ASTM D6178-19

Standard Practice for Estimation of Short-Term Inhalation Exposure to Volatile Organic Chemicals Emitted from Bedding Sets

SIGNIFICANCE AND USE
5.1 The objective of this practice is to provide procedures for estimation of human inhalation exposure to VOCs emitted from bedding sets in homes. The estimated inhalation exposure can be used as an input for characterization of health risks from short-term VOC exposures.  
5.2 The results of exposure estimation for specific raw materials and components, or processes used in manufacturing different bedding sets, can be used to compare their relative impacts on exposures.
SCOPE
1.1 This practice describes the procedures for estimation of short-term human inhalation exposure to volatile organic compounds (VOCs) emitted from bedding sets when a new bedding set is first brought into a bedroom.  
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 other household furnishings, usually are highest when the products are new. Procedures described in this practice are applicable to both new and used bedding sets.  
1.4 Exposure to airborne VOC emissions in a residence is estimated for a household member, based on location and activity patterns.  
1.5 The estimated exposure may be used for characterization of health risks that could result from short-term exposures to VOC emissions.  
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 safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Oct-2019
• ICS: 13.040.99 - Other standards related to air quality
• Technical Committee: D22 - Air Quality
• Drafting Committee: D22.05 - Indoor Air

Relations

• Replaces: ASTM D6178-14 - Standard Practice for Estimation of Short-term Inhalation Exposure to Volatile Organic Chemicals Emitted from Bedding Sets
• Effective Date: 01-Nov-2019
• Refers: ASTM D1356-20a - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-Sep-2020
• Refers: ASTM D1356-20 - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 15-Mar-2020
• Refers: ASTM D6177-19 - Standard Practice for Determining Emission Profiles of Volatile Organic Chemicals Emitted from Bedding Sets
• Effective Date: 01-Nov-2019
• Refers: ASTM D5157-19 - Standard Guide for Statistical Evaluation of Indoor Air Quality Models
• Effective Date: 01-Aug-2019
• Refers: ASTM D6670-18 - Standard Practice for Full-Scale Chamber Determination of Volatile Organic Emissions from Indoor Materials/Products
• Effective Date: 01-Sep-2018
• Refers: ASTM D5116-17 - Standard Guide for Small-Scale Environmental Chamber Determinations of Organic Emissions from Indoor Materials/Products
• Effective Date: 01-Nov-2017
• Refers: ASTM D1356-15a - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 15-Oct-2015
• Refers: ASTM D1356-15 - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-Jul-2015
• Refers: ASTM D1356-14b - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-Dec-2014
• Refers: ASTM D6177-14 - Standard Practice for Determining Emission Profiles of Volatile Organic Chemicals Emitted from Bedding Sets
• Effective Date: 15-Oct-2014
• Refers: ASTM D5157-97(2014) - Standard Guide for Statistical Evaluation of Indoor Air Quality Models
• Effective Date: 01-Sep-2014
• Refers: ASTM D1356-14a - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-May-2014
• Refers: ASTM D1356-14 - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 15-Jan-2014
• Refers: ASTM D6670-13 - Standard Practice for Full-Scale Chamber Determination of Volatile Organic Emissions from Indoor Materials/Products
• Effective Date: 01-Apr-2013

Overview

ASTM D6178-19 is the Standard Practice for Estimation of Short-Term Inhalation Exposure to Volatile Organic Chemicals Emitted from Bedding Sets, developed by ASTM International. This standard outlines procedures to estimate the short-term human inhalation exposure to volatile organic compounds (VOCs) released from bedding sets, particularly when they are newly brought into residential bedrooms. The estimated inhalation exposure levels established using this standard can be used to assess potential health risks associated with short-term exposure to VOCs in indoor environments.

This document is relevant for manufacturers, regulators, indoor air quality professionals, and public health specialists concerned with indoor VOC emissions, product safety, and consumer health.

Key Topics

• VOC Emission Assessment: Describes processes for determining and modeling VOC emission profiles from bedding sets, with special attention to the higher emission rates from new products.
• Exposure Scenario Development: Involves characterizing exposure based on product type, environmental conditions, occupant activity, and other variables impacting VOC concentrations.
• Estimation Methods: Presents simplified indoor air models and guidance on selecting appropriate model parameters like bedroom volume, air change rate, and emission rates.
• Health Risk Characterization: The calculated inhalation exposures serve as key inputs for evaluating potential short-term health impacts resulting from exposure to VOCs emitted from bedding materials.
• Reporting: Specifies essential components for documentation, including bedding set description, emissions data, scenario assumptions, modeling approach, and exposure estimates.
• Use of SI Units: All values and results are stated in SI units for consistency.

