Thread: Laundry Room and Dryer Exhaust Vents

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Originally Posted by Clay White

Dryer exhaust vent line is installed between the wall framing and insulation.

Why oh why would they do that?!

Clay, if the area your working in is under the IRC chech 1502 in the 2006 IRC.

Originally Posted by Clay White

John, are you saying that the way the routed the dryer line is wrong? If so, why?

Well, for one thing, it compresses the insulation. But honestly, I can't imagine why anyone would run the vent there instead of on the inside of the framing. It boggles my mind.

Originally Posted by Jerry McCarthy

Clay, if the area your working in is under the IRC chech 1502 in the 2006 IRC.

Jerry M,

Would this application be considered concealed under same section IRC 2003?

From what can be seen in the pic it looks there is quite a long run of dryer vent, what was the total ft or dryer vent?

Originally Posted by Jerry McCarthy

Clay, if the area your working in is under the IRC chech 1502 in the 2006 IRC.

Jerry Mc.,

Is that saying 'Yes, it is okay.', or, 'No, that is not okay because of ... '?

What *part* of 1502 are you thinking about?

IRC-2006 - SECTION M1502
CLOTHES DRYER EXHAUST M1502: 1 General. Dryer exhaust systems shall be independent of all other systems, and shall convey the moisture to the outdoors.
Exception: This section shall not apply to listed and labeled condensing (ductless) clothes dryers.
M1502.2 Duct termination. Exhaust ducts shall terminate on the outside of the building. Exhaust duct terminations shall be in accordance with the dryer manufacturer’s installation instructions. Exhaust ducts shall terminate not less than 3 feet (914 mm) in any direction from openings into buildings. Exhaust duct terminations shall be equipped with a backdraft damper. Screens shall not be installed at the duct termination.
M1502.3 Duct size. The diameter of the exhaust duct shall be as required by the clothes dryer’s listing and the manufacturer’s installation instructions.
M1502.4 Transition ducts. Transition ducts shall not be concealed within construction. Flexible transition ducts used to connect the dryer to the exhaust duct system shall be limited to single lengths, not to exceed 8 feet (2438 mm) and shall be listed and labeled in accordance with UL 2158A.
M1502.5 Duct construction. Exhaust ducts shall be constructed of minimum 0.016-inch-thick (0.4 mm) rigid meta ducts, having smooth interior surfaces with joints running in the direction of air flow. Exhaust ducts shall not be connected with sheet-metal screws or fastening means which extend into the duct.
M1502.6 Duct length. The maximum length of a clothes dryer exhaust duct shall not exceed 25 feet (7620 mm) from the dryer location to the wall or roof termination. The maximum length of the duct shall be reduced 2.5 feet (762 mm) for each 45-degree (0.8 rad) bend and 5 feet (1524 mm) for each 90-degree (1.6 rad) bend. The maximum length of the exhaust duct does not include the transition duct.
Exceptions:
1. Where the make and model of the clothes dryer to be installed is known and the manufacturer’s installation instructions for the dryer are provided to the building official, the maximum length of the exhaust duct, including any transition duct, shall be permitted to be in accordance with the dryer manufacturer’s installation instructions.
2. Where large-radius 45-degree (0.8 rad) and 90-degree (1.6 rad) bends are installed, determination
of the equivalent length of clothes dryer exhaust duct for each bend by engineering calculation in accordance with the ASHRAE Fundamentals Handbook shall be permitted.

Find Waldo?

Originally Posted by Jerry McCarthy

IRC-2006 - SECTION M1502
CLOTHES DRYER EXHAUST M1502: 1 General. Dryer exhaust systems shall be independent of all other systems,

M1502.4 Transition ducts. Transition ducts shall not be concealed within construction.

Find Waldo?

My vote,

Originally Posted by Jeff Eastman

duct is not concealed.

Before or after you remove the braces?

M1502.4 Transition ducts. Transition ducts shall not be concealed within construction.

That's not "transition" duct, anyway, is it?

