1、Designation: D6332 12 (Reapproved 2017)Standard Guide forTesting Systems for Measuring Dynamic Responses ofCarbon Monoxide Detectors to Gases and Vapors1This standard is issued under the fixed designation D6332; the number immediately following the designation indicates the year oforiginal adoption
2、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 guide describes testing systems used for measuringresponses of carbon mo
3、noxide (CO) alarms or detectorssubjected to gases, vapors, and their mixtures.1.2 The systems are used to evaluate responses of COdetectors to various CO concentrations, to verify that thedetectors alarm at certain specified CO concentrations, and toverify that CO detectors do not alarm at certain o
4、ther specifiedCO concentrations.1.3 The systems are used for evaluating CO detector re-sponses to gases and vapors that may interfere with the abilityof detectors to respond to CO.1.4 Major components of such a testing system include achamber, clean air supply module, humidification module, gasand v
5、apor delivery module, and verification and control instru-mentation.1.5 For each component, this guide provides a comparisonof different approaches and discusses their advantages anddisadvantages.1.6 The guide also presents recommendations for a mini-mum configuration of a testing system.1.7 UnitsTh
6、e values stated in SI units are to be regardedas standard. No other units of measurement are included in thisstandard.1.8 This 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-pria
7、te safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.For more specific safety precautionary information, see 6.2.1.9 This international standard was developed in accor-dance with internationally recognized principles on standard-izati
8、on established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD1356 Terminology
9、Relating to Sampling and Analysis ofAtmospheresD1945 Test Method for Analysis of Natural Gas by GasChromatographyD3162 Test Method for Carbon Monoxide in the Atmo-sphere (Continuous Measurement by Nondispersive Infra-red Spectrometry)D3195 Practice for Rotameter CalibrationD3249 Practice for General
10、 Ambient Air Analyzer Proce-duresD3687 Practice for Analysis of Organic Compound VaporsCollected by the Activated Charcoal Tube AdsorptionMethod2.2 Other Standards:UL 2034 Single and Multiple Station Carbon MonoxideAlarms3CFR 1910.1450 Occupational Exposure to HazardousChemicals in Laboratories43. T
11、erminology3.1 DefinitionsFor definitions of terms used in this guide,refer to Terminology D1356.3.2 Definitions of Terms Specific to This Standard:3.2.1 air change rate, nthe volume of clean, humidifiedair plus contaminants that enters the chamber in 1 h, divided bythe internal volume of the chamber
12、, expressed as air changesper hour (h1).1This guide is under the jurisdiction of ASTM Committee D22 on Air Qualityand is the direct responsibility of Subcommittee D22.05 on Indoor Air.Current edition approved Oct. 1, 2017. Published October 2017. Originallyapproved in 1998. Last previous edition app
13、roved in 2012 as D6332 12. DOI:10.1520/D6332-12R17.2For 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 ASTM website.3Available
14、 from Underwriters Laboratories (UL), 2600 N.W. Lake Rd., Camas,WA 98607-8542, http:/.4Available from U.S. Government Printing Office, Superintendent ofDocuments, 732 N. Capitol St., NW, Washington, DC 20401-0001, http:/www.access.gpo.gov.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C
15、700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the
16、World Trade Organization Technical Barriers to Trade (TBT) Committee.13.2.2 chamber, nan enclosed test volume composed ofchemically inert materials supplied with a mixture of air, gases,or vapors, or combination thereof, having known composi-tions.3.2.3 CO alarm/detector, nan alarm device consisting
17、 ofan assembly of electrical and mechanical components withchemical, electrochemical, solid-state electronic, or other typesof sensors to detect the presence of CO gas in specified rangesof concentrations.3.2.4 sensor, nthe component included in the CO alarm/detector that senses CO gas.4. Summary of
18、 Guide4.1 This guide describes components of systems for testingCO detectors with mixtures of air and CO at different concen-trations of CO. The systems are also used for evaluating theresponses of CO detectors to mixtures of air and various gasesor vapors, or both. Such systems require clean air wi
19、th apreselected level of relative humidity supplied to an environ-mental chamber. Gases and vapors are introduced in the cleanair supply or placed directly in the chamber to achieve desiredchamber concentration. The components of such systemsinclude devices or modules for supplying pure air, humidif
