Smoke Detection Configuration Help Needed

[sbex55]

As mentioned in a previous post, I have homerun 4-wire to several locations where I plan to locate smoke detectors. Since I cannot now easily run wire between two of the locations I believe I have two options.

Option 1 - use 4-wire smokes and setup 2 separate zones.

Option 2 - use 2-wire smokes and make connections at my home run to setup a single zone.

Recommendations are appreciated. I'm not sure of the pros and cons of 4-wire vs 2-wire smoke detectors vs the tradeoff of 1 vs 2 zones for smoke detection.

Thanks for the help!

 

[Del91574]

Option 2.

Running multiple 4 wire fire zones, then adding supervision relays, then adding a reversing relay (if this is to meet code)....vs. smoke detector and reversing relay only. Also takes the inherent issues of a fire reset or tandem ring putting multiple zones into fire trouble.

 

[sbex55]

Option 2.

Running multiple 4 wire fire zones, then adding supervision relays, then adding a reversing relay (if this is to meet code)....vs. smoke detector and reversing relay only. Also takes the inherent issues of a fire reset or tandem ring putting multiple zones into fire trouble.

Del - Thank you. I will plan on 2-wire smokes. On a previous post you mentioned ... "If price were no object, I'd suggest looking at some of the smaller addressable panels that support 25 devices, then integrate with a host panel.". I am planning on having 6 smokes on my panel. Would an addressable panel provide any additional benefits to me? What products would you reccommend?

Thanks for the help!

 

[Del91574]

I doubt you'd see the benefits to justify the price of installing one of the small addressable panels. I'd say that until you hit 15, it's really not worth it.

 

[apostolakisl]

Consider what addressable does for you. It tells you from the panel (or via remote communication with the panel) which detector triggered the alarm. Do you really need to know which one triggered when you only have 6? I'll answer. Almost certainly not. If the house is actually on fire, should be easy to spot. .. assuming you don't live in a 50,000sf house. If it is a false alarm, the blinking light on the detector will do the job. Since you only have 6, it won't take but a minute to find the one with the blinking light.

Heat detector that might be hidden next to you hvac, in an attic, or in the garage might be more tricky to find. You can zone those by themselves. They don't have sounders and are not powered so you don't have to worry about resetting them or reversing polarity. They are mechanical devices that self reset in the event of rate of rise alarm. If you hit the max temp and it melts the conductor. . .it is non-resettable . . . needs to be replaced.

 

[newalarm]

Haa, I made the same mistake. I also ran wrong wire gauge though. I ended up re-running new red fire wire and left the old, figuring I could use it for another device. Live and learn.

 

[newalarm]

I have a furnace room with a oil furnace and gas water heater. Actually, there are three small rooms, all have cased openings for now though we may add doors down the road. I was going to install heat in this space since i though the oil furnace may create false alarms. Any recommendations? Should there be a heat above the furnace, and a smoke farther away?

 

[apostolakisl]

Heat above and a couple feet away from the furnace/water heaters. Code typically states that each occupied floor of the house must have a smoke detector. If your basement is a living space than you should have one. If it is strictly mechanical room space, I would doubt a smoke detector is necessary. Perhaps you want one there anyway. . .that would be your choice, but not in the same room with the furnace.

You would use smoke detectors with sounders. To a large extent the purpose of having them in all occupied parts of a structure is for the sounder. Even if you feel that the area is very low risk for starting a fire, you would want to notify any occupants.

You might also consider CO detectors near the stuff with burners.

Just curious. . . did you say you have a natural gas water heater and fuel oil furnace? Or is it a a propane water heater? Either way, you don't usually see mixing and matching like that. NG tends to be so much cheaper and you would probably not want to pay for a fuel oil tank and propane tank when one or the other would do the trick.

 

[newalarm]

Oil furnace was good so we kept it. but when it goes, we can change to gas. Plus it is nice being independent for heat anyway... Not too worried about code since this is a secondary system. We already have hardwired smokes throughout. The elk smokes/thermals will be monitored, that is why we added them.

I installed COs last night. There is one outside utility room (where furnace sleeps), separated by a door. I did not locate one inside utility room. Is it good idea to have one there? should it be on different zone than rest of house? I figured no one would be sleeping there, or working for long periods. There is currently one CO on each floor.

 

[chrisexv6]

My basement is half finished, half unfinished. The unfinished side has the oil fired furnace and hot water heater and that side is separated by a door to the finished side that is open almost 100% of the time.

The finished side of the basement is open to the first floor (stairs with a half wall and no door upstairs).

