ASHRAE Standard 55
ASHRAE Standard 55-2023 is titled “Thermal Environmental Conditions for Human Occupancy” and describes how comfort is achieved in buildings by a combination of temperature, humidity, thermal radiation, and airspeed. Since controlling temperature and humidity are often the most energy-consuming options of the four to reach comfort, several different energy efficiency measures may be evaluated by BEM software to achieve comfort using radiant heating and cooling or ceiling fans. Most BEM software includes comfort models that can be used to evaluate how occupants will respond to the building environment and report values that are tied to the terminology described in Standard 55.
Purpose and Scope
The purpose and scope of the standard is:
1. PURPOSE
The purpose of this standard is to specify the combinations of indoor thermal environmental factors and personal factors that will produce satisfactory thermal environmental conditions acceptable for a majority of the occupants within the space.
2. SCOPE
2.1 The environmental factors addressed in this standard are temperature, thermal radiation, humidity, and airspeed; the personal factors are those of activity and clothing.
2.2 It is intended that all of the criteria in this standard be applied together, as comfort in the indoor environment is complex and responds to the interaction of all of the factors that are addressed herein.
2.3 This standard specifies thermal environmental conditions acceptable for healthy adults at atmospheric pressure equivalent to altitudes up to 3000 m (10,000 ft) in indoor spaces designed for human occupancy for periods not less than 15 minutes.
2.4 This standard does not address such nonthermal environmental factors as air quality, acoustics, illumination, or other physical, chemical, or biological space contaminants that may affect comfort or health.
2.5 This standard shall not be used to override any safety, health, or critical process requirements.
Procedures
Six factors are important for determining acceptable thermal comfort:
- Metabolic rate
- Clothing insulation
- Air temperature
- Radiant temperature
- Airspeed
- Humidity
Several different methods of evaluating thermal comfort are described in the standard, including:
- Graphic comfort zone method
- Analytic comfort zone method
- Elevated air speed
- Local thermal discomfort
- Temperature variation with time
- Natural ventilation with occupant controls
More Information
A Wikipedia article <link> already provides a great resource that is publicly available.
Resources
Wikipedia article on ASHRAE Standard 55
ASHRAE Standard 55 landing page including links to training materials
ASHRAE Bookstore page on Standard 55
CBE Thermal Comfort Tool and Documentation
Fundamentals of ASHRAE Standard 55 Video (older but still very useful)
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