Dryer vent booster fans new info

[vern p]

Got this off the ICC website today. Thought I'd post it for your info. ICC answer to booster fans.

swansont
Posts: 159
Registered: Jun 2000
posted 03-07-2005 12:55 PM
--------------------------------------------------------------------------------
Well it appears that all of our concerns were shared to some extent. Here is the reply I received today from Larry.
Code Question:


Code Edition: 2003 IMC

Code Section: 504.6

Code Question:

Why is the exception, for a booster fan on the dryer duct, in the IRC and not included in the IMC? I have a R-2 application that was trying to use that exception, which they found in the IRC, and I am not allowing it, because of the absence of it in the IMC. I feel there must be a reason, not just an oversite.


ANSWER: The booster fans have now been removed from the IRC following the 03/04 code hearings. RM6-04/05 attempted to put them back during last week’s code hearings and the IRC committee disapproved the code change. As of now, the booster fans won’t be in either the IMC or the IRC in the 2006 editions.


As Mr. Battles told you, they are different in the 2003 codes because different committees control the content of the two codes. The NAHB has more control of the IRC committee and they approved booster fans for the 2003 code, but the IMC committee disapproved them because no dryer manufacturer permits them in their installation instructions.

I have let the developer know that I am not going to allow them. Thanks for all the feed back.

[Carnak]

I can see banning them on new construction, they should have the dryer along an outside wall in the first place.

[vern p]

Just shows you the thinking process between a mech. engineer and an architect

[Carnak]

Don't say the E word X may catch on.

[old educator]

VernP
Although the 03 IMC is silent on the booster fan, the ICC Commentary for the 03 IMC states in its last paragraph under section 504.6.1 that "...Another option is clothes dryer booster fans, which would have to be approved by the code official, because the code does not currently address booster fans..." It goes on to mention lack of dryer listing or booster fan interlock but it does leave it up to the local code official.

[vern p]

Old Educator, thats the reason I posted this from the ICC. It removes the speculation on the mater and no longer gives the Code Official leeway, or am I reading it wrong?

ANSWER: The booster fans have now been removed from the IRC following the 03/04 code hearings. RM6-04/05 attempted to put them back during last week’s code hearings and the IRC committee disapproved the code change. As of now, the booster fans won’t be in either the IMC or the IRC in the 2006 editions.


As Mr. Battles told you, they are different in the 2003 codes because different committees control the content of the two codes. The NAHB has more control of the IRC committee and they approved booster fans for the 2003 code, but the IMC committee disapproved them because no dryer manufacturer permits them in their installation instructions.

[hearthman]

Now makes it required to provide makeup air. If a builder tries to claim passive infiltration, it must be proven with a blower door test.

62.2 may not be a code in your area but it is a nationally recognized std. If there ever is an Ooops!, this std. will certainly be waved around in court. It's about time guys started adding the 'V' into their H_AC titles. Yes, I realize how abrasive this sounds but in this day and time to install exhaust equipment without properly balanced makeup air and therefore ventilation is negligent.

In the case with such a booster fan, it could be installed with a slave switch to a makeup air device. When the booster or even dryer kicks in, so does the makeup air fan. One problem with attic installations is the passive exfiltration which exacerbates the depressurization.

Fire away!

[Xavier]

Vern, as we discussed yesterday a Booster Fan (by definition) will reduce flow.

Most College Graduate "E" and People with common sense know this.

I think even Abby Un-normal would agree.

Now if only the codes could properly size make-up and combustion air, residential homes would be safer!

[vern p]

X, welcome back, the banter will at least be humorous for some of us, lol.
Re: the make up and combustion issues as we discussed yesterday, the codes can be offered a change by anyone regardless of affiliation, in the prescribed manner, per ICC's website, http://www.iccsafe.org
Now if you'd like to attend our next seminar on March 17th in Warren on the combustion air code presented by Mr. Guy Mitchell of Royal Oak, we'd be glad to have you there with your questions and comments. I talked with Mitchell today about our conversation and the reason given against your interpertation that if 2 appliances are vented in a 5" "B" vent why a 8" combustions air opening?
Answer is its not only combustion air but dilution air as well that the Code is based on. As I told you yesterday, the Code wizards write the code I only enforce it as written.
You can sign up for the seminar at http://www.mechanicalinspector.com or call the Assn. offices at 248-649-5443 to register.
I'm sure Mitchell will welcome all those interested.

[snips]

An inline booster fan for a dryer vent, never heard of it.
You'd think that would stand about a hour of use before the fan would be incased with lint.

[Carnak]

Originally posted by Xavier
Vern, as we discussed yesterday a Booster Fan (by definition) will reduce flow.

But X, some times the booster fan runs.

[Xavier]

Vern, I know that, but do they know that BOTH the combustion air and the dilution air PLUS the volume of fuel, all exhaust through the flue? DA!

Furthermore, the temperature is HIGHER for the air in the flue then both the combustion air and the dilution air?

A booster fan will reduce flow if it is on or off!

[Carnak]

A four inch passive combustion air intake is very limited as to what it can supply, even when you REMOVE THE DAMPER!