20、yingair, supplying gases or vapors, or both, to be tested, referenceinstruments for verifying concentrations of gases and vapors,and a chamber for placing and exposing CO detectors. Theguide describes various options for each component: chamber(Section 6), clean air supply module (Section 7), humidi
21、fica-tion module (Section 8), gas/vapor delivery module (Section9), and verification and control module (Section 10). The guidefurther provides recommendations on a minimum configura-tion for the testing system (Section 11) and reporting results(Section 12).5. Significance and Use5.1 This guide prov
22、ides information on testing systems andtheir components used for measuring responses of CO alarmsor detectors subjected to gases, vapors, and their mixtures.Components of a testing system include a chamber, clean airsupply module, humidification module, gas and vapor deliverymodule, and verification
23、 and control instrumentation.5.2 The CO detector is tested by sequential exposure to COand interference gases at the specified challenge concentra-tions. A properly functioning alarm/detector will sound uponsufficient exposure to CO but will not sound upon any exposureto interference gases consisten
24、t with applicable standards (forexample, IAS 6-96 (1),5L 2034).6. Chamber6.1 Types of ChamberThere are two types of chambersstatic and dynamic. In a static chamber, air and knownquantities of gases are introduced and then the chamber issealed. In a dynamic chamber, a characterized air-gas mixtureis
25、continually introduced at a rate sufficient to maintain targetconcentrations.6.2 HazardsIn a dynamic chamber, the air exiting cham-ber will contain CO and interference gases or vapors that maybe toxic. To avoid undue exposures of toxic gases and vaporsto occupants of the laboratory (where the chambe
26、r is located),the chamber should be properly vented to outside with anappropriate stack. For a static chamber, exposures to test gasesshould be avoided in operating (for example, opening) thechamber.6.3 Size of the ChamberThe chamber size can be large(that is, room-size) or small and depends on the
27、number ofdetectors to be tested. Detectors should be placed on a wirerack or similar supporting structure. Detectors should be placedat least 0.10-m away from the chamber walls. If multipledetectors are undergoing simultaneous testing, they should bespaced at least 0.051 m from each other. The chamb
28、er sizerequired by UL 2034 is a 0.91 by 0.91 by 0.91-m box, whichhas been found to be practical for testing several detectors at atime.6.4 Material of ConstructionThe chamber should be madeof relatively inert materials, such as glass, stainless steel, orcertain types of polymers/plastics. Materials,
29、 such as wood orgypsum board, may not be appropriate because of theirabsorption, adsorption, and leakage characteristics. Jointsshould be well-sealed using inert caulking/sealing materials.Gaskets should be used around doors and other closableopenings to achieve a good seal when closed.6.5 Air Chang
30、e RateThe air change rate of a dynamicchamber should be sufficient (for example, 1 h1or higher) toovercome loss of chamber air through leakage and the deple-tion of test gases and vapors due to factors, such as consump-tion through a chemical reaction or deposition.6.6 MixingTo provide a uniform con
31、centration for testing,the chamber air should be well mixed. With an adequate airchange rate (for example, 1 h1or higher), mixing can beachieved through proper placement and design of inlet andoutlet ports. The design and placement should be such that anyshort-circuiting of flow from inlet to outlet
32、 ports is avoided. Abetter alternative to promote mixing is to use a fan that isappropriately sized for the chamber volume. For example,mixing within a large chamber having 23-m3volume can beachieved by an 0.38-m3/s fan. Ideally, the fan should bemounted on a shaft through the chamber wall, and the
33、fanmotor should be external to the chamber to prevent contami-nation and heat load in the chamber. If a fan is used, the sensorports should be shielded from direct air impingement. Inaddition to providing a uniform air concentration, the combi-nation of air change rate and mixing should be such that
34、 itprovides sufficient face velocity (for example, over 1 m/s) atsensor head(s) through the detector housing.6.7 The chamber should be able to provide accurate controlof temperature and relative humidity at ambient pressure asindicated in Table 1. The chamber should be airtight tominimize any leakag