Applications

ASTM D6178-19 offers practical value in several contexts:

• Product Development and Comparison:
  • Enables bedding manufacturers to evaluate and compare VOC emissions and their potential exposure impacts from different materials and production processes.
  • Supports innovation in low-emission bedding products for improved indoor air quality.
• Regulatory and Health Risk Assessment:
  • Provides a basis for regulators to set exposure limits and guidelines related to VOCs from bedding and other household products.
  • Facilitates health risk assessments by providing standardized exposure estimation methods.
• Indoor Air Quality Evaluation:
  • Assists indoor air quality professionals in identifying and quantifying VOC exposure sources within homes, especially bedrooms.
  • Useful for consultants and researchers conducting exposure and risk studies in residential environments.
• Consumer Protection:
  • Ensures transparency regarding the emissions performance of bedding sets, supporting informed consumer choices.

Related Standards

To implement the guidance in ASTM D6178-19, several other ASTM standards and resources may be referenced, including:

• ASTM D1356: Terminology relating to sampling and analysis of atmospheres.
• ASTM D5116: Guide for small-scale environmental chamber determinations of organic emissions from indoor materials/products.
• ASTM D5157: Guide for statistical evaluation of indoor air quality models.
• ASTM D6177: Practice for determining emission profiles of volatile organic chemicals emitted from bedding sets.
• ASTM D6670: Practice for full-scale chamber determination of volatile organic emissions from indoor materials/products.

Keywords

volatile organic compounds, VOC exposure, bedding emissions, inhalation exposure, indoor air quality, emission profile, exposure scenario, air change rate, ASTM standards, health risk assessment, residential indoor environment, bedding set safety.

