ASTM D6670-18

Standard Practice for Full-Scale Chamber Determination of Volatile Organic Emissions from Indoor Materials/Products

SIGNIFICANCE AND USE
5.1 VOCs emitted from materials/products affect indoor air quality (IAQ) in buildings. To determine the impact of these emissions on IAQ, it is necessary to know their emission rates over time. This practice provides guidelines for using a full-scale environmental chamber for testing large materials and full-scale material systems/assemblies.  
5.2 While this practice is developed for measuring VOC emissions, the chamber facilities and methods of evaluation presented in this practice are also useful for a variety of purposes including: (1) testing the emissions during the application process (for example, painting), or other related sources; (2) developing scaleup methods (for example, from small chamber results to a full-scale scenario); (3) studying the interaction between sources and sinks, and validating source/sink models which are the basis for IAQ prediction; (4) testing interactions between source emissions and other compounds in the air (for example, NOx, ozone, SOx); and (5) evaluating the performance of air cleaning devices intended to remove contaminants from indoor air.
SCOPE
1.1 This practice is intended for determining volatile organic compound (VOC) emissions from materials and products (building materials, material systems, furniture, consumer products, etc.) and equipment (printers, photocopiers, air cleaners, etc.) under environmental and product usage conditions that are typical of those found in office and residential buildings.  
1.2 This practice is for identifying VOCs emitted and determining their emission rates over a period of time.  
1.3 This practice describes the design, construction, performance evaluation, and use of full-scale chambers for VOC emission testing.  
1.4 While this practice is limited to the measurement of VOC emissions, many of the general principles and procedures (such as methods for evaluating the general performance of the chamber system) may also be useful for the determination of other chemical emissions (for example, ozone, nitrogen dioxide). Determination of aerosol and particle emissions is beyond the scope of this document.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 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.  
1.7 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-Aug-2018
• ICS: 13.040.20 - Ambient atmospheres
• Technical Committee: D22 - Air Quality
• Drafting Committee: D22.05 - Indoor Air

Relations

• Replaces: ASTM D6670-13 - Standard Practice for Full-Scale Chamber Determination of Volatile Organic Emissions from Indoor Materials/Products
• Effective Date: 01-Sep-2018
• Refers: ASTM D7706-17(2023) - Standard Practice for Rapid Screening of VOC Emissions from Products Using Micro-Scale Chambers
• Effective Date: 01-Sep-2023
• 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 E779-19 - Standard Test Method for Determining Air Leakage Rate by Fan Pressurization
• Effective Date: 01-Jan-2019
• Refers: ASTM E779-10(2018) - Standard Test Method for Determining Air Leakage Rate by Fan Pressurization
• Effective Date: 15-Jul-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 D7706-17 - Standard Practice for Rapid Screening of VOC Emissions from Products Using Micro-Scale Chambers
• Effective Date: 01-May-2017
• Refers: ASTM D6196-15 - Standard Practice for Choosing Sorbents, Sampling Parameters and Thermal Desorption Analytical Conditions for Monitoring Volatile Organic Chemicals in Air
• Effective Date: 01-Nov-2015
• 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 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 E741-11 - Standard Test Method for Determining Air Change in a Single Zone by Means of a Tracer Gas Dilution
• Effective Date: 01-Sep-2011

Overview

ASTM D6670-18: Standard Practice for Full-Scale Chamber Determination of Volatile Organic Emissions from Indoor Materials/Products provides comprehensive protocols for measuring volatile organic compound (VOC) emissions from building materials, products, and equipment under environmental conditions characteristic of office and residential buildings. Maintaining healthy indoor air quality (IAQ) is essential in all built environments, and understanding VOC emission rates is critical for manufacturers, architects, indoor air quality professionals, and regulatory authorities. This standard establishes best practices for full-scale environmental chamber testing, offering guidance on the design, operation, and use of these chambers to assess real-world emissions and their potential impact on IAQ.

Key Topics

• VOC Emissions and Indoor Air Quality
  VOCs (volatile organic compounds) emitted from indoor materials and products can significantly affect indoor air quality, influencing occupant health and comfort.

• Full-Scale Environmental Chamber Testing
  This standard covers the use of room-size (full-scale) environmental chambers, including their design, construction, and the control of critical parameters such as temperature, humidity, air change rates, and air velocity.

• Emission Measurement and Analysis
  The practice details procedures for sampling and analyzing air from the chamber to identify emitted VOCs and determine their emission rates over time.

• Variables Affecting Emission Rates
  Several factors, including material properties, temperature, humidity, air velocity, and the chamber’s loading ratio, play important roles in VOC emission dynamics.

• Multi-Purpose Utility
  While optimized for VOCs, these chamber facilities and methods can also support emissions testing during application processes (like painting), development of scale-up methods, study of source/sink interactions, validation of IAQ predictive models, assessment of interactions with pollutants (ozone, NOx, SOx), and evaluation of air cleaners.

Applications

ASTM D6670-18 serves a broad range of practical applications aimed at improving indoor environments:

• Building Material and Product Certification
  Manufacturers can use chamber testing as part of product development and certification to ensure compliance with IAQ requirements and to qualify for green building certifications.

• Equipment Emissions Evaluation
  The standard applies to emissions from equipment such as printers, photocopiers, and air cleaning devices, allowing objective comparisons across brands and models.

• Research and Validation
  Researchers use the chamber method to refine source and sink models, support epidemiological studies, or validate IAQ simulation tools for new buildings or renovations.

• Regulatory and Reference Testing
  Regulatory authorities and third-party certifiers rely on the standard’s protocols for compliance testing and to validate claims regarding low-emitting products.

• Air Cleaner Performance Testing
  The chamber method can be adapted to evaluate how effectively air cleaning devices reduce indoor VOC concentrations.

Related Standards

Understanding and applying ASTM D6670-18 can be enhanced with reference to additional guidance and standards, including:

• ASTM D5116 - Guide for Small-Scale Chamber Determinations of Organic Emissions
• ASTM D1356 - Terminology Relating to Sampling and Analysis of Atmospheres
• ASTM D5197, D5466, D6196 - Various test methods for VOC analysis and sampling
• ASHRAE 62.1 and 62.2 - Standards for ventilation and acceptable indoor air quality in buildings
• ISO 14644-1 - Cleanroom air cleanliness classification
• U.S. EPA TO-15, TO-17 - Compendiums for toxic organic compound determination in air

Conclusion

ASTM D6670-18 is an essential standard for full-scale chamber testing of VOC emissions, supporting efforts to improve and verify healthy indoor air quality. By following its clearly defined protocols, stakeholders can better assess emissions from materials, products, and equipment under authentic use conditions, ultimately contributing to safer, healthier, and more sustainable building environments.

