Calibrated Blower Door Test graphic.

[Nick Gromicko]

http://www.nachi.org/gallery/insulat...-door-test.jpg

[Scott Gilligan, CMI]

Originally Posted by gromicko

http://www.nachi.org/gallery/insulat...-door-test.jpg

Your red arrows should indicate inward leaking air at the windows if the house is being depressurized by a blower door.

[James H. Bushart]

Needs work.

[Brian A. MacNeish]

Originally Posted by gromicko

http://www.nachi.org/gallery/insulat...-door-test.jpg

Don't try to re-invent the wheel. There are hundreds if not thoussands of good graphics about air leakage and blower doors.

[Patrick Carter]

poor illustration...

[Peter W. Bennett]

An anigif with infrared showing the correct airflow would whoop it up some!

[Nick Gromicko]

Re-built: http://www.nachi.org/gallery/insulat...lower-door.jpg

Better?

[Ben J. Gromicko]

Originally Posted by Brian A. MacNeish

Don't try to re-invent the wheel. There are hundreds if not thoussands of good graphics about air leakage and blower doors.

Thousands. Really? Where?
If I had a gun to my head, I couldn't find five, online, equivalent to http://www.nachi.org/gallery/insulat...lower-door.jpg, which BTW is excellent.

[Nick Gromicko]

I think this new image is much better (at least for my purposes). I needed an image that can be used in marketing pieces or InspectorPages sites to quickly convey (in layman's terms) what a blower door is.... and... the image had to look good.

Now for member purposes, the other reason we need our own good-looking images is so that members can use them (without fear of copyright infringement).

www.nachi.org/gallery/

[James H. Bushart]

Originally Posted by gromicko

I think this new image is much better (at least for my purposes). I needed an image that can be used in marketing pieces or InspectorPages sites to quickly convey (in layman's terms) what a blower door is.... and... the image had to look good.

Now for member purposes, the other reason we need our own good-looking images is so that members can use them (without fear of copyright infringement).

www.nachi.org/gallery/

It fails, Nick.

Prettier picture of a house, indeed...but the information it conveys is incomplete and incorrect.

[Brian A. MacNeish]

Originally Posted by bgromicko

Thousands. Really? Where?
If I had a gun to my head, I couldn't find five, online, equivalent to http://www.nachi.org/gallery/insulat...lower-door.jpg, which BTW is excellent.

In the training manuals and some government online stuff.....more about the air leakage sites though!

[Nick Gromicko]

Jim, how is the information it conveys "incorrect?"

[James H. Bushart]

Originally Posted by gromicko

Jim, how is the information it conveys "incorrect?"

Just for starters...during a blower door test all buffer zones (garage, attic, unconditioned basement, porch, crawlspace) should be open to the outside.

Remember, Nick...a blower door test quantifies the air exchange rate between the conditioned area of the home and the outdoors. For proper measurement, all unconditioned space should be allowed to match exterior pressure.

There is much more...but takes too much time to post.

[Nick Gromicko]

How could we convey that in an image? What if we removed the word "leaking" from the yellow arrow in the key? In other words, change "Inward Leaking Air" to "Inward Air" or "Incoming Air." ??

Would that help?

[James H. Bushart]

Originally Posted by gromicko

How could we convey that in an image? What if we removed the word "leaking" from the yellow arrow in the key? In other words, change "Inward Leaking Air" to "Inward Air" or "Incoming Air." ??

Would that help?

Starting with a full understanding of what a blower door test actually measures, I think your illustration should show a cross-section of the interior (not exterior) of the home. It might point arrows at common leakage points between conditioned and unconditioned spaces, perhaps, but the entry points are secondary to the blower door test and the information it is designed to provide.

Using an exterior view of the home is of no value since air actually leaks through construction materials during a blower door test. 5/8" OSB will leak at the rate of .09 CFM for ever 100 sq ft when the blower door is depressurizing at 50 Pa.