Blower Door

[Brian A. MacNeish]

Originally Posted by rmisener

Joe,

Do you have any links or articles on this? I'd be interested to read on it. I haven't heard this come up yet.

IMHO, some scare tactics being "thought" up by someone not understanding the process!! I should be sued by now if I was making people sick with blower door testing since I began doing it in 1981. Never had a complaint about dust and mould entering the house from the walls.

The highest pressure differential created across a wall in a blower door test is 60 pascals. 60 pascals is velocity pressure of a 22.3 mile per hour wind!!!

Our houses experience winds that are much higher than 22.4 mph many times a year. So if people are afraid of the pressures created in a blower door test---60 pascals........ they should really be afraid of the pressures created when the wind blows 50 miles an hour---261 pascals. That should should be enough air velocity to really clean the walls out until the same time next year!!!

[Joe Farsetta]

Brian,

I have heard from a number of reliable sources that blower door tests have either been eliminated from the list of approved procedures or soon will be. The announcement will come from the EPA, with support from the CDC.

As I understand it, the blower door significantly de-pressurizes the dwelling, and allows any number of conditions to occurr regarding Indoor Air Quality.

It has been documented that such tests actually suck in contaminents from a variety of sources, including wall cavities. Depending on what exists in these cavities (including dust, mold spores, dander, mice hair, feces, etc), these contaminents quickly permeate throughout the dwelling, landing on furniture, people, pets, food, etc.

And this is why the EPA now believes that the upside to using this technology is outweighed by the negative effects it results in.

It's not a scare tactic on my part by any stretch of the imagination. De-pressurization is a genuine issue. For instance,studies have confirmed that high efficiency furnaces and boilers, absent of having sources of exterior combustion air, can depressurize a structure enough to cause the premature failure of thermopane window and door seals. If this moderate source of suction can cause these sort of problems, just imagine what a huge source of depressurization can cause.

[Rodney Misener]

Joe,

Can you provide any documentation to support?

[Brian A. MacNeish]

[quote=jfarsetta;436074]Brian,

I have heard from a number of reliable sources that blower door tests have either been eliminated from the list of approved procedures or soon will be. The announcement will come from the EPA, with support from the CDC.

As I understand it, the blower door significantly de-pressurizes the dwelling, (re-read my previous post....regular winds create much stronger presssure differentials across walls....do we do away the winds also?) and allows any number of conditions to occurr regarding Indoor Air Quality.

It has been documented that such tests actually suck in contaminents from a variety of sources, including wall cavities. Depending on what exists in these cavities (including dust, mold spores, dander, mice hair, feces, etc), these contaminents quickly permeate throughout the dwelling, landing on furniture, people, pets, food, etc.

And this is why the EPA now believes that the upside to using this technology is outweighed by the negative effects it results in.

It's not a scare tactic on my part by any stretch of the imagination. De-pressurization is a genuine issue. For instance,studies have confirmed that high efficiency furnaces and boilers, absent of having sources of exterior combustion air, can depressurize a structure enough to cause the premature failure of thermopane window and door seals. If this moderate source of suction can cause these sort of problems, just imagine what a huge source of depressurization can cause.[/quote]

Joe:
I'm sorry to say that you're just hearing stories from the street with no actual factual basis. Stuff from the street has a way of being not that good a source of info......check your sources. Remember in the mid 80's with AIDS being only a gay male disease until some guy got it from his girlfriend!! I have seen some very well respected contractors not have a clue about this stuff but spout "facts" like they knew it inside out.

I have worked with airtight housing since 1977 and have not heard anything like this. I believe you're as least a bit familiar wth Canada's R2000 system with which I worked for 9+ years. During that period, two of my clients were named Canada's R2000 "Builder of the Year". I was a site advisor/inspector/certifying air leakage tester/"troubleshooter" for the local New Brunswick as well as doing follow-up research after the homes were lived in to ensure unforseen problems were not occurring.

Joe Lstiburek was involved in the forerunner program to and the early R2000 program and helped set the standards for the system. He's been a main partner of the "Building America" program and sat of the board of directors of the Energy-Efficient Buildings Association and was co-chair of the American Lung Association's "Health House" technical committee. To date, I have not heard anything from his organization to this effect......and they have been leaders in this field for years!!!

Check your sources!!!

BPI has had a recommendation of no blower testing for houses known to contain ACM's such asbestos containing loose fill vermiculite insulation.

[Nick Gromicko]

The biggest causes of depressurization in a home are (in order):

1. Stack effect (especially in the winter).
2. Venturi effect (wind passing across open windows and other openings).


Not flues or appliances.

[James E. Braun, CMI]

Why not just presuurize the home instead? Blower doors can run both ways.

[Yuri Olhovsky]

Jim, how are you going to find air leaks by pressurizing the house?

[David A. Andersen]

With the blower door, that is what it does. Measures air flow.

[Yuri Olhovsky]

Yes, the blower door measures pressure differential or air flow. I'm asking about finding particular places that loose heat by air leakage. You can only find them when the house is de-pressurized, not pressurized.

[David A. Andersen]

Why can't chemical smoke pass out of the building envelope when pressurized?

Instead of blowing away from an opening, it will get sucked in.

I am in favor of sucking over blowing, but it can be done.
It may have to be done at a higher pressure (60 vs 20 pascal), but it can be done.

[James E. Braun, CMI]

I have seen it done with a smoke pen. It is pretty freaky to see smoke draw out of house.

[Yuri Olhovsky]

Well, gentlemen, the smoke pencil is a chemical, and I don't use chemicals. The back of my hand works equally well but only during the de-pressurization test.

[Justo Mickey Rivera]

Originally Posted by yolhovsky

the smoke pencil is a chemical, and I don't use chemicals.

How much smoke do you use? Not trying to be funny. But in the big scheme of things........it can't be any worse than when I pass gas. If I had to compare the two, I think people would rather have the smoke than my gas.

You could use one of those theatrical foggers also.

Or as a last resort I could stand on one side of the wall and pass my gas and you on the other to sniff it out. LOL . Sorry I couldn't resist that one.

Mic

[Rodney Misener]

There is about as much smoke from a smoke pencil as there from a cigarette. Pressurization works fine, depressurization is a bit easier thats all. Its not like the h/o is in contact with the smoke, the air pushes/pulls it outside the home in a matter of seconds.

[Kevin A. Richardson]

Originally Posted by yolhovsky

Yes, the blower door measures pressure differential or air flow. I'm asking about finding particular places that loose heat by air leakage. You can only find them when the house is de-pressurized, not pressurized.

Not accurate!!

You can use a blower door to "pressurize" the building and then use an Infrared Camera to detect air exfiltration on the exterior envelope. This survey is usually conducted a night or two hours post sunset.

Remember that due to the principles of "stack effect", air infiltrates in the lower plane of a building, while air exfiltrates in the upper plane of a building.

However, I've never really found the need to use a blower door, and I've conducted hundreds of energy audits using ITI. When I first started doing them with infrared, I would conduct them during normal business hours (daytime), but I have since changed that and conduct all of my energy audits at night. That way I can detect both air infiltration/exfiltration by conducting interior/exterior scans. Plus, in my area (wash DC) you get a way better temperature differential at night.

Kevin