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: D6670 − 18
Standard Practice for
Full-Scale Chamber Determination of Volatile Organic
Emissions from Indoor Materials/Products
This standard is issued under the fixed designation D6670; 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 is intended for determining volatile or-
D1356 Terminology Relating to Sampling and Analysis of
ganiccompound(VOC)emissionsfrommaterialsandproducts
Atmospheres
(building materials, material systems, furniture, consumer
D1914 PracticeforConversionUnitsandFactorsRelatingto
products, etc.) and equipment (printers, photocopiers, air
Sampling and Analysis of Atmospheres
cleaners, etc.) under environmental and product usage condi-
tions that are typical of those found in office and residential D5116 Guide for Small-Scale Environmental Chamber De-
terminations of Organic Emissions from Indoor Materials/
buildings.
Products
1.2 This practice is for identifying VOCs emitted and
D5197 Test Method for Determination of Formaldehyde and
determining their emission rates over a period of time.
OtherCarbonylCompoundsinAir(ActiveSamplerMeth-
1.3 This practice describes the design, construction, perfor-
odology)
mance evaluation, and use of full-scale chambers for VOC
D5466 Test Method for Determination of Volatile Organic
emission testing.
Compounds in Atmospheres (Canister Sampling Method-
ology)
1.4 While this practice is limited to the measurement of
D6196 Practice for Choosing Sorbents, Sampling Param-
VOCemissions,manyofthegeneralprinciplesandprocedures
eters and Thermal Desorption Analytical Conditions for
(such as methods for evaluating the general performance of the
Monitoring Volatile Organic Chemicals in Air
chamber system) may also be useful for the determination of
D6345 Guide for Selection of Methods for Active, Integra-
other chemical emissions (for example, ozone, nitrogen diox-
tive Sampling of Volatile Organic Compounds in Air
ide).Determinationofaerosolandparticleemissionsisbeyond
D7706 Practice for Rapid Screening of VOC Emissions
the scope of this document.
from Products Using Micro-Scale Chambers
1.5 The values stated in SI units are to be regarded as
E741 Test Method for Determining Air Change in a Single
standard. No other units of measurement are included in this
Zone by Means of a Tracer Gas Dilution
standard.
E779 Test Method for DeterminingAir Leakage Rate by Fan
1.6 This standard does not purport to address all of the Pressurization
safety concerns, if any, associated with its use. It is the E1333 Test Method for Determining Formaldehyde Concen-
responsibility of the user of this standard to establish appro- trations in Air and Emission Rates from Wood Products
priate safety, health, and environmental practices and deter- Using a Large Chamber
mine the applicability of regulatory limitations prior to use.
2.2 Other Documents:
1.7 This international standard was developed in accor-
ASHRAE 62.1–2010 Ventilation for Acceptable Indoor Air
dance with internationally recognized principles on standard-
Quality
ization established in the Decision on Principles for the
ASHRAE 62.2–2010 Ventilation and Acceptable Indoor Air
Development of International Standards, Guides and Recom-
Quality in Low-Rise Residential Buildings
mendations issued by the World Trade Organization Technical
CMEIAQ 1999a A Method for Sampling and Analysis of
Barriers to Trade (TBT) Committee.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
This practice is under the jurisdiction ofASTM Committee D22 on Air Quality Standards volume information, refer to the standard’s Document Summary page on
and is the direct responsibility of Subcommittee D22.05 on Indoor Air. the ASTM website.
Current edition approved Sept. 1, 2018. Published September 2018. Originally Available from American Society of Heating, Refrigerating, and Air-
approved in 2001. Last previous edition approved in 2013 as D6670 – 13. DOI: Conditioning Engineers, Inc. (ASHRAE), 1791 Tullie Circle, NE, Atlanta, GA
10.1520/D6670-18. 30329, http://www.ashrae.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6670 − 18
Volatile Organic Compounds in Emission Testing of 3.2.5 emission factor—the mass of a VOC or total VOC
Building Materials, Final Report 1.1 Consortium for emitted per unit time and per unit amount of source tested.
Material Emissions and Indoor Air Quality (Institute for Depending on the type of source, the amount of source may be
Research in Construction) expressed by its exposed surface area (that is, an area source
CMEIAQ 1999b Models for Predicting Volatile Organic such as a painted gypsum wallboard surface), its dominant
Compound (VOC) Emissions from Building Materials, dimension (that is, a line source such as a caulk or sealant), its
Final Report 3.1 Consortium for Material Emissions and mass, or its standard setup (that is, a “unit” source such as a
Indoor Air Quality (Institute for Research in Construc- predefined work station system). As a result, the unit for the
4 2
tion) emission factor will be mg/h, mg/(m h), mg/(m h), mg/(kg h),
EPA-600/4-89/017 Compendium of Methods for Determina- and mg/(m h) for the “unit,” line, area, mass, and volume
tion of Toxic Organic Compounds in Ambient Air (this emission sources, respectively.
report contains TO-17)
3.2.6 emission rate—see definition of emission rate in
EPA/625/R-96-010b Compendium of Methods for the De-
Terminology D1356 – 17.
termination of Toxic Organic Compounds inAmbientAir,
3.2.7 full-scale chamber—a room-size chamber that can
Compendium Methods TO-15 and TO-17, January 1999
house the material/product to be tested in its real dimensions,
ISO 14644-1:1999 Cleanrooms and Associated Controlled
and provide the required environmental conditions
Environments—Part 1: Classification of Air Cleanliness
(temperature, relative humidity, air exchange, and air velocity)
that are similar to the material/product use in full-scale room
3. Terminology
conditions.
3.1 Definitions—For definitions and terms commonly used
3.2.8 time zero—the start time when the emission factor is
inASTM standards, including this standard, refer to Terminol-
measured. It will depend on the purpose of the testing. For
ogy D1356. For an explanation of units, symbols, and conver-
example, time zero may be defined as the time when the test
sion factors, refer to Practice D1914.
specimen is loaded into the chamber if the test specimen is
3.2 Definitions of Terms Specific to This Standard:
preparedoutsidethechamber.Alternatively,whentheemission
3.2.1 air change rate (1/h)—the flow rate of air into the
during an application process (for example, painting) is to be
chamber divided by the net chamber volume usually expressed
tested, time zero may be defined as the time when the
in unites of 1/h. The clean air flow rate may be measured
application begins.
directly at the clean air supply duct. The clean air change rate
3.2.9 total volatile organic compound (TVOC)— the sum of
can also be determined by conducting a tracer gas test (for
theconcentrationsofalltheindividualVOCscapturedfromair
example, a tracer gas decay test) in the chamber. Note that the
by a given sorbent, or a given combination of several sorbents,
air exchange rate (in units of 1/h) is abbreviated as ACH.
thermally desorbed into and eluted from a given gas chromato-
3.2.2 chamber loading ratio—the total amount of test speci-
graphic system, and measured by a given detector. For VOC
men exposed in the chamber divided by the net or corrected
definition, see Terminology D1356 (formaldehyde and other
internal air volume of the chamber.
very volatile organic compounds are included in this defini-
3.2.3 clean air—defined in this practice as air that satisfies
tion).
all of the following criteria:
3.2.9.1 Discussion—The measured value of TVOC will
(1) concentrations of total VOCs ≤10 µg/m ;
depend on the collection and desorption efficiency of the
(2) concentration of any individual compound to be mea-
sorbent trap; the efficiency of transfer to the GC column; the
sured ≤2.0 µg/m ;
type and size of the GC column; the GC temperature program
(3) particle concentrations ≤35 200 particles/m of 0.5 µm
and other chromatographic parameters; the type of GC
diameter or larger (that is, the ISO Class 6 according to ISO
detector, as well as the calibration method and peak integration
14644-1:1999;
process. Compounds such as formaldehyde, which are typi-
(4) concentrations of ozone and other potentially reactive
callymonitoredusinganalyticalsystemsotherthanGC,arenot
species such as nitrogen oxides (NO ) and sulfur oxides (SO )
x x included in the TVOC value.
should be at or below detectable levels (for example, <10
3.2.10 tracer gas—a gaseous compound that can be used to
µg/m ).
determine the mixing characteristics of the test chamber and be
3.2.4 dry materials—materials such as carpets, wood-based
a cross-check of the air change rate.The tracer gas must not be
products, and polyvinyl chloride (PVC) floorings, whose
emitted by the test specimen and must not be contained in the
emission is generally controlled by diffusion processes within
supply air.
the bulk of the material.
3.2.11 wet materials—materials such as paints, stains, and
varnishes, whose initial emission period is primarily controlled
Available from National Research Council Canada, 1200 Montreal Road,
by evaporative mass transfer and therefore dependent on
Building M-58, Ottawa, Ontario K1A 0R6, https://www.nrc-cnrc.gc.ca.
surface air velocity.
AvailablefromUnitedStatesEnvironmentalProtectionAgency(EPA),William
Jefferson Clinton Bldg., 1200 Pennsylvania Ave., NW, Washington, DC 20460,
http://www.epa.gov. 4. Summary of Practice
Available from International Organization for Standardization (ISO), ISO
4.1 Materials or products are placed in a full-scale test
Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,
Geneva, Switzerland, http://www.iso.org. chamber within which temperature, relative humidity, and air
D6670 − 18
change rate are controlled according to set parameters. Air is concentrations of the air exhausted from the chamber and the
sampled at the exhaust of or inside the chamber, and analyzed clean airflow rate (refer to Section 11 for the actual calculation
by appropriate methods to identify the major emitted com- procedure). The concentrations and clean airflow rate must be
pounds and their concentrations as a function of time. The determined for the same temperature condition since the air
measured concentrations are then used to determine the emis- volume changes with air temperature. For example, when
sion rates or the emission characteristics, or both, of the testing products that generate significant heat (for example,
material or product. This information can be used to assess the copiers), the exhaust air temperature will be higher than the
contributionofthematerialsandproductstotheconcentrations supply air temperature. If the concentration is measured at the