By following ASTM D6178-19, organizations and professionals can systematically evaluate the short-term inhalation exposure to VOCs from bedding, promoting healthier indoor environments and scientifically sound risk management decisions.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D6178 − 19
Standard Practice for
Estimation of Short-Term Inhalation Exposure to Volatile
Organic Chemicals Emitted from Bedding Sets
This standard is issued under the fixed designation D6178; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This practice describes the procedures for estimation of
short-term human inhalation exposure to volatile organic D1356 Terminology Relating to Sampling and Analysis of
Atmospheres
compounds (VOCs) emitted from bedding sets when a new
bedding set is first brought into a bedroom. D5116 Guide for Small-Scale Environmental Chamber De-
terminations of Organic Emissions from Indoor Materials/
1.2 The estimated exposure is based on an estimated emis-
Products
sion profile of VOCs from bedding sets.
D5157 GuideforStatisticalEvaluationofIndoorAirQuality
1.3 The VOC emission from bedding sets, as in the case of
Models
other household furnishings, usually are highest when the
D6177 Practice for Determining Emission Profiles of Vola-
products are new. Procedures described in this practice are
tile Organic Chemicals Emitted from Bedding Sets
applicable to both new and used bedding sets.
D6670 Practice for Full-Scale Chamber Determination of
Volatile Organic Emissions from Indoor Materials/
1.4 Exposure to airborne VOC emissions in a residence is
Products
estimated for a household member, based on location and
activity patterns.
3. Terminology
1.5 The estimated exposure may be used for characteriza-
3.1 Definitions—For definitions and terms used in this
tion of health risks that could result from short-term exposures
practice, refer to Terminology D1356.
to VOC emissions.
3.2 Definitions of Terms Specific to This Standard:
1.6 The values stated in SI units are to be regarded as
3.2.1 bedding set, n—an ensemble that includes a mattress
standard. No other units of measurement are included in this
for sleeping and a supporting box spring.
standard.
3.2.2 emission profile, n—a time-series of emission rates of
1.7 This standard does not purport to address all of the
one or more compounds.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 3.2.3 exposure scenario, n—a description of how and where
priate safety, health, and environmental practices and deter- an estimated exposure occurs, including (1) the location and
mine the applicability of regulatory limitations prior to use. emission profile of the product or material that causes
exposure, (2) the indoor environment where the individual is
1.8 This international standard was developed in accor-
dance with internationally recognized principles on standard- exposed to airborne emissions from the product or material,
and (3) the location and activity patterns of the exposed
ization established in the Decision on Principles for the
individual.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
3.2.4 potential inhaled dose, n—the product of air concen-
Barriers to Trade (TBT) Committee.
tration to which an individual is exposed multiplied by the
breathing rate times duration of exposure.
This practice is under the jurisdiction ofASTM Committee D22 on Air Quality
and is the direct responsibility of Subcommittee D22.05 on Indoor Air. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2019. Published December 2019. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1997. Last previous edition approved in 2014 as D6178 – 14. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D6178-19. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6178 − 19
3.2.4.1 Discussion—The potential inhaled dose is different 6.3 Modeling Approach:
from the dose actually absorbed by a target organ. 6.3.1 There are a several methods to model indoor air
concentrations. Multizone models, such as CONTAM (3) or
3.2.5 short-term exposure, n—an exposure of one week or
the Multi- Chamber Concentration and Exposure Model (MC-
less in duration.
CEM) (4), can be used to determine indoor air concentrations
4. Summary of Practice
or interzonal airflow rates, or both. However, interzonal air-
flows has not been well characterized in the literature, and
4.1 This practice describes procedures for estimation of
airflow patterns between the immediate vicinity of the bed and
inhalation exposure to VOCs emitted from new and used
the rest of the room are also not well-known or easily
bedding sets in homes. A recent literature review of human
characterized.Computationalfluiddynamicmodelscanalsobe
exposure to indoor air pollutants in sleep microenvironments
used to model indoor environments. But these models require
