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ASHRAE Technical Committee
2.1 - Physiology and Human Environment
Frequently Asked Questions
| Question |
How does thermal comfort affect employee productivity? |
| Quick Answer |
Productivity is sometimes hard to measure and to determine
the reason for changes. However, the relationship between
air quality (including thermal comfort) has been studied
and results published.
ASHRAE Standard 55-2004 - Thermal Environmental Conditions
for Human Occupancy. This standard specifies conditions
or comfort zones where 80% of sedentary or slightly
active persons find the environment thermally acceptable.
ASHRAE Thermal Comfort Tool CD provides a user-friendly
interface for calculating thermal comfort parameters
and making thermal comfort predictions using several
thermal comfort models.
The standard and the other publications may be purchased
and downloaded on-line at our website, www.ashrae.org
or by calling 1-800-527-4723 in the USA and Canada or
1-404-636-8400 worldwide.
|
Long Answer
|
Productivity is sometimes hard to measure and to determine
the reason for changes. However, the relationship between
air quality (including thermal comfort) has been studied
and results published. Some recent publications include:
IEQ and the Impact on Building Occupants (ASHRAE Journal,
vol. 44, no. 4, p. 50-52)
How IEQ Affects Health, Productivity (ASHRAE Journal,
vol. 44, no. 5, p. 56-58)
Health and Productivity Benefits of Improved Indoor
Air Quality: A Litereature Survey (ASHRAE Transactions
Vol.104, Part 1#4164)
A Human Factors Approach to Performance and Productivity
(ASHRAE Transactions Vol. 100, Part 2 #OR-94-08-1)
A Human Factors Approach to Performance and Productivity
(ASHRAE Transactions Vol. 100, Part 2 #OR-94-08-1)
Environmentally Responsive Workstations and Office
Worker
Productivity (ASHRAE Transactions Vol. 100, Part 2 #OR-94-08-3)
Productivity in the U.S. A Question of Capacity or
Motivation? (ASHRAE Transactions Vol. 100, Part 2 #OR-94-13-4)
Indoor Relative Humidities in Winter and Related Absenteeism.
(ASHRAE Transactions Vol. 91 Part 1B pp. 643-653)
An Assessment of the Influence of the Indoor Environment
on the Productivity of Occupants in Offices. (1998 IAQ
Conference "Design, Construction and Operation
of Healthy Buildings" Proceedings)
The Impact of the Building Indoor Environment on Occupant
Productivity, Part I, Recent Studies. (ASHRAE Transactions
Vol. 100, Part 2 #OR-94-8-2)
The standard and the other publications may be purchased
and downloaded on-line at our website, www.ashrae.org
or by calling 1-800-527-4723 in the USA and Canada or
1-404-636-8400 worldwide.
|
| ASHRAE Pubs |
ASHRAE Thermal Comfort Tool CD
Standard 55-2004 - Thermal Environmental Conditions for
Human Occupancy |
| Topic References |
thermal comfort, employee productivity |
| Question |
Is there a thermal comfort standard for the maximum
allowable amount of temperature variation between rooms
in a residence? |
| Quick Answer |
No |
| Long Answer |
In the 2003 ASHRAE Applications Handbook, Chapter 46--Design
and Application of Controls--on page 19 it is noted that
"Areas or rooms having dissimilar load characteristics
………… should be controlled individually."
The handbook and the other publications may be purchased
and/or individual chapters of the handbook may be purchased
and downloaded on-line at our website, www.ashrae.org
or by calling 1-800-527-4723 in the USA and Canada or
1-404-636-8400 worldwide.
|
| ASHRAE Pubs |
ASHRAE 2003 Applications Handbook |
| Topic References |
None |
| Question |
What is the recommended indoor humidity level for
homes? |
| Quick Answer |
ANSI/ASHRAE Standard 55-2004, "Thermal Environmental
Conditions for Human Occupancy", plus ASHRAE BOD
approved Addenda relates reported human comfort to temperature
and humidity levels, and establishes a range of temperatures
and humidities that are considered comfortable by 80%
or more of the test subjects.
The handbook and standards may be purchased and/or
individual chapters of the handbook may be purchased
and downloaded on-line at our website, www.ashrae.org
or by calling 1-800-527-4723 in the USA and Canada or
1-404-636-8400 worldwide.
|
Long
Answer
|
ANSI/ASHRAE Standard 55-2004, "Thermal Environmental
Conditions for Human Occupancy", plus ASHRAE BOD
approved Addenda relates reported human comfort to temperature
and humidity levels, and establishes a range of temperatures
and humidities that are considered comfortable by 80%
or more of the test subjects.
The handbook and standards may be purchased and/or
individual chapters of the handbook may be purchased
and downloaded on-line at our website, www.ashrae.org
or by calling 1-800-527-4723 in the USA and Canada or
1-404-636-8400 worldwide.
|
| ASHRAE Pubs |
2001 ASHRAE Fundamentals Handbook, Chapter 8
ANSI/ASHRAE Standard 55-2004
|
| Topic References |
None |
| Question |
What are the recommended indoor temperature and humidity
levels for homes? |
| Quick Answer |
ASHRAE Standard 55-2004 notes that for thermal comfort
purposes, temperature could range from between approximately
67 and 82 °F. A more specific range can be determined
from the standard but depends on relative humidity, season,
clothing worn, activity levels, and other factors. The
standard notes that HVAC systems must be able to maintain
a humidity ratio of at or below 0.012. This corresponds
to an upper relative humidity level as high as about 80%
at low dry bulb temperatures but can be lower dependant
upon factors such as temperature and the other factors
listed above. The standard does not specify a lower humidity
limit but notes that non-thermal comfort factors may place
limits on acceptability of very low humidity environments.
ASHRAE Standard 62.1-2004 recommends that relative
humidity in occupied spaces be controlled to less than
65% to reduce the likelihood of conditions that can
lead to microbial growth.
The handbook and standards may be purchased and/or
individual chapters of the handbook may be purchased
and downloaded on-line at our website, www.ashrae.org
or by calling 1-800-527-4723 in the USA and Canada or
1-404-636-8400 worldwide.
|
| Long Answer |
ASHRAE Standard 55-2004, Thermal Environmental Conditions
for Human Occupancy, notes that for thermal comfort purposes,
temperature could range from between approximately 67
and 82 °F. A more specific range can be determined
from the standard but depends on relative humidity, season,
clothing worn, activity levels, and other factors. The
standard notes that HVAC systems must be able to maintain
a humidity ratio of at or below 0.012. This corresponds
to an upper relative humidity level as high as more than
80% at low dry bulb temperatures but may be lower dependant
upon factors such as temperature and the other factors
listed above. The standard does not specify a lower humidity
limit but notes that non-thermal comfort factors such
as skin drying, irritation of mucus membranes, dry eyes,
and static electricity may place limits on acceptability
of very low humidity environments.
ASHRAE Standard 62.1-2004 recommends that relative
humidity in occupied spaces be controlled to less than
65% to reduce the likelihood of conditions that can
lead to microbial growth.
The handbook and standards may be purchased and/or
individual chapters of the handbook may be purchased
and downloaded on-line at our website, www.ashrae.org
or by calling 1-800-527-4723 in the USA and Canada or
1-404-636-8400 worldwide.
|
| ASHRAE Pubs |
ASHRAE Standard 55-2004 plus BOD approved addenda
ASHRAE Standard 62.1-2004 plus BOD approved addenda
2001 ASHRAE Fundamentals Handbook, Chapter 8 - Thermal
Comfort
|
| Topic References |
temperature, humidity, comfort, set point, moisture,
dry, humid, microbial growth |
|
