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Carbon Monoxide/Smoke Alarm Interlock

JohnNY Member Posts: 3,152
This is code now in NYC. All boilers must be installed with a CO alarm interlock.

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  • icesailor
    icesailor Member Posts: 7,265
    CO Code requirements:

    Its been code in Massachusetts for a few years now, only as part of the Gas Code. Any NEW installation requires battery back-up smoke/co detectors. In most cases and in all new constriction, they must be hard wired.

    Nice to see New York getting on board with Public Safety. Now, if the rest of the state could get on board, and electricians putting the detectors on circuits that can be shut off in the panel. we'd all be getting somewhere.
  • Bob Harper
    Bob Harper Member Posts: 977
    Is this really a good thing?

    Can someone provide a link to this new law?

    On the outside, it sounds glorious. Great. We're being responsible providing protection, right? Right? Well, not so fast. Let's examine the issue.

    You want to protect the occupants from CO, right? Ok, choose one:

    A) protection from CO poisoning or

    b) protection from CO death?

    What is the best way to do this? Place sensors at just one of many potential sources or scatter them throughout the structure in a pattern that covers the actual places the gas would be breathed in by occupants?

    What type of sensor do you use? One that meets UL2034/ 2075 (sounds impressive) or an unlisted low level fast alerting model (sounds risky).

    What do you do with the information should a sensor detect an unacceptable level?

    a) shutoff a combustion appliance heating the building and preventing pipes from freezing?

    b) send out a signal to automatic ventilation louvers and fans?

    c) send out audible and visual alert signals to the entire building or just the space where the unacceptable level was detected?

    d) send a signal to a PLC/ DCS/ BACnet or similar automation system?

    e) send the signal to a datalogger?

    f) send a signal over the Internet to alert : building owner, 911, fire marshal's office, CPSC?

    What is the action plan in the event of an alert? Silence the alarm? Call 911? Call for HVAC service? Go back to bed?

    How is an alert differentiated between the connected appliance that gets shut off from extraneous sources of CO? False positives?

    If the connected appliance is shut off but the CAZ is depressurized, the loss of draft can actually exacerbate the issue causing more CO to spill back into the CAZ.

    What pre-installation inspection and testing must be done prior to placing such a system into service?

    In the event of multiple combustion appliances common vented, must it d/c power to all or one?

    I have more questions but let's see where these get us for now.
  • Tim McElwain
    Tim McElwain Member Posts: 4,588
    I could not get access to the

    information, however this sounds like a real problem. What level will the "interlock" shut off the heating equipment. Will it also shut off the water heater, gas oven, outdoor grill, etc. This is not a good thing and it does not solve anything just as what Mass does is not the answer. It just keeps the plumbing and mechanical boards happy that they think they have done something. Read Bobs posting as I agree fully with everything he posted.
  • JohnNY
    JohnNY Member Posts: 3,152
    Are you sure you're not overthinking this?

    If the boiler room fills with CO gas, the alarm sounds and the boiler or whatever else is interlocked in the circuit will be de-energized.

    Sure, the presence of high CO levels could be traced to something else, but chances are pretty good the boiler's the source.

    Most larger renovations I do now include a central alarm system that kills power to the mechanical equipment and alerts a monitoring service based on information read all over the building and not just the boiler room. This is just a smaller scale safety measure.

    I agree with you, Bob, and Tim, of course, but if you did nothing based on the existence of "what ifs" then nothing would ever get done.


    Happy Sunday.

    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
    Plumbing in NYC or in NJ.
    Take his class.
  • bill_105
    bill_105 Member Posts: 429
    I think it's a great idea...

    and so what if something else shuts off the heater. Nuisance trips would be avoided by just no longer barbecuing in the boiler room;)
  • heatpro02920
    heatpro02920 Member Posts: 991
    I have been doing this for a while

    I offer it to customers for cost of materials on a new install, some go for it some don't.. I use a BRK 9120 with a RM4, costs under $100 with the boxes. The 9120 is a combo smoke co and seems to be very reliable. I have a post around here somewhere that we talked about this..

