# What to do when your dryer duct is too far away to terminate



## jar546 (Feb 1, 2011)

You do this of course.  Remember when......


----------



## rshuey (Feb 1, 2011)

That's a commercial smoothie maker. you have the pic turned 90 degrees too far.


----------



## jar546 (Feb 1, 2011)

Did anyone notice the upside down insulation?


----------



## Pcinspector1 (Feb 1, 2011)

This problem starts with design, let's see, where should I draw in the washer/dryer closet, I know, how bout in the the middle of the house in the hallway, ya thats it!


----------



## north star (Feb 1, 2011)

** * * **

Shouldn't the paper on that thermal insulation overlap on to the individual

joist / studs and be attached to them?.....Also, shouldn't the lengths of

insulation be one continuous length?

** * * **


----------



## jar546 (Feb 1, 2011)

north star said:
			
		

> ** * * **Shouldn't the paper on that thermal insulation overlap on to the individual
> 
> joist / studs and be attached to them?.....Also, shouldn't the lengths of
> 
> ...


Absolutely not.  The paper is never required to cover the face/edge of the joist/stud.  Except for the joist bay that has the fan in it, the others are installed upside-down anyway.


----------



## mark handler (Feb 1, 2011)

getting back to the booster fan, other than the placement, what is the problem?

http://fantech.net/docs-resi/802003-dbf4xlt-submittal.pdf


----------



## north star (Feb 1, 2011)

** * * **

Jeff,

In reading some of the manufacturer's literature, the thermal insulation

can be inserted in to the individual cavities or stapled to the framing

( see the attached link to Johns-Manville - Installation Guide for one

of their products ).

*http://www.specjm.com/files/pdf/bid0016.pdf*






** * * **


----------



## fatboy (Feb 1, 2011)

Dryer booster fans are not specified as an option for length limitations in the 2009 IRC. (I suppose if you had manufacturers specs for the dryer that allowed it) The booster fan was included in the 2003 IRC, but went away in the 2006 IRC, was never in the IMC. And, I never did find one that was fully listed in the US, the motors were, not the assembly.


----------



## jar546 (Feb 1, 2011)

north star said:
			
		

> ** * * **Jeff,
> 
> In reading some of the manufacturer's literature, the thermal insulation
> 
> ...


It can be but the code does not require it.  Drywall contractors who glue an screw will hate you if you do it.


----------



## north star (Feb 1, 2011)

*$ $ $ $*



> It can be but the code does not require it. Drywall contractors who glue an screw will hate you if you do it.


That ship has already sailed!    *$ $ $ $*


----------



## pwood (Feb 1, 2011)

here the paper cannot be left exposed for fire danger reasons. read the warning on the facing sometime. our energy code says to staple the facing to the face of the stud/joist for optimum energy performance.


----------



## Jobsaver (Feb 1, 2011)

The OP appears to be of a floor cavity, not a wall cavity. Excepting manufactured housing, the insulation in a floor cavity is vitually always installed after the subfloor, and the kraft face, even when installed correctly, rarely will overlap the top of the joists.

Is the OP showing a floor or ceiling cavity? If a ceiling cavity, the reverse backing only applys to the cavity containing the vent.


----------



## jar546 (Feb 1, 2011)

Basement.  You are looking a the floor joists for the 1st floor.


----------



## jim baird (Feb 1, 2011)

Blame it on the architects who always want the laundry room in the middle of the McHouse.

Also, manufacturer's specs can get 'em off the hook, no?

One I wrote up produced documents stating THEIR dryer would push the lint etc 40+ feet.


----------



## mtlogcabin (Feb 1, 2011)

> Also, manufacturer's specs can get 'em off the hook, no?


Yes

2009 IRC

M1502.4.4.2 Manufacturer's instructions.

The size and maximum length of the exhaust duct shall be determined by the dryer manufacturer's installation instructions. The code official shall be provided with a copy of the installation instructions for the make and model of the dryer at the concealment inspection. In the absence of fitting equivalent length calculations from the clothes dryer manufacturer, Table M1502.4.4.1 shall be used.


----------



## fatboy (Feb 1, 2011)

Yes, and I was tongue-in-cheek suggesting a manufacturers spec may allow the use of a booster, I seriously doubt it, but was just sayin.........


----------



## mark handler (Feb 1, 2011)

http://www.specsserver.com/CACHE/FRWFNDRDKTCT.PDF

These guys say "Rigid metal" no ell's 64 ft (page11)


----------



## fiddler (Feb 1, 2011)

Personally I really hate that addition to the code. There is no way to ensure that future owners of the house will have a dryer with the same capacity. Or for that matter when the existing owners replace said dryer.


----------



## JBI (Feb 1, 2011)

The nailing of kraft paper to the insides of studs is a convenience to the drywallers, but a detriment to the longevity of the building. Air, spelled m-o-i-s-t-u-r-e moves through those spaces causing problems... As infrequently as all other details get done correctly, like cutting around boxes, etc it's hard to get anyone to understand this one.


