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#93735 06/08/05 06:15 PM
Joined: Jun 2004
Posts: 613
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Is romex (NM) allowed to be used in the walls and ceilings of a horse barn in areas specified by 547.1 where it will be concealed by a finish surface such as wood on the walls and plastered ceilings?

shortcircuit

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Joined: Mar 2005
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The way I read it, I think you're OK.

Joined: Jun 2004
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Can anyone explain what the last sentance of 334.10(3) means or maybe have a link to such list as described?

"Cables shall be concealed within walls, floors, or ceilings that provide a thermal barrier of material that has at least a 15-minute finish rating as identified in listings of fire-rated assemblies."

My concern is if romex (NM) is concealed behind finish walls of wood on the interior of a horse barn, is the wood wall finish acceptable as a 15-minute fire-rated assembly?

shortcircuit

Joined: Dec 2003
Posts: 751
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As I recall, 1/2 inch wallboard has a 15 minute rating.
Let me check the UL book for others.


Earl
Joined: Dec 2003
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Nope, no wood. All the listed assemblies are gypsum wallboard, plaster, cement block, masonry or 24 gauge metal panels.


Earl
Joined: Dec 2003
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Oh yeah, and concrete.


Earl
Joined: Dec 2003
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Now you got me going.

My rule of thumb is just not sufficient. the finish ratings go all over the chart, depending on the manufacturer and the product. Examples: American Gypsum Co. 5/8 inch Gypsum board Types AGX-1,2&3 have 23 minute finish ratings. AGX-5 has a 26 minute finish rating. US Gypsum Co. 1/2 inch Gypsum Wallboard (GWB) Types AR, FRX-G, SCX, SHX or WRX all have a 29 minute finish rating.
There are hundreds more. But, the lowest rating I could find for 1/2 inch GWB was 20 minutes. The rating for some 3/8 inch GWB was 8 minutes, so watch out!
The assembly also required paper tape over the joints, and usually a minimum of 2 coats of joint finishing compound.

Sounds like, to make your installation code compliant, you need to add 1/2 GWB over the walls of the barn where you have run the romex.


Earl
Joined: Dec 2003
Posts: 751
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You can research them yourself at: http://www.ul.com/fire/building.html
Click on the picture of the front cover of the building materials directory.


Earl
Joined: Dec 2003
Posts: 751
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http://database.ul.com/cgi-bin/XYV/...d=1074327030&cfgid=1073741824&ve rsion=versionless&parent_id=1073984818&sequence=1


Earl
Joined: Jun 2004
Posts: 613
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Thanx earlydean, but I couldn't navigate through to where I could find specific listings on sheetrock and wood?

shortcircuit

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