1、Designation: D2843 10Standard Test Method forDensity of Smoke from the Burning or Decomposition ofPlastics1This standard is issued under the fixed designation D2843; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This fire-test-response test method cover
3、s a laboratoryprocedure for measuring and observing the relative amounts ofsmoke obscuration produced by the burning or decompositionof plastics. It is intended to be used for measuring thesmoke-producing characteristics of plastics under controlledconditions of combustion or decomposition. Correlat
4、ion withother fire conditions is not implied. The measurements aremade in terms of the loss of light transmission through acollected volume of smoke produced under controlled, stan-dardized conditions. The apparatus is constructed so that theflame and smoke is observable during the test.21.2 During
5、the course of combustion, gases or vapors, orboth, are evolved that are potentially hazardous to personnel.Adequate precautions shall be taken to protect the operator.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationpurposes only
6、.1.4 This standard is used to measure and describe theresponse of materials, products, or assemblies to heat andflame under controlled conditions , but does not by itselfincorporate all factors required for fire hazard or fire riskassessment of the materials, products, or assemblies underactual fire
7、 conditions.1.5 Fire testing is inherently hazardous. Adequate safe-guards for personnel and property shall be employed inconducting these tests. Specific safety warning statements aregiven in 1.2 and 9.11.1.6 This standard does not purport to address all of thesafety problems, if any, associated wi
8、th 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.NOTE 1There is no known ISO equivalent to this standard.2. Referenced Documents2.1 ASTM Standards:3D618 Pract
9、ice for Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD1600 Terminology for Abbreviated Terms Relating toPlasticsE84 Test Method for Surface Burning Characteristics ofBuilding MaterialsE176 Terminology of Fire StandardsE662 Test Method for Specific Optical Density of SmokeGen
10、erated by Solid MaterialsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE906 Test Method for Heat and Visible Smoke ReleaseRates for Materials and Products Using a ThermopileMethodE1354 Test Method for Heat and Visible Smoke ReleaseRates for Materials
11、 and Products Using an Oxygen Con-sumption Calorimeter3. Terminology3.1 DefinitionsThe terminology used in this test method isin accordance with Terminologies D883 and D1600 (termsrelating to plastics) and Terminology E176 (terms relating tofire).4. Summary of Test Method4.1 The test specimen is exp
12、osed to flame for the duration ofthe test, and the smoke is substantially trapped in the chamberin which combustion occurs. A 25 by 25 by 6-mm (1 by 1 by14-in.) specimen is placed on supporting metal screen andburned in a laboratory test chamber (Fig. 1) under active flameconditions using a propane
13、burner operating at a pressure of276 kPa (40 psi). The 300 by 300 by 790-mm (12 by 12 by31-in.) test chamber is instrumented with a light source,1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.30 on Thermal Properties(
14、Section D20.30.03).Current edition approved Jan. 1, 2010. Published February 2010. Originallyapproved in 1970. Last previous edition approved in 2004 as D2843 - 99 (2004)1.DOI: 10.1520/D2843-10.2Anonymous, “A Method of Measuring Smoke Density,” NFPA Quarterly,QNFPA, Vol 57, January 1964, p. 276. Rep
15、rint NFPA Q57-9. Available from NFPA,60 Batterymarch St., Boston, MA 02110.3For 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.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.1. Specimen HolderA Stainless steel screenB Calcium-silicate sheetC Adjusting knobD Quench pan2. Ignition
17、A Burner 4. PhotometerB Propane tank A Visual system (exit sign)C Gas shut-off valve B Measuring systemD Pressure regulator adjustment 1 Light source and adjusting transformerE Pressure indicator 2 Photronic cell and grid (to block stray light)F Burner-positioning knob 3 Meter (indicating percent of
18、 light absorbed)3. Cabinet (shown without door) 4 Temperature compensationA Hinges (door gasketed three sides) 5 Photocell temperature monitorB Vents (25-mm (1-in.) high opening four sides) 6 Range changeC Blower (damper on mounting side) 5. TimerD Control (blower on when damper is open) A Indicator
19、, 0 to 5 min (friction reset)FIG. 1 Schematic Diagram of Smoke ChamberD2843 102photoelectric cell, and meter to measure light absorptionhorizontally across the 300-mm (12-in.) light beam path. Thechamber is closed during the 4-min test period except for the25-mm (1-in.) high ventilation openings aro