describes the range of issues surrounding exposure during
significant effort to define the environment (air inlets and
sleep (1). This estimation of bedding exposure is based on the
outlets, windows, furniture, wall thermal properties). Other
emission profiles for a bedding set, the environmental condi-
issues, such as the impacts of increased localized surface
tions in a residence where the bedding set is being used, and
temperature and moisture near the human body, along with
the location and activity patterns of an exposed individual.
sleepingposition,areusuallynotaccountedforinthesemodels
Emission profiles are derived from environmental chamber
(1). Because models will result in unknown errors dependent
emission tests (see Practice D6670, Guide D5116, and Practice
upon numerous assumptions the user may not be familiar with,
D6177).
this practice uses a simplified box model to estimate inhalation
4.2 Estimation of exposure involves development of expo-
concentrations for the bedding occupant.
sure scenarios, modeling of indoor-air concentrations, and
6.4 Bedroom Volume:
selection and calculation of exposure measures.
6.4.1 The indoor location for the bedding set is assumed to
be a bedroom. The interquartile (or middle 50 %) volume of
5. Significance and Use
500 bedrooms in Denmark measured by Beko et al. (5) was 20
5.1 The objective of this practice is to provide procedures
3 3
m to 30 m . Select a room volume or range of room volumes
for estimation of human inhalation exposure to VOCs emitted
that is appropriate for the exposure scenario. The National
from bedding sets in homes.The estimated inhalation exposure
Association of Home Builders determined that the average
canbeusedasaninputforcharacterizationofhealthrisksfrom
American master bedroom occupies 10.7 % of the floor area of
short-term VOC exposures.
new homes (total average area 270 m ) built in 2018 (6).
5.2 The results of exposure estimation for specific raw
6.5 Emitting Product or Material:
materials and components, or processes used in manufacturing
6.5.1 For this practice, the emitting product is a bedding set.
different bedding sets, can be used to compare their relative
Specify the assumed age, emission profile, and size of the
impacts on exposures.
bedding set of interest.
6.5.2 For a conservative estimate of exposure, assume that
6. Procedures for Exposure Estimation
the bedding set has just been purchased and the wrapper is not
6.1 The procedures for exposure estimation include devel-
removed until it is placed in the residence.
opment of an exposure scenario and modeling of breathing
6.5.3 Select a size of bedding set that is appropriate for the
zone concentrations accounting for emission rates, room size,
size of the bedroom (king, queen, full, twin, crib) and the
air change rate, concentration distribution, occupant age, and
occupant (adult or infant).
activity patterns.
6.5.4 Estimate the bedding emission profile using Practice
6.2 Development of Exposure Scenarios:
D6177. The time varying emission rate determined for new
6.2.1 An exposure scenario describes how and where expo-
bedding in Practice D6177 includes a first order emission rate
sure occurs. In specifying the exposure scenario(s), include a
decay constant.
description of (1) the emitting product or material, in terms of
6.6 Air Change Rate:
its age, emission profile, and location; (2) the indoor environ-
6.6.1 In general, building air change rates vary with time;
ment where exposure occurs; and (3) the location and activity
ranging by at least a factor of five or more for a given building
patterns of an exposed individual.
due to weather and occupant actions (opening windows) (7).
6.2.2 Akeydecisionindeterminingtheexposurescenariois
Roomairchangeratesarehardertodefineandmeasureduethe
determining the appropriate occupant for the bedding set (adult
complexities of interzonal airflows.
or infant). Infants inhale roughly six times more air per unit of
6.6.2 Air change rates in 500 bedrooms in apartments,
body mass than adults and sleep longer (2). Hence, emissions
single family homes, and rowhouses in Denmark were mea-
from crib bedding should be analyzed differently than adult
suredbyBekoetal. (5).Thelognormallydistributedairchange
bedding.
rates varied from 0.05 1/h to 4.5 1/h with a geometric mean
value of 0.46 1/h.
6.6.3 Selectavalueorrangeofvaluesfortheairchangerate
for the bedroom to be modeled. Smaller rooms and those with
more windows and door openings tend to have higher air
The boldface numbers in parentheses refer to the list of references at the end of
the standard. change rates (5).
D6178 − 19
6.7 Room Air Concentration Calculation: 6.9.2 Potential Inhaled Dose—The potential inhaled dose is
6.7.1 Theroomairconcentrationforthechemicalofinterest the product of indoor air concentration times volumetric
emitting
...

