Lint Trap

[Steven Hockstein]

An HVAC contractor told me that a lint trap is required by code in this dryer vent and he installed this in a laundry room. The vent is suppose to be ducted up through the ceiling but if you look carefully you can see that the bottom is also open and there is a trap door planned below. This is a new one to me. There is no requirement in the dryer installation manual and I told the contractor to follow the manufacturer's requirements.  It seems to me that this would cause problems with the air flow. 

Anyone want to comment?

[Jim Baird]

Very funny.

Ask him for a codes quote.  Up is always the wrong direction for dryer venting and commercial (but not residential) requires a power boost for the up vents.

[Jim Katen]

1 hour ago, Jim Baird said:

Very funny.

Ask him for a codes quote.  Up is always the wrong direction for dryer venting and commercial (but not residential) requires a power boost for the up vents.

Why is up always the wrong direction? I'd think that the buoyancy of the warm air would help move it along in the up direction. 

[Darren]

In newer townhouses, I've seen where there is a 'clean-out' door about 18 inches below the dryer connection.

[Jim Baird]

15 hours ago, Jim Katen said:

Why is up always the wrong direction? I'd think that the buoyancy of the warm air would help move it along in the up direction. 

Up is allowed, but to me common sense says lint falls more than it flies.

[Marc]

I just cleaned out my dryer exhaust in my 40 yr old home for the first time.  I inserted a tool into the vent from inside the attic down to the bottom of the vent, which ends several inches below the dryer connection.  Must have been 6 inches of packed lint in there.  I think air velocity carries most of it upwards and out but a little prevails against the flow and settles at the bottom.

Edited February 1, 2018 by Marc

[Steven Hockstein]

1 hour ago, Darren said:

In newer townhouses, I've seen where there is a 'clean-out' door about 18 inches below the dryer connection.

Maybe it is a NJ thing. This "trap" is about 5 feet deep.

[Jim Katen]

3 hours ago, Jim Baird said:

Up is allowed, but to me common sense says lint falls more than it flies.

Sure. But isn't that a good thing? The lint tends to accumulate in the bottom trap. 

[John Kogel]

My son's dryer is below ground level, so his dryer vent goes to an elbow and then vertical rise for 6 or 7 feet. When he bought the place I told him to pull the vent pipe and clean it. He got around to it about 3 years later, and found no lint. Lint accumulates at the top on the mesh cap where the pipe exits the basement.

I imagine the lint is dry enough and the blower is strong enough to work in that case. A weaker dryer might not do as well.

So I think the trap is not a bad addition, providing it is airtight.

Lint Trap

[BADAIR]

https://dryerbox.com/building-code.htm

all depends on which code cycle the muni has adopted

the wording has been around since 2009 if memory seves

Cleanout. Each vertical riser shall be provided with a means for cleanout. 

mesh cap? Screens shall not be installed at the duct termination.

Edited February 2, 2018 by BADAIR

[Marc]

46 minutes ago, BADAIR said:

https://dryerbox.com/building-code.htm

all depends on which code cycle the muni has adopted

the wording has been around since 2009 if memory seves

Cleanout. Each vertical riser shall be provided with a means for cleanout. 

mesh cap? Screens shall not be installed at the duct termination.

Doesn't say anything about up/down, as long as a clean-out is there (2012 IRC).

[BADAIR]

7 hours ago, Marc said:

Doesn't say anything about up/down, as long as a clean-out is there (2012 IRC).

i'll concede vertical

was/is known to have a different interpretation in cajun land, at least whenever i worked across the Red ;~))

Edited February 2, 2018 by BADAIR

[Marc]

2 hours ago, BADAIR said:

i'll concede vertical

was/is known to have a different interpretation in cajun land, at least whenever i worked across the Red ;~))

Dem dryer pipes, dey dont matter if dey go up or down no! Pooooe!

[Jim Baird]

11 hours ago, BADAIR said:

https://dryerbox.com/building-code.htm

Thanks for posting this.  Notice the reference calling for cleanout is from the IMC not the IRC, which means it does not apply to houses.

[Steven Hockstein]

Typically the manufacturer's published installation requirement/specifications "Trump" the code requirements. I advise my clients to follow the specifications.

[Les]

I don't have a dryer.  Rope and two cedar posts in the back yard. 

 

My gas dryer vent is 22'long.  90 out of dryer, 7' rise, 90, then 15' to exterior wall.  Too long, but I clean it every six months or so and am always surprised how little lint there is.  I clean it with the air setting and from the exterior inward abt 18'.  I suppose a family of three or four would need to clean more often. 

 

[Jim Katen]

Regarding lint accumulation, I've noticed that what you wash matters. If your household consists of older people whose entire wardrobe tends to be older, well-worn clothing, the dryer generates very little lint. If you've got a bunch of small kids who need new clothes every few months, the lint load skyrockets. Newer clothing seems to generate a lot more lint. 

(This not meant as a reflection upon Les or his wardrobe. . . ) 

[Nolan Kienitz]

13 minutes ago, Jim Katen said:

Regarding lint accumulation, I've noticed that what you wash matters. If your household consists of older people whose entire wardrobe tends to be older, well-worn clothing, the dryer generates very little lint. If you've got a bunch of small kids who need new clothes every few months, the lint load skyrockets. Newer clothing seems to generate a lot more lint. 

(This not meant as a reflection upon Les or his wardrobe. . . ) 

Well then this is something to consider. 

[RK52]

On 2/3/2018 at 8:58 AM, Les said:

I don't have a dryer.  Rope and two cedar posts in the back yard. 

 

My gas dryer vent is 22'long.  90 out of dryer, 7' rise, 90, then 15' to exterior wall.  Too long, but I clean it every six months or so and am always surprised how little lint there is.  I clean it with the air setting and from the exterior inward abt 18'.  I suppose a family of three or four would need to clean more often. 

 

Sounds like my old one. 90 to an riser... 9 feet, then 21 feet to the exterior. Moisture and lint built up, rotted a connection, and damaged a ceiling. I replaced it with a 90 down 2 feet, and 15 feet out... Towels took 70 minutes to dry previously. Now, 30.