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#67735 - 07/13/06 10:08 PM Duct Detectors  
Dnkldorf  Offline
Member
Joined: Dec 2004
Posts: 1,064
nowhere usa
Need some info on when they are needed if you don't mind..

Reason, HVAC contractor adding new RTU's. Existing RTU's have Duct detectors installed.
Wouldn't these new ones need these and be tied into the fire system?

Thx..


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#67736 - 07/14/06 05:24 AM Re: Duct Detectors  
hypress  Offline
Member
Joined: Jul 2004
Posts: 129
Charleston WV
Duct detectors are needed if the unit CFM rating is 2000 or greater on the return side.
If your unit is 4000 or greater you need them on supply and return. About the only thing they do is tell you that your duct has dust in it when the heat comes on.As far as early fire detection they are useless. Think about it you have a small fire in a room your HVAC is drawing clean air from other parts of the building when it gets back to the unit the air is so doluted there is no smoke to detect. But I know THE CODE REQUIRES THEM. I use to work for a fire alarn distributior we had Notifier and Pyrotronics equipment.


#67737 - 07/14/06 08:21 AM Re: Duct Detectors  
golf junkie  Offline
Member
Joined: Apr 2001
Posts: 507
York, NE
I'm not that familiar with fire code so I can't say for sure what the code says.

We recently had a bid for a bank building, all smoke detection was removed because the building was sprinkled.


#67738 - 07/14/06 09:47 AM Re: Duct Detectors  
eprice  Offline
Member
Joined: Aug 2003
Posts: 64
North Logan, Utah, USA
The requirement comes from the mechanical code. In the IMC it is found in section 606. There are a couple of exceptions there that will often apply. There will be a simular section in the UMC.


#67739 - 07/14/06 10:28 AM Re: Duct Detectors  
Ron  Offline
Member
Joined: Mar 2002
Posts: 582
White Plains, NY
Depending on the applicable mechanical code, most require connection the the building fire alarm system for monitoring (if there is a building fire alarm system).


Ron

#67740 - 07/14/06 01:10 PM Re: Duct Detectors  
HotLine1  Offline


Member
Joined: Apr 2002
Posts: 6,885
Brick, NJ USA
Dnk:
From the Fire Sub-Code Insp (NJ)here, exactly as Hypress said. IF system within structure it must be interconnected to provide notification.

In instances of nuisance activation (dust/humidity/etc) PERMISSION can be granted for local alarm only.

NOTE WORD "PERMISSION"

John


John

#67741 - 07/14/06 07:26 PM Re: Duct Detectors  
Gregtaylor  Offline
Member
Joined: Mar 2005
Posts: 212
Boise, Idaho, USA
I would like to add that if the total CFM of all units in a discrete area (say a single tenant) is 2000 or more then the detectors are required. Not just the CFM of any one unit. They must be wired for unit shutdown and be monitored by the buildings central system. I'll quote NFPA when I find my book in this messy office.


#67742 - 07/14/06 07:37 PM Re: Duct Detectors  
Dnkldorf  Offline
Member
Joined: Dec 2004
Posts: 1,064
nowhere usa
Single building, single tennant.

30,000 Sq/ft

Had 5 RTU's initially, 5 more added.

The orginal 5 have (DD), but the newer ones do not.

Typical fire system installed, building is sprinklered, and has been since the orginal build.

Are they not needed if sprinklered then?


#67743 - 07/14/06 08:20 PM Re: Duct Detectors  
LK  Offline
Member
Joined: Jan 2003
Posts: 1,429
New Jersey
"Are they not needed if sprinklered then?"

Still need the detectors, the idea is to get notification, before the heat builds to trigger a sprinkler.


#67744 - 07/15/06 10:21 AM Re: Duct Detectors  
Gregtaylor  Offline
Member
Joined: Mar 2005
Posts: 212
Boise, Idaho, USA
Agree. Someone missed something somewhere.



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