1、Designation: D 6178 97 (Reapproved 2008)Standard Practice forEstimation of Short-term Inhalation Exposure to VolatileOrganic Chemicals Emitted from Bedding Sets1This standard is issued under the fixed designation D 6178; the number immediately following the designation indicates the year oforiginal
2、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 covers the procedures for estimation ofshort-term huma
3、n inhalation exposure to volatile organicchemicals (VOCs) emitted from bedding sets when a newbedding set is first brought into a house.1.2 The estimated exposure is based on an estimated emis-sion profile of VOCs from bedding sets.1.3 The VOC emission from bedding sets, as in the case ofother house
4、hold furnishings, usually are highest when theproducts are new. Procedures described in this practice also areapplicable to used bedding sets.1.4 Exposure to airborne VOC emissions in a residence isestimated for a household member, based on location andactivity patterns.1.5 The estimated exposure ma
5、y be used for characteriza-tion of health risks that could result from short-term exposuresto VOC emissions.1.6 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-priate safety
6、and health practices and determine the applica-bility of regulatory limitations prior to its use.2. Referenced Documents2.1 ASTM Standards:2D 1356 Terminology Relating to Sampling and Analysis ofAtmospheresD5116 Guide for Small-Scale Environmental Chamber De-terminations of Organic Emissions From In
7、door Materials/ProductsD 5157 Guide for Statistical Evaluation of Indoor Air Qual-ity ModelsD 6177 Practice for Determining Emission Profiles of Vola-tile Organic Chemicals Emitted from Bedding Sets3. Terminology3.1 DefinitionsFor definitions and terms used in thispractice, refer to Terminology D 13
8、56.3.2 Definitions of Terms Specific to This Standard:3.2.1 air change rate, nthe volume of outdoor air thatenters the indoor environment in one hour, divided by thevolume of the indoor space.3.2.2 bedding set, nan ensemble that includes a mattressfor sleeping and a supporting box spring.3.2.3 emiss
9、ion profile, na time-series of emission rates ofone or more compounds.3.2.4 exposure scenario, na description of how and wherean estimated exposure occurs, including (1) the location andemission profile of the product or material that causes expo-sure, (2) the indoor environment where the individual
10、 isexposed to airborne emissions from the product or material,and (3) the location and activity patterns of the exposedindividual.3.2.5 potential inhaled dose, nthe product of air concen-tration to which an individual is exposed times breathing ratetimes duration of exposure.3.2.5.1 DiscussionThe po
11、tential inhaled dose is differentfrom the dose actually absorbed by a target organ.3.2.6 short-term exposure, nan exposure of one week orless in duration.3.2.7 volatile organic chemical, nan organic compoundwith saturation vapor pressure greater than 102kPa at 25C.4. Summary of Practice4.1 This prac
12、tice describes procedures for estimation ofinhalation exposure to VOCs emitted from new bedding sets(1)3. The estimation of exposure is based on the emissionprofiles for a bedding set, the environmental conditions in aresidence where the bedding set is being used, and the locationand activity patter
13、ns of an exposed individual. Emission1This practice 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, 2008. Published July 2008. Originallyapproved in 1997. Last previous edition appro
14、ved in 2003 as D 6178 - 97(2003).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.3The boldface numbers in par
15、entheses refer to the list of references at the end ofthe standard.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.profiles are derived from environmental chamber emissiontests (2) (see Guide D5116and Practice D 6177).4.2 Estimation
16、of exposure involves development of expo-sure scenarios, modeling of indoor-air concentrations, andselection and calculation of exposure measures.5. Significance and Use5.1 The objective of this practice is to provide proceduresfor estimation of human inhalation exposure to VOCs emittedfrom bedding
17、sets. The estimated inhalation exposure can beused as an input to characterization of health risks fromshort-term VOC exposures.5.2 The results of exposure estimation for specific rawmaterials and components, or processes used in manufacturingdifferent bedding sets, can be used to compare their rela
18、tiveimpacts on exposures.6. Procedures for Exposure Estimation6.1 The procedures for exposure estimation include devel-opment of exposure scenarios, modeling of indoor-air concen-trations, selection and calculation of exposure measures, andmodel evaluation.6.2 Development of Exposure Scenarios:6.2.1
