Message Board Thread - "Add the cfm"

Title	By	Posted On
Add the cfm	cannman	3/23/2010
when inspecting buildings for energy loss or diagnostics. ask for the prints if available- look at the CFM of the exhaust and outside air. This will tell you if its negative to start with. Either way its important to know every makes mistakes. It may be unknowingly designed negative .
Re:Add the cfm	Tony C.	4/27/2010
It would appear that you are discussing commercial buildings by your simplistic understanding of exhaust and supply air volumes. That is only one part of the pressure differntial equation. The other factors include wind pressures and stack effect pressures. More correctly you need to be using a manometer that measures pressure differntials between the interior and exterior to acurately determine both the amount of pressure and if it is positive or negative to the building interior. And since these are variable you should have a good idea of the variability during the inspection. You can use an anemometer to determine the specific air flow through any one area of the building enclosure in combination with the manometer readings.