in the space of interest (for example, the occupied zone). chamber exhaust while airflow rate is measured at the chamber
supply, the supply airflow rate must be first adjusted to the
5. Significance and Use
equivalent airflow rate under the exhaust air temperature (that
5.1 VOCs emitted from materials/products affect indoor air
is, multiplied by the ratio of exhaust to supply air temperature
quality (IAQ) in buildings. To determine the impact of these
in degrees Kelvin) before it is used for determining the
emissions on IAQ, it is necessary to know their emission rates
emission rate.
over time. This practice provides guidelines for using a
Note that, in addition to the uniform VOC concentration
full-scale environmental chamber for testing large materials
assumption, Eq 1 also assumes no chemical reaction in the
and full-scale material systems/assemblies.
chamber, no air entry into the chamber other than the supply
air, and a negligible VOC concentration at the supply air,
5.2 While this practice is developed for measuring VOC
compared to that measured at the chamber exhaust. The
emissions, the chamber facilities and methods of evaluation
validity of using Eq 1 depends on how well the chamber’s
presented in this practice are also useful for a variety of
actual operation meets these assumptions. Therefore, the per-
purposes including: (1) testing the emissions during the appli-
formance of the chamber must be evaluated against certain
cationprocess(forexample,painting),orotherrelatedsources;
criteria in order to obtain reliable and reproducible test results
(2) developing scaleup methods (for example, from small
(see Section 8).
chamber results to a full-scale scenario); (3) studying the
interaction between sources and sinks, and validating source/
6.2 Tests Under Non-Uniform Concentration Conditions—
sink models which are the basis for IAQ prediction; (4) testing
The full-scale chamber system can also be used to simulate the
interactions between source emissions and other compounds in
room airflow conditions in real buildings, which are not
the air (for example, NO , ozone, SO ); and (5) evaluating the
x x
necessarily well mixed (for example, in the case of a displace-
performance of air cleaning devices intended to remove
ment ventilation system). In this case, the VOC concentrations
contaminants from indoor air.
measured within a defined occupied zone in the chamber (for
example, concentrations measured at the center of or various
6. Principles
locations within the chamber) can be used directly to simulate
6.1 Tests Under Uniform Chamber Concentration
the impact of the test materials/products on the VOC concen-
Conditions—Assuming that the concentration of each emitted
tration levels in the room under a specified material/product
VOC tested in the chamber air is uniform as a result of good
loading ratio and ventilation rate conditions that are similar to
mixing,theconcentrationisthengovernedbythemassbalance
those expected in real buildings. Such tests may be useful in
equation:
evaluating complex field situations. However, a detailed un-
dC t
~ !
derstanding of air movement and emission dynamics for each
V 5 R~t! 2 QC~t! 2 S~t! (1)
dt
simulationisnecessaryinordertoextrapolatethetestresultsto
other field situations.
where:
Typical airflow patterns and air distributions in ventilated
V = air volume of the chamber excluding air volume
spaces may be simulated by appropriate designs of supply air
taken by test specimens, m ,
diffusers and return air grilles with appropriate recirculated
t = time, h,
airflow rate if the goal is to assess emissions under realistic
C(t) = concentration of the emitted VOC in the air ex-
airflow conditions. The total air change rate (outdoor/clean
hausted from the chamber at time t (can be measured
3 airflow rate plus the recirculated airflow rate) in office build-
at the chamber return or exhaust air ducts), mg/m ,
ings may range from 1.0 to 9.0/h, depending on the heating/
R(t) = emission rate at time t, of the source(s) in the
cooling requirements for the space. Typical types of air
chamber, mg/h,
diffusers and airflow patterns in ventilated rooms are described
Q = cleanairflowratesuppliedtothechamber(measured
in ASHRAE (1).
at clean air supply duct or determined by a tracer gas
test), m /h, and,
6.3 Variables Affecting Emission Rates—The emission of
S(t) = sink term representing loss (or re-emission if nega-
pollutants from indoor materials/products generally involves
tive) of the VOC at time t due to adsorption/
three mass transfer processes: (1) diffusion of pollutants from
desorption effect on the interior surfaces of the
within the material to the surface; (2) thermal dynamic mass
chamber and ducts, mg/h (see 8.6 for its
equilibrium conditions at the material/air interface (that is, at
determination).
thesurface);and(3)convectionfromthesurfacetotheambient
Based on Eq 1, theVOC emission rates of a test specimen as air. Variables affecting emission rates include those related to
a function of time can be determined by measuring the the materials/products themselves (emitting source variables)
D6670 − 18
and those related to the environment within which they are For products that generate significant heat (for example,
tested or used (environmental variables). Other factors that copy machines), a relatively large variation of air temperature
and airflow pattern in the chamber may be present due to the
may affect emission rates include chemical reactions or oper-
convective heat transfer from the test product. Ideally, the
ating conditions of the test product (for example, emissions
from office machines may depend upon conditions of use). chamber air temperature should be controlled to typical indoor
air temperatures when evaluating heat generating devices, as
6.3.1 Emitting Source Variables—Emitting source variables
happens in mechanically ventilated buildings [Brown (4)].
include the physical and chemical properties of the materials/
Where this is not possible due to limitations of the chamber
products/application such as chemical composition, density,
system, the test protocol should define the chamber operating
thickness, internal structure, surface characteristics, and ways
procedures consistent with the test objectives and the test
materials are applied. These are related to raw materials,
protocol should address the impact of temperature on determi-
additives, the manufacturing processes, and operating condi-
nation and comparability of emission rates.
tions. These variables influence the type of VOCs that are
6.3.2.2 Relative Humidity—Relative humidity may affect
emitted, their diffusion coefficients within the material, their
emissions of pollutants that are hydrophilic or pollutants
adsorption/desorption equilibrium constants over the surface,
generated by chemical reactions with water. It may also affect
and ultimately their emission rate profiles.
VOC emissions from materials that are hygroscopic since the
The physical and chemical properties of manufactured
adsorbed water may change the diffusion properties of the
products may change with time and may be affected by
material and how the VOC desorbs from the surface. For
environmental conditions. Therefore, it is necessary to know
emission sources that contain water (for example, water-based
theageofmaterialsorproductstobetested.Itisalsoimportant
paints, water-based cleaners, and water-based adhesives), rela-
to document the history (for example, environmental condi-
tive humidity may have a profound impact on the VOC
tions during storage and transportation periods before testing)
emissions because it controls the rate of water evaporation
of the test specimens from their manufacture until testing. If
from the source. The extent to which the relative humidity
the goal of the testing is to compare the emission characteris-
affects VOC emissions depends on specific materials and
tics of different materials or products of the same type, all test
VOCs emitted according to Wolkoff (
2) and Roache et al. (5).
specimens should be approximately the same age and have
As detailed information on the effect of relative humidity on
approximately the same history of exposure to environmental
emission rates is not available, chamber tests are usually
conditions.
conducted under a single relative humidity (for example, 50 6
6.3.2 Environmental Variables—Local environmental con-
5 % RH) for products that do not adsorb or generate significant
ditions can significantly affect VOC emissions. Major factors
amounts of moisture. Ideally, test specimens should be precon-
includetemperature,relativehumidity,airmotion(velocityand
ditioned under the test relative humidity condition before
turbulence), and VOC concentrations in the ambient air. The
testing. However, this is usually not practical because exposing
ventilation rate in test chambers (or building space) and the
the test specimen to conditioned air also means emittingVOCs
loading (amount of product used in a certain space volume)
before the test is actually started. As a result, test products are
also affect the VOC emissions, since they affect the local VOC
usually wrapped or sealed in their original package materials/
concentrations and airflow conditions in the chamber/space.
containers for temperature conditioning only before testing.
These environmental factors can change the VOC emission
For moisture-adsorbing products (for example, fresh furni-
rates at any given time and, therefore, produce different
ture materials) or moisture-generating products (for example,
emission profiles. The following sections briefly review the
printers,liquidchemicalproducts),alargervariationofrelative
effects of these environmental factors.
humidity may be allowed in the chamber. Similar to the
6.3.2.1 Temperature—An increase in the temperature of the
temperature variation in the chamber when testing a heat-
materials and or the ambient air can result in an increase in
generating product (see 6.3.2.1), the moisture variation in the
diffusivities and evaporative mass transfer coefficients. More
chamber when testing moisture-adsorbing or moisture-
importantly, increasing temperature will significantly increase generating products also depends on the chamber operation.
the vapor pressure of VOCs. For instance, a temperature
Specific chamber operating procedure and acceptable variabil-
increase from 23 to 33°C will increase the mass transfer ity of relative humidity in the chamber should be established in
coefficient for decane by only 6 %, but will increase the vapor a product-specific test protocol based on the test objectives.
pressure for decane by 83 %. This will lead to an increase in
6.3.2.3 Air Velocity and Turbulence—Air velocity and tur-
VOC emission rates, since emission rate is proportional to the
bulence affect the evaporative mass transfer from both solid
vapor pressure of the VOC for “wet” emitting sources. The