20、und the bottom.4.2 The light-absorption data are plotted versus time. Atypical plot is shown in Fig. 2. Two indexes are used to rate thematerial: the maximum smoke produced and the smoke-densityrating.5. Significance and Use5.1 Tests made on a material under conditions hereinprescribed are of consid
21、erable value in comparing the relativesmoke obscuration characteristics of plastics.5.2 This test method serves to determine the extent to whichplastic materials are likely to smoke under conditions of activeburning and decomposition in the presence of flame.NOTE 2The visual and instrumental observa
22、tions from this testcompare well with the visual observations of the smoke generated byplastic materials when added to a freely burning large outdoor fire.45.3 The usefulness of this test procedure is in its ability tomeasure the amount of smoke obscuration produced in asimple, direct, and meaningfu
23、l manner under the specifiedconditions. The degree of obscuration of vision by smokegenerated by combustibles is known to be affected by changesin quantity and form of material, humidity, draft, temperature,and oxygen supply.6. Apparatus6.1 The smoke chamber shall be constructed essentially asshown
24、in Fig. 1.56.1.1 Chamber:6.1.1.1 The chamber shall consist of a 14-gage (Bcompensations shall therefore be made.NOTE 5Do not operate the photocell at temperatures exceeding 50C.6.1.4.4 The meter shall have two ranges. The range changeshall be accomplished by shunting the meter to one tenth of itssen
25、sitivity. When smoke accumulates to absorb 90 percent ofthe light beam, a momentary switch shall be depressed return-ing the meter to its basic sensitivity. By doing this the meterscale will then read from 90 to 100 % instead of 0 to 100 %.6.1.5 Timing DeviceA clock to indicate 15-s intervalsshall b
26、e used. If the time intervals are audibly marked it will beconvenient for the operator to record his observations. A clutchshall be used to reset the clock at the start of a test. The blockshall be coupled to the burner-positioning device and it shallstart when the burner is swung into test position
27、.6.1.6 PlanimeterA planimeter or other suitable meansshall be used for measuring the area under the light-absorptioncurve.7. Test Specimen7.1 The standard specimen shall be 25.4 6 0.3 by 25.4 60.3 by 6.2 6 0.3 mm (1 6 0.01 by 1 6 0.01 by14 6 0.01 in.).Material thinner than 6.2 6 0.3 mm shall be test
28、ed by stackingand forming a composite specimen 6.2 6 0.3 mm thick.Material thicker than 6.2 mm (14 in.) shall be tested bymachining the material down to a thickness of 6.2 6 0.3 mm.7.2 The specimens shall be sanded, machined, or die cut ina manner that produces a cut surface that is free fromproject
29、ing fibers, chips, and ridges.7.3 The test sample shall consist of three specimens.8. Conditioning8.1 ConditioningCondition the test specimens at 23 62C (73.4 6 3.6F) and 50 6 5 % relative humidity for not lessthan 40 h prior to test in accordance with Procedure A ofPractice D618, for those tests wh
30、ere conditioning is required.In cases of disagreement, the tolerances shall be 61C(61.8F) and 62 % relative humidity.8.2 Test ConditionsConduct tests in the standard labora-tory atmosphere of 23 6 2C (73.4 6 3.6F) and 50 6 5%T = Temperature-sensitive winding in or on meter case to increase in resist
31、ance in proportion to increase in meter resistance with temperature.R = Potentiometer with calibrated scale to reduce resistance in proportion to decrease in photocell output with rise in temperature.C = Potentiometer to calibrate total resistance of shunt to change meter sensitivity exactly by 10:1
32、 ratio.FIG. 4 Smoke Density Test Chamber PhotometerD2843 105relative humidity, unless otherwise specified in the test meth-ods or in this test method. In cases of disagreement, thetolerances shall be 1C (61.8F) and 62 % relative humidity.8.3 Tests shall be conducted in a hood that has a window forob
33、serving the test.9. Standard Procedure9.1 Turn on the photometer lamp, exit sign, and exhaustblower.9.2 Turn on the propane, immediately ignite the burner, andadjust the propane pressure to 276 kPa (40 psi).9.3 Set the temperature compensation.9.4 Adjust the lamp control to zero percent light absorp
34、tion.9.5 Lay the test specimen flat on the screen in such aposition that the burner flame will be directly under thespecimen when the burner is swung into position.9.6 Set the timer to zero.9.7 Shut off the exhaust blower, close the smoke chamberdoor, and immediately position the burner under the sp
