Zonal Pressure Testing

Replies to This Discussion

Permalink Reply by Silvie Votrubova on December 10, 2010 at 8:58am

If I am understanding this correctly when the house is at 50Pa relative to outside and the attic is at 2Pa relative to outside then there is not much connection between those two zones. The 2Pa in the attic could even be due to stack. Sounds like they have a very tight ceiling.

 

Silvie Votrubova, Retrotec

Permalink Reply by Paul Morin on January 13, 2011 at 5:51am

Here are a couple of things to remember when measuring zonalpressures.  First is that you want tomeasure the change in pressure caused by the Blower Door, so you will need torecord a baseline attic to outside pressure. Secondly zonal pressures do not tell you the size of the leakage betweenthe house and the attic.  The zonalpressure tells you the leakage ratio between the house and attic compared tothe leakage between the attic and the outside. For example, if the attic to outside number is 25 pa, then the hole sizebetween the house and attic is the same as between the attic and outside.  If the attic to outside number is 2 pa, thenthe ratio is 1 to 8.  It is possible tohave a attic to outside zonal pressure of 2 pa on one house and 25 pa onanother house and have an equal hole size between the house and attic.