Open Raceway from Attic to Crawlspace

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jamesoftn

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While inspecting a HVAC job the installer has run a 1 1/2 PVC Conduit SCH 40 in a chase. This vertical raceway goes from the attic space to the crawl space. Both ends are open and there are 3 NMB cables installed. Does this violate any codes I believe this is not in compliance with 300.21. I recall in the past there something pertaining to the chimney effect as this would transfer fire by drafting it up the raceway?
 
jamesoftn said:
While inspecting a HVAC job the installer has run a 1 1/2 PVC Conduit SCH 40 in a chase. This vertical raceway goes from the attic space to the crawl space. Both ends are open and there are 3 NMB cables installed. Does this violate any codes I believe this is not in compliance with 300.21. I recall in the past there something pertaining to the chimney effect as this would transfer fire by drafting it up the raceway?
Click to expand...

This is done quite frequently and I don't see it as a problem if the ends are closed with duct seal or the like. Can fire actually travel up thru the pipe or is there some other reason it is a problem? I don't know for sure..
 
Are any of the floors it passes through rated? ie. 1-2 hour for fire seperation. Is the chase (hate that word) it is in supposed to be rated? If so I'm not sure there is a product that will close the pentrations into and out of the space with PVC - most are rated for use with metallic conduit. There may be some sealant prducts - But I have not used them since locally, I can not install PCV above grade or without encasement - But thats here.... IMO the point is mute about the ends of the conduit being open when the conduit itself is as or more combustable than what is inside it...

Looking to see of there are PVC rated sealants I found these....
http://www.mikeholt.com/technical.php?id=nec/unformatted/pvcfirerating&type=u&title=Fire%20Rating%20Assembly%20-%20PVC%20Conduit%20(01-03-01K)

http://www.ramset.com.au/fileupload/resources/fire%20collar%20bro.pdf

http://www.fireretardantsinc.com/3m/images/ppd_plastic_pipe.pdf
 
Open Raceway from Attic to Crawlspace

Started not to open this can of worms, but here goes.
I used to do that allot in the past so we could add circuits later if needed.
But I have found that now-days if you wire a house according to the NEC, which I usually do more than that, you don't need to.
If I do run into a situation like that I usually fill each end with fire caulk like I would bored holes in studs.
Don't know if even fire caulk in bored holes even works but its the code and I haven't had a problem.
Semper Fi Buddy
 
Brady Electric said:
Started not to open this can of worms, but here goes.
I used to do that allot in the past so we could add circuits later if needed.
But I have found that now-days if you wire a house according to the NEC, which I usually do more than that, you don't need to.
Semper Fi Buddy
Click to expand...

Buddy You can overwire a house till you drop but there always seems to be a need for getting up to the attic-- for whatever purpose. I have seen gas lines installed in conduits I have put in for future use. I like to install 2 Conduits- one for power and one for whatever.
 
The customer will always find some way to make life difficult, I had one add a jaccuzi tub in his basement, loadcenter at one end, Jaccuzi at the other, full sheetrock ceiling. The only saving thing was it was a 24" factory truss floor joist system. The HVAC contractor had a skinny kid that worked for him, so I hired him to drag a 6-3 through the joist from an access hole that I cut in the ceiling in front of the loadcenter.
 
hillbilly1 said:
The customer will always find some way to make life difficult, I had one add a jaccuzi tub in his basement, loadcenter at one end, Jaccuzi at the other, full sheetrock ceiling. The only saving thing was it was a 24" factory truss floor joist system. The HVAC contractor had a skinny kid that worked for him, so I hired him to drag a 6-3 through the joist from an access hole that I cut in the ceiling in front of the loadcenter.
Click to expand...
I've seen an RC 4wd truck used for similar work, and I've heard of a trained ferret used to drag a pull-string.
 
Dennis Alwon said:
Buddy You can overwire a house till you drop but there always seems to be a need for getting up to the attic-- for whatever purpose. I have seen gas lines installed in conduits I have put in for future use. I like to install 2 Conduits- one for power and one for whatever.
Click to expand...
I always try to do the same but I will not do it for free. A hundred bucks will save you a bundle in the future two 1 1/2 pvc risers are priceless.
 
jamesoftn said:
While inspecting a HVAC job the installer has run a 1 1/2 PVC Conduit SCH 40 in a chase. This vertical raceway goes from the attic space to the crawl space. Both ends are open and there are 3 NMB cables installed. Does this violate any codes I believe this is not in compliance with 300.21. I recall in the past there something pertaining to the chimney effect as this would transfer fire by drafting it up the raceway?
Click to expand...

300.21, if the penatrations are not thru fire-rated items, then it shall be
made to not substantially increase the spread of fire.

If thru fire-rated items, then it needs to be firestopped using approved
methods to maintain the fire-rating.
 
benaround said:
300.21, if the penatrations are not thru fire-rated items, then it shall be
made to not substantially increase the spread of fire.

If thru fire-rated items, then it needs to be firestopped using approved
methods to maintain the fire-rating.
Click to expand...

Yes so if you caulk around the pipe where it pass thru the floor then this should cover what you stated, however the pipe itself is allowing air to go from the crawl to the attic. Is this a problem? I am not sure but I would close the ends with tape or duct seal.
 
ultramegabob said:
why not just install a box and lid on each end of the conduit?
Click to expand...

Ever price a large PVC box? It is quite expensive and a pain in the butt if you are running long runs of nm.
 
ultramegabob said:
I would use metal boxes, and change to THHN inside the conduit.
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I am talking an 1/1/2" conduit so you would need to use a large metal box. All the ones I have seen state (on the inside of the box) they are not to be used with npnmetallic canles or raceways. Why? I don't know but they do state that.
 
Dennis Alwon said:
I am talking an 1/1/2" conduit so you would need to use a large metal box. All the ones I have seen state (on the inside of the box) they are not to be used with npnmetallic canles or raceways. Why? I don't know but they do state that.
Click to expand...


then use EMT.... LOL, I didnt catch what size conduit you were talking about before.
 
Dennis Alwon said:
All the ones I have seen state (on the inside of the box) they are not to be used with npnmetallic canles or raceways.
Click to expand...

where do they say that? is it stamped in the metal or have a sticker? I have never noticed anything like that in the boxes I use. what brand do you use?
 
ultramegabob said:
where do they say that? is it stamped in the metal or have a sticker? I have never noticed anything like that in the boxes I use. what brand do you use?
Click to expand...
There is a sticker in the box that is hard to remove :)but I cannot remember the brand.
 
ultramegabob said:
and how do you know that??:grin:
Click to expand...
I wanted to take it out to show someone...:D I did ground the box. That must be the reason since there are no provisions to ground the darn things
 
Dennis Alwon said:
Yes so if you caulk around the pipe where it pass thru the floor then this should cover what you stated, however the pipe itself is allowing air to go from the crawl to the attic. Is this a problem? I am not sure but I would close the ends with tape or duct seal.
Click to expand...

Dennis, The way I read the NECHandbook 300.21, fpn, and comontarys, the

intent ( regaurding the open ends of the conduit(s) ) is to maintain whatever

rating the conduits pass thru. I'm sure duct tape is not going to help that

much. I remember seeing a film on this subject, there was a shot of a 1/2"

hole thru concrete with about a 3' flame coming thru it and it sounded like

a cutting torch !! The fpn also refers to building codes.
 
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