ASHRAE has announced its newly published Cold-Climate Buildings Design Guide, which provides information on the issues commonly faced in designing buildings for arctic and subarctic climates. The idea for the guide came from a working session at the seventh International Cold-Climate Design Conference held in 2012 and co-sponsored by ASHRAE, Scandinavian Federation of Heating, Ventilation and Sanitary Engineering Associations (SCANVAC), and Federation of European Heating, Ventilation and Air Conditioning Associations (REHVA).
“Harmonizing human comfort with the climatic realities of these environments is a balancing act,” said Erich Binder, who oversaw the writing of the guide. “Strategic design is key to building, commissioning, and operating efficient and long-lasting cold-climate structures.”A cold climate is defined by a combination of factors that create a unique set of building design challenges. These factors include temperature, frozen precipitation, wind, humidity, thermal comfort, thermal envelope/enclosure, maintainability, permafrost and frozen ground, and remote building locations.
The following are tips for designing, operating, and maintaining buildings and systems in cold climates:
- What happens when building air exfiltrates a building envelope in cold weather is similar to what happens in cooling coils in hot humid weather — understanding psychrometrics is essential to understanding building envelope performance in cold climates.
- The colder the climate, the more important it is for critical equipment to be sheltered — you can’t expect service personnel to properly repair HVAC equipment in a winter blizzard.
- In extreme climates, windblown snow takes on a consistency similar to sand and requires special design techniques to keep it from getting into the HVAC intakes.
- The manual also covers the design impacts from non-mechanical components of a facility such as the building envelope and roof construction. For instance, snow and ice sliding down off a metal roof can shear off mechanical roof penetrations as well as hoods on the exterior wall below.
- A building envelope must address all modes of heat loss to be truly efficient; ignoring any mode of loss may lead to excessive thermal transfer.
- Frost can be devastating for HVAC equipment, blocking intake hoods, filters, coils, etc.
- Design out cold bridges in both building fabric and engineering penetrations.
- Avoid or minimize any external service pipe runs.
- Locate air inlets and exhausts in locations that avoid snow drift and blockage.
- Ensure condensing pipes never freeze and block.
- Provide safe access to roof mechanical plants in all weather — frozen roof surfaces can be a hazard.