ASTM D6245-18
(Guide)Standard Guide for Using Indoor Carbon Dioxide Concentrations to Evaluate Indoor Air Quality and Ventilation
Standard Guide for Using Indoor Carbon Dioxide Concentrations to Evaluate Indoor Air Quality and Ventilation
SIGNIFICANCE AND USE
5.1 Indoor CO2 concentrations have been described and used by some people as an indicator of indoor air quality. These uses have included both appropriate and inappropriate interpretations of indoor CO2 concentrations. Appropriate uses include estimating expected levels of occupant comfort in terms of human body odor, studying occupancy patterns, investigating the levels of contaminants that are related to occupant activity, and screening for the sufficiency of ventilation rates relative to occupancy. Inappropriate uses include the application of simple relationships to determine outdoor air ventilation rates per person from indoor CO2 concentrations without verifying the assumptions upon which these relationships are based, and the interpretation of indoor CO2 concentrations as a comprehensive indicator of indoor air quality.
5.2 Outdoor air ventilation rates affect contaminant levels in buildings and building occupants' perception of the acceptability of the indoor environment. Minimum rates of outdoor air ventilation are specified in building codes and indoor air quality standards, for example, ASHRAE Standard 62. The compliance of outdoor air ventilation rates with relevant codes and standards are often assessed as part of indoor air quality investigations in buildings. The outdoor air ventilation rate of a building depends on the size and distribution of air leakage sites, pressure differences induced by wind and temperature, mechanical system operation, and occupant behavior. Given all of this information, ventilation rates are predictable; however, many of these parameters are difficult to determine in practice. Therefore, measurement is required to determine outdoor air change rates reliably.
5.3 The measurement of CO2 concentrations has been promoted as a means of determining outdoor air ventilation rates per person. This approach, referred to in this guide as equilibrium analysis, is based on a steady-state, single-zone mass balance of CO2 in the bui...
SCOPE
1.1 This guide describes how measured values of indoor carbon dioxide (CO2) concentrations can be used in evaluations of indoor air quality and building ventilation.
1.2 This guide describes the determination of CO2 generation rates from people as a function of body size and level of physical activity.
1.3 This guide describes the experimentally-determined relationship between CO2 concentrations and the acceptability of a space in terms of human body odor.
1.4 This guide describes the following uses of indoor CO2 concentrations to evaluate building ventilation–mass balance analysis to determine the percent outdoor air intake at an air handler, the tracer gas decay technique to estimate whole building air change rates, and the constant injection tracer gas technique at equilibrium to estimate whole building air change rates.
1.5 This guide discusses the use of continuous monitoring of indoor and outdoor CO2 concentrations as a means of evaluating building ventilation and indoor air quality.
1.6 This guide discusses some concentration measurement issues, but it does not include or recommend a method for measuring CO2 concentrations.
1.7 This guide does not address the use of indoor CO2 to control outdoor air intake rates.
1.8 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.9 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.
1.10 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 th...
General Information
Relations
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: D6245 − 18
Standard Guide for
Using Indoor Carbon Dioxide Concentrations to Evaluate
Indoor Air Quality and Ventilation
This standard is issued under the fixed designation D6245; 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 1.10 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 This guide describes how measured values of indoor
ization established in the Decision on Principles for the
carbon dioxide (CO ) concentrations can be used in evalua-
Development of International Standards, Guides and Recom-
tions of indoor air quality and building ventilation.
mendations issued by the World Trade Organization Technical
1.2 This guide describes the determination of CO genera-
2 Barriers to Trade (TBT) Committee.
tion rates from people as a function of body size and level of
2. Referenced Documents
physical activity.
2.1 ASTM Standards:
1.3 This guide describes the experimentally-determined re-
D1356 Terminology Relating to Sampling and Analysis of
lationship between CO concentrations and the acceptability of
Atmospheres
a space in terms of human body odor.
D3249 Practice for General Ambient Air Analyzer Proce-
1.4 This guide describes the following uses of indoor CO
dures
concentrations to evaluate building ventilation–mass balance
E741 Test Method for Determining Air Change in a Single
analysis to determine the percent outdoor air intake at an air
Zone by Means of a Tracer Gas Dilution
handler, the tracer gas decay technique to estimate whole
2.2 Other Documents:
building air change rates, and the constant injection tracer gas
ASHRAE Standard 62.1 Ventilation for Acceptable Indoor
technique at equilibrium to estimate whole building air change
Air Quality
rates.
