Blower Pressure Converter

Convert infiltration flow per exterior area measured at a particular blower door pressure to flow per exterior area measured at a typical building pressure.

This is accomplished by computing a normalized-area air mass flow coefficient that is derived the power law relationship between pressure and air flow. Cqa = Qblow / dPblow^n And then using the coefficient to approximate air flow at typical building pressure. Qbldg = Cqa * dPbldg^n

where: Cqa: Air mass flow coefficient per unit meter at 1 Pa [kg/m2/s/P^n] Qblow: Blower-induced volumetric air flow rate per area [m3/s/m2] dPblow: Blower-induced change in pressure across building envelope orifice [Pa] Qbldg: Typical building volumetric air flow rate per area [m3/s/m2] dPbldg: Typical building change in pressure across building envelope orifice [Pa] d: Air density [1.2041 kg/m3] n: Air mass flow exponent [0.65]

Inputs

A numerical value for the intensity of air flow induced by blower pressure in m3/s per square meter of exterior surface area.

A number representing the pressure differential in Pascals (Pa) between indoors/outdoors at which the specified _infilt_per_exterior occurs. Typical pressures induced by blower doors are 75 Pa and 50 Pa. (Default: 75).

The reference air pressure difference across building envelope under typical conditions in Pascals. (Default: 4).

Outputs

The intensity of infiltration in m3/s per square meter of exterior surface area at the input *bldg_pressure*.

Air mass flow coefficient per square meter at 1 Pa [kg/m2/s/P^n].

Last modified 1mo ago