    I love the idea and think it should be code everywhere...
  • Bob Harper
    Bob Harper Member Posts: 977
    false sense of security

    Hp, not to bust on you but I'm curious of your take by line item on my initial post. Do any of my points ring with you? For instance, what if this UL listed alarm alerts in a boiler room? Who is going to hear it and recognize it as a problem that requires action? When a UL listed CO alarm alerts, what does that mean to you in regards to actual exposure to CO?

    Let's say one of your alarms is sounding in a boiler room under an apartment building. A tenant is motivated to open the door and enter to see what is causing the noise. Is that a problem to you?

    On a side note, the alarm Hp specified is a cheap ionization sensor smoke alarm that senses free burning flames and not smoldering ones that take a photoelectric sensor. FYI,to be of any real benefit, ALL smoke alarms should be dual sensor.

    In the case of an apartment bldg. for ex., let's say your alarm alerted and shut down the boiler(s). How do you know the boiler(s) was/were the source? If you have an underground parking garage, it must have a hard wired CO alarm system that goes back to a control panel to alert "someone" and do "something". Does this bldg. have such a system, is it working and how do you know? Do they hire a factory authorized pro to perform the initial calibration and test them do it again annually replacing sensors as needed? Does anyone perform any sort of test on these systems when they are first installed? In other words, are you certified to test these CO alarms and do you carry a calibration kit including test gas and flush gas with you? If not, how do you know what you installed is doing its job? Again, not to single you out but to illustrate my point. This law merely provides relief to a few people's conscience but does not come close to addressing the real issues. I am a mfrs rep. for MSA and sell professional hard-wired systems daily. It kills me to see UL listed systems but that is what is written in the codes so my clients are forced to comply. You have to reach such levels of sophistication before you get any sort of break from insurance carriers as one point. BTW, if a listed CO alarm is alerting in a boiler room, you don't want anyone walking in there without SCBA and backup. If a boiler is producing sufficient levels of CO to cause a UL listed alarm to alert then those room levels are already very high. If you kill the boiler, you remove the primary exhaust system for the room. The chimney cools and all that CO spills back into the CAZ and the ambient levels skyrocket. That's why post purge should be mandatory but that's another fight. So, someone enters by themselves with no one else in the world aware they are there or why. They silence the alarm, become overcome and pass out then die. Your body is found by itself only hours later when someone goes to investigate why the building is getting cold.

     Sorry but the more I study this, the worse its looking.
  • icesailor
    icesailor Member Posts: 7,265
    Good Points:

    I did service work for over 20 years in a nursing home with all the toots and whistles of alarm systems. Everything was interlocked. If anything went off, the entire ventilation system shut down. Because so many things were interconnected, I became the only person around who consistently worked there and developed a total understanding of how the systems worked and are interconnected. I went through a few "Maintenance Supervisors". They all called upon me when the problems started. Except the last one. He was a lot smarter than I was. His experience was a construction supervisor on highway bridges. Anything wrong, I explained to him what was what. He ignored me.

    One day, he called me ( in desperation) because the range hood in the kitchen wasn't sucking range exhaust and they couldn't figure out why. I went by and sure enough, it wasn't sucking. I went upstairs to the mechanical room and the particular blower was running. Then, I noticed that the main heat recovery/ventilation unit wasn't running. I asked him what was done and who did it. It is supposed to be running and all the switches were on. In 20+ years, the HRCV was never off except to service it. He then told me that they had a strange electrician who found a wire in a junction box that he switched to get the hood fan motor to run. I told him that under no circumstances should that one wire have been changed because it was part of the alarm interlock that controlled ALL the fire dampers and the alarm sensors. What was done in here? Finally, it came out that they had changed to a new digital fire alarm panel a few days before. Did the problems start after that? Yes. Call the installer and tell them to change a wire because they had it wrong. The company said they were right. They told me that I was wrong. If what I said was true, the owners would have to pay to have all the controllers (over 25) changed. BS. It worked before you changed the panel. The controls are wired to be powered open. When the power goes off, the controls all close and motor relays go off. You need to switch 2 low voltage wires in the panel you just installed and I'm not looking for which ones they are and YOU get your behind over here and fix it.

