# Sampling tubes



## Ldj (Mar 11, 2014)

Can anyone tell me where to find the code requirements for duct detector sampling tube support? The HVAC Foreman is saying 2' or more requires me penetrating the other side of the duct, I Know I can go up to 3' without support, but thats only experiential knowledge. Where can I find an actual code citation and support requirements?


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## NacBooster29 (Oct 25, 2010)

The instructions! 
Install per instructions and you will meet code. 
I don't recall seeing any specific language in nfpa 72 pertaining to sample tube installations.


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## Ldj (Mar 11, 2014)

yeah, that was my argument with him that the instructions says up to 36" without support, he went with it, but I like to chase stuff down for future reference in case next time I dont have instructions before me as we speak about it


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## NacBooster29 (Oct 25, 2010)

What brand? If memory serves me the Siemens ones I just installed said 3'. But for some reason the system sensor ones I thought were 5'. 
I would have to read the instructions. My memory is too full of useless stuff.


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## CADPoint (Jul 5, 2007)

Required to cover 2/3rds the width of the Duct.

Electrical Contractor article.

*Code Requiring HVAC Sampling Tube Article*

*Looks like three articles*


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## halfamp (Jul 16, 2012)

If you are working with fire alarms and want to chase stuff down for future reference, pick up a copy of nfpa 72


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