The building envelope. When architects, building engineers and owners talk about that barrier to the great outdoors, the one thing everyone knows and acknowledges is that it will never be perfectly sealed. Careful door selection, however, can bring buildings closer to the ideal.
Buildings are among the country's largest users – and wasters – of energy in keeping the interior comfortable and productive. According to the EPA, commercial buildings consume around 15% of the country's energy, yet they emit 20% of the country's greenhouse gases – which both pollutes the environment and can increase operations costs.
One challenge to envelope integrity is specifying and installing doors that minimize this energy loss while allowing access to the facility, especially those large doorways that handle vehicular traffic. Throughout a year, thousands of dollars in energy can blow through these massive openings.
The conventional wisdom around exterior doorways or for doors on walls that separate two extreme temperature differential environments is that the door panel has to match the thickness and insulation of the wall to which it is attached – to protect the doorway. This way of thinking prevailed in the building energy codes until recently – the problem is that a fat door is a slow door.
Previously, building managers in facilities with a high rate of traffic had to make a choice – get a door that can go with the flow or one that can contain energy. Thanks to research recently released by the Door and Access Systems Manufacturers Association (DASMA), commercial bbuilding owners and facility managers can be comfortable with achieving both the speed to keep the operation moving while protecting against energy loss and wasted cost.
Depending up on the rate at which traffic moves through the doorway, door speed becomes more of a factor than the traditionally regarded door panel R-value for preventing energy loss and maintaining a productive environment. DASMA research found, factoring in average door size and other factors, that once the daily cycles hit around 55, the facility realizes the energy-saving benefits of high-speed doors operating over 30 inches per second.
There are doors that operate more frequently than 55 times – at many industrial and distribution facilities, doors can cycle as much as 400 times a day. For these doorways, rapid door operation significantly minimizes the amount of time the door is open once a vehicle passes through the doorway. At this point, air exchange becomes more of an energy loss issue than heat transmittal though the door panel.
Doorways on interior walls tend to see the highest traffic rates. Exterior doorways, though, are generally large, and along with the potentially high-energy loss, people tend to work around these doorways. Imagine the impact on productivity in winter when a heavy, lumbering door is taking many seconds to open and close, letting teeth-chatteringly cold air into the building.
In 2015, this new criteria for doors will likely impact the standards incorporated by the American Society of Heating, Refrigeration and Air-Conditioning Engineers and the International Energy Conservation Code. As a result, building owners and facility managers can put to use the kind of doors they know they need, not the kind they think they need.
Jeff Wendt is dealer development manager at Rytec High-Performance Doors. He can be reached at firstname.lastname@example.org.
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