While it is true that all buildings allow for some air leaks, the difference is how much air is leaked from building to building. The air infiltration and exfiltration happens through the walls, roofs, and windows of the building envelope. The severity of the air leaks can be problematic as varying temperatures, water leakage, and drafts can cause building structure damage and waste energy.
Air leaks can cause a variety of problems at different severity. Factors which affect this include the air flows direction along with other environmental factors. These problems can include:
Water leaks – A water leak can be analyzed by a technician to prevent internal leaks and the damage they cause. If the leak is combined with air infiltration, the water can find its way into the building envelope where serious damage can be done.
Condensation – Condensation occurs when warm, humid air moves its way through a leaky envelope and finds an area at or below the dew point. Air leaks that lead to condensation can occur because of both infiltration and exfiltration.
Mechanical systems and occupant complaints – Air leaks can stress the load on mechanical systems and weaken their efficiency. Both infiltration and exfiltration can increase the stress on mechanical systems and make them work harder which can lead to occupant discomfort and potential mechanical system failure.
For air leaks to be corrected or prevented, an air barrier needs to be in place. The barriers location is determined by the installation factors. Air barriers also need to be able to withstand both negative and positive pressures.
Air barriers can be in many forms, in veneer or cladding construction, the air barrier can be a self-adhered asphalt-modified-membrane or building wrap. If the building is made of concrete, the air barrier is the concrete and sealant at the joints. In glass or metal wall curtains, the air barrier is the glazing gaskets on the interior and the seals at the joint frames.
It is also important for facility managers to consider the weatherproofing reliability and functionality of doors and windows.
Facility managers must establish an working, reliable air barrier for their building envelopes to protect against water leaks and condensation within the system taking into consideration all of the details, components, transition, and material of the building envelope.