The HVAC system of a building has three primary tasks: to deliver air, to return air, and to make up air.

To fulfill the air delivery task, the HVAC system conveys to occupied building zones or conditioned spaces, air that has been pressurized, heated cooled, humidified, dehumidified, washed or filtered. In it’s air return role, the HVAC system extracts air from occupied building zones or conditioned spaces in order to pressurize, heat, cool, humidify, dehumidify, wash or filter it. To accomplish the make-up air task, the HVAC system carries air to occupied building zones or conditioned spaces to replace air being moved by equipment such as range hoods or spray booths.

Maintenance Requirements of the HVAC System

Properly maintaining the HVAC system of a building requires several ongoing activities:

Inspection Checklist, Schedule and Log

In all but the smallest buildings, a written inspection checklist should be drawn up. This inspection checklist should be sufficiently detailed to serve unaided as documentation to guide an inspector unfamiliar with both the building and its HVAC system through the entire inspection program. The procedure should be updated at least annually, or more often as changes may dictate, to ensure that it reflects the most recent additions to or alterations in the components of the HVAC system. The inspection procedure, each time it is updated, should be dated or coded in such a way that it’s versions may be controlled. Some care should be exercised to limit the number of copies that are made to guard against inadvertent use of an expired version of the procedure. Whenever a new version is created, all copies of the previous version should be discarded. A copy of the current version should be under control of the chief building engineer, or of a person in an equivalent position, whose responsibility it is to see that orderly and regular inspections are carried out as called for in the inspection procedure. This person should be prepared to produce this copy for examination by the building engineer audit team or auditor, should such an audit be common practice in the building.