19、 An exposure scenario describes how and where expo-sure occurs. In specifying the exposure scenario(s), include adescription of (1) the emitting product or material, in terms ofits age, emission profile, and location, (2) the indoor environ-ment where exposure occurs, and (3) the location and activi
20、typatterns of an exposed individual.6.2.2 Emitting Product or MaterialFor this practice, theemitting product is a bedding set. Specify the assumed age,emission profile, indoor location, and size of the bedding set ofinterest.6.2.2.1 For a conservative estimate of exposure, assume thatthe bedding set
21、 has just been purchased and the wrapper is notremoved until it is placed in the residence.6.2.2.2 Estimate the emission profile using adjusted cham-ber air concentrations (Practice D 6177).6.2.2.3 The indoor location for the bedding set is assumed tobe a bedroom.6.2.2.4 Select a size of bedding set
22、 that is appropriate for thesize of the bedroom.6.2.3 Indoor Environment:6.2.3.1 Conceptualize the indoor environment as consistingof the following three zones: (1) the immediate vicinity of thebedding set; (2) the remainder of the bedroom in which thebedding set is located; and (3) the remainder of
23、 the house.Specify a volume for the entire residence and for each of thezones. For a typical volume of the total residence, use theaverage value (369 m3) listed in the Exposure Factors Hand-book (3). For a conservative value of the residential volume,use one of the 10th percentile values (147 m3or 1
24、67 m3) listedin the Exposure Factors Handbook. See X1.1 for examplecalculations to determine the volumes for the bedroom and thevicinity of the bedding set.6.2.3.2 To simplify calculations, the indoor environment canbe considered as consisting of just two zones, the bedroom andthe remainder of the h
25、ouse. Such calculations would result inless realistic yet useful estimates for screening purposes.6.2.4 Location and Activity PatternsSpecify the locationsof an exposed individual throughout a 24-h (or longer) periodin relation to the two or three indoor zones previouslydescribed . Also specify the
26、time spent outside the house,during which the individual is assumed not to be exposed tochemical emissions from the bedding set. See X1.2 forexamples of location and activity patterns.6.3 Modeling of Indoor-air Concentrations:6.3.1 The two major steps in modeling are selection of amodel and provisio
27、n of model input parameters.6.3.2 Model SelectionSelect a model that is capable ofestimating indoor-air concentrations in multiple zones andallows the user to specify various types of emission profiles inaddition to the indoor zones, their volumes, their interzonalairflow rates, and zonal airflow ra
28、tes to and from the outdoors.Three models that are known to meet these criteria areCONTAM (4), EXPOSURE (5), and MCCEM (6). All threemodels have been developed by or for U.S. governmentagencies, and are therefore in the public domain. Each modelhas advantages and disadvantages in terms of completene
29、ss,simulation capabilities, the user interface, and how it addressesexposure. For example, CONTAM has the capability of calcu-lating airflows among zones whereas for EXPOSURE andMCCEM, the airflows need to be specified by the user;MCCEM includes a library of airflow rates for selectedresidences.6.3.
30、3 Model InputsIn addition to emission profiles, indoorzones, and location and activity patterns as previously de-scribed, specify (1) an air change rate for the residence, (2)airflow rates among the indoor zones, and (3) parametersrelated to indoor sinks. Some models may also require or allowthe use
31、r to choose a time step.6.3.3.1 Select a value for the air change rate for theresidence to be modeled. The air change rate for the residencewith the outdoors has units of inverse hours (h1). A measuredvalue for the residence representing the conditions to bemodeled, if available, should be used as a
32、 first choice. Analternative is to select a value based on appropriate cases in theliterature. For example, a conservative value in the range from0.1 to 0.2 h1and a central value in the range from 0.4 to 0.6h1were reported by Koontz and Rector (7) based on ananalysis of measurements from several res
33、idential field studies.Representative values for the residential building stock are notavailable.6.3.3.2 Multiply the air change rate by the zonal volume toobtain the airflow rate to and from the outdoors, in m3h1. Thesimplifying assumption can be made that each zone has abalanced inflow and outflow
34、 with respect to outdoors. Whilethis is generally not the case in a real building, one must havemeasured interzonal airflow rates or rates that were calculatedwith a multi-zone airflow model (such as CONTAM) to avoidusing this assumption.6.3.3.3 Use measured values, if available, for interzonalairfl