35、ecimenand start the timer.9.8 If in a hood, shut off the hood fan and close the hooddoor to within 50 mm (2 in.) of the bottom of the hood.9.9 Record the percent light absorbed at 15-s intervals for 4min.9.10 Record observations during the conduct of the test.Include the time it takes for the sample
36、 to burst into flame, thetime for flame extinguishment or specimen consumption, theobscuration of the exit sign by smoke accumulation, and anygeneral or unusual burning characteristics noted such asmelting, dripping, foaming, or charring.9.11 Upon completion of the test, turn on the exhaustblower to
37、 ventilate the combustion products from the chamber.NOTE 6All products of combustion are toxic. Care shall be taken toguard the operator from the effects of these gases. The ventilating fan inthe hood must be turned on and the damper opened immediately after thetest is completed before opening the h
38、ood door in order to remove anyirritating or toxic products of the test. The exhaust fan is turned off and thehood damper closed during the test to prevent back draft.9.12 Open the door and clean the combustion deposits fromthe photometer, exit sign, and door glass with detergent andwater. Burn off
39、any material remaining on the screen or replacethe screen and square of14-in. thick calcium silicate for thenext test.9.13 Run all tests in triplicate.9.14 At the beginning of each series or at least once a day,check the light absorption of the meter against a calibratedneutral filter of approximate
40、ly 50 % absorption. Check the100 % absorption point against an opaque plate.10. Special Procedure10.1 For materials that drip, a second or auxiliary burner(with separate propane gas supply) shall be introduced into thechamber. See Fig. 5 and auxiliary burner parts list.10.2 The auxiliary burner shal
41、l be ignited at the same timethe standard burner is ignited. The auxiliary burner shall beoperated at 138 kPa (20 psi) and it shall be positioned in sucha manner that its flame is directed at the center of the collectortray.10.3 To prevent movement of the burner during the test,place a lightweight,
42、about 1100 g (2.5 lbs), on the aluminummounting plate (Item 12, Fig. 5).10.4 In all other respects the procedures of Section 8 shallbe followed.11. Optional Procedures11.1 Data acquisition hardware or a potentiometric recordercan be employed to record the output of the photocell versustime.11.2 With
43、 a suitably sensitive meter, more than one decadechange must be used to separate readings in the very densesmoke range.12. Treatment of Data12.1 Average the readings at 15-s intervals of light absorp-tion for the three specimens in each group. Plot the averagelight absorption against time. Fig. 2 is
44、 a sample curve.12.2 Read the maximum smoke density as the highest pointon the curve.12.3 Determine the total smoke produced by measuring thearea under the curve. The smoke density rating represents thetotal amount of smoke present in the chamber for the 4-mintime interval. Measure the total smoke p
45、roduced by dividingthe area under the curve of light absorption versus time, by thetotal area of the graph, 0-4 min 0-100 % light absorption, times100.NOTE 7ExampleIn the light absorption-time plot in Fig. 2, the plothas been made using 10 mm (0.39 in.) equal to 10 % as the ordinate and10 mm (0.39 i
46、n.) equal to 0.25 min as the absicca. The graph area for 4min is found to be 16 000 mm2(24.80 in.2). The area under the curve isfound to be 12 610 mm2(19.55 in.2). The smoke density rating, %, is thencomputed as follows:Smoke density rating= (12610/16000 3 100 = 78.8(dimensions in millimetres)= (19.
47、55/24.80) 3 100 = 78.8(dimensions in inches)13. Report13.1 Report the following information:13.1.1 Identification of the material,13.1.2 Dimensions of the specimen,13.1.3 Readings of light absorption at 15-s intervals foreach test and average,13.1.4 Plots of average light absorption versus time,13.1
48、.5 Maximum smoke density in percent light absorption,13.1.6 Area in percent under the light absorption-time curve(smoke density rating),13.1.7 Observations on behavior of material,13.1.8 Observations on obscurement of exit sign,13.1.9 The details of any departure from the specificationsof the method
49、 for testing, and13.1.10 The caveat contained in 1.4 herein shall be incor-porated in its entirety in the report issued.14. Precision and Bias (Standard Procedure)614.1 Table 1 is based on a round robin completed in 1998 inaccordance with Practice E691, involving five materials tested6Supporting data are available from ASTM Headquarters. Request RR:D20-1203.D2843 106by six laboratories. For each material, all the samples wereprepared at one source, but the individual specimens wereprepared at the laboratories that tested them. Each test resultwas the avera
