Fire and CO alarm system, feedback requested..

[twistedtree]

The Conception boat fire has spurred a lot of people into a closer examination of their own boat's fire alarm system, and escape routes. It sure has for me.


I'm about to start commissioning a 68' boat and am currently designing the fire and CO alarm system. We started talking about this in this thread on the NTSB report on the Conception fire, and I thought it would be better to make this a separate thread.

 

[twistedtree]

Here was the first question from the other thread.

What is supplying power? What happens if a fire cuts the power source?
What happens if the connection to the central alarm corrodes? Can you get out the hatch of your sleeping berth?

Nobody plans on having an accident or a fire, and all the tech equipment can fail. Have a lot of redundancy and a well practiced escape drill.

Of course no system is perfect, but here's what I have in mind. This is all just on paper right now, so I would really like to hear comments and suggestions.


I'm planning to build the whole system using UL components designed for commercial and residential fire alarms. In other words, it will be the same stuff that you would find in a business, or in a good residential system that meets modern standards for new construction.


A few characteristics of such a system which will address the specific questions are:


- The system is AC powered, which on this boat will come from an inverter system that is operational 100% of the time. The system also has a self-contained battery backup that will carry it over for some number of hours in the event of an AC power outage. I think that's about as reliable as you could make the power system, and fortunately that's how they are all built right out of the box.


- All the sensors are "supervised", which is alarm system lingo for continuous monitoring and health checking of the sensors. If a wire run is shorted or goes open circuit, it will generate a so-called "Tamper" or "Trouble" alarm indicating that there has been an attempt to tamper with the system, or that some fault has occurred.


- My goal is to use all wired sensors, but there may be places where I will use wireless. These are similarly supervised, with a periodic check between the central control box and each sensor. If a sensor doesn't report in as expected, it generates a Trouble alarm. It also specifically detects if the sensor has been removed from the base, and reports when there is a low battery condition.


As for accompanying all this with planned escape routes, and practice to ensure people can actually get out via those routes.... I couldn't agree more.

 

[twistedtree]

The plan is to have Smoke/heat detectors for fire detection, and separate CO detectors. They are separate because they generate different alarms, and it's easier to wire them as separates vs using combined detectors.


Each detector will be wired as it's own zone, so an alarm will be for a specific location. It's more wiring, but I think this is much better vs lumping a bunch of detectors together without any indication if exactly where the problem is.


The Fire detector locations are planned for:


- Salon/galley (maybe two to cover the space better)
- Outside master stateroom

- Hall outside guest bunks
- Pilot house
- Laz, located near the batteries, inverters, chargers, and DC electric panel
- Engine room

- Inside the space behind the main electric panel
- Inside the space behind the PH electric sub panel
- Inside the PH console where all the nav and other electronics are located


CO detectors are planned for:


- Outside master stateroom door
- Hall outside guest bunks
- Pilot house (there is a jump bed there)


I'm leaning towards one, or perhaps two sounders that will go off on any alarm.

 

[w8n4sun]

Are you home running all these devices to a fire alarm control panel? If so you can get an intelligent panel and run your initiating devices on a class A or class B wiring scheme.

 

[Alaskaflyer]

Since you are putting so much effort into this (kudos) you might consider emergency lighting too, similar to what commercial vessels have. Oh, not every space by any means, but perhaps in a key passageway.

 

[twistedtree]

Are you home running all these devices to a fire alarm control panel? If so you can get an intelligent panel and run your initiating devices on a class A or class B wiring scheme.

Yes, home run, but pardon my ignorance.... What is a class A or class B wiring scheme?

 

[twistedtree]

OK, I should have googled first. Always learning. I'm doing Class A wiring, using so-called "4-wire" detectors, with end of line resistor(s).


I think that's good, right?


As you can tell, I only know enough about alarm systems to be dangerous.

 

[twistedtree]

Since you are putting so much effort into this (kudos) you might consider emergency lighting too, similar to what commercial vessels have. Oh, not every space by any means, but perhaps in a key passageway.

I'll give it some thought. An alarm output from the main alarm board could drive some number of LED lights. Not sure how many, but it wouldn't take much. Thanks for the suggestion.


I do place flashlights in all the rooms, and various other strategic locations, so there is always one close at hand. But they do require presence of mind to find and grab.

 

[w8n4sun]

OK, I should have googled first. Always learning. I'm doing Class A wiring, using so-called "4-wire" detectors, with end of line resistor(s).


I think that's good, right?


As you can tell, I only know enough about alarm systems to be dangerous.

