ASTM E1678-2002 Standard Test Method for Measuring Smoke Toxicity for Use in Fire Hazard Analysis《火灾分析中测量烟气毒性的标准试验方法》.pdf

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1、Designation: E 1678 02An American National StandardStandard Test Method forMeasuring Smoke Toxicity for Use in Fire Hazard Analysis1This standard is issued under the fixed designation E 1678; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r

2、evision, the year 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.INTRODUCTIONThe pyrolysis or combustion of every combustible material or product produces smoke that is toxi

3、c.It is, therefore, desirable to establish a test method for the development of data characterizing smoketoxicity as an element of fire hazard analyses for both pre-flashover and post-flashover fires. The testmethod includes quantification of the toxicity of the smoke and ascertain whether the obser

4、ved toxicitycan be attributed to the major common toxicants.1. Scope1.1 This fire-test-response standard covers a means fordetermining the lethal toxic potency of smoke produced froma material or product ignited while exposed to a radiant heatflux of 50 kW/m2for 15 min.1.2 This test method is limite

5、d to test specimens no largerthan 76 by 127 mm (3 by 5 in.), with a thickness no greaterthan 51 mm (2 in.). Specimens are intended to be representa-tive of finished materials or products, including composite andcombination systems. This test method is not applicable toend-use materials or products t

6、hat do not have planar, or nearlyplanar, external surfaces.1.3 Lethal toxic potency values associated with 30-minexposures are predicted using calculations that use combustionatmosphere analytical data for carbon monoxide, carbon diox-ide, oxygen (vitiation) and, if present, hydrogen cyanide,hydroge

7、n chloride, and hydrogen bromide. The calculationmethod is therefore limited to those materials and productswhose smoke toxicity can be attributed to these toxicants.1.4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.5 This

8、standard measures and describes the response ofmaterials, products, or assemblies in response to heat undercontrolled conditions, but does not by itself incorporate allfactors required for fire hazard of fire risk assessment of thematerials, products, or assemblies under actual fire conditions.1.6 T

9、his 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 (particularly with regard to thec

10、are and use of experimental animals) prior to use. For specifichazards statements, see Section 7 and Note X1.1.2. Referenced Documents2.1 ASTM Standards:E 176 Terminology of Fire Standards2E 800 Guide for Measurement of Gases Present or Gener-ated During Fires22.2 ISO Document:TR 9122 (Parts 15) Tox

11、icity Testing of Fire Effluents33. Terminology3.1 DefinitionsFor definitions of general terms used inthis test method, refer to Terminology E 176.3.2 Definitions of Terms Specific to This Standard:3.2.1 carboxyhemoglobin saturation, nthe percent ofblood hemoglobin converted to carboxyhemoglobin from

12、 re-action with inhaled carbon monoxide.3.2.2 concentration-time curve, na plot of the concentra-tion of a gaseous toxicant as a function of time.3.2.3 Ct product, nthe concentration-time product inppmmin obtained by integration of the area under aconcentration-time curve.3.2.4 fractional exposure d

13、ose (FED), nthe ratio of the Ctproduct for a gaseous toxicant produced in a given test to thatCt product of the toxicant which has been determined statisti-cally from independent experimental data to produce lethalityin 50 % of test animals within a specified exposure andpostexposure time. Since the

14、 time values in this ratio numeri-cally cancel, the FED is also simply the ratio of the average1This test method is under the jurisdiction of ASTM Committee E05 on FireStandards and is the direct responsibility of Subcommittee E05.21 on Smoke andCombustion Products.Current edition approved Oct. 10,

15、2002. Published November 2002. Originallypublished as E 1678 95. Last previous edition E 1678 97.2Annual Book of ASTM Standards, Vol 04.07.3Available from American National Standards Institute, 25 W. 43rd St., 4thFloor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box

16、C700, West Conshohocken, PA 19428-2959, United States.concentration of a gaseous toxicant to its LC50value for thesame exposure time. When not used with reference to a specifictoxicant, the term FED represents the summation of FEDs forindividual toxicants in a combustion atmosphere.3.2.5 LC50, na me

17、asure of lethal toxic potency; theconcentration of gas or smoke calculated statistically fromconcentration-response data to produce lethality in 50 % of testanimals within a specified exposure and postexposure time.3.2.6 mass loss concentration, nthe mass loss of a testspecimen per unit exposure cha

18、mber volume in gm3.3.2.7 post-flashover, adjthe stage of a fire at which theaverage air temperature in the upper half of the room exceeds600C.4. Summary of Test Method4.1 This test method subjects a test specimen to ignitionwhile it is exposed for 15 min to a radiant heat flux of 50kW/m2. (See X1.2.

