1、Designation: D6178 97 (Reapproved 2008)D6178 14Standard Practice forEstimation of Short-term Inhalation Exposure to VolatileOrganic Chemicals Emitted from Bedding Sets1This standard is issued under the fixed designation D6178; the number immediately following the designation indicates the year ofori
2、ginal 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 of short-te
3、rm human inhalation exposure to volatile organic chemicals(VOCs) emitted from bedding sets when a new bedding set is first brought into a house.1.2 The estimated exposure is based on an estimated emission profile of VOCs from bedding sets.1.3 The VOC emission from bedding sets, as in the case of oth
4、er household furnishings, usually are highest when the productsare new. Procedures described in this practice also are applicable to used bedding sets.1.4 Exposure to airborne VOC emissions in a residence is estimated for a household member, based on location and activitypatterns.1.5 The estimated e
5、xposure may be used for characterization of health risks that could result from short-term exposures to VOCemissions.1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.7 This standard does not purport to address all of the
6、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 its use.2. Referenced Documents2.1 ASTM Standards:2D1356 Terminology Relating
7、to Sampling and Analysis of AtmospheresD5116 Guide for Small-Scale Environmental Chamber Determinations of Organic Emissions from Indoor Materials/ProductsD5157 Guide for Statistical Evaluation of Indoor Air Quality ModelsD6177 Practice for Determining Emission Profiles of Volatile Organic Chemicals
8、 Emitted from Bedding SetsD6670 Practice for Full-Scale Chamber Determination of Volatile Organic Emissions from Indoor Materials/Products3. Terminology3.1 DefinitionsFor definitions and terms used in this practice, refer to Terminology D1356.3.2 Definitions of Terms Specific to This Standard:3.2.1
9、air change rate, nthe volume of outdoor air that enters the indoor environment in one hour, divided by the volume ofthe indoor space.3.2.2 bedding set, nan ensemble that includes a mattress for sleeping and a supporting box spring.3.2.3 emission profile, na time-series of emission rates of one or mo
10、re compounds.3.2.4 exposure scenario, na description of how and where an estimated exposure occurs, including (1) the location andemission profile of the product or material that causes exposure, (2) the indoor environment where the individual is exposed toairborne emissions from the product or mate
11、rial, and (3) the location and activity patterns of the exposed individual.1 This practice is under the jurisdiction of ASTM Committee D22 on Air Quality and is the direct responsibility of Subcommittee D22.05 on Indoor Air.Current edition approved April 1, 2008Oct. 15, 2014. Published July 2008Nove
12、mber 2014. Originally approved in 1997. Last previous edition approved in 20032008 asD6178 - 97D6178 97 (2008).(2003). DOI: 10.1520/D6178-97R08.10.1520/D6178-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of
13、 ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This 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 technicall
14、y possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions 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 C7
15、00, West Conshohocken, PA 19428-2959. United States13.2.5 potential inhaled dose, nthe product of air concentration to which an individual is exposed times breathing rate timesduration of exposure.3.2.5.1 DiscussionThe potential inhaled dose is different from the dose actually absorbed by a target o
16、rgan.3.2.6 short-term exposure, nan exposure of one week or less in duration.3.2.7 volatile organic chemical, nan organic compound with saturation vapor pressure greater than 102 kPa at 25C.4. Summary of Practice4.1 This practice describes procedures for estimation of inhalation exposure to VOCs emi
17、tted from new bedding sets(“Assessment of Potential Health Risks Resulting from Chemical Emissions from New Bedding Sets,” Project 2797,Prepared for Sleep Products Safety Council, Versar, Inc., Springfield, VA, July 1995.(1).)3. The estimation of exposure isbased on the emission profiles for a beddi
18、ng set, the environmental conditions in a residence where the bedding set is being used,and the location and activity patterns of an exposed individual. Emission profiles are derived from environmental chamberemission tests (Research Triangle Institute, “Final Report-Performance of Testing in Suppor
19、t of Research by the SPSC Indoor AirQuality Task Force,” RTI/5736/0002RFR, Research Triangle Park, NC, September 1995.) (see Practice D6670, Guide D5116, andPractice D6177).4.2 Estimation of exposure involves development of exposure scenarios, modeling of indoor-air concentrations, and selectionand
20、calculation of exposure measures.5. Significance and Use5.1 The objective of this practice is to provide procedures for estimation of human inhalation exposure to VOCs emitted frombedding sets. The estimated inhalation exposure can be used as an input to characterization of health risks from short-t
21、erm VOCexposures.5.2 The results of exposure estimation for specific raw materials and components, or processes used in manufacturing differentbedding sets, can be used to compare their relative impacts on exposures.6. Procedures for Exposure Estimation6.1 The procedures for exposure estimation incl