    You can't EVER trust an alarm system that is in place because you don't know what or who has futzed with it. The electrician would have re-wired the whole building and then most of the alarm system wouldn't be active. All over a crossed wire.

    When cost/money conflict with public safety, the cost cutters take control and people get sick and/or die.

    Just look at that Korean passenger ferry. A Canoe has more stability that that ferry. Blame the Captain and crew for a design flaw. Just like they want us to make everything safe.
  • heatpro02920
    heatpro02920 Member Posts: 991
    edited May 2014
    9120B is the actual number


    pretty simple to wire wire the 3 wire side of the detector as you would normally wire 2 detectors together- l1, l2 and signal, then on the other side of the rm4 wire the brown in from l1 and the grey out to the boilers l1 feed {I wire it before the fireomatic}, there is also a blue contact you can wire to an external 120v alarm or strobe...

    read the instructions, I may have mixed up some of the colors, I haven't done it in over a month...

    PS if you are doing this on a gas boiler and dont want to wire it high voltage you can break 24v to the gas valve and wire it in how a roll out would be wired, but this makes things tougher since you need hv and lv in the same box...

    As far as it being a bad idea, I think its coming and it will be here to stay, so it will get "perfected" and we will live with it, like we did LWCO's, high limits, firomatics, proving switches, ect , I have installed a bunch of these setups with the cheap co's and the relay, they havent caused any negative effects as of yet, I install them a little ways from the units and they are on the ceiling, so IMO if co gets up there and at a level to set the unit off having the boiler shut down isn't a bad idea, now if the customer ignores a co detector or resets it or unplugs it ect, they will still be calling for service when they have no DHW or heat, that's when a pro can come and look at it.. I have stickers printed with my number and co on them that says "In the event of an alarm please turn stairway emergency switches to off position, evacuate area, and call for service." Not that I expect many to follow the instructions since I have a sticker I put on the oil boilers I service that says "DO NOT DEPRESS RESET BUTTON MORE THAN ONE TIME! CALL FOR SERVICE EVEN IF BURNER RUNS AFTER RESET!" and I still go to house where they pressed it 25 times because they thought it was running for 15 seconds at a time...
  • heatpro02920
    heatpro02920 Member Posts: 991
    Yes the co120x

    is pretty much identical to the item I listed, normally a couple bucks more, I have used both and I have both in my stock bin, but rm4 is easier to remember than co120x, lol... I buy which ever is in stock, there is also another unit that comes in a box, I forget the part number {GE brand} but its sealed with screw/lug conns, and costs 3 times as much as the rm4,..

    I am sure it will be code everywhere soon {not that its a bad thing, if it saves 1 life then its worth it and the idea has the potential to do so}, then after its code there will be a few brands to choose from for a few years then after that Honeywell and the other control companies will build it into their controls, by then another new safety issue will come up and someone will come up with a way to warn and prevent it and we will be discussing that, its a viscous circle....
  • Bob Harper
    Bob Harper Member Posts: 977
    making my point

    Sorry guys but you advocates seem to be making my point. You are putting them in the wrong places. You expect a human to enter a toxic environment to hush/ investigate the alarm. You claim no negative effects: how many times have your sensors failed to alert when they should have? How do you know when one of your alarms alerts? Do you have any sort of central station monitoring with data logging? Sorry but this issue is far more complex than LWCOs or spill switches. My overriding concern is the false sense of security you are breeding with these installations. No, I don't see this getting "perfected" in this generation by a long shot. 
  • NYplumber
    NYplumber Member Posts: 503
    Over Complicating

    Just another obstacle for legitimate folks to adhere to pushing more work to the flybynights.

    Its time to go back to old school ways. Take the training wheels away from the people and make them use their scenes rather then live in a world full of fluff.