and liquid sources. For “wet” materials such as paints, stains,
strength of this temperature effect depends on specific materi-
varnishes, and caulks/sealants whose initial emission period is
als and VOCs emitted according to Wolkoff (2) and Van der
primarily controlled by evaporative mass transfer, increasing
Waletal. (3). Relationships between the ambient air tempera-
the air velocity and turbulence will lead to an increase in
ture and emission rates have yet to be developed. Full-scale
emission rates of VOCs. The effect becomes smaller as the
chamber tests are currently conducted under a standard tem-
materials become drier according to Roache et al. (5) and
perature (for example, 23 6 0.5°C for non heat-generating Zhang et al. (6). For dry materials such as carpets, wood-based
products). Specimens are, therefore, preconditioned under the
products, and polyvinyl chloride (PVC) floorings, air velocity
same temperature before testing. andturbulenceaffectemissionratesonlywithinthefirst5to10
D6670 − 18
h of being exposed to the ambient air. After that, the effect emission factor) as a function of time, environmental condi-
becomes insignificant because the emissions will be controlled tions (temperature, humidity, and air velocity, etc.), or source
by internal diffusion, according toAwad (7),Yang (8),Wolkoff (initial VOC content and composition, density, etc.) variables,
et al. (9), Little et al. (10), and Roache et al., (5). or combination thereof. These models are useful for designing
full-scale experiments. For example, they can be used to select
In office and residential buildings, the magnitude of air
air sampling intervals and experimental conditions. They are
velocities over material surfaces is typically in the range of 0
also useful for analyzing emission test results from which the
to 0.25 m/s according to Mathews et al. (11) and Zhang et al.
coefficients of selected models are estimated (see Section 11).
(12). Turbulence kinetic energy is typically in the range of 0 to
Finally, the models can be used to extrapolate short-term
0.01 (m/s) . In full-scale chambers, these air velocity and
emission test data to a longer term and from environmental
turbulence levels can be simulated if the testing purpose is to
chamber test conditions to field conditions. However, care
simulate a real room airflow condition. Because the actual air
should always be exercised in the extrapolation since any
velocity and turbulence levels will be different from location to
model has its limitations [CMEIAQ 1999b, Guo (16), Little et
location in the chamber, multi-point measurements should be
al. (10), and Zhang and Shaw (17)].
taken near the surfaces (for example, 1.0 cm from the surface)
of test specimens to verify that the desired air velocity and
7. Facilities and Equipment
turbulence levels are achieved. This is especially important for
testing convective-controlled emission sources such as paints
7.1 General Considerations for Chamber System Design
and wood stains. For internal diffusion-controlled emission
and Construction—A complete full-scale chamber test facility
sources such as carpets and engineered wood products, precise
consists of: a full-scale chamber and its heating, ventilation,
controls of the air velocity and turbulence over the surfaces of
and air-conditioning (HVAC) system for air supply and
testspecimensarenotrequiredunlesstheemissionratesduring
conditioning, an air sampling and analysis system, and a data
the first 5–10 h are of interest. For internal diffusion-controlled
acquisition and recording system. The system should be
emission sources a general specification on air velocity (for
housed in a clean and air-conditioned laboratory space. Fol-
example, in the range of 0.05 to 0.25 m/s) is usually sufficient.
lowing are the general design and construction considerations:
6.3.2.4 VOC Concentrations in Air, Air Change Rate, and
7.1.1 The chamber should be large enough to accommodate
Loading Ratio—For an emitting material in the absence of
the products to be tested and allow the simulation of the
other strong sources, the VOC concentration at the material
product use in full-scale room conditions.
surface is generally higher than that in the surrounding air. A
7.1.2 The chamber HVAC system must provide stable and
higher VOC concentration in the air will lead to a lower
accurate control of the airflow rate, temperature, differential
concentration gradient between the material surface and the
pressure (pressure relative to the ambient pressure outside the
surrounding air, and hence a lower convective mass transfer
chamber), and relative humidity within the chamber, and have
rate from the surface to the air. The emission rate decreases as
the capacity to operate over the entire range of desired
the VOC concentration in the chamber increases (for example,
operating/testing conditions, considering the generation of heat
during the initial emission period of “wet” materials).
and moisture from sources to be tested.
VOC concentrations in a chamber/space are dependent on
7.1.3 The chamber, air cleaning, and distribution compo-
the air change rate (ventilation rate) or material loading ratio,
nents must be constructed of materials that minimize adsorp-
or both, for a given emission source.Ahigh air change rate or
tion and emission of VOCs [for example, stainless steel, glass,
a low material loading ratio will result in a low concentration
polytetrafluoroethylene (PTFE)]. Fans and bearings must be
in the chamber or space, and hence increase the emission rates.
designed to prevent intrusion of emissions from lubricants into
In addition, increasing the air change rate can also result in an
the clean air system.
increase in velocity and turbulence levels over the emitting
7.1.4 The chamber system should be airtight in order to
surfaces, and hence the convective mass transfer coefficient.
minimize any air leakage between the inside and the outside of
Chamber tests can be conducted to simulate the impact of
the chamber system.
outdoor/clean air supply on room VOC concentrations. In
7.1.5 The chamber system should be capable of providing
office and residential buildings, outdoor air change rates may
sufficient mixing in the chamber for testing under the uniform
range from 0.05 to 1.5 air changes per hour [ASHRAE (13),
VOC concentration assumption. If the chamber is intended to
ASHRAE (14), and Reardon and Zhang (15)]. ASHRAE
simulate airflow patterns, air distribution, air velocity, and
62.1–2010 and ASHRAE 62.2–2010 specify the outdoor air
turbulence levels that are typically found in real ventilated
flow requirements for achieving acceptable IAQ. Additional
rooms, in addition to having the capability to accurately
recirculated air is required to meet the heating or cooling
determine the emissions from indoor products, the chamber
requirements for the space. If the purpose of a chamber test is
should be designed to accommodate both types of studies.
to evaluate the impact of clean/outdoor air change rate on the
7.1.6 The chamber system should be able to provide on-line
VOC concentration levels, a mixing fan may be placed in the
monitoring of the test conditions including airflow rates (clean
chamber to achieve adequate mixing for emission tests (see
and recirculated air), air temperature, relative humidity, and
6.1). When this is done, however, airflow patterns in actual
differential pressure inside the chamber and in the ventilation
rooms are not simulated in the chamber.
ducts. For example, a data acquisition system may be set up to
6.4 The Role of Source Emission Models—Source emission monitor these conditions every minute. (Note that the reading
models are used to describe the VOC emission rates (or frequencyrequiredforachievinggoodcontrolaccuracymaybe
D6670 − 18
FIG. 1 Schematic of a Full-Scale Chamber System—Example 1 (EPA and NRC Chambers)
much smaller, but will depend on the chamber system.) This wire brushing or mechanical grinding. If a highly polished
will facilitate the detection of any malfunction of the system surface finish is desired, matte-finish stainless steel sheets
and help diagnose problems. should be used since they can be more easily polished
7.1.7 The chamber system should have adequate sampling mechanicallyafterconstructiontoasemi-mirrorfinish(equiva-
ports for taking air samples both within the chamber and in the lenttothesterilefinishusedinhospitals).Ideally,itisdesirable
ventilation ducts. to electro-polish the surface to minimize the sink effect on the
7.1.8 All components of the chamber system (such as ducts, surfaces, but this is generally not practical because of the size
fans, cooling/heating coils) should be thoroughly cleaned of the chamber.
before they are installed. Effort should also be made to avoid
7.2.2 Chamber Door—The chamber door must be large
contamination during the construction period.
enough to accommodate the largest material/product compo-
7.1.9 The chamber system and all components should be
nents to be tested. The seals between the door and chamber
easily accessible for cleaning and maintenance.
surfaces must be made of non-emitting and non-adsorbing
materials (such as PTFE) and be adequate to maintain chamber
7.2 The Full-Scale Chamber:
leakratesatorbelowacceptablelevels.PTFEgasketsanddoor
7.2.1 Construction Material—Materials such as stainless
clamps are usually used. If the door opens to the inside and the
steel,glass,aluminum,andPTFEcoatingareacceptableforthe
chamber will operate under a positive pressure relative to the
construction of the interior surfaces of the chamber, with
outside of the chamber, the positive pressure in the chamber
stainless steel being the most common choice.Type 304 or 316
will improve the tightness of the door during chamber opera-
stainless steel with No. 4 finishing (a general purpose polished
tion. If the door opens to the outside and the chamber is
finish that finds wide applications in restaurant, dairy, food
operated under a positive pressure, at least two clamps on each
processing, medical, and chemical equipment as well as
side of the doorframe are usually necessary to ensure proper
various architectural products) may be used as the interior wall
airtightness. In either case, the door should be operable from
and floor surface. For example, 11 gage stainless steel panels
inside and outside the chamber for safety purposes. For
may be used for the floor, and 14 gage used for the ceiling and
experiments in which a technician will enter and exit the
walls.Sectionscanbefastenedtogetherbycontinuouswelding
chamber (painting, etc.), it is desirable to have a small entry
at the joints of two panels and by tack welding to their
chamber with its own airtight door.
supporting frame. Some discoloration may be observed in the
vicinity of the welded lines due to the heat and oxidation in the 7.2.3 Lighting and Observation Windows—Lights may be