22、ude development of exposure scenarios, modeling of indoor-air concentrations,selection and calculation of exposure measures, and model evaluation.6.2 Development of Exposure Scenarios:6.2.1 An exposure scenario describes how and where exposure occurs. In specifying the exposure scenario(s), include
23、adescription of (1) the emitting product or material, in terms of its age, emission profile, and location, (2) the indoor environmentwhere exposure occurs, and (3) the location and activity patterns of an exposed individual.6.2.2 Emitting Product or MaterialFor this practice, the emitting product is
24、 a bedding set. Specify the assumed age, emissionprofile, indoor location, and size of the bedding set of interest.6.2.2.1 For a conservative estimate of exposure, assume that the bedding set has just been purchased and the wrapper is notremoved until it is placed in the residence.6.2.2.2 Estimate t
25、he emission profile using adjusted chamber air concentrations (Practice D6177).6.2.2.3 The indoor location for the bedding set is assumed to be a bedroom.6.2.2.4 Select a size of bedding set that is appropriate for the size of the bedroom.6.2.3 Indoor Environment:6.2.3.1 Conceptualize the indoor env
26、ironment as consisting of the following three zones: (1) the immediate vicinity of thebedding set; (2) the remainder of the bedroom in which the bedding set is located; and (3) the remainder of the house. Specify avolume for the entire residence and for each of the zones. For a typical volume of the
27、 total residence, use the average value(369(492 m3) listed in the Exposure Factors Handbook (12).). For a conservative value of the residential volume, use one of the10th percentile values (147value (154 m3 or 167 m3) listed in the Exposure Factors Handbook. See X1.1 for example calculationsto deter
28、mine the volumes for the bedroom and the vicinity of the bedding set.6.2.3.2 To simplify calculations, the indoor environment can be considered as consisting of just two zones, the bedroom andthe remainder of the house. Such calculations would result in less realistic yet useful estimates for screen
29、ing purposes.6.2.4 Location and Activity PatternsSpecify the locations of an exposed individual throughout a 24-h (or longer) period inrelation to the two or three indoor zones previously described 6.2.3.1.Also specify the time spent outside the house, during whichthe individual is assumed not to be
30、 exposed to chemical emissions from the bedding set. See X1.2 for examples of location andactivity patterns.3 The boldface numbers in parentheses refer to the list of references at the end of the standard.D6178 1426.3 Modeling of Indoor-air Concentrations:6.3.1 The two major steps in modeling are se
31、lection of a model and provision of model input parameters.6.3.2 Model SelectionSelect a model that is capable of estimating indoor-air concentrations in multiple zones and allows theuser to specify various types of emission profiles in addition to the indoor zones, their volumes, their interzonal a
32、irflow rates, andzonal airflow rates to and from the outdoors.Three models that are known to meet these criteria are CONTAM (23),), EXPOSURE(34),), and MCCEM (45).). All three models have been developed by or for U.S. government agencies, and are therefore in thepublic domain. Each model has advanta
33、ges and disadvantages in terms of completeness, simulation capabilities, the user interface,and how it addresses exposure. For example, CONTAM has the capability of calculating airflows among zones whereas forEXPOSURE and MCCEM, the airflows need to be specified by the user; MCCEM includes a library
34、 of airflow rates for selectedresidences.6.3.3 Model InputsIn addition to emission profiles, indoor zones, and location and activity patterns as previously described,specify (1) an air change rate for the residence, (2) airflow rates among the indoor zones, and (3) parameters related to indoor sinks
35、.Some models may also require or allow the user to choose a time step.6.3.3.1 Select a value for the air change rate for the residence to be modeled. The air change rate for the residence with theoutdoors has units of inverse hours (h1). A measured value for the residence representing the conditions
36、 to be modeled, ifavailable, should be used as a first choice. An alternative is to select a value based on appropriate cases in the literature. Forexample, a conservative value in the range from 0.1 to 0.2 h1 and a central value in the range from 0.4 to 0.6 h1 were reportedby Koontz and Rector (56)
37、 based on an analysis of measurements from several residential field studies. Representative valuesfor the residential building stock are not available.6.3.3.2 Multiply the air change rate by the zonal volume to obtain the airflow rate to and from the outdoors, in m3 h1. Thesimplifying assumption ca
38、n be made that each zone has a balanced inflow and outflow with respect to outdoors. While this isgenerally not the case in a real building, one must have measured interzonal airflow rates or rates that were calculated with amulti-zone airflow model (such as CONTAM) to avoid using this assumption.6.