----------



## mtlogcabin (Feb 2, 2011)

fiddler said:
			
		

> Personally I really hate that addition to the code. There is no way to ensure that future owners of the house will have a dryer with the same capacity. Or for that matter when the existing owners replace said dryer.


I don't like it either but like most products it will have a warning label about as effective as "Danger Will Robinson Danger"

M1502.4.5 Length identification.

Where the exhaust duct is concealed within the building construction, the equivalent length of the exhaust duct shall be identified on a permanent label or tag. The label or tag shall be located within 6 feet (1829 mm) of the exhaust duct connection.


----------



## mark handler (Feb 2, 2011)

http://www.usfa.dhs.gov/downloads/pdf/statistics/Residential_Structure_and_Building_Fires.pdf

Less than 5 % of reported residential fires (2005) are attributed to Laundry areas


----------



## jar546 (Feb 2, 2011)

mark handler said:
			
		

> http://www.usfa.dhs.gov/downloads/pdf/statistics/Residential_Structure_and_Building_Fires.pdfLess than 5 % of reported residential fires (2005) are attributed to Laundry areas


You can look at it that way to give the perception that it is not a big deal.

5% of the total fires IS a big number and can be preventable.  That is the reality.  I would think most of these issues are maintenance related.


----------



## mark handler (Feb 2, 2011)

jar546 said:
			
		

> You can look at it that way to give the perception that it is not a big deal.5% of the total fires IS a big number and can be preventable.  That is the reality.  I would think most of these issues are maintenance related.


I did not say that was a good or bad number. Zero would be a good number.


----------



## jar546 (Feb 2, 2011)

OK, people can look at it that way.  I was not being specific to you.  Nice link btw.


----------



## Yankee (Feb 2, 2011)

fiddler said:
			
		

> Personally I really hate that addition to the code. There is no way to ensure that future owners of the house will have a dryer with the same capacity. Or for that matter when the existing owners replace said dryer.


There is hope, the 2009 requires the developed length of the duct to be permanently labeled by the machine. At lease now there is an OPPORTUNITY to get it right with a dryer replacement. Wooops, already answered by a previous post.Anyway, 5% of fires for just ONE CAUSE is a high number


----------



## Yankee (Feb 2, 2011)

JBI said:
			
		

> The nailing of kraft paper to the insides of studs is a convenience to the drywallers, but a detriment to the longevity of the building. Air, spelled m-o-i-s-t-u-r-e moves through those spaces causing problems... As infrequently as all other details get done correctly, like cutting around boxes, etc it's hard to get anyone to understand this one.


Yes, I am really starting to have a hard time with it, , , sheetrock and other finish materials have similar vapor retardant properties, why is having an additional vapor retarder necessary in those locations? The PROBLEM is that the building is not ventilated, , , I am getting really sick of this energy baloney. . . can you tell?


----------



## rheckle (May 19, 2011)

Booster Fans are allowed now ! , fan tech has a listed approved fan and UL has the standard for it. Please remember to check with UL and the Fan must be listed and approved.It will be in the 2015 code!


----------



## fatboy (May 19, 2011)

"Booster Fans are allowed now !"

No, they aren't. Fantech may have received a listing, but they are still not specifically allowed in the 09, or the 12 codes.

"It will be in the 2015 code!"

Interesting comment, since the 2015 code change hearings have yet to even start. There's a long row to hoe there, my friend.

Welcome to the forum, didn't see any particulars in your profile. Where you from, what codes, what is your interest in the codes, your trade????????

Can you please cite your resource on this?


----------



## NH09 (May 20, 2011)

I just had a contractor give me the specs for a dryer booster fan (sold at a major retailer) and the the specs do not specifically state the fan meets the requirements of the 2009 IRC nor does it give any specs on an assembly (40' with 5 90's, 30' with 2 45's and 1 90..etc.). I had to turn him down, there was not enough documentation to back up the installation.


----------



## Big Mac (May 24, 2011)

Any pictures as to how they plan to provide access tothat for servicing, replacment, etc.  Any type of access panel I can immagine would really look great in a finished ceiling.


----------



## mark handler (May 24, 2011)

Big Mac said:
			
		

> Any pictures as to how they plan to provide access tothat for servicing, replacment, etc.  Any type of access panel I can immagine would really look great in a finished ceiling.


 Attic Access.....







In ceiling, cant say I like the flex line, but


----------



## peach (May 24, 2011)

local amendment..

access?  don't worry about the insulation; the wood will catch fire first..

wouldn't it be nice to replace the fan (with some kind of disconnect) thru an access panel?

toss the dice.. or don't approve it.


----------



## pyrguy (May 24, 2011)

Just caught up with this thread.

I have seen "UL listed" , according to the documentation, booster fans before.  When I looked at the documentation only the motor was listed, the whole fan assembly was not.


----------



## Dr. J (May 24, 2011)

Agree with those who say boosters are not in the code.  It would have to be an approved alternative method.

What is baking my noodle is if that we are looking up at a basement ceiling, that means the basement is outside the thermal envelope, and therefore the basement should be considered unconditioned.