19、2.) The smoke produced is collected for 30min within a 200-L chamber communicating with the combus-tion assembly through a connecting chimney. Concentrationsof the major gaseous toxicants are monitored over the 30-minperiod, with Ct products for each being determined fromintegration of the areas und

20、er the respective concentration-timeplots. The Ct product data, along with the mass loss of the testspecimen during the test, are then used in calculations topredict the 30-min LC50of the test specimen. The predictedLC50is then confirmed in comparable tests by exposing sixrats, restrained for head-o

21、nly exposure, for 30 min to the smokeproduced from that mass of the test specimen whose mass lossconcentration during the 30-min period is approximately(610 %) equivalent to 70 % and to 130 % of its estimatedLC50. If no more than one rat dies during the 30-min exposure,or within 14-days postexposure

22、 to the mass loss concentrationcorresponding to 70 % of the LC50, and at least five rats dieduring the 30-min exposure, or within 14-days postexposure tothe mass loss concentration corresponding to 130 % of theLC50, the predicted LC50is considered to be confirmed.Confirmation ensures that the monito

23、red toxicants account forthe observed toxic effects.4.2 For calculation of hazard from pre-flashover, flamingfires, the toxicant gas yields and LC50values are to be used asexperimentally determined. For calculation of hazard frompost-flashover fires, the yields of carbon monoxide are aug-mented to r

24、eflect the higher yields produced in such fires. Theexperimental LC50values are then adjusted using a specifiedcalculation to produce LC50(post-flashover) values.5. Significance and Use5.1 This test method has been designed to provide data forthe mathematical modeling of fire hazard as a means for t

25、heevaluation of materials and products and to assist in theirresearch and development.5.2 This test method is used to predict, and subsequentlyconfirm, the lethal toxic potency of smoke produced upon theexposure of a material or product to specific fire test condi-tions. Confirmation determines whet

26、her certain major gaseoustoxicants account for the observed toxic effects and lethal toxicpotency. If a predicted lethal toxic potency value is notconfirmed adequately, indicating a potential for unusual orunexplained toxicity, the lethal toxic potency will need to beinvestigated using other methodo

27、logy, such as conducting anexperimental determination of the LC50using the apparatusdescribed. (See X1.3.1 and X1.3.2.)5.3 This test method produces lethal toxic potency valuesthat are appropriate for use in the modeling of both pre-flashover and post-flashover fires. Most fire deaths due tosmoke in

28、halation in the U.S. occur in areas other than the roomof fire origin and are caused by fires that have proceededbeyond the room of fire origin. It is assumed that these areflashover fires. Therefore, the principal emphasis is placed onevaluating toxic hazard under these conditions. In post-flashove

29、r fires, large concentrations of carbon monoxide resultsfrom reduced air supply to the fire plume and other room-scalefactors. Bench-scale tests do not have the capacity to simulatethese phenomena. The lethal toxic potency values determinedin this test method are obtained from fuel/air ratios morere

30、presentative of pre-flashover, rather than post-flashover con-ditions. In cases where a pre-flashover fire representation isdesired in fire hazard modeling, these LC50values are appro-priate. Lethal toxic potency and carbon monoxide yield valuesdetermined in this test method require adjustment for u

31、se inmodeling of the hazard from post-flashover conditions. (SeeX1.4.1.)5.4 The lethal toxic potency values determined in this testmethod have a level of uncertainty in their accuracy when usedto predict real-scale toxic potencies. (See X1.4.2.)5.4.1 The accuracy of the bench-scale data for pre-flas

32、hoverfires has not been established experimentally. The combustionconditions in the apparatus are quite similar to real pre-flashover fires, although the mass burning rate may be higher atthe 50 kW/m2irradiance of the test method.5.4.2 Comparison of the toxicant yields and LC50(post-flashover) value

33、s obtained using this method have been shownin limited tests (22) to reproduce the LC50values fromreal-scale, post-flashover fires to within an accuracy of ap-proximately a factor of three. Therefore, LC50(post-flashover)values differing by less than a factor of three are indistinguish-able from eac

34、h other. (See X1.4.2.)5.5 This test method does not attempt to address thetoxicological significance of changes in particulate and aerosolsize, smoke transport, distribution, or deposition or changes inthe concentration of any smoke constituent as a function oftime as may occur in a real fire.5.6 Th

