1、Designation:D729506 Designation: D7295 11Standard Practice forSampling and Determination of Hydrogen Cyanide (HCN) inCombustion Effluents and Other Stationary Sources1This standard is issued under the fixed designation D7295; the number immediately following the designation indicates the year oforig
2、inal 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 practice is used to determine the concentration of gaseous
3、 hydrogen cyanide (HCN) from any combustion device oratmosphere where cyanide may be present. While primarily designed for the measurement of gas phase HCN, the sample collectiondescribed in this practice also includes cyanide ion (CN-) absorbed particles that may be present in the sampling atmosphe
4、re.1.1.1 Samples can be collected from a closed chamber such as the NBS smoke box described in Test Method E662 providedit is equipped with sampling ports.1.1.2 Open chambers such as industrial work areas or large scale fires can be monitored for HCN with this practice.1.1.3 The HCN emissions of a f
5、low through system can be determined by sampling from its discharge stack. Examples of suchsystems include large scale manufacturing applications and the cone calorimeter described in Test Method E1354.1.2 This practice can be used to monitor HCN levels in lab scale fire smoke effluents in order to
6、estimate toxicity of gasesproduced from burning materials. See Guide E800.1.3 The concentration range of hydrogen cyanide will be dependent on the volume of gas sampled, the volume of sodiumhydroxide solution placed in the impinger during sampling, and the analytical method used to measure cyanide.
7、For example, thelower limit of detection would be 0.002-mg/m3when 0.1-m3of combustion effluent is collected into 100-mL sodium hydroxidesolution based on a detection limit of 0.002 mg/L cyanide in the impinger solution when using the flow injection analysis (FIA)system described in Test Method D6888
8、.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Do
9、cuments2.1 ASTM Standards:2D1193 Specification for Reagent WaterD1356 Terminology Relating to Sampling and Analysis of AtmospheresD2036 Test Methods for Cyanides in WaterD2777 Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on WaterD3154 Test Method for A
10、verage Velocity in a Duct (Pitot Tube Method)D3614 Guide for Laboratories Engaged in Sampling and Analysis of Atmospheres and EmissionsD3685/D3685M Test Methods for Sampling and Determination of Particulate Matter in Stack GasesD4841 Practice for Estimation of Holding Time for Water Samples Containi
11、ng Organic and Inorganic ConstituentsD5337 Practice for Flow Rate Calibration of Personal Sampling PumpsD6696 Guide for Understanding Cyanide SpeciesD6888 Test Method for Available Cyanide with Ligand Displacement and Flow Injection Analysis (FIA) Utilizing GasDiffusion Separation and Amperometric D
12、etectionD7365 Practice for Sampling, Preservation and Mitigating Interferences in Water Samples for Analysis of CyanideE337 Test Method for Measuring Humidity with a Psychrometer (the Measurement of Wet- and Dry-Bulb Temperatures)1This practice is under the jurisdiction of ASTM Committee D22 on Air
13、Quality and is the direct responsibility of Subcommittee D22.03 on Ambient Atmospheres andSource Emissions.Current edition approved Oct. 1, 2006. Published October 2006. DOI: 10.1520/D7295-06.Current edition approved March 1, 2011. Published March 2011. Originally approved in 2006. Last previous edi
14、tion approved in 2006 as D7295 - 06. DOI:10.1520/D7295-11.2Reagent Chemicals, American Chemical Society Specifications, Am. Chemical Soc., Washington, DC. For suggestions on the testing of reagents not listed by theAmerican chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., P
15、oole, Dorset, U.K., and the United States Pharmacopeia.2For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.1Thi
16、s document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editio
17、ns as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.E662 Test Method for Specific Optical Density of Sm
18、oke Generated by Solid MaterialsE800 Guide for Measurement of Gases Present or Generated During FiresE1354 Test Method for Heat and Visible Smoke Release Rates for Materials and Products Using an Oxygen ConsumptionCalorimeter3. Terminology3.1 Refer to Terminology D1356 for terminology related to sam
19、pling and analysis of atmospheres.3.2 For definitions of terms related to cyanide testing, refer to Guide D6696 and Test Method D6888.3.3 For definitions of terms related to the measurement of gases present or generated during fires, refer to Guide E800.3.4 For additional information related to samp
