ASTM E1678-2008 Standard Test Method for Measuring Smoke Toxicity for Use in Fire Hazard Analysis.pdf

《ASTM E1678-2008 Standard Test Method for Measuring Smoke Toxicity for Use in Fire Hazard Analysis.pdf》由会员分享，可在线阅读，更多相关《ASTM E1678-2008 Standard Test Method for Measuring Smoke Toxicity for Use in Fire Hazard Analysis.pdf（14页珍藏版）》请在麦多课文档分享上搜索。

1、Designation: E 1678 08An 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 () indicates an editorial change since the last revision or reapproval.INTRODUCTIONThe pyrolysis or combustion of every combustible material or product produces smoke that is toxic

3、.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 observ

4、ed 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 limited

5、 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 th

6、at 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,hydrogen

7、 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 s

8、tandard 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 Th

9、is 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 theca

10、re and use of experimental animals) prior to use. For specifichazards statements, see Section 7 and Note X1.1.2. Referenced Documents2.1 ASTM Standards:2E 176 Terminology of Fire StandardsE 800 Guide for Measurement of Gases Present or Gener-ated During Fires2.2 ISO Document:TR 9122 (Parts 15) Toxic

11、ity 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 r

12、e-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 dos

13、e (FED), nthe ratio of theintegrated area under the concentration-time curve for agaseous toxicant or the sum of all combustion productsproduced in a given test to that integrated C(t) area which hasbeen determined statistically from independent experimentaldata to produce lethality in 50 % of test

14、animals within aspecified exposure and postexposure time.1This 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 Aug. 15, 2008. Published September 2008. Origin

15、allyapproved in 1995. Last previous edition approved in 2007 as E 1678 07.2For referenced ASTM standards, 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

16、ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.4.1 DiscussionWhen C is nearly constant ov

17、er time,the time values in this ratio numerically cancel, and the FED issimply the ratio of the average concentration of a gaseoustoxicant to its LC50value for the same exposure time. Whenonly a single measurement of C is made during a test, theaccuracy of this simplification is not known. When not

18、usedwith reference to a specific toxicant, the term FED representsthe summation of FEDs for individual toxicants in a combus-tion atmosphere.3.2.5 LC50, na measure of lethal toxic potency; theconcentration of gas or smoke calculated statistically fromconcentration-response data to produce lethality

19、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 chamber volume in gm3.3.2.7 post-flashover, n and adjreferring to the state of afire after flashover.4. Summary of Test Method4.1 This test metho

20、d subjects a test specimen to ignitionwhile it is exposed for 15 min to a radiant heat flux of 50kW/m2. (See X1.2.2.) 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 toxicant

21、s are monitored over the 30-minperiod, with Ct products for each being determined fromintegration of the areas under 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 th

22、e test specimen. The predictedLC50is then confirmed in comparable tests by exposing sixrats, restrained for head-only 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

23、130 % of its estimatedLC50. If no more than one rat dies during the 30-min exposure,or within 14-days postexposure 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 corre

24、sponding to 130 % of theLC50, the predicted LC50is considered to be confirmed.Confirmation ensures that the monitored 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

25、 determined. For calculation of hazard frompost-flashover fires, the yields of carbon monoxide are aug-mented to reflect 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

26、.1 This test method has been designed to provide data forthe mathematical modeling of fire hazard as a means for theevaluation 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

27、produced upon theexposure of a material or product to specific fire test condi-tions. Confirmation determines whether certain major gaseoustoxicants account for the observed toxic effects and lethal toxicpotency. If a predicted lethal toxic potency value is notconfirmed adequately, indicating a pote

28、ntial for unusual orunexplained toxicity, the lethal toxic potency will need to beinvestigated using other methodology, 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 a

29、ppropriate for use in the modeling of both pre-flashover and post-flashover fires. Most fire deaths due tosmoke inhalation 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 fir

30、es. Therefore, the principal emphasis is placed onevaluating toxic hazard under these conditions. In post-flashover 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

31、 phenomena. The lethal toxic potency values determinedin this test method are obtained from fuel/air ratios morerepresentative 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-pr

32、iate. Lethal toxic potency and carbon monoxide yield valuesdetermined in this test method require adjustment for use 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 wh

33、en usedto predict real-scale toxic potencies. (See X1.4.2.)5.4.1 The accuracy of the bench-scale data for pre-flashoverfires 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

34、atthe 50 kW/m2irradiance of the test method.5.4.2 Comparison of the toxicant yields and LC50(post-flashover) values 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 thr

35、ee. Therefore, LC50(post-flashover)values differing by less than a factor of three are indistinguish-able from each 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 depositi

36、on or changes inthe concentration of any smoke constituent as a function oftime as may occur in a real fire.5.6 The 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 syst

37、em. (See X1.2.5.)5.7 This test method does not assess incapacitation. Inca-pacitation must be inferred from lethal toxic potency values.5.8 The effects of sensory irritation are not addressed by thistest method.E16780826. Apparatus6.1 Animal Exposure ChamberShown in Figs. 1 and 2,atransparent polyca

38、rbonate or polymethylmethacrylate chamberwith a nominal volume of 0.2 m3(200 L). (See X1.2.6.) Itsinside dimensions are 1220 by 370 by 450 mm (48 by 1412 by1734 in.). The six animal ports, intended for head-only expo-sure, are located in a horizontal row, approximately half wayfrom the bottom to the

39、 top of the chamber, in the front wall. Aplastic bag with an approximate volume of 0.05 m3(50 L orapproximately 13 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 geo

40、metric center of the exposurechamber and with a port for returning gases in the end wallclosest to the gas analyzers. 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 c

41、ombustion cell and in the end wallnearest the animal ports. The purpose of the doors is to allowfor cleaning and 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 st

42、eel plate and situatedinside the animal exposure chamber. It is positioned so that itwill close over the chimney 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 irradia

43、tion. A wire attached tothe shutter and a simple push rod are provided for gentleclosing of the shutter. A wire attached 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 insulati

44、on (approximately 65 kg/m3),which is further covered with stainless steel foil.6.3 Chimney (Fig. 3)A stainless steel 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 div

45、ided into threechannels by stainless steel dividers. The center channel isapproximately 150 mm (6 in.) wide. The 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 topro

46、vide air to the combustion cell. The chimney is connected tothe underside of the animal exposure chamber by clamps,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 theco

47、mbustion cell by an H-shaped trough with a small quantity ofthe same fiber insulation in the trough.6.4 Combustion 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 ou

48、ter joint at the other end.Asealed innerjoint serves as a removable plug for the open end (Fig. 6). Thecombustion 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

49、 connecting the specimen support platform and loadcell. The sealed end of the combustion cell is fitted with a 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 be 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