3. Terminology
1.5 This guide discusses the use of continuous monitoring
3.1 Definitions—For definitions and terms used in this
of indoor and outdoor CO concentrations as a means of
guide, refer to Terminology D1356.
evaluating building ventilation and indoor air quality.
3.2 Definitions of Terms Specific to This Standard:
1.6 This guide discusses some concentration measurement
3.2.1 air change rate, n—the total volume of air passing
issues, but it does not include or recommend a method for
through a zone to and from the outdoors per unit time, divided
measuring CO concentrations.
–1 –1 4
by the volume of the zone (s ,h ).
1.7 This guide does not address the use of indoor CO to
3.2.2 bioeffluents, n—gases emitted by people as a product
control outdoor air intake rates.
of their metabolism that can result in unpleasant odors.
1.8 Units—The values stated in SI units are to be regarded
3.2.3 single-zone, n—an indoor space, or group of spaces,
as standard. No other units of measurement are included in this
wherein the CO concentration is uniform and that only
standard.
exchanges air with the outdoors.
1.9 This standard does not purport to address all of the
4. Summary of Guide
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4.1 When investigating indoor air quality and building
priate safety, health, and environmental practices and deter- ventilation, a number of tools are available. One such tool is
mine the applicability of regulatory limitations prior to use.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
This guide is under the jurisdiction of ASTM Committee D22 on Air Quality the ASTM website.
and is the direct responsibility of Subcommittee D22.05 on Indoor Air. Available from American Society of Heating, Refrigerating, and Air-
Current edition approved June 1, 2018. Published June 2018. Originally Conditioning Engineers, Inc. (ASHRAE), 1791 Tullie Circle, NE, Atlanta, GA
approved in 1998. Last previous edition approved in 2012 as D6245 – 12. DOI: 30329, http://www.ashrae.org.
4 -1
10.1520/D6245-18. Acommonwayofexpressingairchangerateunitsish =airchangesperhour.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6245 − 18
the measurement and interpretation of indoor and outdoor CO ships are based, and the interpretation of indoor CO concen-
2 2
concentrations. Using CO concentrations to evaluate building trations as a comprehensive indicator of indoor air quality.
indoor air quality and ventilation requires the proper use of the
5.2 Outdoor air ventilation rates affect contaminant levels in
proceduresinvolved,aswellasconsiderationofseveralfactors
buildings and building occupants’ perception of the acceptabil-
related to building and ventilation system configuration, occu-
ity of the indoor environment. Minimum rates of outdoor air
pancy patterns, non-occupant CO sources, time and location
ventilation are specified in building codes and indoor air
of air sampling, and instrumentation for concentration mea-
quality standards, for example, ASHRAE Standard 62. The
surement. This guide discusses ways in which CO concentra-
compliance of outdoor air ventilation rates with relevant codes
tions can be used to evaluate building indoor air quality and
and standards are often assessed as part of indoor air quality
ventilation.
investigations in buildings. The outdoor air ventilation rate of
a building depends on the size and distribution of air leakage
4.2 Section 6 discusses the rate at which people generate
sites, pressure differences induced by wind and temperature,
CO and the factors that affect this rate.
mechanicalsystemoperation,andoccupantbehavior.Givenall
4.3 Section 7 discusses the use of indoor concentrations of
of this information, ventilation rates are predictable; however,
CO as an indicator of the acceptability of a space in terms of
many of these parameters are difficult to determine in practice.
perceptions of human body odor.
Therefore, measurement is required to determine outdoor air
change rates reliably.
4.4 Section 8 describes the use of mass balance analysis to
determine the percent outdoor air intake at an air handler based
5.3 The measurement of CO concentrations has been
on the measured CO concentrations in the supply, return, and
promoted as a means of determining outdoor air ventilation
outdoor air intake airstreams.
rates per person. This approach, referred to in this guide as
equilibrium analysis, is based on a steady-state, single-zone
4.5 Section 9 describes the use of the tracer gas decay
mass balance of CO in the building and is sometimes
technique to determine building air change rates using 2
presented with little or no discussion of its limitations and the
occupant-generated CO as a tracer gas. The tracer gas decay
assumptions on which it is based. As a result, in some cases,
technique is described in detail in Test Method E741, and this
the technique has been misused and indoor CO concentration
section discusses the application of this test method to the 2
measurements have been misinterpreted.
special case of occupant-generated CO after the occupants
have left the building.