35、e propensity for smoke from any material to have thesame effects on humans in fire situations can be inferred onlyto the extent that the rat is correlated with humans as abiological system. (See X1.2.5.)5.7 This test method does not assess incapacitation. Inca-pacitation must be inferred from lethal

36、 toxic potency values.5.8 The effects of sensory irritation are not addressed by thistest method.6. Apparatus6.1 Animal Exposure ChamberShown in Figs. 1 and 2, atransparent polycarbonate or polymethylmethacrylate chamberwith a nominal volume of 0.2 m3(200 L). (See X1.2.6.) Itsinside dimensions are 1

37、220 by 370 by 450 mm (48 by 1412 byE16780221734 in.). The six animal ports, intended for head-only expo-sure, are located in a horizontal row, approximately half wayfrom the bottom to the top of the chamber, in the front wall. Aplastic bag with an approximate volume of 0.05 m3(50 L orapproximately 1

38、3 gal) is attached to the port at the end of thechamber during a test to provide for gas expansion. Theexposure box is equipped with a gas sampling port at theanimal nose level in the geometric center of the exposurechamber and with a port for returning gases in the end wallclosest to the gas analyz

39、ers. A thermocouple shall be providedto monitor the temperature at the level of the animal ports.There are two doors in the exposure chamber, in the front wallnear the connection to the combustion cell and in the end wallnearest the animal ports. The purpose of the doors is to allowfor cleaning and

40、maintenance of the chamber, chimney, andsmoke shutter and to provide fresh air during calibration of theheat lamps and immediately prior to testing.6.2 Smoke Shutter, made of stainless steel plate and situatedinside the animal exposure chamber. It is positioned so that itwill close over the chimney

41、opening. It is hinged and providedwith a positive locking mechanism. The purpose of the shutteris to seal the combustion chamber and chimney from theexposure chamber at the end of irradiation. A wire attached tothe shutter and a simple push rod are provided for gentleclosing of the shutter. A wire a

42、ttached to a clamp locks theshutter in place. To produce a gas-tight seal, the underside ofthe shutter is covered with a 12-mm (0.5-in.) thick blanket oflow-density ceramic fiber insulation (approximately 65 kg/m3),which is further covered with stainless steel foil.6.3 Chimney (Fig. 3)A stainless st

43、eel assembly approxi-mately 30 by 300 mm (114 by 1134 in.), inside dimensions, and300 mm (1134 in.) wide. It connects the combustion cell to theanimal exposure chamber. The chimney is divided into threechannels by stainless steel dividers. The center channel isapproximately 150 mm (6 in.) wide. The

44、purpose of thedividers is to induce smoke to travel up through the centerportion of the chimney, while air from the animal exposurechamber is drawn down through the outside channels toprovide air to the combustion cell. The chimney is connected tothe underside of the animal exposure chamber by clamp

45、s,permitting its removal for cleaning. It is sealed to the animalchamber by low-density ceramic fiber insulation (approxi-mately 65 kg/m3). The other end of the chimney is sealed to thecombustion cell by an H-shaped trough with a small quantity ofthe same fiber insulation in the trough.6.4 Combustio

46、n CellShown in Figs. 4-6, a horizontalquartz tube with a 127-mm (5-in.) inside diameter and approxi-mately 320 mm (1212 in.) long. It is sealed at one end and hasa large standard taper outer joint at the other end. A sealed innerjoint serves as a removable plug for the open end (Fig. 6). Thecombusti

47、on cell has a rectangular opening on the top parallel tothe axis of the cylinder with a “collar” that allows it to fitsecurely into the chimney. The bottom of the cell has a hole forthe rod connecting the specimen support platform and loadcell. The sealed end of the combustion cell is fitted with a

48、glasscollar to accommodate the electric sparker.6.4.1 The combustion cell is supported by a metal frame thatalso holds the load cell (Figs. 4 and 5). This entire frame issupported by a laboratory jack that holds the combustion celltightly to the chimney during experimentation and allows thecell to b

49、e lowered for removal and cleaning. The load cell isalways at a fixed distance from the combustion cell.6.5 Radiant Heaters:6.5.1 The active element of the heater consists of four quartzinfrared lamps (with tungsten filaments), rated at 2000 W at240 V. The lamps (two on each side) are encased in water-cooled holders with parabolic reflectors. These holders (Fig. 4)are attached to adjustable metal frames, which allow the lampsto be moved vertically and laterally and rotated in such a wayas to provide a uniform flux field across the sample surface.Cooling water mus