1、Designation: D6332 12Standard 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 or, in the case of
2、 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 monoxide (CO) alarms
3、 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 other specifiedCO c
4、oncentrations.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 vapor delivery modu
5、le, 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 UnitsThe values stated in
6、 SI units are to be regardedas standard. No other units of measurement are included in thisstandard.1.8 This 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 pr
7、actices and determine the applicability of regulatorylimitations prior to use. For more specific safety precautionaryinformation, see 6.2.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD1356 Terminology Relating to Sampling and Analysis ofAtmospheresD1945 Test Method
8、 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 Ambient Air Analyzer Proce-duresD3687 Practice for Analysis of
9、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. Terminology3.1 Definitions:For definitions of terms used in this
10、guide, refer to Termi-nology D1356.3.2 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
11、 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/detectoran alarm device consisting of anassembly of electrical and mechanical components with chemi-cal, electrochemical, solid-state
12、electronic, or other types ofsensors to detect the presence of CO gas in specified ranges ofconcentrations.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 April 1, 2012. Published
13、 May 2012. Originallyapproved in 1998. Last previous edition approved in 1999 as D6332 - 99 (2005).DOI: 10.1520/D6332-12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refe
14、r to the standards Document Summary page onthe ASTM website.3Available from Underwriters Laboratories (UL), 2600 N.W. Lake Rd., Camas,WA 98607-8542, http:/.4Available from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http:/
15、www.access.gpo.gov.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.4 sensorthe component included in the CO alarm/detector that senses CO gas.4. Summary of Guide4.1 This guide describes components of systems for testingCO detecto
16、rs 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 apreselected level of relative humidity supplied to an environ-mental c
17、hamber. 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, supplying gases or vapors, or both, to be tested, referenceinstru
18、ments 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 module (Section 8), gas/vapor delivery module (Section9), and ve
19、rification 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 information on testing systems andtheir components used for measuring
20、 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 instrumentation.5.2 The CO detector is tested by sequential e
21、xposure 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 applicable standards (forexample, IAS 6-96 (1)5, UL 2034).6. Chambe
22、r6.1 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 continually introduced at a rate sufficient to maintain targetconcentrat
23、ions.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 is located),the chamber should be properly vented to outside with anap
24、propriate 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 number ofdetectors to be tested. Detectors should be placed on a wirerac
25、k 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 chamber sizerequired by UL 2034 is a 0.91 by 0.91 by 0.91-m box, whichhas bee
26、n found to be practical for testing several detectors at atime.6.4 Material of ConstructionThe chamber should bemade of relatively inert materials, such as glass, stainless steel,or certain types of polymers/plastics. Materials, such as woodor gypsum board, may not be appropriate because of theirabs
27、orption, 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 Change RateThe air change rate of a dynamicchamber should be sufficient (for
28、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 concentration for testing,the chamber air should be well mixed. With an ade
29、quate 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 ports is avoided. Abetter alternative to promote mixing is to use a fan
30、 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 fanmotor should be external to the chamber to prevent contami-nation and
31、 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 itprovides sufficient face velocity (for example, over 1 m/s) atsensor
32、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 leakage of ambient air into or chamber air out ofthe system. The environmental
33、 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)to achieve target concentrations that should be adhered to sothat undue exposures are avoided.6.8 DiscussionThe advantage of the static chamber is th
34、atthe setup is simple, basically requiring only a sealable box. The5The boldface numbers in parentheses refer to references at the end of thisstandard.TABLE 1 General Specifications for Test ChamberSpecification Control Range Control PrecisionTemperature 10 to 52C 6 0.5CRelative humidity 15 % to 95
35、%(noncondensing)6 5.0 %D6332 122major disadvantage of the static chamber is that the gases maybe 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 conc
36、entrations and other related param-eters. The dynamic chamber requires a continuous and con-trolled 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 obtai
37、ning 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 moisture. This second approach requires equip-ment for removing particle and gas contaminants and moisturefrom the ambient air. Clean air can be genera
38、ted to meetspecifications for different requirements of stringency. Preas-sembled equipment 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 cyli
39、nders of clean air or zero air withcertain specifications. Recommended specifications are: lessthan 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 o
40、f pure gases and gasmixtures.7.3 Clean Air Generation ModuleA basic clean air gen-eration module has the following components: oil-less com-pressor, desiccant to remove moisture, particle filter to removesuspended particles, and activated charcoal filter or catalystbed, or both, to remove gaseous im
41、purities. In addition to thesecomponents, a storage tank, high pressure lines, and regulatorare necessary. A radiative cooler may be necessary to coolcompressed 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
42、through a radiative cooler.Liquid water generated by the compressing and cooling isremoved with 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 syste
43、m is used to remove organic com-pounds (such as alkanes) as well as inorganic gases (such asCO). 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
44、 a downstream activated charcoalfilter to remove water vapor and oxides of nitrogen, respec-tively, that are generated from the catalyst bed.7.4 Alternate Clean Air ModuleAir from outdoors orfrom the laboratory can be conditioned and cleaned by passingit through particulate filters to remove suspend
45、ed solid par-ticles, preheat coil and a chilled water dehumidifying coil toremove excess moisture, a desiccant dehumidifier to furtherdehumidify air, a catalytic bed to remove background CO, andan activated carbon adsorbent bed to remove volatile organiccompounds in the air.7.5 DiscussionThe use of
46、prepackaged clean air requiresa minimal initial investment. The laboratory shall provide forsafe 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 t
47、he level of use of clean air. Theuse of a clean air module, on the other hand, requires an initialinvestment 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 specifica
48、tions 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 tha
49、n 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 contain chilled water coolingcoils, a reheat coil, and steam humidifier to obtain desiredtemperature and relative humidity. Such conditioning can beachieved as p
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