5.4 When the assumptions upon which equilibrium analysis
is based are valid, the technique can yield reliable measure-
4.6 Section 10 describes the use of the constant injection
ments of outdoor air ventilation rates. In addition, indoor CO
tracer gas technique with occupant-generated CO to estimate
concentrations can be used to determine other aspects of
outdoor air ventilation rates. This technique is sometimes
building ventilation when used properly. By applying a mass
referred to as equilibrium analysis, and Section 10 discusses
balance at an air handler, the percent outdoor air intake in the
the use of this technique and the assumptions upon which it is
supply airstream can be determined based on the CO concen-
based.
trations in the supply, return, and outdoor air. This percentage
4.7 Section11discussestheuseofcontinuousmonitoringof
can be multiplied by the supply airflow rate of the air handler
CO concentrations as a means of evaluating indoor air quality
2 to yield the outdoor air intake rate of the air handler. In
and ventilation in buildings. In this discussion, continuous
addition, the decay of indoor CO concentrations can be
refers to real-time concentration measurement recorded with a
monitored in a building after the occupants have left to
datalogging device, generally over several days.
determine the outdoor air change rate of the building.
4.8 Section 12 discusses CO concentration measurement
5.5 Continuous monitoring of indoor and outdoor CO
issues, including measuring outdoor concentrations, sample concentrationscanbeusedtostudysomeaspectsofventilation
locations for indoor concentration measurements, establishing
system performance, the quality of outdoor air, and building
the uncertainty of measured concentrations, and calibration.
occupancy patterns.
6. CO Generation Rates
5. Significance and Use 2
6.1 Human metabolism consumes oxygen and generates
5.1 Indoor CO concentrations have been described and
CO at rates that depend on the level of physical activity, body
usedbysomepeopleasanindicatorofindoorairquality.These
size, and diet.
uses have included both appropriate and inappropriate inter-
pretations of indoor CO concentrations. Appropriate uses
6.2 The rate of carbon dioxide generation of an individual
include estimating expected levels of occupant comfort in V in L/s per person, at an air temperature of 273 K and an
CO2
terms of human body odor, studying occupancy patterns,
air pressure of 101 kPa, is given by Eq 1, the derivation of
investigating the levels of contaminants that are related to which is described in detail in Ref (1):
occupant activity, and screening for the sufficiency of ventila-
V 5 RQ BMR M 0.000569 (1)
CO
tion rates relative to occupancy. Inappropriate uses include the
application of simple relationships to determine outdoor air
ventilation rates per person from indoor CO concentrations
2 The boldface numbers in parentheses refer to a list of references at the end of
without verifying the assumptions upon which these relation- this standard.
D6245 − 18
where: 7. CO as an Indicator of Body Odor Acceptability
RQ = respiratory quotient, dimensionless (defined in 6.3),
7.1 This section describes the use of CO to evaluate indoor
BMR = basal metabolic rate, MJ/day, and
air quality in terms of human body odor acceptability and
M = metabolic rate per unit of surface area, met
therefore, the adequacy of the ventilation rate to control body
(dimensionless).
odor. The material in this section is based on a number of
For other values of air temperature T and pressure P, V is experimental studies in both chambers and real buildings and
CO2
describes the most well-established link between indoor CO
given by Eq 2.
concentrations and indoor air quality.
V 5 RQ BMR M T ⁄ P 0.000211 (2)
~ !
CO
7.2 At the same time people are generating CO they are
6.3 The respiratory quotient, RQ, is the ratio of the volu-
also producing odor-causing bioeffluents. Similar to CO
metric rate at which CO is produced by an individual to the
generation, the rate of bioeffluent generation depends on the
rate at which oxygen is consumed. The value of RQ depends
level of physical activity. Bioeffluent generation also depends
primarily on diet (2). Based on data on human nutrition in the
on personal hygiene such as the frequency of baths or showers.
United States, primarily the ratios of fat, protein, and carbo-
Because both CO and bioeffluent generation rates depend on
hydrate intake, RQ equals about 0.85 (3).
physical activity, the concentrations of CO and the odor
6.4 Values of BMR are a function of sex, age, and body
intensity from human bioeffluents in a space exhibit a similar
mass. Equations for the calculation of BMR are given in Table
dependence on the number of occupants and the outdoor air
1 (4).
ventilation rate.