Quote from Jerry Mc.'s post:
IRC-2006 - SECTION M1502
- CLOTHES DRYER EXHAUST M1502: 1 General. Dryer exhaust systems shall be independent of all other systems, and shall convey the moisture to the outdoors. (Jerry P. note: It is.)
- - Exception: This section shall not apply to listed and labeled condensing (ductless) clothes dryers. (Jerry P. note: This does not apply.)
- M1502.2 Duct termination. Exhaust ducts shall terminate on the outside of the building. Exhaust duct terminations shall be in accordance with the dryer manufacturer’s installation instructions. Exhaust ducts shall terminate not less than 3 feet (914 mm) in any direction from openings into buildings. Exhaust duct terminations shall be equipped with a backdraft damper. Screens shall not be installed at the duct termination. (Jerry P. note: It does go outside. Regarding the other parts of this section - insufficient information given.)
- M1502.3 Duct size. The diameter of the exhaust duct shall be as required by the clothes dryer’s listing and the manufacturer’s installation instructions. (Jerry P. note: It looks like 4 inch, which is good, unless the manufacturer states larger - insufficient information given to know that.)
- M1502.4 Transition ducts. Transition ducts shall not be concealed within construction. Flexible transition ducts used to connect the dryer to the exhaust duct system shall be limited to single lengths, not to exceed 8 feet (2438 mm) and shall be listed and labeled in accordance with UL 2158A. (Jerry P. note: Transition ducts are the dryer connectors - those plastic and foil thingys which should be either rigid or flexible metal. Thus, this does not apply to that duct.)
- M1502.5 Duct construction. Exhaust ducts shall be constructed of minimum 0.016-inch-thick (0.4 mm) rigid meta ducts, having smooth interior surfaces with joints running in the direction of air flow. Exhaust ducts shall not be connected with sheet-metal screws or fastening means which extend into the duct. (Jerry P. note: Looks like it meets that, but I was not there and did not put my gage on it. Regarding the other parts of this section - insufficient information given)
- M1502.6 Duct length. The maximum length of a clothes dryer exhaust duct shall not exceed 25 feet (7620 mm) from the dryer location to the wall or roof termination. The maximum length of the duct shall be reduced 2.5 feet (762 mm) for each 45-degree (0.8 rad) bend and 5 feet (1524 mm) for each 90-degree (1.6 rad) bend. The maximum length of the exhaust duct does not include the transition duct. (Jerry P. note: Looks like it meets the exceptions - see Exceptions.)
- - Exceptions:
- - - 1. Where the make and model of the clothes dryer to be installed is known and the manufacturer’s installation instructions for the dryer are provided to the building official, the maximum length of the exhaust duct, including any transition duct, shall be permitted to be in accordance with the dryer manufacturer’s installation instructions. (Jerry P. note: Some allow for up to 90 feet, most allow for up to 50 feet. Not enough information given to know for sure.)
- - - 2. Where large-radius 45-degree (0.8 rad) and 90-degree (1.6 rad) bends are installed, determination of the equivalent length of clothes dryer exhaust duct for each bend by engineering calculation in accordance with the ASHRAE Fundamentals Handbook shall be permitted. (Jerry P. note: See response to Exception 1. above.)

Find Waldo?(Jerry P. note: NOPE.)

How about you telling me where Waldo is?

Originally Posted by John Arnold

M1502.4 Transition ducts. Transition ducts shall not be concealed within construction.

That's not "transition" duct, anyway, is it?

John A.

IRC 2003 M1501.1

Flexible transition ducts shall be limited to single lengths,not to exceed 8 feet. (It's not flexible so it's not transition duct?)

I cast my Vote whats yours?

Originally Posted by Billy Stephens

I cast my Vote whats yours?

Billy,

Not sure what you cast your vote for, but if it is that flexible duct laying on the ceiling, that is the laundry room exhaust duct, not the dryer duct, that (the dryer exhaust duct) is run behind the truss next to the insulation.

So, I guess I'm asking ... What did you vote for?