20、ling and analysis of atmospheres, see Guide D3614.4. Summary of Practice4.1 A known volume of gaseous sample is bubbled through an impinger containing 0.1M sodium hydroxide solution utilizinga calibrated pumping system. Particulates that may pass through the impinger are captured on a glass fiber fi
21、lter then recombinedback into the impinger solution prior to analysis. Because HCN is soluble in aqueous solutions, it may be present in water dropletsformed from either a wet scrubber system or condensation in the stack. Because of this, samples that contain moist air should besampled near isokinet
22、ic conditions.4.2 During the sampling process, hydrogen cyanide (HCN) is converted to cyanide ion (CN-) in the sodium hydroxide solution.The CN-is analyzed with a flow injection analysis (FIA) system described in Test Method D6888 or with a suitable analyticalmethod such as ion chromatography descri
23、bed in Test Methods D2036.4.2.1 Colorimetric and ion selective electrode methods, also described in Test Methods D2036 can be used for screeningpurposes.4.3 The concentration of HCN in the atmosphere or stack is calculated as described in 9.6.5. Significance and Use5.1 Hydrogen cyanide is highly tox
24、ic. In relatively low quantities, hydrogen cyanide can cause asphyxia and death.5.2 The National Fire Protection Association has assigned a flammability rating of 4 (severe fire hazard) to hydrogen cyanide.6. Apparatus6.1 Sample Collection Train6.1.1 Constant Flow Pumping SystemPumps used to collect
25、 samples should be able to accurately pump from 0.1-L/min to15-L/min or at the desired flow rate. Personal industrial hygiene sampling pumps or high volume sampling pumps may be utilized.More than one sample can be collected with a single pump using a manifold with flow control valves. The system sh
26、ould becalibrated as described in Practice D5337 or using a suitable commercially available calibrator.6.1.2 Impinger Sample Collection VesselsStandard mini or midget impingers with standard tip. Greenberg-Smith impingersequipped with a standard tip with 500-mL capacity may be used when larger flow
27、rates are desired. Impinger connections shouldconsist of leak free ground glass joints to avoid the loss of HCN during sampling and should be free of any silicone grease. Theuse of a single impinger has shown to yield an average of 97 % efficiency in combustion effluents; however, higher efficiencie
28、sare possible using additional impingers in series. Without prior knowledge of the atmosphere, it is recommended to use a backupimpinger to determine if breakthrough occurs. Test each impinger for cyanide as a separate sample in order to demonstrate captureefficiency; mathematically combine the resu
29、lts by adding the observed concentrations.6.1.3 Sample Collection Tubing and ProbesCollection tubing and probes should be constructed of inert material such PTFEor PTFE-lined stainless steel. Vinyl tubing can be used in the sample train where flexible tubing is necessary, but theaforementioned are p
30、referred. The sample lines should be heated at 120 6 5C when sampling stack emissions in moist air in orderto prevent condensate from forming in the sample train.6.1.4 Glass Fiber FiltersType A/E, 1 m binder free borosilicate glass fiber filter and cassette assembly cartridge for airsampling applica
31、tions. The filters are used between the impingers and pumping system to capture fine particulates that may passthrough the impingers and to protect the pumping system. It is recommended to use 13-mm filters for mini-impingers and 47-mmfilters for Greenberg-Smith impingers.6.1.5 Duplicate and Matrix
32、Spike Sample TrainsIt is recommended to setup duplicate impingers to evaluate precision. Inaddition, a second set of impingers can be fortified with a known amount of cyanide (see 8.11) to evaluate recovery. Fig. 1 showsan example of such a system.6.1.6 ThermometerMeasure the temperature of the stac
33、k or atmosphere with a mercury thermometer or an equivalent digitalthermometer capable of accurately reading within 60.1C.7. Interferences7.1 Sulfide, aldehydes, and oxidizing agents in the atmosphere are possible interferences.7.2 Prior to conducting sampling and analysis, review 9.4 in order to av
34、oid cyanide degradation or inaccurate results.D7295 1128. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents shall conform to the specifications of the American Chemical Society, where such speci