6.5 The variable M (in dimensionless units of met) is used
7.3 Experimental studies have been conducted in chambers
to describe the ratio of the human energy use associated with a
and in occupied buildings in which people evaluated the
particular physical activity to the BMR of an individual as
acceptability of the air in terms of body odor (8-12). These
discussed in detail in Ref (1).There are two primary references
experiments studied the relationship between outdoor air
for obtaining met levels for different physical activities (5, 6).
ventilation rates and odor acceptability, and the results of these
Tables 2 and 3 contain met levels for many common indoor studies were considered in the development of most ventilation
activities drawn from those two references.
standards and guidelines (including ASHRAE Standard 62.1).
This entire section is based on the results of these studies.
6.6 Table 4 lists CO generation rates for ranges of ages and
7.3.1 These studies concluded that about 7.5 L/s of outdoor
met levels estimated using the body mass data for males and
air ventilation per person will control human body odor such
females in the EPAExposure Factors Handbook (7), assuming
that roughly 80 % of unadapted persons (visitors) will find the
RQ is equal to 0.85.
odor at an acceptable level. These studies also showed that the
6.7 To reflect the importance of variations in body size, that
same level of body odor acceptability was found to occur at a
is, mass, in estimating CO generation rates, Fig. 1 and Fig. 2
CO concentration that is about 650 ppm(v) above the outdoor
showthevariationin V withageandbodymassforfemales
CO2
concentration.
and males, respectively. Each plot displays V for 13 age
CO2
7.3.2 Fig. 3 shows the percent of unadapted persons (visi-
ranges from<1yto≥ 80 y and for six met levels from 1 to 4.
tors) who are dissatisfied with the level of body odor in a space
The plotted generation rates are calculated using RQ equal to
as a function of the CO concentration above outdoors (13).
0.85. Each vertical box-whisker plot displays the range of CO
This figure accounts only for the perception of body odor and
th
generation rates from the 10 percentile value of body ma
...
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: D6245 − 12 D6245 − 18
Standard Guide for
Using Indoor Carbon Dioxide Concentrations to Evaluate
Indoor Air Quality and Ventilation
This standard is issued under the fixed designation D6245; 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 guide describes how measured values of indoor carbon dioxide (CO ) concentrations can be used in evaluations of
indoor air quality and building ventilation.
1.2 This guide describes the determination of CO generation rates from people as a function of body size and level of physical
activity.
1.3 This guide describes the experimentally-determined relationship between CO concentrations and the acceptability of a
space in terms of human body odor.
1.4 This guide describes the following uses of indoor CO concentrations to evaluate building ventilation–mass balance analysis
to determine the percent outdoor air intake at an air handler, the tracer gas decay technique to estimate whole building air change
rates, and the constant injection tracer gas technique at equilibrium to estimate whole building air change rates.
1.5 This guide discusses the use of continuous monitoring of indoor and outdoor CO concentrations as a means of evaluating
building ventilation and indoor air quality.
1.6 This guide discusses some concentration measurement issues, but it does not include or recommend a method for measuring
CO concentrations.
1.7 This guide does not address the use of indoor CO to control outdoor air intake rates.
1.8 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this
standard.
1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.10 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
D3249 Practice for General Ambient Air Analyzer Procedures
E741 Test Method for Determining Air Change in a Single Zone by Means of a Tracer Gas Dilution
2.2 Other Documents:
ASHRAE Standard 62.1 Ventilation for Acceptable Indoor Air Quality
This guide 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, 2012June 1, 2018. Published May 2012June 2018. Originally approved in 1998. Last previous edition approved in 20072012 as
D6245 – 07.D6245 – 12. DOI: 10.1520/D6245-12.10.1520/D6245-18.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc., Inc. (ASHRAE), 1791 Tullie Circle, NE, Atlanta, GA 30329.30329,
http://www.ashrae.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6245 − 18
3. Terminology
3.1 Definitions—For definitions and terms used in this guide, refer to Terminology D1356.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 air change rate, n—the total volume of air passing through a zone to and from the outdoors per unit time, divided by the
–1 –1 4
volume of the zone (s , h ).
3.2.2 bioeffluents, n—gases emitted by people as a product of their metabolism that can result in unpleasant odors.
3.2.3 single-zone, n—an indoor space, or group of spaces, wherein the CO concentration is uniform and that only exchanges
air with the outdoors.