Originally Posted by Billy Stephens

Before or after you remove the braces?

I'm going with concealed.( Part concealed.)

A little concealed. Not much concealed.


Or maybe independent .(Craw Fishing)

Originally Posted by Billy Stephens

I'm going with concealed.( Part concealed.)

A little concealed. Not much concealed.

*WHAT* concealed?

"M1502.4 Transition ducts. Transition ducts shall not be concealed within construction."?

There are no "transition ducts" in that photo ... thus I am not following you "concealed" part.

Originally Posted by Jerry Peck

*WHAT* concealed?

"M1502.4 Transition ducts. Transition ducts shall not be concealed within construction."?

There are no "transition ducts" in that photo ... thus I am not following you "concealed" part.

Mr. Peck not all Ducts label as transition are the slinky style. It looks like the termination
point would be at the soffet thus a metal transition duct.( just guessing )

Originally Posted by Billy Stephens

It looks like the termination point would be at the soffet thus a metal transition duct.( just guessing )

A transition duct connects the appliance to the (main?) duct. It does not connect the appliance to the backdraft damper or whatever termination is used.

Originally Posted by Billy Stephens

Mr. Peck not all Ducts label as transition are the slinky style. It looks like the termination
point would be at the soffet thus a metal transition duct.( just guessing )

Billy,

Again ... you are looking at the wrong duct.

LOOK at the duct behind the truss, with insulation behind it. *THAT* is (to my understanding of this photo) the dryer duct. (But, I could be wrong.)

Originally Posted by RobertSmith

1-Dryer vent slopes upward but as it reaches the termination point, the duct slopes downward.

2- Duct IS NOT properly routed, secured and you can see in the photo, it IS compressing the insulation, reducing the R-value.

Originally Posted by RobertSmith

Jerry P and all: Would you agree with #1 & #2?

1) Dryer duct does not need to slope down, in fact, it may go straight up and out the roof, or down and out below a second floor, or pretty much wherever you need it to go - it is just air (no grease, just lint) and does not require a slope, up or down.

2) Not properly routed HOW?

Regarding the insulation, that is not covered in Jerry Mc.'s code reference, which is what I was, am, asking Jerry Mc. about. Yes, though, it is crushing the insulation, but, does that insulation still meet minimum or specified requirements? Maybe it does, maybe not - not enough information to be able to answer that.

Originally Posted by John Arnold

A transition duct connects the appliance to the (main?) duct. It does not connect the appliance to the backdraft damper or whatever termination is used.

John A,

I'm probably wrong about WALDO. But there is more than one kind /type/application
of/for a transition duct. Duct Transition - Home & Garden - Compare Prices, Reviews and Buy at NexTag - Price - Review

Originally Posted by Billy Stephens

I'm probably wrong about WALDO. But there is more than one kind /type/application of/for a transition duct. Duct Transition - Home & Garden - Compare Prices, Reviews and Buy at NexTag - Price - Review

Billy,

There are different "transitions" and "transition ducts", however, when referring to clothes dryers, this ( ANTOnline.com - Lambro Industries 495P 4X5 DRYER TRANSITION DUCT ) type is NOT allowed for use with clothes dryers.

However, this ( Amazon.com: WESTAFLEX W5025 Aluminum Flexible Duct: Home Improvement ) type of transition duct is allowed for use with clothes dryers.

Woa!!

$42.72 for SLINKY!

Mr. Peck,

I'm not saying my link to transition ducts are the type connected directly to a dryer.

If the run in or termination of duct had a solid metal transition duct that was concealed would that violate the( concealed transition duct portion of the code?)

Or does the meaning of transition duct only mean slinky and not the other types ?

Billy,

A "transition duct" (in regards to clothes dryers) is the duct/connector which is connected to the outlet on the clothes dryer and connected to the inlet on the dryer duct.

The dryer duct is required to be of rigid metal, smooth on the inside, etc., and is allowed to be "concealed" within and behind walls, ceilings, floors, etc.

