Blower Door Test Method B

The Blower Door Test Method B is an airtightness test on a building still under construction to timely detect which areas may generate depressurization in the rooms. To that end, we seal all openings to the outside before detecting those critical areas creating the problems. Hence, we take the following steps:

  • We seal all openings to the outside whether there are fixtures or not (unlike what happens with the Blower Door Test Method A where windows must be installed and are closed to simulate the real conditions of use). All of the internal doors shall be left completely open.
  • Plug up all syphons and exhaust ducts.
  • Seal the hood exhaust duct (if a valve is installed, we ensure it is closed).
  • Seal the gas exhaust hole.
  • Check that the electrical system is installed mounted according to the design to check the airtightness of each outlet box
  • Turn off and seal the eventual mechanical ventilation.
  • Seal off any fireplace flue (after cleaning any ash from the unit).
  • Seal off the eventual mail slot.

These precautions allow us to carry out the Blower Door Test Method B with total sealing conditions towards the outside. Once that has been done, we can detect leaks with the procedures listed in the operation of the blower door test description.

We generally perform the Blower Door Test Method B during construction, before foundation layers and finishings are installed since the correction of possible leaks is easier and quicker if detected during testing.


During the Blower Door Test a thermographic inspection is also performed to detect air leakage and infiltrations. 

If you are interested in a Blower Door Test Method B