35、e of ambient air into or chamber air out ofthe system. The environmental conditions cited in Table 1cover ranges specified in standards listed in 2.2 and in theliterature (1). Also, UL 2034 prescribes certain time period(s)5The boldface numbers in parentheses refer to references at the end of thisst
36、andard.D6332 12 (2017)2to achieve target concentrations that should be adhered to sothat undue exposures are avoided.6.8 DiscussionThe advantage of the static chamber is thatthe setup is simple, basically requiring only a sealable box. Themajor disadvantage of the static chamber is that the gases ma
37、ybe consumed or generated in the chamber, resulting in anenvironment that is different than originally specified. For thisreason, the composition of the atmosphere should be monitoredcontinuously for CO concentrations and other related param-eters. The dynamic chamber requires a continuous and con-t
38、rolled supply and exhaust of air and gases to be tested butprovides an environment that does not undergo changes as anartifact of testing.7. Clean Air Supply Module7.1 TypesThere are two approaches for obtaining a cleanair supply: (1 ) to use a prepackaged supply of clean air; and (2)to generate cle
39、an air by processing ambient air to removeimpurities and moisture. This second approach requires equip-ment for removing particle and gas contaminants and moisturefrom the ambient air. Clean air can be generated to meetspecifications for different requirements of stringency. Preas-sembled equipment
40、for processing ambient air is also availablefrom commercial gas supply vendors. Some details on the twoapproaches are given below.7.2 Packaged Clean AirUse of packaged air involvespurchase of pressurized cylinders of clean air or zero air withcertain specifications. Recommended specifications are: l
41、essthan 0.5 ppm(v) (0.33 mg/m3of methane equivalent) of totalhydrocarbons, water vapor less than 3.5 ppm(v) (2.6 mg/m3),and CO less than 1 ppm(v) (1.1 mg/m3). Such gases areavailable from commercial vendors of pure gases and gasmixtures.7.3 Clean Air Generation ModuleA basic clean air gen-eration mo
42、dule has the following components: oil-lesscompressor, desiccant to remove moisture, particle filter toremove suspended particles, and activated charcoal filter orcatalyst bed, or both, to remove gaseous impurities. In additionto these components, a storage tank, high pressure lines, andregulator ar
43、e necessary. A radiative cooler may be necessary tocool compressed air. An example flow diagram for a clean airgeneration module is shown in Fig. 1. Room air is compressedand then cooled by passing the air through a radiative cooler.Liquid water generated by the compressing and cooling isremoved wit
44、h a coalescer filter and may be stored in a storagetank. The compressed air is purified by passing the air througha desiccant, activated charcoal filter, and catalyst bed. Catalyticbeds or a catalytic system is used to remove organic com-pounds (such as alkanes) as well as inorganic gases (such asCO
45、). However, if a verification and control module (describedin Section 10) is used to monitor CO concentrations, a catalystbed to remove CO may not be necessary. If a catalyst bed isused, use a desiccant and a downstream activated charcoalfilter to remove water vapor and oxides of nitrogen,respective
46、ly, that are generated from the catalyst bed.7.4 Alternate Clean Air ModuleAir from outdoors or fromthe laboratory can be conditioned and cleaned by passing itthrough particulate filters to remove suspended solid particles,preheat coil and a chilled water dehumidifying coil to removeexcess moisture,
47、 a desiccant dehumidifier to further dehu-midify air, a catalytic bed to remove background CO, and anactivated carbon adsorbent bed to remove volatile organiccompounds in the air.7.5 DiscussionThe use of prepackaged clean air requires aminimal initial investment. The laboratory shall provide forsafe
48、 storage of pressurized cylinders. Pressurized cylinders ofclean air that meet or exceed specifications can be purchasedthrough commercial gas supply vendors. However, this canbecome costly depending on the level of use of clean air. Theuse of a clean air module, on the other hand, requires an initi
49、alinvestment in a compressor and filtration/dehumidificationequipment. The completed module supplies clean air at lowercost if the clean air supply is used regularly. Further, properselection of specifications will provide adequate repeatabilityin testing results without undue high cost. There are variouslevels of clean air that can be achieved. For testing COdetectors, ultra-pure air (total hydrocarbon content 0.1ppm(v) or 0.06 mg/m3) is generally unnecessary. A totalhydrocarbon content of less than 0.5 ppm(v) (0.33 mg/m3)isconsidered to be adequat
