1、Designation: D 6332 99 (Reapproved 2005)Standard Guide forTesting Systems for Measuring Dynamic Responses ofCarbon Monoxide Detectors to Gases and Vapors1This standard is issued under the fixed designation D 6332; the number immediately following the designation indicates the year oforiginal adoptio
2、n or, in the case of revision, 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.1. Scope1.1 This guide describes testing systems used for measuringresponses of carbon
3、 monoxide (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 certai
4、n other 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, gasan
5、d vapor 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 This
6、 guide does not purport to address all of the safetyconcerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use. For more specific safety prec
7、autionaryinformation, see 6.2.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification For Reagent WaterD 1356 Terminology Relating to Sampling and Analysis ofAtmospheresD 1945 Test Method for Analysis of Natural Gas by GasChromatographyD 3162 Test Method for Carbon Monoxide in the Atmo-spher
8、e (Continuous Measurement by Nondispersive Infra-red Spectrometry)D 3195 Practice for Rotameter CalibrationD 3249 Practice for General Ambient Air Analyzer Proce-duresD 3687 Practice for Analysis of Organic Compound VaporsCollected by the Activated Charcoal Tube AdsorptionMethod2.2 Other Standards:B
9、S 7860 Specification for Carbon Monoxide Detectors(Electrical) For Domestic Use3UL 2034 Single and Multiple Station Carbon MonoxideDetectors4CFR 1910.1450 Occupational Exposure to HazardousChemicals in Laboratories53. Terminology3.1 Definitions:For definitions of terms used in this guide, refer to T
10、ermi-nology D 1356.3.2 Definitions of Terms Specific to This Standard:3.2.1 air change ratethe volume of clean, humidified airplus contaminants that enters the chamber in 1 h, divided bythe internal volume of the chamber, expressed as air changesper hour (h1).3.2.2 chamberan enclosed test volume com
11、posed ofchemically inert materials supplied with a mixture of air, gases,or vapors, or combination thereof, having known composi-tions.1This guide is under the jurisdiction of ASTM Committee D22 on Sampling andAnalysis of Atmospheres and is the direct responsibility of Subcommittee D22.05on Indoor A
12、ir.Current edition approved January 1, 2005. Published January 2005. Originallyapproved in 1998. Last previous edition approved in 1999 as D 6332 - 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStan
13、dards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from British Standards Institute (BSI), 389 Chiswick High Rd.,London W4 4AL, UK4Available from Underwriters Laboratories (UL), Corporate Progress, 333Pfingsten Rd., Northbrook, IL 60062.5Available fr
14、om U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.3 CO alarm/detectoran alarm device consisting of anassemb
15、ly of electrical and mechanical components with chemi-cal, electrochemical, solid-state electronic, or other types ofsensors to detect the presence of CO gas in specified ranges ofconcentrations.3.2.4 sensorthe component included in the CO alarm/detector that senses CO gas.4. Summary of Guide4.1 Thi
16、s 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 with apreselect
17、ed 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, humidifyingair, supp
18、lying 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), humidifica-tion mod
19、ule (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 provides informat
20、ion 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 and control
21、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 consistent with applic
22、able standards (forexample, IAS 6-96 (1)6, BS 7860, UL 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 co
23、ntinually 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 chamber
24、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 nu
25、mber ofdetectors to be tested. Detectors should be placed on a wirerack or similar supporting structure. Detectors should be placedat least 0.1-m 4-in. away from the chamber walls. If multipledetectors are undergoing simultaneous testing, they should bespaced at least 0.05 m 2 in. from each other. T
26、he chamber sizerequired by UL 2034 is a 0.9 by 0.9 by 0.9-m 3 by 3 by 3-ftbox, which has been found to be practical for testing severaldetectors at a time.6.4 Material of ConstructionThe chamber should bemade of relatively inert materials, such as glass, stainless steel,or certain types of polymers/
27、plastics. Materials, such as woodor gypsum 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
28、closed.6.5 Air Change 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 p
29、rovide a uniform concentration 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
30、from inlet to outlet 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-m3800-ft3 volumecan be achieved by an 378 l-s1800-cfm fan. Ideally, the fanshould be mounted on a shaft
31、through the chamber wall, andthe fan motor should be external to the chamber to preventcontamination and heat load in the chamber. If a fan is used, thesensor ports should be shielded from direct air impingement. Inaddition to providing a uniform air concentration, the combi-nation of air change rat
32、e and mixing should be such that itprovides sufficient face velocity (for example, over1ms1or3.3 ft s1) at sensor 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 chambe
33、r should be airtight tominimize any leakage of ambient air into or chamber air out ofthe system. The range of environmental conditions cited inTable 1 cover ranges specified in standards listed in 2.2 and inthe literature (1). Also, UL 2034 prescribes certain time6The boldface numbers in parentheses
34、 refer to references at the end of thisstandard.TABLE 1 General Specifications for Test ChamberSpecification Control Range Control PrecisionTemperature 10 to 52C 14 to 126F 6 0.5C 6 0.9FRelative humidity 15 % to 95 %(noncondensing)6 5.0 %D 6332 99 (2005)2period(s) to achieve target concentrations th
35、at should beadhered to so that 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 maybe consumed or generated in the chamber, resulting in ane
36、nvironment 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-trolled supply and exhaust of air and gases to be tested bu
37、tprovides 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 clean air by processing ambient air to removeimpurities and mo
38、isture. 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 for processing ambient air is also availablefrom commercial
39、 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: lessthan 0.5 ppm(v) (0.33 mg m3of methane equivalent) of tot
40、alhydrocarbons, 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 module has the following components: oil-less com-pressor, de
41、siccant to remove moisture, particle filter to removesuspended particles, and activated charcoal filter or catalystbed, or both, to remove gaseous impurities. In addition to thesecomponents, a storage tank, high pressure lines, and regulatorare necessary. A radiative cooler may be necessary to coolc
42、ompressed 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 with a coalescer filter and may be stored in a storagetank.
43、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). However, if a verification and control module (describ
44、edin 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, respec-tively, that are generated from the catalyst bed.7.4 Altern
45、ate Clean Air ModuleAir from outdoors orfrom the laboratory can be conditioned and cleaned by passingit through particulate filters to remove suspended solid par-ticles, preheat coil and a chilled water dehumidifying coil toremove excess moisture, a desiccant dehumidifier to furtherdehumidify air, a
46、 catalytic bed to remove background CO, andan activated carbon adsorbent bed to remove volatile organiccompounds in the air.7.5 DiscussionThe use of prepackaged clean air requiresa minimal initial investment. The laboratory shall provide forsafe storage of pressurized cylinders. Pressurized cylinder
47、s 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 initialinvestment in a compressor and filtration/dehumidific
48、ationequipment. 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 tes
49、ting 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 adequate.8. Humidification Module8.1 Air from the clean air module is fed to a humidificationmodule. This module controls the relative humidity of theair-gas mixture delivered to the chamber. Depending on therange of specifications for humidification, the humidificationmodule can be achieved in one of at least two ways:8.1.1 The simple module will co