4. Summary of Guide
4.1 When investigating indoor air quality and building ventilation, a number of tools are available. One such tool is the
measurement and interpretation of indoor and outdoor CO concentrations. Using CO concentrations to evaluate building indoor
2 2
air quality and ventilation requires the proper use of the procedures involved, as well as consideration of several factors related
to building and ventilation system configuration, occupancy patterns, non-occupant CO sources, time and location of air sampling,
and instrumentation for concentration measurement. This guide discusses ways in which CO concentrations can be used to
evaluate building indoor air quality and ventilation.
4.2 Section 6 discusses the rate at which people generate CO and the factors that affect this rate.
4.3 Section 7 discusses the use of indoor concentrations of CO as an indicator of the acceptability of a space in terms of
perceptions of human body odor.
4.4 Section 8 describes the use of mass balance analysis to determine the percent outdoor air intake at an air handler based on
the measured CO concentrations in the supply, return, and outdoor air intake airstreams.
4.5 Section 9 describes the use of the tracer gas decay technique to determine building air change rates using occupant-generated
CO as a tracer gas. The tracer gas decay technique is described in detail in Test Method E741, and this section discusses the
application of this test method to the special case of occupant-generated CO after the occupants have left the building.
4.6 Section 10 describes the use of the constant injection tracer gas technique with occupant-generated CO to estimate outdoor
air ventilation rates. This technique is sometimes referred to as equilibrium analysis, and Section 10 discusses the use of this
technique and the assumptions upon which it is based.
4.7 Section 11 discusses the use of continuous monitoring of CO concentrations as a means of evaluating indoor air quality
and ventilation in buildings. In this discussion, continuous refers to real-time concentration measurement recorded with a
datalogging device, generally over several days.
4.8 Section 12 discusses CO concentration measurement issues, including measuring outdoor concentrations, sample locations
for indoor concentration measurements, establishing the uncertainty of measured concentrations, and calibration.
5. Significance and Use
5.1 Indoor CO concentrations have been described and used by some people as an indicator of indoor air quality. These uses
have included both appropriate and inappropriate interpretations of indoor CO concentrations. Appropriate uses include estimating
expected levels of occupant comfort in terms of human body odor, studying occupancy patterns, investigating the levels of
contaminants that are related to occupant activity, and screening for the sufficiency of ventilation rates relative to occupancy.
Inappropriate uses include the application of simple relationships to determine outdoor air ventilation rates per person from indoor
CO concentrations without verifying the assumptions upon which these relationships are based, and the interpretation of indoor
CO concentrations as a comprehensive indicator of indoor air quality.
5.2 Outdoor air ventilation rates affect contaminant levels in buildings and building occupants’ perception of the acceptability
of the indoor environment. Minimum rates of outdoor air ventilation are specified in building codes and indoor air quality
standards, for example, ASHRAE Standard 62. The compliance of outdoor air ventilation rates with relevant codes and standards
are often assessed as part of indoor air quality investigations in buildings. The outdoor air ventilation rate of a building depends
on the size and distribution of air leakage sites, pressure differences induced by wind and temperature, mechanical system
operation, and occupant behavior. Given all of this information, ventilation rates are predictable; however, many of these
parameters are difficult to determine in practice. Therefore, measurement is required to determine outdoor air change rates reliably.
5.3 The measurement of CO concentrations has been promoted as a means of determining outdoor air ventilation rates per
person. This approach, referred to in this guide as equilibrium analysis, is based on a steady-state, single-zone mass balance of CO
in the building and is sometimes presented with little or no discussion of its limitations and the assumptions on which it is based.
As a result, in some cases, the technique has been misused and indoor CO concentration measurements have been misinterpreted.
-1
A common way of expressing air change rate units is h = air changes per hour.
D6245 − 18
5.4 When the assumptions upon which equilibrium analysis is based are valid, the technique can yield reliable measurements
of outdoor air ventilation rates. In addition, indoor CO concentrations can be used to determine other aspects of building
ventilation when used properly. By applying a mass balance at an air handler, the percent outdoor air intake in the supply airstream
can be determined based on the CO concentrations in the supply, return, and outdoor air. This percentage can be multiplied by
the supply airflow rate of the air handler to yield the outdoor air intake rate of the air handler. In addition, the decay of indoor CO
concentrations can be monitored in a building after the occupants have left to determine the outdoor air change rate of the building.
5.5 Continuous monitoring of indoor and outdoor CO concentrations can be used to study some aspects of ventilation system
performance, the quality of outdoor air, and building occupancy patterns.