----------



## fatboy (May 25, 2011)

That's what I ran into pyrguy, and others I spoke with.


----------



## globe trekker (Jan 29, 2013)

I am resurrecting this thread again to see if there is any updated information.

Also, I have a customer that wants to install a booster fan & "new" exhaust

ducting on to their existing residential dryer. Their existing exhaust duct is

an underground pvc duct that terminates below grade oudoors, and fills up

with water when it rains.

The customer is not really interested in any type of approved assemblies

vs. approved motors issues, but DOES seek to have a safe and functional

install. They also do not want to relocate their dryer to an exterior wall!

I will have a licensed electrician install the circuit to the motor.

How does these booster fans activate, ..automatically, ..by the user & a

switch, other?

Any input will be greatly appreciated! Thanks!

.


----------



## mtlogcabin (Jan 29, 2013)

Appliance411 FAQ: How long can my dryer vent be?

A new dryer might be better, Check out the additional length some of the new dryers can meet.


----------



## ICE (Jan 29, 2013)

globe trekker said:
			
		

> Their existing exhaust duct is an underground pvc duct that terminates below grade oudoors, and fills up with water when it rains.


http://www.thebuildingcodeforum.com/forum/residential-mechanical-codes/9662-dwv-under-slab-dryer-duct.html


----------



## klarenbeek (Jan 30, 2013)

Also, if elbows are part of the length issue you can use long sweep elbows to reduce the deduction of 5' for each 90 (if there is room for them). See 504.6.4.1 of the 2009 IMC. We see these used fairly often, and they do make a difference for distance. We actually allowed them under the 2006 as alternate methods, because the ones we see are ul listed as dryer elbows with an equivalent length of 1' 6".


----------



## klarenbeek (Jan 30, 2013)

globe trekker said:
			
		

> The customer is not really interested in any type of approved assemblies
> 
> vs. approved motors issues, but DOES seek to have a safe and functional
> 
> ...


If He really wants a safe installation, he should avoid a booster fan altogether! If it quits working, it becomes nothing more than a lint trap, and it's one of those things that easily becomes "out of sight, out of mind".


----------



## globe trekker (Jan 30, 2013)

Continuing some more with this interesting topic..

I have tried to offer some other alternatives to this customer, but they are insistent

on installing a booster fan. They do not want to move the dryer away from the washer,

to an exterior wall and run a "new" exhaust duct & elec. circuit, nor do they want to

create a drainage trench leading away from the existing, below grade termination

point of the pvc duct. This is an older house with a slab-on-grade foundation and

the pvc pipe was installed yrs. ago.

What would you (or ya`ll) do ?

FWIW, "klarenbeek", it's not a He!    

.


----------



## ICE (Jan 30, 2013)

klarenbeek said:
			
		

> If He really wants a safe installation, he should avoid a booster fan altogether! If it quits working, it becomes nothing more than a lint trap, and it's one of those things that easily becomes "out of sight, out of mind".


Require an interlock.  Redundant fans.  A sprinkler system.  Fire watch.  Trained Beagle.


----------



## mtlogcabin (Jan 30, 2013)

*PVC Pipe Basics*


PVC pipe was first developed in the 1950s, and its durability, ease of use  and resistance to bacteria quickly made its use in plumbing systems very  popular. PVC pipe is commonly available in many sizes (diameters) and strengths  (schedules), and it is still widely used in residential and commercial  cold-water pipes. Because PVC pipe can warp and weaken when exposed to  temperatures above 140 degrees Fahrenheit, it is not used for hot-water systems,  which tend to consist of copper or galvanized steel.

*Dangers of PVC Pipe*


PVC pipe's sensitivity to heat is a big reason why it is not recommended for  use in dryer vents. The exhaust from a clothes dryer can reach temperatures  ranging from 120 degrees to 200 degrees Fahrenheit, which could cause the pipe  to soften and fail. PVC pipe is also prone to static electricity buildup, which  can attract lint and cause it to accumulate inside the pipe. This not only  reduces the efficiency of your dryer (which could lead to overheating), but it  can also increase the risk of fire and exacerbate condensation  issues.

*ICC Codes*


The nonprofit International Code Council (ICC) develops building codes and  guidelines for residential and commercial construction. Most cities, counties  and states in the United States tend to adopt the ICC codes or to model their  requirements closely on ICC recommendations. The ICC code for dryer exhaust  ducts specifies the use of smooth, rigid metal ducting

Read more:  Types of PVC Pipe Used for Dryer Vents | eHow.com Types of PVC Pipe Used for Dryer Vents | eHow.com







An example why you don't use PVC for a dryer duct


----------



## ICE (Jan 30, 2013)

It's good to know that the ICC is a nonprofit.

I didn't know about the static electricity.

Wow 200 degrees....I can bake bread while drying underwear.....I can call it sock loaf......talk about loaded with fiber


----------



## globe trekker (Jan 30, 2013)

> I can call it sock loaf


He said, followed by the sound of "rim shot" !  

.


----------