39、3.3.3 Use measured values, if available, for interzonal airflow rates between the bedroom and the remainder of the house.Alternatively, interzonal flows can be estimated using the CONTAM model (or some other multizone airflow model) or an equationsuch as the following:Q 5V 0.07810.31N! (1)where:Q =
40、interzonal flow rate, m3h1,V = volume of the house, m3, andN = air change rate of the house, h1.The above empirical equation is based on an analysis of flow rates from several hundred nonrandomly selected residences (56).6.3.3.4 If three zones are elected for calculations, the bedroom area in the vi
41、cinity of the bedding set is assumed to exchangeair only with the rest of the bedroom. See X1.3 for example calculations to determine the airflow rate between the vicinity of thebedroom set and the remainder of the bedroom.6.3.3.5 For a conservative approach, assume no indoor sinks. If indoor sinks
42、are present, they are likely to be reversible. BothCONTAM and EXPOSURE are capable of handling reversible sinks. The MCCEM allows only a one-way sink, expressed as afirst-order rate constant in units of h1.6.3.3.6 If the model requires or allows user input for the time step, then specify a time step
43、 of no longer than 15 min, andpreferably as short as 5 min or 1 min. A shorter time step will result in longer execution time but will increase the resolution ofthe results.6.4 Selection and Calculation of Exposure Measures:6.4.1 Two commonly used measures of exposure are the potential inhaled dose
44、and the maximum indoor concentration to whichan individual is exposed.6.4.2 Potential Inhaled DoseThe potential inhaled dose is the product of indoor-air concentration times breathing rate timesduration of exposure. This dose needs to be calculated separately for each contiguous period of time when
45、the exposed individualis in a different zone of the indoor environment; the resultant estimates are then summed to determine the total inhaled dose. Thetime period over which the total inhaled dose is determined could be 1 h, 8 h, or 24 h, or longer, depending on the health end pointof potential con
46、cern.6.4.3 Maximum Indoor ConcentrationThe maximum indoor concentration to which an individual is exposed typically isintegrated over a relatively short time period such as 1 h or 8 h, depending on the reference value against which the time-integratedconcentration will be compared. In determining th
47、is maximum concentration, it is necessary to track the exposed individualslocation within the indoor environment, integrating across contiguous time periods in each zone as previously described for thepotential inhaled dose.6.5 Model EvaluationIdeally, the models that predict indoor air concentratio
48、ns for the purposes of exposure estimation shouldbe evaluated with concentration measurements from actual residences. Use tools described in Guide D5157 to judge thecomparability of predicted and measured concentrations.D6178 1437. Report7.1 The report on estimation of inhalation exposure should con
49、tain the sections listed as follows:7.2 Bedding Set SamplesGive description of the bedding sets (for example, size, style), sample selection process (for example,random), and brand name (if appropriate).7.3 Emission ProfilesList the time-varying emissions, or provide an equation describing the time-varying emissions, for eachchemical emitted from a bedding set. Describe the chamber conditions and the technique used for estimating emissions from thechamber data.7.4 Exposure ScenariosDescribe all assumptions used in estimating exposures, includ
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