welding process. The interior welded joints may be cleaned by installed above ceiling glass panels sealed with PTFE gaskets.
D6670 − 18
PTFE-gasket-sealed observation windows may be installed on reaching a flow-regulating valve that is linked via process
walls or the chamber door. controllers to a turbine flowmeter. Chamber pressure can be at
7.2.4 Insulation—The floor, ceiling, walls, and door of the
0-250 Pa above the ambient pressure in the laboratory space,
chamber should be well insulated to minimize the influence of
and requires no extraction fan for operation. An air-
temperature fluctuation outside the chamber on the air tem-
conditioning plant operates between the flow regulating valve
perature in the chamber.
and the meter, conditioning only the supply air. Air enters the
7.2.5 Air Sampling Ports—Sampling ports should be in-
chamber along a central, perforated duct at ceiling level. Two
stalled at desired locations depending on the test purpose (for
similar ducts at floor level are connected to a supply duct via
example, at the mid-height of walls). Stainless steel feed-
a fan so that chamber air can be recirculated. Extra heater and
through connectors with sealing caps may be used for this
chiller components are located in the recirculation duct. The
purpose.The length of the sampling line between the sampling
clean supply air is forced from the chamber under positive
device (for example, adsorbent tube) and the sampling location
pressure via six exhaust ports in the chamber walls. This
should be minimized in order to reduce the effect of VOC
chamber can operate under the FE and RC modes described
adsorption/desorption in the sampling line on the measure-
above, but without humidification of recirculated air.
ments.
7.3.2 Air Preconditioning—The air supplied to the system
7.3 The HVAC System for the Full-Scale Chamber:
may come either directly from outdoors or from the laboratory
7.3.1 System Design—Different approaches may be used to
space. The supply air must be preconditioned to avoid con-
supplycontrolledandconditionedairflowtothechamber.Figs.
tamination of the chamber system and to allow the chamber
1and2showtwodifferentexamplesystems.Dependingonthe
system to operate at all designed temperature and humidity
purpose of testing, System 1 (Fig. 1) may operate in several
conditions. For example, in System 1 (Fig. 1), preconditioning
modes: (1) full exhaust (FE) mode, in which all the supply air
is accomplished by passing the air through a particulate filter,
is exhausted with no air recirculated back to the chamber; (2)
an electric preheater, a chilled water cooling unit, and a
recirculation(RC)mode,inwhichpartoralloftheairfromthe
desiccant dehumidifier. A single-speed fan is used to circulate
chamber is recirculated back to the chamber; and (3) by-pass
the air in the preconditioning loop. This preconditioning loop
(BP) mode, in which part or all the air from the chamber is
allows the system to operate at –40 to 30°C outdoor air
recirculated back to the chamber, bypassing the heating and
temperature and up to 95 % relative humidity. The precondi-
cooling coils and humidifier. The BP mode may be used to
tioning equipment should be sized to condition the air to the
determine if the HVAC components have significant
temperature and humidity ranges that can be handled by the
adsorption/desorption effects for the VOCs measured. System
conditioning components downstream in the recirculation loop
2(Fig. 2) uses a completely different design for air supply,
to achieve the required control accuracy. In example System 2,
conditioning, and handling of air to the chamber.Air supply is
from a compressor at 690 kPa, regulated to 150 kPa before air delivered from the compressor is passed through two
FIG. 2 Schematic of a Full-Scale Chamber System—Example 2 (OCSIRO Chamber)
D6670 − 18
oil-coalescing filters and a refrigerative dryer, and then im- differential) control algorithms programmed in the DDC or the
proved by purification. dedicated computer. In example System 2, temperature,
7.3.3 Air Purification—The supply air should be cleaned to humidity, and supply air flow are controlled by PID-
satisfy the criteria of clean air (see 3.2.3). This can be programmable process controllers in all processes except
accomplished by passing the air through a catalytic oxidation recirculation flow, which is controlled by a fan speed control
system, activated carbon filters or packed beds, and a high- module (calibrated in-situ). The temperature, humidity, and
efficiency particulate air (HEPA) filter. These filters or chemi- supply airflow conditions achieved within the chamber are
cal adsorption beds should have sufficient capacity and be monitored by dual sensors in the chamber and the output from
easily accessible for replacement. the turbine flowmeter, all connected to a data logger. Chamber
7.3.4 Heating,Cooling,andHumidification—Thesupplyair pressure is adjusted manually within the 0–250 Pa above the
should be further conditioned to achieve the required tempera- ambientpressureinthelaboratoryspacebyopeningextravents
ture and humidity control.This may be achieved by passing air in the chamber walls. Recommendations on control accuracy
through cooling/heating coils and a steam or other humidifier. are described in 8.3.
All the components which are exposed to the supply air stream
7.3.6 Air Distribution in the Chamber—To achieve good air
should be made of inert materials such as stainless steel or
mixing in the chamber, air should be introduced through air
tin-plated copper. PTFE gaskets must be used to seal the
diffusers that create air jets (for example, ceiling radial square
various joints (for example, between air duct sections, between
diffusers like those used in cold air distribution systems
the cooling/heating component and ducts). The water supplied
[Kirkpatrick and Elleson (18)]), or introduced through tube(s)
to the humidifier must be purified and deionized.
with small perforated holes that distribute air evenly across the
7.3.5 Control of System Operation—The operation of the
chamber. The tubes are usually located at the floor or ceiling
chamber system may be controlled by a stand-alone DDC
level.Air is usually exhausted at or close to the ceiling or floor
(direct digital control) controller or a dedicated computer. The
level. If the purpose is to study the spatial distribution of VOC
set points for airflow rates, temperature, and relative humidity
concentrations in ventilated spaces, stainless steel diffuser(s)
can be set by a microcomputer, which also monitors, displays,
should be made to represent actual air diffusers that produce
and records the operation conditions. The sensor reading
realistic airflow distributions.
frequency should be at least once every second, and the control
7.4 Sample Collection and Analysis:
system should be able to make the control adjustment to
7.4.1 General Considerations—There are many ways to
achieve continuous control (refer to 8.3 and Table 1). One
collect, detect, and quantify VOCs emitted from products.
minute average of the 1 s readings may be recorded every
Every approach has its applications and limitations. Selection
minute. In System 1 (Fig. 1), airflow rates are measured by
of the appropriate sampling and analysis strategies often
using orifice plates at the outdoor air supply duct, the precon-
dependsuponthegoalsofthetestingandresourcesavailableas
ditioning loop, immediately before the activated carbon
well as the nature of the source emissions. It is often necessary
adsorber, immediately before and after the chamber, and the
totailorsamplingstrategiestotestconditionsandtoanalytesof
exhaust duct. By controlling the positions of the interlocked air
interest or employ several sampling strategies, or both, in order
dampers at the exhaust and recirculation ducts, the exhaust
to characterize emissions from a particular source and test
airflowrate(andthereforethecleanairsupplyflowrate)canbe
condition. General considerations that are generic to source
controlled. The total supply airflow rate is controlled by
characterization using large chambers are presented in this
adjusting the position of the air damper upstream of the return
practice [see Fortmann et al. (19) for a more detailed discus-
fan (Fig. 1). The chamber pressure is controlled by the air
sion]. Detailed considerations specific to individual sources are
damper installed upstream of the activated charcoal filter.
beyond the scope of this document. CMEIAQ 1999a describes
These controls are accomplished by PID (proportional integral
detailed considerations in sampling and analysis for testing
VOC emissions from building materials.
A A
TABLE 1 Recommended Control Accuracy and Precision in a
24-Hour Assessment Test Many of the procedures and equipment items utilized for
characterization of indoor air source emissions are adapted
Control Accuracy, ∆ Control Precision, Γ
Parameter
(expressed as bias)
from methods developed for ambient air sampling and analy-
Temperature, °C ±0.5 ±0.5
sis. The general applicability of a particular method for source
Relative humidity, % ±2 ±5
B characterization will depend upon the nature of the source, test
Chamber pressure, Pa ±10 % of the set point, ±20 % of the set point, or
or conditions, and limitations of the sampling and analysis meth-
±5 Pa, whichever is ±10 Pa, whichever is
ods. For example, a broad range of VOC emissions may be
greater greater
C collected on sorbent media. Analytes are typically thermally
Airflow rates, L/s ±3 % of the set point ±5 % of the mean value
desorbed from the sampling media, concentrated on a second-
A
Defined as the standard deviations of the measured parameters.
B
ary trap, then flash-desorbed in an inert gas flow to the column
Static chamber pressure referenced to the pressure outside the chamber.
C
Including clean airflow rate, total supply airflow rate, return airflow rate, and
of a gas chromatograph (GC) for separation and subsequent
exhaust airflow rate. Tracer gas tests should also be conducted to determine the
detection and quantitation. Accurate quantitation of chamber
clean air change rate and demonstrate its consistence with the clean airflow rate
measured at the clean air supply duct. Note that the above criteria are provided as emissions depends upon collection efficiency of the sampling
a guide for evaluating the integrity of the chamber facility. Specific and possibly
system, stability of analytes during storage, transfer efficiency
different criteria may be established in product-specific test protocols according to
oftheconcentratorsystem,separationefficiencyofthecolumn,
specific test purposes.
and sensitivity and range of the detection system. Such a
D6670 − 18
system may be optimized for accurate determination of a broad trap is placed upstream of the sample collection device, it may
range of non-polar VOCs. Optimization of the system for a be necessary to demonstrate quantitative recovery of analytes.
particular
...

