0.45T12 Tw! (5)where:T1= layer temperature, K, andTw= wall temperature, K.(3) Finally, some models (5,6) use an even more complexapproach in which the heat transfer coefficient is

43、calculatedfrom the Nusselt Number (Nu), which is a function of theGrashof Number (Gr) and the Prandtl number (Pr) in thefamiliar form:Nu hlk5 C1GrPr!y(6)where:h = convective heat transfer coefficient, W/m2K,l = characteristic length of surface, m,k = thermal conductivity of the fluid, W/mK,C1= a con

44、stant, andy = a constant.(4) The equation implies that heat transfer is dominated bynatural convection. This is not always true and not everywherethe case in room fires. For example, plume and vent flowsgenerate significant velocities that drive heat transfer. Since thevelocity is generated external

45、 to the heat transfer process, theconvection heat transfer between walls or objects and theseflows is forced rather than natural. For forced convection, thefollowing equation for the Nusselt Number as a function of theReynolds Number (Re) and the Prandtl number shall be used:Nu hlk5 C2RexPry(7)where

46、:C2= a constant, andx = a constant.6.3.3 Apparatus to Be UsedUnless there is a need (andavailability) of a heat transfer coefficient for a specific situa-tion, sufficient accuracy should be provided by selecting avalue (or deriving one) judiciously from tabular data (andformulas). If experimental da

47、ta are desired, the apparatusrequired may vary depending on the problem being explored.6.4 Density:6.4.1 Introduction:6.4.1.1 The density of a material is the mass of material perunit volume. In fire models, density is usually expressed askg/m3.6.4.1.2 There are two reasons for density to change as

48、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 (7), many models use constant (room)temperature values.6.4.2 Procedures to Obtain Density:6.4.2.1 The

49、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 D 2395for wood and wood-base materials.6.4.2.2 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 (7,8).E15910736.4.3 Apparatus to Be Used:6.4.3.1 Mass Balance (or equivalent).6.4.3.2 C