Smoke Detectors

[VTP99]

Was working on a walk-in cooler last week and being a nosey rosey i noticed the a/c guy had not installed a smoke detector on his unit as the prints had called for. When i asked him i was told 5ton and under did not require one. Any one got the code on this ?

[superfittertech]

Was working on a walk-in cooler last week and being a nosey rosey i noticed the a/c guy had not installed a smoke detector on his unit as the prints had called for. When i asked him i was told 5ton and under did not require one. Any one got the code on this ?

that is correct only if cfm's ( i.e. 6 ton or higher) above 2000 are duct smoke detectors required. prints were probably cookie cutter prints

[fxb80]

Here, we have to install on anything 2000 CFM and above, so a five ton gets a detector.

But how can you decide not to do something shown on the prints based on Code? If it's on the prints and isn't less stringent than Code, you do it, unless...

In this case, if the project manual says detector on greater than 2000 CFM, and local code says detector on greater than 2000 CFM, but prints show one, the next question would be which has precedence, the prints, the project manual, or local Code? If there is no project manual, how do you know the owner does or doesn't intentionally want to exceed Code? If it's on the prints and I don't want to do it for what seems to me a valid reason, there has to be Request For Information to the Owner or the Owner's Representative to clarify the issue.

[zzonko]

Both the NFPA and the IMC require a duct detectors on any unit over 2000 cfm. NFPA says supply side, IMC says return. They also require one each on the supply and return on units over 15,000 cfm. Your local code authority will tell you which to follow

[amickracing]

Around here a lot of people will say "it balanced out below 2000 cfm" and don't install one. And in most cases, the unit was never balanced either... Gotta love those grey areas!

[zzonko]

Around here a lot of people will say "it balanced out below 2000 cfm" and don't install one. And in most cases, the unit was never balanced either... Gotta love those grey areas!

Ya aint that the truth. Down here in Fl its the same, but when the trial in court for burning down the house is going all the lawyer has to do is present the cut sheet from the unit stating the specs are 2000 cfm. I like to play it safe

[Tech23]

Around here on 5 tons and down we do not, since the standard direct drive 5 tons of most manufacturers is actually 1950 cfm and code says 2000CFM and above.

However if we order one and specify belt driven on a 5 ton, then we have to.

[Tech23]

Actually, I think what I have been told about most units being 1950 CFM may not be true as I was just looking at the blower performance on a Rheem 5 Ton.

But our inspectors around here only ask about the smoke detectors if it is larger than 5 ton.

I will have to do some checking into this.

[VTP99]

Thanks guys for the posting. Just one of those things i never gave much thought to till it came up. It looks like 2000cfm's is the answer. So it's O.K. to move smoke through a building at 1950cfm's but not 2000. Who dreams up the break point ?