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: D6670 − 13 D6670 − 18
Standard Practice for
Full-Scale Chamber Determination of Volatile Organic
Emissions from Indoor Materials/Products
This standard is issued under the fixed designation D6670; 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 is intended for determining volatile organic compound (VOC) emissions from materials and products (building
materials, material systems, furniture, consumer products, etc.) and equipment (printers, photocopiers, air cleaners, etc.) under
environmental and product usage conditions that are typical of those found in office and residential buildings.
1.2 This practice is for identifying VOCs emitted and determining their emission rates over a period of time.
1.3 This practice describes the design, construction, performance evaluation, and use of full-scale chambers for VOC emission
testing.
1.4 While this practice is limited to the measurement of VOC emissions, many of the general principles and procedures (such
as methods for evaluating the general performance of the chamber system) may also be useful for the determination of other
chemical emissions (for example, ozone, nitrogen dioxide). Determination of aerosol and particle emissions is beyond the scope
of this document.
1.5 Values stated in the International System of Units (SI) The values stated in SI units are to be regarded as the standard. No
other units of measurement are included in this standard.
1.6 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.
1.7 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
D1914 Practice for Conversion Units and Factors Relating to Sampling and Analysis of Atmospheres
D3686 Practice for Sampling Atmospheres to Collect Organic Compound Vapors (Activated Charcoal Tube Adsorption Method)
D5116 Guide for Small-Scale Environmental Chamber Determinations of Organic Emissions from Indoor Materials/Products
D5197 Test Method for Determination of Formaldehyde and Other Carbonyl Compounds in Air (Active Sampler Methodology)
D5466 Test Method for Determination of Volatile Organic Compounds in Atmospheres (Canister Sampling Methodology)
D6196 Practice for Choosing Sorbents, Sampling Parameters and Thermal Desorption Analytical Conditions for Monitoring
Volatile Organic Chemicals in Air
D6345 Guide for Selection of Methods for Active, Integrative Sampling of Volatile Organic Compounds in Air
D7706 Practice for Rapid Screening of VOC Emissions from Products Using Micro-Scale Chambers
E741 Test Method for Determining Air Change in a Single Zone by Means of a Tracer Gas Dilution
E779 Test Method for Determining Air Leakage Rate by Fan Pressurization
E1333 Test Method for Determining Formaldehyde Concentrations in Air and Emission Rates from Wood Products Using a
Large Chamber
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, 2013Sept. 1, 2018. Published April 2013September 2018. Originally approved in 2001. Last previous edition approved in 20072013 as
D6670 – 01 (2007).D6670 – 13. DOI: 10.1520/D6670-13.10.1520/D6670-18.
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’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
D6670 − 18
IEEE/ASTM SI-10 Standard for Use of the International System of Units (SI): The Modern Metric System
2.2 Other Documents:
ACGIH 2012 (American Conference of Governmental Industrial Hygienists), Threshold Limit Values (TLVs) for Chemical
Substances and Physical Agents and Biological Exposure Indices. Cincinnati, OH
ASHRAE 2010a, ASHRAE 62.1-201062.1–2010 “VentilationVentilation for Acceptable Indoor Air Quality,”
QualityAmerican Society of Heating, Refrigerating, and Air-Conditioning Engineers. Atlanta, GA.
ASHRAE 2010b, ASHRAE 62.2-201062.2–2010 “VentilationVentilation and Acceptable Indoor Air Quality in Low-Rise
Residential Buildings,” BuildingsAmerican Society of Heating, Refrigerating, and Air-Conditioning Engineers, Atlanta, GA.
CMEIAQ 1999a “AA Method for Sampling and Analysis of Volatile Organic Compounds in Emission Testing of Building
Materials.”Materials, Final Report 1.1 Consortium for Material Emissions and Indoor Air Quality, InstituteQuality (Institute
for Research in Construction, Construction)National Research Council Canada, Ottawa, Canada
CMEIAQ 1999b “ModelsModels for Predicting Volatile Organic Compound (VOC) Emissions from Building
Materials.”Materials, Final Report 3.1 Consortium for Material Emissions and Indoor Air Quality, InstituteQuality (Institute
for Research in Construction, Construction)National Research Council Canada, Ottawa, Canada
ECA-IAQ (European Collaborative Action) “Indoor Air Quality and Its Impact on Man,” 1997. Total volatile organic
compounds (TVOCs) in indoor air quality investigations. Report No. 19. EUR 17675 EN. Luxembourg: Office for Official
Publications of the European Community
U.S. EPAEPA-600/4-89/017 Compendium of Methods for Determination of Toxic Organic Compounds in Ambient Air, Report
EPA-600/4-89/017 available through the National Technical Information Service, Springfield, VA 22161; PB90-116989. This
report contains TO-17Air (this report contains TO-17)
World Health Organization, 1989 “Indoor Air Quality: Organic Pollutants,” EURO Reports and Studies No. 111, World Health
Organization, Copenhagen, pp. 1-64
ISO 14644-1:1999 Cleanrooms and Associated Controlled Environments—Part 1: Classification of Air Cleanliness
EPA/625/R-96-010b Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air, Compen-
dium Methods TO-15 and TO-17, EPA/625/R-96-010b, January 1999, 1999(NTIS No. PB99-172355)
ISO 14644-1:1999 Cleanrooms and Associated Controlled Environments—Part 1: Classification of Air Cleanliness
3. Terminology
3.1 Definitions—orFor definitions and terms commonly used in ASTM standards, including this standard, refer to Terminology
D1356. For an explanation of units, symbols, and conversion factors, refer to Practice D1914.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 air change rate (1/h)—the flow rate of air into the chamber divided by the net chamber volume usually expressed in unites
of 1/h. The clean air flow rate may be measured directly at the clean air supply duct. The clean air change rate can also be
determined by conducting a tracer gas test (for example, a tracer gas decay test) in the chamber. Note that the air exchange rate
(in units of 1/h) is abbreviated as ACH.
3.2.2 chamber loading ratio—the total amount of test specimen exposed in the chamber divided by the net or corrected internal
3 3 2 3 3 3
air volume of the environmental test chamber in 1/mchamber. , m/m , m /m , and m /m for unit, line, area, and volume emission
sources, respectively (see 3.2.5).
3.2.3 clean air—defined in this practice as air that satisfies all of the following criteria:
(1) concentrations of total VOCs ≤ 10 ≤10 μg/m ;
(2) concentration of any individual compound to be measured ≤ 2.0 ≤2.0 μg/m ;
(3) particle concentrations ≤ 35,200≤35 200 particles/m of 0.5 μm diameter or larger (that is, the ISO Class 6 according to
ISO 14644;14644-1:1999;
(4) concentrations of ozone and other potentially reactive species such as nitrogen oxides (NO ) and sulfur oxides (SO ) should
x x
be at or below detectable levels (for example, <10 μg/m ).
3.2.3 clean air change rate (1/h)—the flow rate of clean air (defined in 3.2.2) in m /h supplied into the chamber divided by the
net air volume (in m ) of the environmental test chamber (that is, volume of an empty chamber minus the volume taken by all
contents in the chamber during testing such as the test specimen, sampling ports). The clean air flow rate may be measured directly
at the clean air supply duct. The clean air change rate can also be determined by conducting a tracer gas test (for example, a tracer
gas decay test) in the chamber. Note that the air exchange rate (in units of 1/h) is abbreviated as ACH.
Available from American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc. (ASHRAE), 1791 Tullie Circle, NE, Atlanta, GA 30329,
http://www.ashrae.org.
Available from National Research Council Canada, 1200 Montreal Road, Building M-58, Ottawa, Ontario K1A 0R6, https://www.nrc-cnrc.gc.ca.
Available from United States Environmental Protection Agency (EPA), William Jefferson Clinton Bldg., 1200 Pennsylvania Ave., NW, Washington, DC 20460,
http://www.epa.gov.
Available from International Organization for Standardization (ISO), ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
Switzerland, http://www.iso.org.
D6670 − 18
3.2.4 dry materials—materials such as carpets, wood-based products, and polyvinyl chloride (PVC) floorings, whose emission
is generally controlled by diffusion processes within the bulk of the material.
3.2.5 emission factor—the mass of a VOC or total VOC emitted per unit time and per unit amount of source tested. Depending
on the type of source, the amount of source may be expressed by its exposed surface area (that is, an area source such as a painted
gypsum wallboard surface), its dominant dimension (that is, a line source such as a caulk or sealant), its mass, or its standard setup
(that is, a “unit” source such as a predefined work station system). As a result, the unit for the emission factor will be mg/h, mg/(m
2 3
h), mg/(m h), mg/(kg h), and mg/(m h) for the “unit,” line, area, mass, and volume emission sources, respectively.
3.2.6 emission rate—the masssee definition of a VOCemission rate or total VOC emitted from all the test specimen(s) present
in the spacein Terminology D1356 per unit time, mg/h. It is equal to the emission factor times the amount of emission source. –
17.
3.2.7 full-scale chamber—a room-size chamber that can house the material/product to be tested in its real dimensions, and
provide the required environmental conditions (temperature, relative humidity, air exchange, and air velocity) that are similar to
the material/product use in full-scale room conditions.
3.2.8 time zero—the start time when the emission factor is measured. It will depend on the purpose of the testing. For example,
time zero may be defined as the time when the test specimen is loaded into the chamber if the test specimen is prepared outside
the chamber. Alternatively, when the emission during an application process (for example, painting) is to be tested, time zero may
be defined as the time when the application begins.
3.2.9 total volatile organic compound (TVOC)— the sum of the concentrations of all the individual VOCs captured from air by
a given sorbent, or a given combination of several sorbents, thermally desorbed into and eluted from a given gas chromatographic
system, and measured by a given detector. For VOC definition, see Terminology D1356 (formaldehyde and other very volatile
organic compounds are included in this definition).
NOTE 1—The measured value of TVOC will depend on the collection and desorption efficiency of the sorbent trap; the efficiency of transfer to the GC
column; the type and size of the GC column; the GC temperature program and other chromatographic parameters; the type of GC detector, as well as
the calibration method and peak integration process. Compounds such as formaldehyde, which are typically monitored using analytical systems other than
GC, are not included in the TVOC value.
3.2.9.1 Discussion—
The measured value of TVOC will depend on the collection and desorption efficiency of the sorbent trap; the efficiency of transfer
to the GC column; the type and size of the GC column; the GC temperature program and other chromatographic parameters; the
type of GC detector, as well as the calibration method and peak integration process. Compounds such as formaldehyde, which are
typically monitored using analytical systems other than GC, are not included in the TVOC value.
3.2.10 tracer gas—a gaseous compound that can be used to determine the mixing characteristics of the test chamber and be a
cross-check of the air change rate. The tracer gas must not be emitted by the test specimen and must not be contained in the supply
air.
3.2.11 wet materials—materials such as paints, stains, and varnishes, whose initial emission period is primarily controlled by
evaporative mass transfer and therefore dependent on surface air velocity.
4. Summary of Practice
4.1 Materials or products are placed in a full-scale test chamber within which temperature, relative humidity, and air change rate
are controlled according to set parameters. Air is sampled at the exhaust of or inside the chamber, and analyzed by appropriate
methods to identify the major emitted compounds and their concentrations as a function of time. The measured concentrations are
then used to determine the emission rates, and/orrates or the emission characteristics characteristics, or both, of the material or
product. This information can be used to assess the contribution of the materials and products to the concentrations in the space
of interest (for example, the occupied zone).
5. Significance and Use
5.1 VOCs emitted from materials/products affect indoor air quality (IAQ) in buildings. To determine the impact of these
emissions on IAQ, it is necessary to know their emission rates over time. This practice provides guidelines for using a full-scale
environmental chamber for testing large materials and full-scale material systems/assemblies.
5.2 While this practice is developed for measuring VOC emissions, the chamber facilities and methods of evaluation presented
in this practice are also useful for a variety of purposes including: (1) testing the emissions during the application process (for
example, painting), or other related sources; (2) developing scaleup methods (for example, from small chamber results to a
full-scale scenario); (3) studying the interaction between sources and sinks, and validating source/sink models which are the basis
for IAQ prediction; (4) testing interactions between source emissions and other compounds in the air (for example, NO , ozone,
x
SO ); and (5) evaluating the performance of air cleaning devices intended to remove contaminants from indoor air.
x
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6. Principles
6.1 Tests Under Uniform Chamber Concentration Conditions—Assuming that the concentration of each emitted VOC tested in
the chamber air is uniform as a result of good mixing, the concentration is then governed by the mass balance equation:
dC t
~ !
