# DPW carbon monoxide /nitric oxide  detection and removal system



## TheCommish (Jan 9, 2012)

Has anyone had experience with a carbon monoxide/ nitric oxide detection and re3moval systems in a commercial vehicle storage garage (DPW)?  The CO/NO system on detection of harmful levels of CO/NO start fans and open louvers

The specific concern is the sequence of operation during a fire event, that being during the fire event there will be high levels CO/NO and the evacuation system will operate, possibly drawing the fire into the ventilation system or form one are to another in the garage.

The main exhaust fan is 12,000 cfm, is this fan required to be shut down as it is over 2000 cfm and should have a smoke detector in it (insert coed section) that shuts the fan down. Or would it be appropriate to have the fire alarm system on a fire signal provide and output to the CO/NO control to shut them down?


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## cda (Jan 9, 2012)

One of our fire stations had co with fans, in the truck parking area.

For some reason the detectors disappeared after awhile.

In your set up I would say no shut down is required, unless ahj asks nicely for it.

But being a garage, and you do not give square footage, there will be overhead doors that unless you drop them, may all be open.

So if the fan comes on, it may not be much if a factor

Forgot your located in the warm area of th us, where you can leave the doors open say two weeks a year


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## TheCommish (Jan 10, 2012)

The build is metal space frame, 20,000 sf, divided by full height walls, into large vehicle storage are drive through, with door on each end, wash bay, 2 bay maintained areas, 4 bay storage garage and a separate administrative offices. Dry fire sprinkler system, monitored alarm by central station, located in a somewhat remote area of town

I see you point about the doors being open, doubtful unless someone was in the building, especially here in New England, cold or bugs.


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## cda (Jan 10, 2012)

maybe install a different exhaust removal system??

http://www.firerescue1.com/fire-products/vehicle-equipment/exhaust-removal-systems/882889-Fire-House-Systems-from-Plymovent/

http://www.firerescue1.com/fire-products/vehicle-equipment/exhaust-removal-systems/


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## TheCommish (Jan 10, 2012)

i am fimular with plymovents they work well in the fire station, this application is a highway garage with no defind parking spots, and  a varity of diffrent equipment coming and going.

could anyone refence the code section that requires HVAC units of 2000 cfm or mor have smoke detection, I may be able to use this to have the exaust fan shut off


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## cda (Jan 10, 2012)

http://www.ecmag.com/?articleID=12361&fa=article

And, but read the first exception

606.2 Where required. Smoke detectors shall be installed where indicated in Sections 606.2.1 through 606.2.3.

Exception: Smoke detectors shall not be required where air distribution systems are incapable of spreading smoke beyond the enclosing walls, floors and ceilings of the room or space in which the smoke is generated.

606.2.1 Return air systems. Smoke detectors shall be installed in return air systems with a design capacity greater than 2,000 cfm (0.9 m3/s), in the return air duct or plenum upstream of any filters, exhaust air connections, outdoor air connections, or decontamination equipment and appliances.

Exception: Smoke detectors are not required in the return air system where all portions of the building served by the air distribution system are protected by area smoke detectors connected to a fire alarm system in accordance with the International Fire Code. The area smoke detection system shall comply with Section 606.4.

606.2.2 Common supply and return air systems. Where multiple air-handling systems share common supply or return air ducts or plenums with a combined design capacity greater than 2,000 cfm (0.9 m3/s), the return air system shall be provided with smoke detectors in accordance with Section 606.2.1.

Exception: Individual smoke detectors shall not be required for each fan-powered terminal unit, provided that such units do not have an individual design capacity greater than 2,000 cfm (0.9 m3/s) and will be shut down by activation of one of the following:

1. Smoke detectors required by Sections 606.2.1 and 606.2.3.

2. An approved area smoke detector system located in the return air plenum serving such units.

3. An area smoke detector system as prescribed in the exception to Section 606.2.1.

In all cases, the smoke detectors shall comply with Sections 606.4 and 606.4.1.


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## TheCommish (Jan 11, 2012)

ah yes after much on line searching through the  refrence codes I found the NFPA requiremnt for duct detection in NFPA 90A, not in 72 as one would think

thanks to all for the help


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## FM William Burns (Jan 12, 2012)

Warning- Warning..........there is conflict between NFPA 90A and the IMC regarding locations for duct detection at 2000 cfm (Supply v Return)  I believe 72 addresses duct detection in the provisions for control functioning detectors and refers one to 90A or B   possibly...


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