The dryer connector/transition is allowed to be of rigid *or* flexible metal and is not allowed to be "concealed". Even if you used rigid for the dryer connector/transition duct, the connection joint at which that connects to the dryer duct is still not allowed to be concealed - even though the dryer duct and the dryer connector are the same rigid material ... the joint is a slip joint, usually with a clamp, but is not "sealed" like joints of the dryer duct are.

The dryer duct is only limited by the specifications of the manufacturer, or, if no dryer is going to be installed, by the code to 25 feet minus 5 feet for each 90 elbow and minus 2-1/2 feet for each 45 elbow.

The dryer connector/transition duct is limited to a maximum of 8 feet.

Originally Posted by Billy Stephens

Woa!!

$42.72 for SLINKY!

That's for ...

Product Description
Product Description
Aluminum Flexible Duct, Diameter 4 Inches, Length 30 Feet, Compressed Size 4 x 30 Inches


... 30 feet of flexible aluminum duct, not a slinky.

Stinky's (foil ones) are like an aluminumized mylar (or some type of plastic which has had an aluminum coating applied to it) with the metal slinky inside it. The aluminum ones do not have a slinky in them.

Mr. Peck,

I'm still looking for WALDO!

Sorry guys, in my usual rush I got confused between the clothes dryer ducting and the so called “exhaust “duct, which I guess we should assume is the laundry room exhaust fan duct? So basically it’s all Clay’s fault and Waldo remains to be found.
However, in an effort to remove some of the omelet from my face let me ask why would the so called laundry room “exhaust duct” not be approved for a clothes dryer duct?

Originally Posted by Jerry McCarthy

Waldo remains to be found.

let me ask why would the so called laundry room “exhaust duct

not be approved for a clothes dryer duct?

NO WALDO??

Exhaust Duct---Clothes Dryer Duct---Approved(concealed--8ft--no run-types of transition)

NO WALDO!!!

Originally Posted by Jerry McCarthy

let me ask why would the so called laundry room “exhaust duct” not be approved for a clothes dryer duct?

Jerry Mc.,

Okay, so it was not I who was totally confused ... Whew!

Well, the reason one would not, er, *should not*, use the laundry room exhaust duct for the clothes dryer duct is that the exhaust duct does not meet the requirements for a clothes dryer duct regarding the material it is made from and how it was made.

IRC Section please for reason not to use as dryer duct as it appears that posting such may be a help to others.

Originally Posted by Jerry McCarthy

IRC Section please for reason not to use as dryer duct as it appears that posting such may be a help to others.

Jerry Mc.,

You posted it. (underlining is mine)

"M1502.5 Duct construction. Exhaust ducts shall be constructed of minimum 0.016-inch-thick (0.4 mm) rigid meta ducts, having smooth interior surfaces with joints running in the direction of air flow. Exhaust ducts shall not be connected with sheet-metal screws or fastening means which extend into the duct."

0.016 inch (0.4 mm) is basically 30 gage galvanized steel (27 gage if not galvanized, but galvanized steel is what is used, so 30 gage is the minimum thickness allowed).

I was at Lowe's this morning, to buy a dryer vent. While there I saw the Mylar covered Slinkys. The Slinky said it was UL Listed.
Question, how can it be UL Listed and not be allowed to use?

Lowe's was out of, or does not sell the white plastic Slinkys, but they did have the heavier corrugated foil type.

Rick - Did it specifically say UL Listed for dryers? I've seen these, too, but I think JP claimed they didn't specify dryers. I could be wrong, as always.

I don't know. I just remember the UL.

Originally Posted by Rick Cantrell

I was at Lowe's this morning, to buy a dryer vent. While there I saw the Mylar covered Slinkys. The Slinky said it was UL Listed.
Question, how can it be UL Listed and not be allowed to use?

They are listed for air connectors (like for exhaust fans). I think I even recall some saying for use with dryers on them, but, read the manufacturers installation instructions for dryers - most *specifically prohibit* the use of 'plastic or foil' dryer connectors, and, the few that I have seen which do not *specifically prohibit* the foil ones state not to use 'plastic dryer connectors or or material which is easily punctured' - which is the foil type.

