Max Number of Kiddie detectors in a residence

[newservice]

The spec sheet under the acrhitectural specs for Kiddie states :
"A maximum of 24 Kidde devices can be interconnected in a multiple station arrangement. The interconnect system must not exceed the NFPA (National Fire Protection Association) limit of 18
initiation devices, of which 12 can be smoke alarms. With 18 initiating devices (smoke, heat, CO, etc.), interconnected, it is still possible to interconnect 6 strobe lights and or relay modules."

Then, under the specs, the following:
"Interconnects: Up to 24 Kidde devices".

Where can this NFPA limit of 12 smokes be found? That doesn't seem like alot, are combinations included? Just wondering if someones dug into this maybe. If 12 is the limit, what can I do to get more? Run another circuit with an interconnected signal wire? :jawdrop:

 

[infinity]

I would start with NFPA72.

 

[newservice]

I would start with NFPA72.

ok, am i on the wrong forum?

 

[infinity]

No, I just don't have access to that document where I could copy and paste the wording. You can view it here after jumping though some hoops. Maybe someone else will chime in.

http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=72

 

[gadfly56]

ok, am i on the wrong forum?

Electricians need to be conversant with more than just the National Electical Code (NFPA 70). NFPA 72 is something you should be familiar with. The Life Safety Code (NFPA 101) is good to know, and the various International codes (building [IBC], plumbing [IPC], mechanical [IMC], etc) can come in handy as well.

To the point you've raised; NFPA 72-2007 states in section 11.8.2.2 that no more than 18 initiating devices can be interconnected, of which 12 may be smoke alarms.

 

[GoldDigger]

To the point you've raised; NFPA 72-2007 states in section 11.8.2.2 that no more than 18 initiating devices can be interconnected, of which 12 may be smoke alarms.

And if you then ask how to handle a situation which needs more smoke detectors, resign yourself that you will have to link two separate interconnected sets to a common controller. (Whether it can be as simple as putting a relay module on each string which will trip the other string is a question I will leave for an expert.)
And if you are in a situation which requires that many smokes, it probably justifies having someone with an alarm background engineer it.

 

[gadfly56]

And if you then ask how to handle a situation which needs more smoke detectors, resign yourself that you will have to link two separate interconnected sets to a common controller. (Whether it can be as simple as putting a relay module on each string which will trip the other string is a question I will leave for an expert.)
And if you are in a situation which requires that many smokes, it probably justifies having someone with an alarm background engineer it.

That ain't gonna happen. Correction; it may happen but no one lists their equipment to do this. In NJ, if you've got a McMansion that really needs more coverage, the DCA says the local AHJ can grant a waiver. Put in a real alarm panel and you're good to go. Of course the CO situation will be interesting...

 

[newservice]

Oh boy. So, when the NFPA says not more than 12 can be smokes, would they be counting the combination CO/smokes in there, or do they mean I can do 12 smokes and 6 CO/smokes?
What is the theory behind this restricition, is it that the battery backup can only signal so many, and apparently it does not matter that the manufacturer says 24 devices are ok? Knowing the AHJ, I think they would be ok with a few more than 12 but I would like to know more before going ahead. thanks

 

[kwired]

Oh boy. So, when the NFPA says not more than 12 can be smokes, would they be counting the combination CO/smokes in there, or do they mean I can do 12 smokes and 6 CO/smokes?
What is the theory behind this restricition, is it that the battery backup can only signal so many, and apparently it does not matter that the manufacturer says 24 devices are ok? Knowing the AHJ, I think they would be ok with a few more than 12 but I would like to know more before going ahead. thanks

You answered your own question in your OP:

The spec sheet under the acrhitectural specs for Kiddie states :
"A maximum of 24 Kidde devices can be interconnected in a multiple station arrangement. The interconnect system must not exceed the NFPA (National Fire Protection Association) limit of 18
initiation devices, of which 12 can be smoke alarms. With 18 initiating devices (smoke, heat, CO, etc.), interconnected, it is still possible to interconnect 6 strobe lights and or relay modules."

Then, under the specs, the following:
"Interconnects: Up to 24 Kidde devices".

Where can this NFPA limit of 12 smokes be found? That doesn't seem like alot, are combinations included? Just wondering if someones dug into this maybe. If 12 is the limit, what can I do to get more? Run another circuit with an interconnected signal wire? :jawdrop:

Initiating devices are the devices that sense things, a horn, strobe or relay module is not an initiating device.

 

[newservice]

I'm thinking the NFPA limits that number of smokes to 12 so you arent running around in a fire trying to figure out which was the initiating device, when you should be getting out of the burning building. (Imagine if you went to the max spec of 24 by the manufacturer). So at that point you need a panel. Ill be calling the manuf in the AM.
In this particular McMansion it will be owner occupied, they have a potential 5 smokes in the basement, and thats where the rub is. There were 5 areas there before the plaster came down, and the walls might go back up in the future. Since its old house, there is no requirement for hardwired smokes, and hence Im thinking I'll split the basement off into a seperate alarming circuit. That way the HO will know if its the basement or upstairs, and upstairs will be below the 12smokes, ugh, Ill be doing some callling tomorrow.

 

[gadfly56]

Oh boy. So, when the NFPA says not more than 12 can be smokes, would they be counting the combination CO/smokes in there, or do they mean I can do 12 smokes and 6 CO/smokes?
What is the theory behind this restricition, is it that the battery backup can only signal so many, and apparently it does not matter that the manufacturer says 24 devices are ok? Knowing the AHJ, I think they would be ok with a few more than 12 but I would like to know more before going ahead. thanks

If you use combination alarms (ie fire and CO) they do not count as 2 of the 12, only 1 of the 12. On the other hand, if it's a smoke/CO it counts as one of your smokes. You could invert your example; use 12 smokes and 6 CO's, or 12 smoke/CO's and 6 CO's, but NOT 12 smokes and 6 smoke/CO's.

 

[newservice]

Thanks to all that replied. Spoke with the AHJ, we decided 2 circuits were ok. So, one circuit will be for the upper floors and one for the basement. The two will work independently. Being an existing single family residence, with no general building permit as the wall coverings were not coming down, only single station battery is required anyhow. He said he thought a fire panel was 'a bit over the top' of a solution. Also said if the NFPA limits you to 12 on a circuit, then have to go with that. Just do more circuits. When you think of a multi family with say 12 common area detectors, theres nothing wrong with putting a seperate interconnected circuit within one of those units, there at least one single station AC detector is required in each unit anyhow.

 

[jdixon]

Had time so I found a copy of NFPA 72 2010 edition handbook. 29.8.2.2 which has the requirement of 18 initiating devices 12 of them smoke detectors if the system is not supervised. If the system is supervised you can have 64 devices w/42 being smoke detectors. In the handbook intent was for unsupervised systems there was no way to monitor the integrity of the interconnecting wiring so was limited to smaller systems

 

[newservice]

Had time so I found a copy of NFPA 72 2010 edition handbook. 29.8.2.2 which has the requirement of 18 initiating devices 12 of them smoke detectors if the system is not supervised. If the system is supervised you can have 64 devices w/42 being smoke detectors. In the handbook intent was for unsupervised systems there was no way to monitor the integrity of the interconnecting wiring so was limited to smaller systems

Ahh. Thanks for that.