Sorry I should have explained further. First detail I don't know is whether or not you will be using a dedicated fire alarm control panel. With such panel, initiating loops are either wired Class B and is considered Zoned circuiting with smoke detectors one after the other, with an EOL end-of-line resistor at the end. If one detector goes off you won't know which detector but only the circuit it is wired on.

Class A, you have a feed and return wiring scheme with the end-of-line resistor set at the control board. You'll know exactly which detector is in alarm and if the wiring is cut on one loop, the detector can still communicate with the panel with the redundant loop.

I don't think you have a fire alarm control panel in mind so this may all be moot point. This is how we wire up commercial vessels like ferries and USCG ice breakers. Pretty neat stuff but spendy.

 

[twistedtree]

Sorry I should have explained further. First detail I don't know is whether or not you will be using a dedicated fire alarm control panel. With such panel, initiating loops are either wired Class B and is considered Zoned circuiting with smoke detectors one after the other, with an EOL end-of-line resistor at the end. If one detector goes off you won't know which detector but only the circuit it is wired on.

Class A, you have a feed and return wiring scheme with the end-of-line resistor set at the control board. You'll know exactly which detector is in alarm and if the wiring is cut on one loop, the detector can still communicate with the panel with the redundant loop.

I don't think you have a fire alarm control panel in mind so this may all be moot point. This is how we wire up commercial vessels like ferries and USCG ice breakers. Pretty neat stuff but spendy.

I'm planning to use a DSC central control panel, and am now thinking that it's Class B, not A. Class A is more sophisticated if it can identify which detector is alarming in the string. But I'm working around the limitation of Class B by only having one detector per zone. So I'll have a lot of zones, but they are cheap, and each can report a unique message to identify the location of the alarm.


Please keep the comments coming. This is very helpful.


BTW, I've been trying to figure out the differences between what the DSC alarm system offers, vs a CG approved system. Sounds like you probably know? I'm not a commercial boat, so the system doesn't need to be CG approved, but I'd like to be aware of what the differences are so I can decide if I think they matter for me. I expect a certified system would be a lot more expensive.

 

[stubones99]

see if the DSC alarm panel includes an IP interface. If so, you could have it send alerts via IP, rather than cellular or dial-up (old way).

From what I recall from ancient memory (35 years ago) you should be able to stack fire sensors, heat rise sensors, door contacts, motions, etc on each separate zone and get them annunciated separately. There are some systems that have point addressible zones with separate devices stacked on a single pair wire (sort of like RS-422 with addressible devices on a multi-hop serial cable.)

 

[O C Diver]

Have you considered 2 separate systems. While having an over engineered system for while your underway is nice, when you are disoriented (asleep in bed) having a wireless lithium battery powered system, that lights the way out, and has reliability in its relative simplicity, is very attractive. When redoing mine earlier this year, I had considered a far more complex system. Ultimately simplicity can equal reliability. For less than a boat unit and under an hour, I can replace every component, battery, sensor, light, alarm, and inch or wire. In maybe 3 hours, I can switch it all out to a different manufacturer.

Food for thought.

Ted

 

[twistedtree]

see if the DSC alarm panel includes an IP interface. If so, you could have it send alerts via IP, rather than cellular or dial-up (old way).

From what I recall from ancient memory (35 years ago) you should be able to stack fire sensors, heat rise sensors, door contacts, motions, etc on each separate zone and get them annunciated separately. There are some systems that have point addressible zones with separate devices stacked on a single pair wire (sort of like RS-422 with addressible devices on a multi-hop serial cable.)

Thanks.


It looks to me like there are detectors with built-in annunciators, and ones without. I think if you have them with annunciators, only the one that trips will scream, but the alarm from the panel will just indicate the zone, and not the specific detector.


The separately addressable, RS-422-like detectors sound like the Class A devices that w8n4sun has described. Since individual zones are cheap and easy, and the detectors inexpensive, I'm inclined to continue in that direction.


I also don't want only the activated detector to sound, since if it's buried in the ER, it might not be heard. I want a sound that can be heard throughout the boat. That's why I'm leaning towards dedicated sounders.

 

[w8n4sun]

I'm planning to use a DSC central control panel, and am now thinking that it's Class B, not A. Class A is more sophisticated if it can identify which detector is alarming in the string. But I'm working around the limitation of Class B by only having one detector per zone. So I'll have a lot of zones, but they are cheap, and each can report a unique message to identify the location of the alarm.


Please keep the comments coming. This is very helpful.


BTW, I've been trying to figure out the differences between what the DSC alarm system offers, vs a CG approved system. Sounds like you probably know? I'm not a commercial boat, so the system doesn't need to be CG approved, but I'd like to be aware of what the differences are so I can decide if I think they matter for me. I expect a certified system would be a lot more expensive.