I don't remember if the ones which said 'for use with dryers' were UL listed or not.

I quit worrying about the UL listing of the foil ones because the manufacturers of the dryers said DO NOT USE THEM ON MY DRYER. That means 'If YOU use them, WHEN YOU HAVE ANY PROBLEM WHATSOEVER - LIKE A DRYER FIRE - DO NOT SUE ME BECAUSE I TOLD YOU NOT TO USE THEM'.

Lowe's was out of, or does not sell the white plastic Slinkys, but they did have the heavier corrugated foil type.

Actually, the white plastic ones are a heavier gage plastic than those thin Mylar foil types.

Keep this UL Standard number handy for the next time you are in a Big Box store and see if it is the same UL number on those things - UL 2158A

M1502.4 Transition ducts.

Transition ducts shall not be concealed within construction. Flexible transition ducts used to connect the dryer to the exhaust duct system shall be limited to single lengths, not to exceed 8 feet (2438 mm) and shall be listed and labeled in accordance with UL 2158A.

I vote for:

Originally Posted by Michael Thomas

I vote for:

Is that white Teflon tape I see on the gas line?

Houston, I think we have a problem.

Thanks JP and I hope folks are downloading those code sections and/or better yet, highlighting them in their code books. This is another example of a vital safety issue that should be carefully looked at during the inspection process. It's always amazing how little builders are aware of this safety defect and how often it slips by the local AHJ's final inspection.

Thanks JP
Sorry for the delay in responce, I just returned to the office. The next time I'm at Lowe's I'll look for the UL listing numbers.

Originally Posted by dan orourke

why can't you use teflon tape on gas line?.....however, sounds like you guys have great eyesight, great catch!

This has been kicked around quite a bit in the past, and, if memory serves, it's one of those questions that never gets entirely resolved. The idea is that regular teflon tape is too thin for gas pipes - pieces supposedly break off and end up clogging valves and burners, etc. In September, 2005, Bob Harper wrote this: "The problem with Teflon, any color, is it tears off and bits clog the valve. This can lead to explosive delayed ignition."

From my notes. Got this off the Dupont site a while back... sorry, no URL, can't find it now:

Teflon (PTFE) tape is color coded by density.

White - Single density, pipes up to 3/8"
Yellow - Double density- yellow double density, gas piping.
Red - Tripled density - pipes 1/2" and larger
Green - High purity, oil-free, oxygen lines.
Copper - Thread lubricant only, not a sealant.

Min 3 full turns, each layer should overlap the previous layer by 1/2 - 2/3, must extend to end of threaded portion of pipe.

Also see:

Threadmaster Teflon and PTFE Threadseal Tape

Tape is UL listed and has to be used per manufacturer's instructions, perhaps Jerry P can help out here.

---------

That appears to me that may be a nat gas pipe, and it does not appear to be connected to anything. Hard to tell from that picture, but looks like the end may not be capped.

Which direction should Teflon tape be wrapped?

• Start wrapping the male threads at end of the pipe but do not lap over the end. Doing so may result in reduced water pressure or even clogs from bits of the tape that get into the water supply.
• Start with a couple loops around at the end, then wrap all the threads, overlapping half the width of the tape on each wind.
• Wrap in the direction of the threads starting from the end and proceeding toward the length of the pipe. Wrapping the wrong way may result in the tape coming unwound as the fittings are tightened.
• As you wrap, keep tension on the tape so that it is pulled into the threads.
• If you loosen or disconnect a fitting, remove the old tape and rewrap with a fresh piece.

Originally Posted by dan orourke

so it sounds like Teflon is okay for gas pipes if installed correctly, right?
however, there is no way to know if it was installed correctly.

Only if by correctly you mean Teflon tape rated for gas usage. Typically that means yellow in color which denotes a thicker product.