35、ow rates between the bedroom and the remainder of thehouse. Alternatively, interzonal flows can be estimated usingthe CONTAM model (or some other multizone airflow model)or an equation such as the following:D 6178 97 (2008)2Q 5 V 0.078 1 0.31N! (1)where:Q = interzonal flow rate, m3h1V = volume of th
36、e house, m3, andN = air change rate of the house, h1.The above empirical equation is based on an analysis of flowrates from several hundred nonrandomly selected residences(7).6.3.3.4 If three zones are elected for calculations, thebedroom area in the vicinity of the bedding set is assumed toexchange
37、 air only with the rest of the bedroom. See X1.3 forexample calculations to determine the airflow rate between thevicinity of the bedroom set and the remainder of the bedroom.6.3.3.5 For a conservative approach, assume no indoorsinks. If indoor sinks are present, they are likely to bereversible. Bot
38、h CONTAM and EXPOSURE are capable ofhandling reversible sinks. The MCCEM allows only a one-waysink, expressed as a first-order rate constant in units of h1.6.3.3.6 If the model requires or allows user input for thetime step, then specify a time step of no longer than 15 min,and preferably as short a
39、s 5 min or 1 min. A shorter time stepwill result in longer execution time but will increase theresolution of the results.6.4 Selection and Calculation of Exposure Measures:6.4.1 Two commonly used measures of exposure are thepotential inhaled dose and the maximum indoor concentrationto which an indiv
40、idual is exposed.6.4.2 Potential Inhaled DoseThe potential inhaled dose isthe product of indoor-air concentration times breathing ratetimes duration of exposure. This dose needs to be calculatedseparately for each contiguous period of time when theexposed individual is in a different zone of the ind
41、oor envi-ronment; the resultant estimates are then summed to determinethe total inhaled dose. The time period over which the totalinhaled dose is determined could be 1 h, 8 h, or 24 h, or longer,depending on the health end point of potential concern.6.4.3 Maximum Indoor ConcentrationThe maximum in-d
42、oor concentration to which an individual is exposed typicallyis integrated over a relatively short time period such as1hor8 h, depending on the reference value against which thetime-integrated concentration will be compared. In determin-ing this maximum concentration, it is necessary to track theexp
43、osed individuals location within the indoor environment,integrating across contiguous time periods in each zone aspreviously described for the potential inhaled dose.6.5 Model EvaluationIdeally, the models that predictindoor air concentrations for the purposes of exposure estima-tion should be evalu
44、ated with concentration measurementsfrom actual residences. Use tools described in Guide D 5157 tojudge the comparability of predicted and measured concentra-tions.7. Report7.1 The report on estimation of inhalation exposure shouldcontain the sections listed as follows:7.2 Bedding Set SamplesGive de
45、scription of the beddingsets (for example, size, style), sample selection process (forexample, random), and brand name (if appropriate).7.3 Emission ProfilesList the time-varying emissions, orprovide an equation describing the time-varying emissions, foreach chemical emitted from a bedding set. Desc
46、ribe thechamber conditions and the technique used for estimatingemissions from the chamber data.7.4 Exposure ScenariosDescribe all assumptions used inestimating exposures, including the age and indoor location ofthe bedding set, the emission profile, the volume and partition-ing of the indoor enviro
47、nment, the air change rate, interzonalairflows, and human location and activity patterns, and asso-ciated breathing rates.7.5 Modeling of Indoor-ConcentrationsDescribe modelselection. List all inputs including the number of zones, airchange rates, interzonal airflow rates, zonal volumes, and thetime
48、 step used in modeling. Include the comparison of pre-dicted and measured concentrations, if available.7.6 Exposure EstimatesDescribe the exposure measuresselected, the manner in which each exposure measure wascalculated, and the resultant exposure estimates.8. Keywords8.1 activity pattern; air chan
49、ge rate; bedding set; emissionprofile; emissions; environmental chamber; exposure assess-ment; exposure scenario; indoor air quality; inhalation expo-sure; potential inhaled doseAPPENDIX(Nonmandatory Information)X1. SUPPLEMENTAL MATERIALX1.1 Example Calculations for Bedroom and Bedding Set:X1.1.1 Volume of BedroomThere is little published infor-mation on measured volumes of bedrooms in residences. Thevolume can vary considerably, with length typically varyingfrom 8 to 12 ft, width from 10 to 20 ft, and ceiling height from7 to 9 ft. Intuitively, a small