6. CO Generation Rates
6.1 Human metabolism consumes oxygen and generates CO at rates that depend on the level of physical activity, body size,
and diet.
6.2 The rate of oxygen consumption carbon dioxide generation of an individual V in L/s of a person per person, at an air
OCO2
temperature of 273 K and an air pressure of 101 kPa, is given by Eq 1:, the derivation of which is described in detail in Ref (1)
:
0.00276 A M
D
V 5 (1)
O
0.23 RQ10.77
~ !
V 5 RQ BMR M 0.000569 (1)
CO
where:
A = DuBois surface area m ,
D
M = metabolic rate per unit of surface area, met (1 met = 58.2 W/m ), and
RQ = respiratory quotient.
RQ = respiratory quotient, dimensionless (defined in 6.3),
BMR = basal metabolic rate, MJ/day, and
M = metabolic rate per unit of surface area, met (dimensionless).
The DuBois surface areaFor other values of equals about 1.8 mair temperature for an average-sized adult and ranges from about
0.8 to 1.4 m for elementary school aged children. Additional information on body surface area is available in the EPA Exposure
Factors Handbook (2). The respiratory quotient, RQ,T is theand pressure ratioP,V of the volumetricis given by Eq 2rate .
CO2
V 5 RQ BMR M T ⁄ P 0.000211 (2)
~ !
CO
at which CO is produced to the rate at which oxygen is consumed. Therefore, the CO generation rate of an individual is
2 2
equal to V multiplied by RQ.
O
6.3 The respiratory quotient, RQ, is the ratio of the volumetric rate at which CO is produced by an individual to the rate at
which oxygen is consumed. The value of RQ depends primarily on diet (2). Based on data on human nutrition in the United States,
primarily the ratios of fat, protein, and carbohydrate intake, RQ equals about 0.85 (3).
6.4 Chapter 9 of the ASHRAE Fundamentals Handbook, Thermal Comfort Values of BMR are (1), contains typical met levels
for a variety of activities. Some of these values are reproduceda function of sex, age, and body mass. Equations for the calculation
of BMR are given in Table 1. (4).
6.5 The value of the respiratory quotientvariable M (in dimensionless units of met) is used to describe the ratio of RQthe
depends on diet, the level of physical activity and the physical condition of the person. human energy use associated with a
particular physical activity to the BMR of an individual as discussed in detail in Ref RQ(1). equals 0.83 for an average adult
TABLE 1 Equations for Calculating BMR (4)
NOTE 1—m is body mass in units of kg.
BMR: MJ/day
Age (y)
Males Females
<3 0.249 m – 0.127 0.244 m – 0.130
3 to 10 0.095 m + 2.110 0.085 m + 2.033
10 to 18 0.074 m + 2.754 0.056 m + 2.898
18 to 30 0.063 m + 2.896 0.062 m + 2.036
30 to 60 0.048 m + 3.653 0.034 m + 3.538
$60 0.049 m + 2.459 0.038 m + 2.755
2 0.725
The body surface area boldface numbers A in mparentheses can be estimated from the formularefer to a list of references at the end Aof = 0.203this standard.H W
D D
0.425 where H is the body height in m and W is the body mass in kg (1).
D6245 − 18
engaged in light or sedentary activities. There are two primary references for obtaining met levels for different physical activities
RQ(5, 6increases).Tables 2 and 3 to a value of about 1 for heavy physical activity, about 5 met. Based on the expected variation
in contain met levels for many common indoor activities drawn from those two references.RQ, it has only a secondary effect on
CO generation rates.
6.5 Fig. 1 shows the dependence of oxygen consumption and CO generation rates on physical activity in units of mets for
average adults with a surface area of 1.8 m . RQ is assumed to equal 0.83 in Fig. 1.
6.6 Based on Eq 1 and Fig. 1, the CO generation rate corresponding to an average-sized adult (A = 1.8 m ) engaged in office
2 D
work (1.2 met) is about 0.0052 L/s. Based on Eq 1, the CO generation rate for a child (A = 1 m ) with a physical activity level
2 D
of 1.2 met is equal to 0.0029 L/s .
6.6 Eq 1Table 4 can be used to estimate lists CO generation rates based on information on body surface area that is available
for ranges of ages and met levels estimated using the body mass data for males and females in the EPA Exposure Factors Handbook
(27)), and other sources. However, these data do not ge
...
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