How many smokes & zones do I need?

[Mr Spock]

New construction home in SoCal. 2 story 3000 square feet with 5 bedrooms. Trying to estimate the number of 2 wire smokes and zones I will need. Also unsure what the laws are regarding the minimums. Thinking of using system sensor 2WTA-B.

My thoughts are:
1) one sensor in each bedroom.
2) one in the kitchen.
3) Two zones; one for upstairs and one for downstairs.

I'm trying to understand what is required as a minimum vs. what I really want to do. I think I'd be OK with just two zones. Some people say they put each smoke on a separate zone, is this really necessary? You will know which room gets tripped, but hey if the house is on fire I think all I really need to know is if it's upstairs or downstairs. Am I missing something?

Thanks.

 

[pete_c]

Here in the midwest and probably ancillary the contractor put one HV / Battery smokes on each floor of the home. In Florida the contractor put one in every room of the house. Personally with the HAI OPII zones; I replicated the smokes / CO detectors accordingly to the HAI OPII panels. Overdoing it a bit with autonomous zones for more of a granular look see. You can though just use one zone for all smokes or CO detectors. I figured you already have the ability with the panel; so I took advantage of it.

It is "wall/ceiling clutter" of sorts to have two sets automously connected. Really though its important you as an occupant being in the house should something occur and triggering the smokes and or CO be alerted due to saftey reasons.

When you are not home its more to know that your house has triggered the zones. Not so much a personal saftey thing but rather just knowing that something is going on in your home. The requirements are different state to state and have changed though in the last few years.

I do believe though that its starting to lean towards a room by room sensor thing these days. Unless your specifications call for an alarm panel; I believe the contractors will typically utilize a one circuit HV with a battery in your home.

There has been discussions of combo HV/Battery and alarm triggering devices and or modifications of said devices on this forum; almost religious like pro's and cons discussions relating to the methodologies.

 

[Del91574]

Present minimum code, and has been for at least 10+ years for fire alarm is one on each habitable floor and one inside each bedroom/sleeping area. There also needs to be one installed outside of the bedroom/sleeping area, however this can be met usually with the single detector that is required per floor.

The areas that most AHJ's tend to be grey on is when there is a long bedroom hallway or there's a multi-story building with a bedroom on the first floor, where the adjacent smoke detector tends to leave too much space open for no detection. Heat detectors are not required, nor are they accepted as a life safety device. Smokes should not be installed in kitchens, garages or uninhabitable spaces such as attics or crawlspaces.

CO detectors would be mandated by your local juristiction, however most states are moving towards requiring at least one detector outside the sleeping areas, with a strong desire to require one per floor of habitable space.

Fire and CO should always be separated, I prefer my CO to be individual zones based on the detectors I install, but fire is perfectly acceptable to be a single zone, or even a zone per floor. I wouldn't necessarily recommend running each smoke as it's own zone, frankly because if you're going that route, by the time the hardware is added up, you might as well install a small addressable fire panel rather than deal with the wiring headaches. If you're wiring conventional, it might be worthwhile, if heats are installed, to put on their own zone, however nowhere is there a mandate to do such.

In your case, a prudent number given 2 floors would be 7 detectors, however if you have a basement, you would need one there as well. General classification of a sleeping area for most AHJ's is whether or not the room has a closet, no matter what it is called on a print.

 

[Mr Spock]

A wealth of info...

Carbon monoxide, yes I need to include that too. Sounds like I need two, one in the upstairs hallway (central to all the bedrooms) and one in the middle of the downstairs. One zone for each.

For the smokes (aka fire?) I think I'm looking at 7 detectors as 2 zones.

Leaning toward an HAI OPII panel with 2 expansion cards.

Thanks.

 

[pete_c]

There are drawings for the separation of the zones and wiring for the Smoke detectors here on the forum. Its similiar to the CO detectors.

I separated the smoke detectors into zones as I did the CO detectors into the HAI OPII panel. It would have been much easier to just configure one smoke zone to all of the smoke detectors and one CO zone to all of the CO detectors; but I decided instead to wire up all of the pieces.

Note it involves additional boards inside of the HAI II panel; at least for me. So basically its three pieces (more for multiple zones etc); boards inside of the panel and EOL type boards. I did also add the basement as separate zones for both CO and Smokes. IE: Polarity reversal module, Power supervision relay and EOL resistor. Attached is a drawing for one zone.

 

[gatchel]

Aren't the smoke power wires supposed to be landed on separate positive terminals? I always thought that this was done so that if one unit was not properly seated on the base or was removed, it would create a trouble condition (ie the power supervision relay would not power up.)

 

[pete_c]

I just wired like the diagram above and it tested fine for me.

 

[Del91574]

Aren't the smoke power wires supposed to be landed on separate positive terminals? I always thought that this was done so that if one unit was not properly seated on the base or was removed, it would create a trouble condition (ie the power supervision relay would not power up.)

As long as the wire is physically broken and not looped through/twisted together, it meets the requirements for supervision, as removal of the smoke from the circuit will open the circuit. While I'd say stick to the terminals as they're labelled, it's a slight technicality.

Of note, the DSC smokes are backwards in electrical operation compared to all other manufacturer's units, and as such, should only be used with DSC's modules/reversing relays, etc. DSC's panels switch the negative, which causes all sorts of issues as it is uncommon to any other manufacturer (barring some Bosch/Radionics panels).

Also, depending on if you control the PRM from the bell output (sampled temp-3 pulse) if you have audible fire panics, it will cause an issue with the smokes.

As far as CO detectors being wired to the same zone, depending on the unit, the wiring can become far more complex as many units have a trouble relay that needs to be wired in series with the EOLR, and wiring multiple units increases the # of conductors required from 4-6 or even 8 depending on the specific unit.

 

[Ira]

...
Smokes should not be installed in kitchens, garages or uninhabitable spaces such as attics or crawlspaces.
...

Assuming the home has a panel, e.g., Elk M1G, is it a good idea to install heat detectors in the above mentioned locations?

 

[pete_c]

I wired the CO detectors separately (autonomous zones) from the smoke detectors.

 

[Del91574]

Assuming the home has a panel, e.g., Elk M1G, is it a good idea to install heat detectors in the above mentioned locations?

That is the purpose and intent of heat detectors, as discussed within code.

Same holds true here, it is mandated for an alarm panel to have separate notification for CO in respect to fire alarm, however they can be daisy chained as long as the end of life function/relay maintains it's proper operation.

I wired the CO detectors separately (autonomous zones) from the smoke detectors.

 

[pete_c]

Is there a rule of thumb for replacement or life expectancy of the Smokes / CO detectors?

In FL I replaced the contractor installed smokes in all of the rooms about 2 years ago; with the home being 8 years old.

It took me a couple of days due to a rewire of the new smokes and doing them in every room.

Is there a life expectancy on these devices or is it just better to replace them after XX years?