35、fications are available3. Othergrades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lesseningthe accuracy of the determination.8.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean reag
36、ent water conforming toType I, II, or III of Specification D1193.8.3 Impinger Solution(0.10 M NaOH)In a 1-L volumetric flask, dissolve 4.0 g NaOH in approximately 800-mL laboratorywater and dilute to 1L.8.4 Ethylenediamine (EDA) SolutionWeigh 3.5 g EDA into a 100-mL volumetric flask and dilute to vo
37、lume with water.8.5 Cadmium Chloridegranular, powdered.8.6 Lead Acetate Test Stripsused to test for the presence of sulfide in the impinger solutions.8.7 Leur Lock Syringe Filter0.45 m filter attached to syringe8.8 KI Starch Paper Test Stripsused to indicate the presence of oxidizing agents8.9 Sodiu
38、m ArseniteNaAsO2is used to neutralize oxidizing agents8.10 pH Indicator Stripswide range pH paper.8.11 Cyanide Matrix Spike Solution (1000 g/mL CN-)Dissolve 2.51 g of KCN and 2.0 g of NaOH in 1 L of water.Standardize with silver nitrate solution as described in Test Methods D2036, paragraph 16.2. St
39、ore the solution under refrigerationand check concentration approximately every six months and correct if necessary. Commercially prepared solutions are alsoavailable and can be used for spiking purposes. (WarningBecause of the toxicity of cyanide, great care must be exercised inits handling. Acidif
40、ication of cyanide solutions produces toxic hydrocyanic acid (HCN). All manipulations must be done in thehood so that any HCN gas that might escape is safely vented.)9. Procedure9.1 Stack Evaluation (Flow Through Systems)9.1.1 Determine the velocity of the stack as described in Test Method D3154 or
41、US EPA Method 24.3Method 2, Velocity - S-type Pitot, U. S. Environmental Protection Agency3Reagent Chemicals, American Chemical Society Specifications, Am. Chemical Soc., Washington, DC. For suggestions on the testing of reagents not listed by theAmerican chemical Society, see Analar Standards for L
42、aboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia .4Method 4, Moisture Content, U. S. Environmental Protection AgencyFIG. 1 Example of Sample Train (Closed Chamber Sampling, Non-Isokinetic)D7295 1139.1.2 Because HCN is soluble in aqueous solutions, it may be pres
43、ent in water droplets formed from either a wet scrubbersystem or condensation in the stack. Because of this, samples that contain moist air should be sampled near isokinetic conditions.To determine if the moisture in the stack is saturated, test with the wet bulb/dry bulb procedure described in Test
44、 Method E337or estimate the moisture content by US EPA Method 45.9.1.3 If isokinetic sampling is required, see Test Methods D3685/D3685M or US EPA Method 56to determine the probediameter and sampling flow rate. This flow rate will be maintained during the entire sampling event.9.2 Open and Closed Ch
45、amber Systems (Non-Flow Through Systems)9.2.1 When samples are collected from workplace monitoring areas or closed chamber combustion devices, the sampling rate(which will determine the volume of sample collected) should be selected based on the expected concentration of HCN or therequired detection
46、 limit.9.2.2 Since open and closed chamber systems are not flow dependent (that is, there is no measurable flow) isokinetic samplingis not possible. Adequate sampling rates and sampling times should be used to collect a representative sample. When comparingcombustion emissions from various materials
47、, it is recommended to keep the sampling rate constant for each test burn.9.3 Sampling9.3.1 Assemble the sample train with an impinger that contains a known volume of the impinger solution (0.1 M NaOH). Thevolume of impinger solution will depend on the size of impinger. It is recommended to use 100
48、mL of the impinger solution whenusing Greenberg-Smith impingers or 20 mLof impinger solution when using mini-impingers. Connect a glass fiber filter (see 6.1.4)between each impinger and the pumping system. The filter will capture any fine particulate that passes through the impinger andwill protect
49、the pumping system and valves.NOTE 1This practice is primarily used to determine the concentration of HCN and any particulate cyanides that are easily dissociated into freecyanide. To specifically determine the particulate cyanides, a prefilter can be placed prior to the impinger(s). After sampling, this filter and the capturedsolids are extracted with 0.1M NaOH then analyzed per the test methods described in 9.5. If the particles contain strong-acid dissociable metal cyanidecomplexes such as potassium ferricyanide or potassium ferrocyanide, it will be nec
