Blower Door Test Calculations

Ordinary least squares regression analysis is then used to calculate the leakage characteristics of the building envelope.

Blower door test calculations.

Total air flow through building envelope. Simply put a blower door is a diagnostic tool used to measure how much air infiltration air leakage occurs in a house. If its blower door flow at 50 pa is 2200 cfm then the air changes per hour ach50 are. A blower door test is used on buildings in order to quantify the amount of air leakage through its enclosure.

Ach 50 cfm 50 x 60 volume ach 50 must be 7 or less ach 50 air changes per hour at 50 pascals cfm 50 cubic feet per minute air movement at 50 pascals from the blower door reading cfm s it takes to achieve 50 pascals pressure difference inside to outside depressurize the building 60 minutes in an hour change equation into hours for answer in hours. The formula is cfm50 x 60 the volume of the house. The air change rate must be below 0 6 airchanges per hour under test conditions. Cubic feet per minute of air leakage at 50 pascals of pressure.

The multi point blower door test procedure results in a series of known values of q n fan and p n building. Ach50 cfm50 60 house volume for example if a house is 40 ft by 50 ft by 8 ft high then its volume is 40 50 8 16 000 cubic ft. 1291 m 3 h. Last year we built an energy star home for a customer and we used a blower door test to evaluate the houses air infiltration performance.

The building or dwelling unit shall be tested and verified as having an air leakage rate of not exceeding 5 air changes per hour. After installation of the complete air distribution system but before installation of insulation and sheet rock. The low air leakage rates that are required in the standard must be proven for each individual building by means of a blower door air tightness test. When the fan is turned on it creates a pressure difference between the outside and the inside.

Where required by the code official testing shall be conducted by an approved third party. Typical p n building values are 5 10 20 30 40 and 50 pascal. Testing shall be conducted with a blower door at a pressure of 0 2 inches w g. C building and n building.

Understanding blower door test results. Blower door sample calculation air infiltration equation. During this test a calibrated fan is installed in an otherwise sealed door or window while all the other openings to the exterior are closed. It is equal to the blower door flow for one hour divided by the house volume in cubic feet.