If you don't mind let me know what model DSC panel you are using, I can look up specs and see the difference between it and Siemens panels we use for USCG and WSF boats.

Btw your use of dedicated devices per zone is the perfect way to make a Class B wiring scheme "smart".

 

[twistedtree]

If you don't mind let me know what model DSC panel you are using, I can look up specs and see the difference between it and Siemens panels we use for USCG and WSF boats.

Btw your use of dedicated devices per zone is the perfect way to make a Class B wiring scheme "smart".

The central control is a PC1864.


I did some reading yesterday trying to see exactly what the USCG regs call for. I think the most interesting thing I found was a CG proposal from 2014 calling for harmonization of the CG requirements with industry standards, including the UL standards that the PC1864 meets, along with the UL standard that all the detectors meet. I don't know the outcome of the proposal, but for me it builds confidence that a UL listed central alarm system is very suitable for a boat like mine where there is no requirement to use a CG approved system. In fact I don't think there is any requirement at all for recreational boats, so all this is above and beyond regulatory requirements.

 

[w8n4sun]

Very true, as along as panels and devices are UL listed you are good to go. The big difference is the method of installation and wiring, there needs to be redundant pathways for the detectors to send their signals back to the panel and this is where Class A Style 7 wiring comes into play. Your plan to use Class B wiring with dedicated devices per loop is perfectly acceptable and safe for your application.


The only other difference between your application and a "required" system would be the use of a red keypad. Will you have the keypad(s) located at your helm, master bedroom, and maybe salon/galley area?


Oh wait, have you figured out a way to send the DSC information onto your N2K backbone? This would be awesome. Way above my technical knowledge.

 

[twistedtree]

Very true, as along as panels and devices are UL listed you are good to go. The big difference is the method of installation and wiring, there needs to be redundant pathways for the detectors to send their signals back to the panel and this is where Class A Style 7 wiring comes into play. Your plan to use Class B wiring with dedicated devices per loop is perfectly acceptable and safe for your application.


The only other difference between your application and a "required" system would be the use of a red keypad. Will you have the keypad(s) located at your helm, master bedroom, and maybe salon/galley area?


Oh wait, have you figured out a way to send the DSC information onto your N2K backbone? This would be awesome. Way above my technical knowledge.

I really appreciate the help on this. I'll try to repay...


I'm planning on the ubiquitous DSC keypad, locations still TBD. But current thinking is that I'll place one inside the salon door entrance, in anticipation of adding intrusion alarming as part of the package. And then a second panel in the PH for quick access while underway.


Oh, one other thing I saw in the CG regs was a requirement for manual alarm pulls, like the ones you set off in high school. I think those are required in commercial buildings too, but not in residential. I'm not planning on any.


Regarding Class A wiring vs what I have planned with single device per zone Class B, can you tell me if this sounds right...? Class A has a redundant communications path, so a wiring failure does not disable the detector. That's good. In my class B approach, a wiring failure will generate a trouble alarm, so I'll know about it and can fix it. That detector will be out of service until I fix the wiring problem. That seems like a small risk, and one where I have a lot of control, so I'm quite comfortable with it. The perhaps bigger risk is that a fire actually gets started, and before it can trigger a detector, it burns through the wire. Then I get a trouble alarm, and even though I have a fire, the screaming sounder won't go off until some other detector triggers. The best way to mitigate this seems to be placement of detectors in the locations where a fire is most likely to get started. Nothing is 100%, but if I'm looking at this correctly, I think I'm comfortable with it.

 

[w8n4sun]

Manual pull stations, as well as notification devices (like horns and horn-strobes) are required on commercial applications. For our use not required and to be frank, not really needed as we can get around the boat fairly quickly.

Class B wiring and strategic placement of detectors will be more practical, especially if you didn't get the wiring installed during construction. NFPA72 also states you will need to install detectors in all sleeping areas, and within 5 feet of all sleeping areas in the hallway. I read where you intend to place detectors and you pretty much have it all covered, especially in areas where there are electronics and charging equipment.

I was going to say your panel will also do intrusion devices and you already have that in the works in the future. If you can figure out how to utilize the data onto your N2K let me know, that would be incredibly useful to monitor via whatever software you have in mind for your N2K. We have Maretron and I am only scratching the surface of systems being monitored.

You will have MORE in the way of a fire alarm system than 99% of the boaters out there (including me), so good for you on making this investment!

 

[w8n4sun]

One more tip - if you install detectors in the galley, anywhere near the stove/oven, be sure to keep the plastic covering for the detector(s). When you plan on cooking with smoke potential place the covers on the detectors until you are done cooking. This will prevent false alarming but be sure to remember to remove the covers once you are done cooking.

