Dryer Vents

[Joe_Carrick]

I've been trying to find a way to vent a clothes dryer more than 15' (2-90 degree elbows) from an exterior wall.  According to some previous threads it's possible to use an in-line exhaust fan such as "FanTech" to extend the allowable distance.  However, the CRC, IRC or any other code I know of doesn't have such a provision.  The City of San Diego has basically refused to allow any extension of the allowable distance.

 

Can anyone quote a code section that allows an exception?  Without some sort of solution the location of a Laundry Room is severely restricted in a single family home.

[kMoquin]

What about using a ventless condensing dryer?

[Richard_Morrison]

Per CMC Sec. 504.4.2, the maximum is 14', not 15'. If the AHJ doesn't approve an extension, I don't see any exceptions.

[Renerabbitt]

This is an excerpt from San Diego's 2013 code changes

Richard pointed out the correct code for type 1 dryers.

There may be some work around's that may or may not be worth the effort. The city can approve a manufacturers allowed installation parameters.

Take a look here: http://epubs.iapmo.org/2016/CMC/mobile/index.html#p=129

[Alaskan_Son]

This is a hotly debated issue.  Boosters were allowed for a little while and then removed in 2006 I think it was.  Problem is that the dryer manufacturer has to approve them, the booster has to be listed, and the jurisdiction has to allow

it.  Some have decided to allow them and some have specifically decided to prohibit them.  

 

Anyway, almost every single code has an alternate means exception if you can provide the proper engineering documentation.  That may be a tall order though as dryer manufacturers are unlikely to accept the risks of approving them, so if your jurisdiction doesn’t allow them, you’ll need some pretty costly independent testing and engineering.  

 

Im curious...if anyone knows...what do most laundromats do?  Are they always limited to top floor or end units?  

[Alaskan_Son]

7 minutes ago, Renerabbitt said:

This is an excerpt from San Diego's 2013 code changes

 

Yep.  The “alternate means” exception I loosely referred to is right there in the beginning of the first sentence.  

[Renerabbitt]

3 minutes ago, Alaskan_Son said:

This is a hotly debated issue.  Boosters were allowed for a little while and then removed in 2006 I think it was.  Problem is that the dryer manufacturer has to approve them, the booster has to be listed, and the jurisdiction has to allow

it.  Some have decided to allow them and some have specifically decided to prohibit them.  

 

Anyway, almost every single code has an alternate means exception if you can provide the proper engineering documentation.  That may be a tall order though as dryer manufacturers are unlikely to accept the risks of approving them, so if your jurisdiction doesn’t allow them, you’ll need some pretty costly independent testing and engineering.  

 

Im curious...if anyone knows...what do most laundromats do?  Are they always limited to top floor or end units?  

They use type II dryers, next page of the link I provided 

[Joe_Carrick]

The basic problem with the stated exception is that you can't be sure the same type (capable) dryer will always be installed.  The originally specified dryer may be replaced at some time in the future with one that doesn't comply.  I personally think there should be an exception based on the air-flow (fan assisted if needed).  How do we get this issue fixed in the codes?