Listed below are some of the design parameters that should be observed when preparing HVAC system designs. Most items listed have been commonly known for over forty years, yet seem to be the source of improper system performance on an all too frequent a basis. Failure to observe these parameters has repeatedly resulted in damages being awarded by the Courts to the building owners and paid for by either the Developer and / or the Architect and /or the Engineers and / or the Contractors.
The North Arrow shown on the site or Architectural plans must be checked for accuracy. If the building heat gain / heat loss calculations are done based on a misdirected North Arrow, then the entire design package is wrong and will not work properly.
The building envelope materials must be obtained in writing from whoever is selecting them. If they are changed during the process of design or construction, then the heat gain /heat loss calculations must be redone.
the minimum air circulation rate for any occupied portion of any building must never be less than six air changes per hour. To obtain this minimum figure multiply the room width by the room length and the room height and then divide by ten. This will give the minimum supply air in CFM fur that space. A ;smaller air quantity will cause uneven air temperatures throughout the space.
Thermostats and humidistats must be located in such a way as to sense the temperature and / or humidity in the spaces they control only. Either on the wall within the space, out of the path of direct sunlight, or within the return air stream from that space only.