We normally install heat detectors in cooking areas to prevent false alarms, but in boats I would stick to smoke detectors so the photoelectric portion of the detector will catch smoldering conditions before it becomes a full on blaze.

 

[twistedtree]

I forgot about how the alarm system will like with other systems like Maretron. So here goes...


I have two DSC-based alarm systems running in dirt dwellings, and with both I have a serial interface installed that spits out all the alarm activity messages. I gather these, and email them to myself, so I pretty quickly see everything that's going on. I plan to do the same thing, but this time will use my PLC to receive the data and send the emails. I'm certain that will be more reliable than what I have been using which is an ancient Visual Basic programming running on Windows XP that has never been satisfactorily reliable.


I do NOT plan to use the normal central station monitoring features where the alarm calls a central monitoring service, who in turn call the police, fire, etc. It just doesn't make sense on a boat.


Another thing I have done with the other DSC systems in use an output to force my thermostats into vacation mode. It's super convenient because when you arm the alarm, it also turns down the heat or HVAC. And when you return and disarm, it all comes back on as normal. I am set up to do the same thing on the boat.


Right now I don't have any linkage planned with Maretron, but I might add that. You might know that you can connect fire detectors directly to Maretron, and I know many people who have done that. It's a form of central alarm, but with no UL or other listing other than for the detectors which are off-the-shelf. I love Maretron, but not for something as mission critical as a fire alarm system. I want something that I can turn on, and 20 years later it will still be running just fine. Plus I want agency listing, even if non-CG. And the DSC system is WAY cheaper, no harder to install, have integral backup power,etc, etc.


That said, one thing I'm doing this time around with Maretron is tapping into the alarm contacts that are present in many marine devices. Auto pilots, radars, sounder, HVAC, chargers, inverters, solar controller, water makers, etc all have these alarms. One of my pet peeves is that when an alarm goes off, I spend way too much time trying to figure out where it's coming from. It's distracting, and slows your response time. There is a big difference in the urgency of a plugged water maker filter vs a fire or flooding bilge. Most of the problem is that the alarm sound they emit is non-directional, at least to my aging ears, so I have to visually start reading displays to find the problem. So by sensing all the alarm contact, I can now have Maretron tell me what's alarming. I'm looking forward to it. I think at a minimum I'll have Maretron sense and report there is a DSC alarm. That way I'll know exactly where to go looking for more detail. And if I want to get really fancy, I could probably figure a way to report individual alarms on Maretron, but I'll save that project for a rainy day.

 

[twistedtree]

One more tip - if you install detectors in the galley, anywhere near the stove/oven, be sure to keep the plastic covering for the detector(s). When you plan on cooking with smoke potential place the covers on the detectors until you are done cooking. This will prevent false alarming but be sure to remember to remove the covers once you are done cooking.

We normally install heat detectors in cooking areas to prevent false alarms, but in boats I would stick to smoke detectors so the photoelectric portion of the detector will catch smoldering conditions before it becomes a full on blaze.

I think I need to do a little more work on my detector selection and placement. I have generally kept smoke detectors out of kitchens, but as nearby as practical. The same is true for garage space. It's a trade-off between false alarms, and quick detection of a fire originating in the kitchen. The compromise I think is what you suggest, namely installing a heat-only detector in the galley, and a smoke/heat nearby. I should be able to do this since our galley opens to the salon. So a heat detector in the galley, and smoke/heat in the salon.


I also need to think more about the staterooms. I have seen placement guidelines that say to locate the detector just outside the room, and some that say inside the room. My leaning is towards either outside the room, or both inside and outside. I'm not a fan of inside only because I think it allows a fire to get going outside the room where there are much more likely sources of ignition, and end up blocking your exit, or at least delaying detection.


I'm expecting that the prospect of wiring some locations will force me to use some number of wireless detectors. Assuming that's the case, at less than $100 a pop, I will likely lean towards more detectors, not less.

 

[w8n4sun]

Install detectors within 5' on either side of the bedroom doors. And yes, hard to wire areas can be covered with wireless detectors, and you have the right attitude of more coverage is better.

Also, if you're really concerned about wires burning before the detector sends an alarm, use 2hr rated cable. It's super spendy though but it sure is fun to spend other peoples money.

 

[twistedtree]

Also, if you're really concerned about wires burning before the detector sends an alarm, use 2hr rated cable. It's super spendy though but it sure is fun to spend other peoples money.

Thanks for the offer Thankfully I'm not worried about the wires burning through.