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. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D6178 − 14 D6178 − 19
Standard Practice for
Estimation of Short-termShort-Term Inhalation Exposure to
Volatile Organic Chemicals Emitted from Bedding Sets
This standard is issued under the fixed designation D6178; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This practice coversdescribes the procedures for estimation of short-term human inhalation exposure to volatile organic
chemicalscompounds (VOCs) emitted from bedding sets when a new bedding set is first brought into a house.bedroom.
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 other household furnishings, usually are highest when the products
are new. Procedures described in this practice also are applicable to both new and used bedding sets.
1.4 Exposure to airborne VOC emissions in a residence is estimated for a household member, based on location and activity
patterns.
1.5 The estimated exposure may be used for characterization of health risks that could result from short-term exposures to VOC
emissions.
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 safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to its use.
1.8 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D1356 Terminology Relating to Sampling and Analysis of Atmospheres
D5116 Guide for Small-Scale Environmental Chamber Determinations of Organic Emissions from Indoor Materials/Products
D5157 Guide for Statistical Evaluation of Indoor Air Quality Models
D6177 Practice for Determining Emission Profiles of Volatile Organic Chemicals Emitted from Bedding Sets
D6670 Practice for Full-Scale Chamber Determination of Volatile Organic Emissions from Indoor Materials/Products
3. Terminology
3.1 Definitions—For definitions and terms used in this practice, refer to Terminology D1356.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 air change rate, n—the volume of outdoor air that enters the indoor environment in one hour, divided by the volume of
the indoor space.
3.2.1 bedding set, n—an ensemble that includes a mattress for sleeping and a supporting box spring.
3.2.2 emission profile, n—a time-series of emission rates of one or more compounds.
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 Oct. 15, 2014Nov. 1, 2019. Published November 2014December 2019. Originally approved in 1997. Last previous edition approved in 20082014
as D6178 – 97 (2008).D6178 – 14. DOI: 10.1520/D6178-14.10.1520/D6178-19.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’sstandard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6178 − 19
3.2.3 exposure scenario, n—a description of how and where an estimated exposure occurs, including (1) the location and
emission profile of the product or material that causes exposure, (2) the indoor environment where the individual is exposed to
airborne emissions from the product or material, and (3) the location and activity patterns of the exposed individual.
3.2.4 potential inhaled dose, n—the product of air concentration to which an individual is exposed times multiplied by the
breathing rate times duration of exposure.
3.2.4.1 Discussion—
The potential inhaled dose is different from the dose actually absorbed by a target organ.
3.2.5 short-term exposure, n—an exposure of one week or less in duration.
–2
3.2.7 volatile organic chemical, n—an organic compound with saturation vapor pressure greater than 10 kPa at 25°C.
4. Summary of Practice
4.1 This practice describes procedures for estimation of inhalation exposure to VOCs emitted from new bedding sets and used
bedding sets in homes. A recent literature review of human exposure to indoor air pollutants in sleep microenvironments describes
the range of issues surrounding exposure during sleep (1). TheThis estimation of bedding exposure is based on the emission
profiles for a bedding 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 chamber emission tests (see Practice
D6670, Guide D5116, and Practice D6177).
4.2 Estimation of exposure involves development of exposure scenarios, modeling of indoor-air concentrations, and selection
and calculation of exposure measures.
5. Significance and Use
5.1 The objective of this practice is to provide procedures for estimation of human inhalation exposure to VOCs emitted from
bedding sets. sets in homes. The estimated inhalation exposure can be used as an input tofor characterization of health risks from
short-term VOC exposures.
5.2 The results of exposure estimation for specific raw materials and components, or processes used in manufacturing different
bedding sets, can be used to compare their relative impacts on exposures.
6. Procedures for Exposure Estimation
6.1 The procedures for exposure estimation include development of an exposure scenarios, modeling of indoor-air
concentrations, selection and calculation of exposure measures, and model evaluation.scenario and modeling of breathing zone
concentrations accounting for emission rates, room size, air change rate, concentration distribution, occupant age, and activity
patterns.
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 a
description of (1) the emitting product or material, in terms of its age, emission profile, and location; (2) the indoor environment
where exposure occurs; and (3) the location and activity patterns of an exposed individual.
6.2.2 A key decision in determining the exposure scenario is determining the appropriate occupant for the bedding set (adult
or infant). Infants inhale roughly six times more air per unit of body mass than adults and sleep longer (2). Hence, emissions from
crib bedding should be analyzed differently than adult bedding.
The boldface numbers in parentheses refer to the list of references at the end of the standard.
D6178 − 19
6.3 Modeling Approach:
6.3.1 There are a several methods to model indoor air concentrations. Multizone models, such as CONTAM (3) or the Multi-
Chamber Concentration and Exposure Model (MCCEM) (4), can be used to determine indoor air concentrations or interzonal
airflow rates, or both. However, interzonal airflows has not been well characterized in the literature, and airflow patterns between
the immediate vicinity of the bed and the rest of the room are also not well-known or easily characterized. Computational fluid
dynamic models can also be used to model indoor environments. But these models require significant effort to define the
environment (air inlets and outlets, windows, furniture, wall thermal properties). Other issues, such as the impacts of increased
localized surface temperature and moisture near the human body, along with sleeping position, are usually not accounted for in
these models (1). Because models will result in unknown errors dependent upon numerous assumptions the user may not be
familiar with, this practice uses a simplified box model to estimate inhalation concentrations for the bedding occupant.
6.4 Bedroom Volume:
6.4.1 The indoor location for the bedding set is assumed to be a bedroom. The interquartile (or middle 50 %) volume of 500
3 3
bedrooms in Denmark measured by Beko et al. (5) was 20 m to 30 m . Select a room volume or range of room volumes that is
appropriate for the exposure scenario. The National Association of Home Builders determined that the average American master
