smoke detector in return duct question

[plazaowner]

I have a 5 ton Comfortmaker rooftop gas furnace/electric a/c unit. My building inspector said there is a OMC code in our state requiring smoke detector suppression system in the return ductwork if the unit has a designed capacity over 2000 cfm.

Does anyone know where I can find the design specs for a ten year old, 5 ton rooftop Comfortmaker to provide proof to the building inspector of the design capacity in cfm?

[Jabarco]

Here you go.
http://www.gocomfortmaker.com/go/ind...77&p=95&ps=523


Jabs

[bwalley]

I have a 5 ton Comfortmaker rooftop gas furnace/electric a/c unit. My building inspector said there is a OMC code in our state requiring smoke detector suppression system in the return ductwork if the unit has a designed capacity over 2000 cfm.

Does anyone know where I can find the design specs for a ten year old, 5 ton rooftop Comfortmaker to provide proof to the building inspector of the design capacity in cfm?

Over 2000 CFM is the key, if it is 2000 CFM or less, then by code you are not required to have smoke detectors, but they are a good idea to have anyway.

5 tons should be 2000 CFM.

Why is the inspector asking questions about an existing 10 year old system?

[plazaowner]

Thanks for the replies. I will pull the model number and serial number off the unit to narrow the search.

bwalley- In order to renovate a vacant space in my plaza, our new city building inspector required architect plans to be submitted for the renovations. He then sent those plans out to a certified master plan examiner who returned the plans with notes. One of the notes included the OMC sections 606.2.1 through 606.4.1 NFPA 72 Section 3-2.5.1 and, in bold, said, "Mechanical contractor shall verify if existing system complies to code."

He then told me that I have to have my HVAC contractor provide written notice about the unit and whether the unit complies with the code. My contractor said it was a 5 ton unit but could not tell me if it the unit actually had a designed capacity over 2000 cfm (wording of the code) or if it was a designed capacity of up to 2000 cfm. So he didn't feel comfortable writing down that no smoke detectors were necessary until we know for sure.

[bwalley]

Thanks for the replies. I will pull the model number and serial number off the unit to narrow the search.

bwalley- In order to renovate a vacant space in my plaza, our new city building inspector required architect plans to be submitted for the renovations. He then sent those plans out to a certified master plan examiner who returned the plans with notes. One of the notes included the OMC sections 606.2.1 through 606.4.1 NFPA 72 Section 3-2.5.1 and, in bold, said, "Mechanical contractor shall verify if existing system complies to code."

He then told me that I have to have my HVAC contractor provide written notice about the unit and whether the unit complies with the code. My contractor said it was a 5 ton unit but could not tell me if it the unit actually had a designed capacity over 2000 cfm (wording of the code) or if it was a designed capacity of up to 2000 cfm. So he didn't feel comfortable writing down that no smoke detectors were necessary until we know for sure.

It might be easier and cheaper just to put a smoke detector in.

[Blackmira]

Check the prints if avail.

[amickracing]

1st priority is to keep the inspectors happy. Putting one in probably isn't that hard and would make him happy.

Though, for a 5 ton unit you could slow the blower down a bit or hire a balance crew to see what the CFM is, or look for the info... or just argue with the inspector. Getting on their bad side (even if they are wrong on a small detail) can be a major pain later on.

[ACFIXR]

How many other units are in the same zone with this unit? If there sre more you need to install detectors in them and have them tied together.If its a single unit your inspector is confused and is only trying to do how he interprets the code. Install it and make him your buddy

[Carnak]

the rule is 2000 CFM but plans reviewers can get a little tired of looking at plans with 5 ton systems moving 1995 CFM

[bwalley]

the rule is 2000 CFM but plans reviewers can get a little tired of looking at plans with 5 ton systems moving 1995 CFM

In Florida Building Code Mechanical, smoke detectors are required in all systems OVER 2000 CFM.

plazaowner showed the code where it stated the same thing.

[Pneuma]

There are exceptions to the duct detector, for instance if the area served is sprinklered, I don't think you need one. I can't remember it clearly right now, but you need to review the fire code and see if any of the exceptions apply and may explain why it did not have one initially.

[Carnak]

In Florida Building Code Mechanical, smoke detectors are required in all systems OVER 2000 CFM.

plazaowner showed the code where it stated the same thing.

A 5 ton unico type of system will move 1250 CFM there or about, easily excempt.

[bwalley]

There are exceptions to the duct detector, for instance if the area served is sprinklered, I don't think you need one. I can't remember it clearly right now, but you need to review the fire code and see if any of the exceptions apply and may explain why it did not have one initially.

In Florida there is no exception on a sprinkled building.

Because you could have a fire in one area and pump the smoke through the rest of the building.

On a monitored building we have all the units shut down if a fire alarm goes off anywhere in the building.

Smoke detectors are a good idea in all units, no matter what the size is.