V 5 R~t! 2QC~t! 2S~t! (1)
dt
where:
V = air volume of the chamber excluding air volume taken by test specimens, m ;
t = time, h;
C(t) = concentration of the emitted VOC in the air exhausted from the chamber at time t (can be measured at the chamber return
or exhaust air ducts), mg/m ;
R(t) = emission rate at time t, of the source(s) in the chamber, mg/h;
Q = clean air flow rate supplied to the chamber (measured at clean air supply duct or determined by a tracer gas test), m /h;
and,
S(t) = sink term representing loss (or re-emission if negative) of the VOC at time t due to adsorption/desorption effect on the
interior surfaces of the chamber and ducts, mg/h (see section 8.6 for its determination).
V = air volume of the chamber excluding air volume taken by test specimens, m ,
t = time, h,
C(t) = concentration of the emitted VOC in the air exhausted from the chamber at time t (can be measured at the chamber return
or exhaust air ducts), mg/m ,
R(t) = emission rate at time t, of the source(s) in the chamber, mg/h,
Q = clean air flow rate supplied to the chamber (measured at clean air supply duct or determined by a tracer gas test), m /h,
and,
S(t) = sink term representing loss (or re-emission if negative) of the VOC at time t due to adsorption/desorption effect on the
interior surfaces of the chamber and ducts, mg/h (see 8.6 for its determination).
Based on Eq 1, the VOC emission rates of a test specimen as a function of time can be determined by measuring the
concentrations of the air exhausted from the chamber and the clean airflow rate (refer to Section 11 for the actual calculation
procedure). The concentrations and clean airflow rate must be determined for the same temperature condition since the air volume
changes with air temperature. For example, when testing products that generate significant heat (for example, copiers), the exhaust
air temperature will be higher than the supply air temperature. If the concentration is measured at the chamber exhaust while
airflow rate is measured at the chamber supply, the supply airflow rate must be first adjusted to the equivalent airflow rate under
the exhaust air temperature (that is, multiplied by the ratio of exhaust to supply air temperature in degrees Kelvin) before it is used
for determining the emission rate.
Note that, in addition to the uniform VOC concentration assumption, Eq 1 also assumes no chemical reaction in the chamber,
no air entry into the chamber other than the supply air, and a negligible VOC concentration at the supply air, compared to that
measured at the chamber exhaust. The validity of using Eq 1 depends on how well the chamber’s actual operation meets these
assumptions. Therefore, the performance of the chamber must be evaluated against certain criteria in order to obtain reliable and
reproducible test results (see Section 8).
6.2 Tests Under Non-Uniform Concentration Conditions—The full-scale chamber system can also be used to simulate the room
airflow conditions in real buildings, which are not necessarily well mixed (for example, in the case of a displacement ventilation
system). In this case, the VOC concentrations measured within a defined occupied zone in the chamber (for example,
concentrations measured at the center of or various locations within the chamber) can be used directly to simulate the impact of
the test materials/products on the VOC concentration levels in the room under a specified material/product loading ratio and
ventilation rate conditions that are similar to those expected in real buildings. Such tests may be useful in evaluating complex field
situations. However, a detailed understanding of air movement and emission dynamics for each simulation is necessary in order
to extrapolate the test results to other field situations.
Typical airflow patterns and air distributions in ventilated spaces may be simulated by appropriate designs of supply air diffusers
and return air grilles with appropriate recirculated airflow rate if the goal is to assess emissions under realistic airflow conditions.
The total air change rate (outdoor/clean airflow rate plus the recirculated airflow rate) in office buildings may range from 1.0 to
9.0/h, depending on the heating/cooling requirements for the space. Typical types of air diffusers and airflow patterns in ventilated
rooms are described in ASHRAE 2009 (1).
6.3 Variables Affecting Emission Rates—The emission of pollutants from indoor materials/products generally involves three
mass transfer processes: (1) diffusion of pollutants from within the material to the surface; (2) thermal dynamic mass equilibrium
conditions at the material/air interface (that is, at the surface); and (3) convection from the surface to the ambient air. Variables
affecting emission rates include those related to the materials/products themselves (emitting source variables) and those related to
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the environment within which they are tested or used (environmental variables). Other factors that may affect emission rates
include chemical reactions or operating conditions of the test product (for example, emissions from office machines may depend
upon conditions of use).
6.3.1 Emitting Source Variables—Emitting source variables include the physical and chemical properties of the materials/
products/application such as chemical composition, density, thickness, internal structure, surface characteristics, and ways
materials are applied. These are related to raw materials, additives, the manufacturing processes, and operating conditions. These
variables influence the type of VOCs that are emitted, their diffusion coefficients within the material, their adsorption/desorption
equilibrium constants over the surface, and ultimately their emission rate profiles.
The physical and chemical properties of manufactured products may change with time and may be affected by environmental
conditions. Therefore, it is necessary to know the age of materials or products to be tested. It is also important to document the
history (for example, environmental conditions during storage and transportation periods before testing) of the test specimens from
their manufacture until testing. If the goal of the testing is to compare the emission characteristics of different materials or products
of the same type, all test specimens should be approximately the same age and have approximately the same history of exposure
to environmental conditions.
6.3.2 Environmental Variables—Local environmental conditions can significantly affect VOC emissions. Major factors include
temperature, relative humidity, air motion (velocity and turbulence), and VOC concentrations in the ambient air. The ventilation
rate in test chambers (or building space) and the loading (amount of product used in a certain space volume) also affect the VOC
emissions, since they affect the local VOC concentrations and airflow conditions in the chamber/space. These environmental
factors can change the VOC emission rates at any given time and, therefore, produce different emission profiles. The following
sections briefly review the effects of these environmental factors.
6.3.2.1 Temperature—An increase in the temperature of the materials and or the ambient air can result in an increase in
diffusivities and evaporative mass transfer coefficients. More importantly, increasing temperature will significantly increase the
vapor pressure of VOCs. For instance, a temperature increase from 23 to 33 °C 33°C will increase the mass transfer coefficient
for decane by only 6 %, but will increase the vapor pressure for decane by 83 %. This will lead to an increase in VOC emission
rates, since emission rate is proportional to the vapor pressure of the VOC for “wet” emitting sources. The strength of this
temperature effect depends on specific materials and VOCs emitted according to Wolkoff 1998 (2) and Van der Wal et al. 1997 (3).
Relationships between the ambient air temperature and emission rates have yet to be developed. Full-scale chamber tests are
currently conducted under a standard temperature (for example, 23 6 0.5 °C 0.5°C for non heat-generating products). Specimens
are, therefore, preconditioned under the same temperature before testing.
For products that generate significant heat (for example, copy machines), a relatively large variation of air temperature and
airflow pattern in the chamber may be present due to the convective heat transfer from the test product. Ideally, the chamber air
temperature should be controlled to typical indoor air temperatures when evaluating heat generating devices, as happens in
mechanically ventilated buildings [Brown, 1999 [Brown (4)]. Where this is not possible due to limitations of the chamber system,
the test protocol should define the chamber operating procedures consistent with the test objectives and the test protocol should
address the impact of temperature on determination and comparability of emission rates.
6.3.2.2 Relative Humidity—Relative humidity may affect emissions of pollutants that are hydrophilic or pollutants generated by
chemical reactions with water. It may also affect VOC emissions from materials that are hygroscopic since the adsorbed water may
change the diffusion properties of the material and how the VOC desorbs from the surface. For emission sources that contain water
(for example, water-based paints, water-based cleaners, and water-based adhesives), relative humidity may have a profound impact
on the VOC emissions because it controls the rate of water evaporation from the source. The extent to which the relative humidity
affects VOC emissions depends on specific materials and VOCs emitted according to Wolkoff 1998 (2) and Roache et al. 1996 (5).
As detailed information on the effect of relative humidity on emission rates is not available, chamber tests are usually conducted
under a single relative humidity (for example, 50 6 5 % RH) for products that do not adsorb or generate significant amounts of
moisture. Ideally, test specimens should be preconditioned under the test relative humidity condition before testing. However, this
is usually not practical because exposing the test specimen to conditioned air also means emitting VOCs before the test is actually
started. As a result, test products are usually wrapped or sealed in their original package materials/containers for temperature
conditioning only before testing.
For moisture-adsorbing products (for example, fresh furniture materials) or moisture-generating products (for example, printers,
liquid chemical products), a larger variation of relative humidity may be allowed in the chamber. Similar to the temperature
variation in the chamber when testing a heat-generating product (see section 6.3.2.1), the moisture variation in the chamber when
testing moisture-adsorbing or moisture-generating products also depends on the chamber operation. Specific chamber operating
procedure and acceptable variability of relative humidity in the chamber should be established in a product-specific test protocol
based on the test objectives.
6.3.2.3 Air Velocity and Turbulence—Air velocity and turbulence affect the evaporative mass transfer from both solid and liquid
sources. For “wet” materials such as paints, stains, varnishes, and caulks/sealants whose initial emission period is primarily
controlled by evaporative mass transfer, increasing the air velocity and turbulence will lead to an increase in emission rates of
VOCs. The effect becomes smaller as the materials become drier according to Roache et al. 1996 (5) and Zhang et al. 1996a (6).
For dry materials such as carpets, wood-based products, and polyvinyl chloride (PVC) floorings, air velocity and turbulence affect
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emission rates only within the first 5 to 10 h of being exposed to the ambient air. After that, the effect becomes insignificant because
the emissions will be controlled by internal diffusion, according to Awad 1999 (7), Yang 1999 (8), Wolkoff et al. 1996 (9), Little
et al. 1994 (10), and Roache et al. 1998 al., (5).
In office and residential buildings, the magnitude of air velocities over material surfaces is typically in the range of 0 to 0.25
m/s according to Mathews et al. 1987 (11) and Zhang et al. 1995 (12). Turbulence kinetic energy is typically in the range of 0 to
0.01 (m/s) . In full-scale chambers, these air velocity and turbulence levels can be simulated if the testing purpose is to simulate
a real room airflow condition. Because the actual air velocity and turbulence levels will be different from location to location in
the chamber, multi-point measurements should be taken near the surfaces (for example, 1.0 cm from the surface) of test specimens
to verify that the desired air velocity and turbulence levels are achieved. This is especially important for testing convective-
controlled emission sources such as paints and wood stains. For internal diffusion-controlled emission sources such as carpets and
engineered wood products, precise controls of the air velocity and turbulence over the surfaces of test specimens are not required
unless the emission rates during the first 5-105–10 h are of interest. For internal diffusion-controlled emission sources a general
specification on air velocity (for example, in the range of 0.05 to 0.25 m/s) is usually sufficient.
6.3.2.4 VOC Concentrations in Air, Air Change Rate, and Loading Ratio—For an emitting material in the absence of other
strong sources, the VOC concentration at the material surface is generally higher than that in the surrounding air. A higher VOC
concentration in the air will lead to a lower concentration gradient between the material surface and the surrounding air, and hence
a lower convective mass transfer rate from the surface to the air. The emission rate decreases as the VOC concentration in the
chamber increases (for example, during the initial emission period of “wet” materials).
VOC concentrations in a chamber/space are dependent on the air change rate (ventilation rate) and/oror material loading ratio
ratio, or both, for a given emission source. A high air change rate or a low material loading ratio will result in a low concentration
in the chamber or space, and hence increase the emission rates. In addition, increasing the air change rate can also result in an