WHITE-Single density- should only be used on NPT threads up to 3/8 inch.
YELLOW- Double Density- yellow double density is often labeled as "Gas type"
RED-Triple Density: (Note-the container is red but the tape itself appears as a pale pink color). Presently required on all joints ½" diameter or greater.
GREEN- Oil Free PTFE tape- Required for use on all lines conveying oxygen (I.E. –medical oxygen or welding oxygen lines).
COPPER COLOR- contains granules of copper and is to be used as a thread lubricant but is not approved as a thread sealant. (Generally it is used as a thread lubricant on bolts or pipe threads for mechanical applications where no physical seal is required.)
PTFE tape is only approved as a thread seal when applied correctly. To apply you begin at the end of the pipe and wrap the tape under tension in the direction of the thread turns. Each successive layer should overlap the previous layer by ½ to 2/3 and continue wrapping until the entire threaded portion of the pipe is covered. (Minimum of 3 full turns).

Originally Posted by dan orourke

Well, white is good for 3/8" and it looks like that pipe is 3/8", at least to me, so it should be fine.

I seldom see black iron pipe less that 1/2" I.D. for gas line to an appliance. I personally prefer pipe dope with a Teflon additive but Rector Seal #5 has been in use for decades and is a very good product..

Originally Posted by dan orourke

Well, white is good for 3/8" and it looks like that pipe is 3/8", at least to me, so it should be fine.

Not if it is a "gas" pipe - needs the thicker stuff which is "yellow" in color.

Originally Posted by Billy Stephens

NO WALDO??

Exhaust Duct---Clothes Dryer Duct---Approved(concealed--8ft--no run-types of transition)

NO WALDO!!!

Originally Posted by Michael Larson

Is that white Teflon tape I see on the gas line?

Houston, I think we have a problem.

Originally Posted by Clay White

pipe doping stuff. .

Pipe Dope Stuff??

TEFLON Tape- White,Yellow,Red,Green,Cooper(no sealant)

Find Waldo??
NO WALDO!!

PIPE DOPE STUFF!!!

Originally Posted by Billy Stephens

Pipe Dope Stuff??

TEFLON Tape- White,Yellow,Red,Green,Cooper(no sealant)

Find Waldo??
NO WALDO!!

PIPE DOPE STUFF!!!

Go to bed Billy you have stopped making any sense.

Originally Posted by Clay White

pipe doping stuff.

Originally Posted by Michael Larson

Go to bed Billy you have stopped making any sense.

Michael,

I've followed this thread for 2 days,Read, RE-Read various sections of code under 2 versions, No dissected codes to try and stretch them to fit a problem that did not exist, and the punch-Line is may
I Quote (Pipe Doping Stuff.)

And I'm not making any sense?

It has been a long day bed does make sense.

Thanks,

I was at Lowe's again this morning. Looked at the dryer vent hose. It is UL listed for use on dryers but did not list the UL number.

Originally Posted by Rick Cantrell

I was at Lowe's again this morning. Looked at the dryer vent hose. It is UL listed for use on dryers but did not list the UL number.

I also went by Lowe's and checked them out.

They do say "UL Listed" on them, but, like Rick said, they do not say to what they are UL Listed.

I looked on the box - nothing. I looked on the instruction sheet inside the box - nothing. I looked on the product itself - nothing.

While I will also add that the ones I looked at were much thicker than the ones of the past.

BUT ... without a UL number stating *to what UL standard* it was UL Listed to, I have to ...

Gong! it.

Besides, as I said in a previous post, even if this turns out to be UL listed to 2158A, if the manufacturer of the clothes dryer says 'do not use that stuff on my dryer', then you still cannot use that stuff on their dryer. Plain and simple.

A UL Listing without a certifiable number is about as good as a roofing contractor who guarantees his new roof covering will not leak until the first rain. I recall years ago China named a suburb of one of their industrial cities “UL” and made millions of unauthorized Christmas lights with a UL tag on them. Unfortunately folks don't even look for a UL tag; much less confirm it’s actually genuine.