I put a heat only detector a few feet from the furnace/water heater. Put a CO and smoke detector on the finished side well away from the door that opens from the unfinished side. 1 CO on each of the other 2 floors, smokes in every bedroom, and heat detector in kitchen to finish it all off.

Considering what I had before I installed my M1 (battery powered smokes, 1 on each floor, and 1 battery powered CO detector on top floor), I already sleep better at night knowing Im safer.

 

[apostolakisl]

To me there is no point in putting CO detectors where there is no combustion. I don't have any CO detectors at all in my house becuase, aside from a propane cooktop in the kitchen, the house is electric.

CO detectors are good to have all over the house if they are not linked together. This is because of the sounder. If the only combustion occurs in the basement, then putting CO's there will catch any CO production. If these are wired to the Elk, then you can rely on the Elk to set of an audible alarm throughout the house. Perhaps a second CO detector is there just for peace of mind that two would have to fail rather than just one.

Consideration for CO detection may also be an issue related to automobile production. Keep in mind that false alarms will occur with non-fuel injected motors since they tend to spit out a bunch when they first turn on. I used to have a Harley (then I had kids). I had a CO in the utility hall (off the garage) and if I started the motorcycle in the garage (even with the overhead door open), it would trip the detector.

 

[Del91574]

Got any ductwork or forced air? Metal chimney or exhaust through living space from your HWH or furnace? Ductwork through a soffit or garage within a soffit? No fuel burning appliances, but plenty of opportunities for CO to be distributed within the living space.

I've seen enough cracked HE's on furnaces that didn't leak CO to the living spaces directly that pegged meters when investigating causes for CO alarms. Also some metal chimneys that were rusty/leaky or poor drafts.

CO's should be located in residences where combustion occurs, near mechanical spaces, as well as located in sleeping areas, frankly, I'd go with the old smoke detector rule....1 on each floor of living space, however in the case of a forced air system...a lot of thought should be given to how dampers and the system itself distributes the air.

 

[apostolakisl]

Got any ductwork or forced air? Metal chimney or exhaust through living space from your HWH or furnace? Ductwork through a soffit or garage within a soffit? No fuel burning appliances, but plenty of opportunities for CO to be distributed within the living space.

I've seen enough cracked HE's on furnaces that didn't leak CO to the living spaces directly that pegged meters when investigating causes for CO alarms. Also some metal chimneys that were rusty/leaky or poor drafts.

CO's should be located in residences where combustion occurs, near mechanical spaces, as well as located in sleeping areas, frankly, I'd go with the old smoke detector rule....1 on each floor of living space, however in the case of a forced air system...a lot of thought should be given to how dampers and the system itself distributes the air.

Agree, furnaces/hot water usually vents out the side, but if it goes up through the house then you have risk all the way up. It has been decades since they did it that way but it sounds like your house might be a bit older.

 

[chrisexv6]

Agree, furnaces/hot water usually vents out the side, but if it goes up through the house then you have risk all the way up. It has been decades since they did it that way but it sounds like your house might be a bit older.

I dont think its just that....if I have a leaking chimney, heat exhanger, etc, the CO will be released into the return/supply air, and then pushed around when the blower kicks on. Good way to distribute CO from a basement to everywhere else in the house.

With hot water heat, the chances of this are much smaller. But I have forced hot air so there are all sorts of air pressure differentials going on in the house that potentially draw CO in/out of rooms. Id rather spend an extra 80 in CO sensors than worry about falling asleep permanently one night with the heat on.

 

[apostolakisl]

I dont think its just that....if I have a leaking chimney, heat exhanger, etc, the CO will be released into the return/supply air, and then pushed around when the blower kicks on. Good way to distribute CO from a basement to everywhere else in the house.

With hot water heat, the chances of this are much smaller. But I have forced hot air so there are all sorts of air pressure differentials going on in the house that potentially draw CO in/out of rooms. Id rather spend an extra 80 in CO sensors than worry about falling asleep permanently one night with the heat on.

OK. . .good point. But I still think a CO detector everywhere you put a smoke detector is overkill. That's a lot of ceiling "warts". I would instead suggest one in the outbound air plenum and one in the furnace room.

From my reading on what is usually the culprit in furnace CO, it is backdrafting the flu.

The air in the heat exchanger would be positive pressure on the house side and negative on the combustion side, so a crack should leak from the house to the combustion . . .not the other way (the exhaust fan "sucks from the combustion chamber and the air handler "pushes" air into the heat exchanger). But one extra CO detector hidden inside the duct is not much to ask. Plus it would be an ideal place to pick some other random source of CO since it would be sampling the entire house.