bedroom occupies 10.7 % of the floor area of new homes (total average area 270 m ) built in 2018 (6).
6.5 Development of Exposure Scenarios:Emitting Product or Material:
6.5.1 An exposure scenario describes how and where exposure occurs. In specifying the exposure scenario(s), include a
description of (For this practice, the 1) the emitting product or material, in terms of its emitting product is a bedding set. Specify
the assumed age, emission profile, and location, (size of2) the indoor environment where exposure occurs, and ( the bedding set
3) the location and activity patterns of an exposed individual.of interest.
6.5.2 Emitting Product or Material—For this practice, the emitting product is a bedding set. Specify the assumed age, emission
profile, indoor location, and size of the bedding set of interest.a conservative estimate of exposure, assume that the bedding set
has just been purchased and the wrapper is not removed until it is placed in the residence.
6.2.2.1 For a conservative estimate of exposure, assume that the bedding set has just been purchased and the wrapper is not
removed until it is placed in the residence.
6.2.2.2 Estimate the 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.
6.5.3 Indoor Environment: Select a size of bedding set that is appropriate for the size of the bedroom (king, queen, full, twin,
crib) and the occupant (adult or infant).
6.2.3.1 Conceptualize the indoor environment as consisting of the following three zones: (1) the immediate vicinity of the
bedding set; (2) the remainder of the bedroom in which the bedding set is located; and (3) the remainder of the house. Specify a
volume for the entire residence and for each of the zones. For a typical volume of the total residence, use the average value (492
m ) listed in the Exposure Factors Handbook (2). For a conservative value of the residential volume, use the 10th percentile value
(154 m ) listed in the Exposure Factors Handbook. See Section X1.1 for example calculations to determine 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 and
the remainder of the house. Such calculations would result in less realistic yet useful estimates for screening purposes.
6.5.4 Location and Activity Patterns—Specify the locations of an exposed individual throughoutEstimate the bedding emission
profile using Practice D6177 a 24-h (or longer) period in relation to the two or three indoor zones previously described 6.2.3.1.
Also specify the time spent outside the house, during which the individual is assumed not to be exposed to chemical emissions
from the bedding set. See SectionThe time varying emission rate determined for new bedding in Practice D6177 X1.2 for examples
of location and activity patterns. includes a first order emission rate decay constant.
6.6 Modeling of Indoor-air Concentrations: Air Change Rate:
6.6.1 The two major steps in modeling In general, building air change rates vary with time; ranging by at least a factor of five
or more for a given building due to weather and occupant actions (opening windows) (7).are selection of a model and provision
of model input parameters. Room air change rates are harder to define and measure due the complexities of interzonal airflows.
6.6.2 Model Selection—Select a model that is capable of estimating indoor-air concentrations in multiple zones and allows the
user to specify various types of emission profiles in addition to the indoor zones, their volumes, their interzonal airflow rates, and
zonal airflow rates to and from the outdoors. Three models that are known to meet these criteria are CONTAM Air change rates
in 500 bedrooms in apartments, single family homes, and rowhouses in Denmark were measured by Beko et al. (3), EXPOSURE
(4), and MCCEM (5). All three models have been developed by or for U.S. government agencies, and are therefore in the public
domain. Each model has advantages 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 for
EXPOSURE and MCCEM, the airflows need to be specified by the user; MCCEM includes a library of airflow rates for selected
residences.The lognormally distributed air change rates varied from 0.05 1/h to 4.5 1/h with a geometric mean value of 0.46 1/h.
D6178 − 19
6.6.3 Model Inputs—In addition to emission profiles, indoor zones, and location and activity patterns as previously described,
specify (Select a value or range of values for the 1) an air change rate for the residence, (bedroom to2) airflow rates among the
indoor zones, and ( be modeled. Smaller rooms and those with more3) parameters related to indoor sinks. Some models may also
require or windows and door openings tend to have higher air change rates allow (5the ).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 the
–1
outdoors has units of inverse hours (h ). A measured value for the residence representing the conditions to be modeled, if
available, should be used as a first choice. An alternative is to select a value based on appropriate cases in the literature. For
–1 –1
example, a conservative value in the range from 0.1 to 0.2 h and a central value in the range from 0.4 to 0.6 h were reported
by Koontz and Rector (6) based on an analysis of measurements from several residential field studies. Representative values for
the residential building stock are not available.
3 –1
6.3.3.2 Multiply the air change rate by the zonal volume to obtain the airflow rate to and from the outdoors, in m h . The
simplifying assumption can be made that each zone has a balanced inflow and outflow with respect to outdoors. While this is
generally not the case in a real building, one must have measured interzonal airflow rates or rates that were calculated with a
multi-zone airflow model (such as CONTAM) to avoid using this assumption.
6.3.3.3 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 equation
such as the following:
Q 5 V ~0.07810.31N! (1)
where:
3 –1
Q = interzonal flow rate, m h ,
V = volume of the house, m , and
–1
N = air change rate of the house, h .
The above empirical equation is based on an analysis of flow rates from several hundred nonrandomly selected residences (6).
6.3.3.4 If three zones are elected for calculations, the bedroom area in the vicinity of the bedding set is assumed to exchange
air only with the rest of the bedroom. See X1.3 for example calculations to determine the airflow rate between the vicinity of the
bedroom set and the remainder of the bedroom.
6.3.3.5 For a conservative approach, assume no indoor sinks. If indoor sinks are present, they are likely to be reversible. Both
CONTAM and EXPOSURE are capable of handling reversible sinks. The MCCEM allows only a one-way sink, expressed as a
–1
first-order rate constant in units of h .
6.3.3.6 If the model requires or allows user input for the time step, then specify a time step of no longer than 15 min, and
preferably as short as 5 min or 1 min. A shorter time step will result in longer execution time but will increase the resolution of
the results.
6.7 Room Air Concentration Calculation:
6.7.1 The room air concentration for the chemical of interest emitting from the bedding sheets can be determined assuming
either steady state or time dependent conditions.
6.7.2 If it is
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