increase in velocity and turbulence levels over the emitting surfaces, and hence the convective mass transfer coefficient.
Chamber tests can be conducted to simulate the impact of outdoor/clean air supply on room VOC concentrations. In office and
residential buildings, outdoor air change rates may range from 0.05 to 1.5 air changes per hour [ASHRAE 2009b (13), ASHRAE
2009c (14), and Reardon and Zhang 1995 (15)]. ASHRAE 62.1-201062.1–2010 and ASHRAE 62.2-201062.2–2010 specify the
outdoor air flow requirements for achieving acceptable IAQ. Additional recirculated air is required to meet the heating or cooling
requirements for the space. If the purpose of a chamber test is to evaluate the impact of clean/outdoor air change rate on the VOC
concentration levels, a mixing fan may be placed in the chamber to achieve adequate mixing for emission tests (see section 6.1).
When this is done, however, airflow patterns in actual rooms are not simulated in the chamber.
6.4 The Role of Source Emission Models—Source emission models are used to describe the VOC emission rates (or emission
factor) as a function of time, environmental conditions (temperature, humidity, and air velocity, etc.), and/oror source (initial VOC
content and composition, density, etc.) variables. variables, or combination thereof. These models are useful for designing
full-scale experiments. For example, they can be used to select air sampling intervals and experimental conditions. They are also
useful for analyzing emission test results from which the coefficients of selected models are estimated (see Section 11). Finally,
the models can be used to extrapolate short-term emission test data to a longer term and from environmental chamber test
conditions to field conditions. However, care should always be exercised in the extrapolation since any model has its limitations
[CMEIAQ 1999b, Guo 1996 (16), Little et al., 1994 al. (10), and Zhang and Shaw 1997 (17)].
7. Facilities and Equipment
7.1 General Considerations for Chamber System Design and Construction—A complete full-scale chamber test facility consists
of: a full-scale chamber and its heating, ventilation, and air-conditioning (HVAC) system for air supply and conditioning, an air
sampling and analysis system, and a data acquisition and recording system. The system should be housed in a clean and
air-conditioned laboratory space. Following are the general design and construction considerations:
7.1.1 The chamber should be large enough to accommodate the products to be tested and allow the simulation of the product
use in full-scale room conditions.
7.1.2 The chamber HVAC system must provide stable and accurate control of the airflow rate, temperature, differential pressure
(pressure relative to the ambient pressure outside the chamber), and relative humidity within the chamber, and have the capacity
to operate over the entire range of desired operating/testing conditions, considering the generation of heat and moisture from
sources to be tested.
7.1.3 The chamber, air cleaning, and distribution components must be constructed of materials that minimize adsorption and
emission of VOCs [for example, stainless steel, glass, polytetrafluoroethylene (PTFE)]. Fans and bearings must be designed to
prevent intrusion of emissions from lubricants into the clean air system.
7.1.4 The chamber system should be airtight in order to minimize any air leakage between the inside and the outside of the
chamber system.
7.1.5 The chamber system should be capable of providing sufficient mixing in the chamber for testing under the uniform VOC
concentration assumption. If the chamber is intended to simulate airflow patterns, air distribution, air velocity, and turbulence
levels that are typically found in real ventilated rooms, in addition to having the capability to accurately determine the emissions
from indoor products, the chamber should be designed to accommodate both types of studies.
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FIG. 1 Schematic of a Full-Scale Chamber System—Example 1 (EPA and NRC Chambers)
7.1.6 The chamber system should be able to provide on-line monitoring of the test conditions including airflow rates (clean and
recirculated air), air temperature, relative humidity, and differential pressure inside the chamber and in the ventilation ducts. For
example, a data acquisition system may be set up to monitor these conditions every minute. (Note that the reading frequency
required for achieving good control accuracy may be much smaller, but will depend on the chamber system.) This will facilitate
the detection of any malfunction of the system and help diagnose problems.
7.1.7 The chamber system should have adequate sampling ports for taking air samples both within the chamber and in the
ventilation ducts.
7.1.8 All components of the chamber system (such as ducts, fans, cooling/heating coils) should be thoroughly cleaned before
they are installed. Effort should also be made to avoid contamination during the construction period.
7.1.9 The chamber system and all components should be easily accessible for cleaning and maintenance.
7.2 The Full-scaleFull-Scale Chamber:
7.2.1 Construction Material—Materials such as stainless steel, glass, aluminum, and PTFE coating are acceptable for the
construction of the interior surfaces of the chamber, with stainless steel being the most common choice. Type 304 or 316 stainless
steel with No. 4 finishing (a general purpose polished finish that finds wide applications in restaurant, dairy, food processing,
medical, and chemical equipment as well as various architectural products) may be used as the interior wall and floor surface. For
example, 11 gage stainless steel panels may be used for the floor, and 14 gage used for the ceiling and walls. Sections can be
fastened together by continuous welding at the joints of two panels and by tack welding to their supporting frame. Some
discoloration may be observed in the vicinity of the welded lines due to the heat and oxidation in the welding process. The interior
welded joints may be cleaned by wire brushing or mechanical grinding. If a highly polished surface finish is desired, matte-finish
stainless steel sheets should be used since they can be more easily polished mechanically after construction to a semi-mirror finish
(equivalent to the sterile finish used in hospitals). Ideally, it is desirable to electro-polish the surface to minimize the sink effect
on the surfaces, but this is generally not practical because of the size of the chamber.
7.2.2 Chamber Door—The chamber door must be large enough to accommodate the largest material/product components to be
tested. The seals between the door and chamber surfaces must be made of non-emitting and non-adsorbing materials (such as
PTFE) and be adequate to maintain chamber leak rates at or below acceptable levels. PTFE gaskets and door clamps are usually
used. If the door opens to the inside and the chamber will operate under a positive pressure relative to the outside of the chamber,
the positive pressure in the chamber will improve the tightness of the door during chamber operation. If the door opens to the
outside and the chamber is operated under a positive pressure, at least two clamps on each side of the doorframe are usually
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necessary to ensure proper airtightness. In either case, the door should be operable from inside and outside the chamber for safety
purposes. For experiments in which a technician will enter and exit the chamber (painting, etc.), it is desirable to have a small entry
chamber with its own airtight door.
7.2.3 Lighting and Observation Windows—Lights may be installed above ceiling glass panels sealed with PTFE gaskets.
PTFE-gasket-sealed observation windows may be installed on walls or the chamber door.
7.2.4 Insulation—The floor, ceiling, walls, and door of the chamber should be well insulated to minimize the influence of
temperature fluctuation outside the chamber on the air temperature in the chamber.
7.2.5 Air Sampling Ports—Sampling ports should be installed at desired locations depending on the test purpose (for example,
at the mid-height of walls). Stainless steel feed-through connectors with sealing caps may be used for this purpose. The length of
the sampling line between the sampling device (for example, adsorbent tube) and the sampling location should be minimized in
order to reduce the effect of VOC adsorption/desorption in the sampling line on the measurements.
7.3 The HVAC System for the Full-scaleFull-Scale Chamber:
7.3.1 System Design—Different approaches may be used to supply controlled and conditioned airflow to the chamber. Figs. 1
and 2 show two different example systems. Depending on the purpose of testing, System 1 (Fig. 1) may operate in several modes:
(1) full exhaust (FE) mode, in which all the supply air is exhausted with no air recirculated back to the chamber; (2) recirculation
(RC) mode, in which part or all of the air from the chamber is recirculated back to the chamber; and (3) by-pass (BP) mode, in
which part or all the air from the chamber is recirculated back to the chamber, bypassing the heating and cooling coils and
humidifier. The BP mode may be used to determine if the HVAC components have significant adsorption/desorption effects for the
VOCs measured. System 2 (Fig. 2) uses a completely different design for air supply, conditioning, and handling of air to the
chamber. Air supply is from a compressor at 690 kPa, regulated to 150 kPa before reaching a flow-regulating valve that is linked
via process controllers to a turbine flowmeter. Chamber pressure can be at 0-250 Pa above the ambient pressure in the laboratory
space, and requires no extraction fan for operation. An air-conditioning plant operates between the flow regulating valve and the
meter, conditioning only the supply air. Air enters the chamber along a central, perforated duct at ceiling level. Two similar ducts
at floor level are connected to a supply duct via a fan so that chamber air can be recirculated. Extra heater and chiller components
are located in the recirculation duct. The clean supply air is forced from the chamber under positive pressure via six exhaust ports
in the chamber walls. This chamber can operate under the FE and RC modes described above, but without humidification of
recirculated air.
7.3.2 Air Preconditioning—The air supplied to the system may come either directly from outdoors or from the laboratory space.
The supply air must be preconditioned to avoid contamination of the chamber system and to allow the chamber system to operate
at all designed temperature and humidity conditions. For example, in System 1 (Fig. 1), preconditioning is accomplished by
passing the air through a particulate filter, an electric preheater, a chilled water cooling unit, and a desiccant dehumidifier. A
single-speed fan is used to circulate the air in the preconditioning loop. This preconditioning loop allows the system to operate at
FIG. 2 Schematic of a Full-Scale Chamber System—Example 2 (OCSIRO Chamber)
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-40–40 to 30 °C 30°C outdoor air temperature and up to 95 % relative humidity. The preconditioning equipment should be sized
to condition the air to the temperature and humidity ranges that can be handled by the conditioning components downstream in
the recirculation loop to achieve the required control accuracy. In example System 2, air delivered from the compressor is passed
through two oil-coalescing filters and a refrigerative dryer, and then improved by purification.
7.3.3 Air Purification—The supply air should be cleaned to satisfy the criteria of clean air (see section 3.2.23.2.3). This can be
accomplished by passing the air through a catalytic oxidation system, activated carbon filters or packed beds, and a high-efficiency
particulate air (HEPA) filter. These filters or chemical adsorption beds should have sufficient capacity and be easily accessible for
replacement.
7.3.4 Heating, Cooling, and Humidification—The supply air should be further conditioned to achieve the required temperature
and humidity control. This may be achieved by passing air through cooling/heating coils and a steam or other humidifier. All the
components which are exposed to the supply air stream should be made of inert materials such as stainless steel or tin-plated
copper. PTFE gaskets must be used to seal the various joints (for example, between air duct sections, between the cooling/heating
component and ducts). The water supplied to the humidifier must be purified and deionized.
7.3.5 Control of System Operation—The operation of the chamber system may be controlled by a stand-alone DDC (direct
digital control) controller or a dedicated computer. The set points for airflow rates, temperature, and relative humidity can be set
by a microcomputer, which also monitors, displays, and records the operation conditions. The sensor reading frequency should be
at least once every second, and the control system should be able to make the control adjustment to achieve continuous control
(refer to 8.3 and Table 1). One minute average of the 1 s readings may be recorded every minute. In System 1 (Fig. 1), airflow
rates are measured by using orifice plates at the outdoor air supply duct, the preconditioning loop, immediately before the activated
carbon adsorber, immediately before and after the chamber, and the exhaust duct. By controlling the positions of the interlocked
air dampers at the exhaust and recirculation ducts, the exhaust airflow rate (and therefore the clean air supply flow rate) can be
controlled. The total supply airflow rate is controlled by adjusting the position of the air damper upstream of the return fan (Fig.
1). The chamber pressure is controlled by the air damper installed upstream of the activated charcoal filter. These controls are
accomplished by PID (proportional integral differential) control algorithms programmed in the DDC or the dedicated computer.
In example System 2, temperature, humidity, and supply air flow are controlled by PID-programmable process controllers in all
processes except recirculation flow, which is controlled by a fan speed control modu
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