Hi friends. Yesterday Pam and I finished up installation of an automatic fire extinguisher for the engine compartment. Our coach has an east-west bed floor plan with a large clothes closet that spans most of the rear of the coach. We decided to mount the tank in the closet. This saves room in the engine compartment and allowed us to use a pretty large volume foam tank. We put in a unit that has two heads that open at 286 deg F.
The first head is above the engine installed with a horizontal alignment to allow it to discharge the foam above the valve cover and below the pipe that goes between the CAC and the air intake manifold. This head should give general coverage to most of the compartment.
The second head is mounted lower on the passenger side of the engine. It's alignment is to hopefully allow it to discharge into the radiator area as well as directly on the side of the engine in the area of the fuel filters and fuel pump.
I'm fairly happy with the installation but it's not my best work. The 2x4 brackets (treated lumber) are a little crude but get the job done and were easy to fabricate. The hoses are made of teflon and braided stainless steel and very stiff. The stiffness makes the installation tedious and challenging to position the heads and tank. The advertisement for the tank said it would ship with a ball valve but it did not. The heads were attached directly to the tank so the hole between the closet and the engine compartment had to be made large enough to pass through the heads.
What do you think of the head mounting locations? I intentionally did not mount a head in close proximity to the turbocharger to avoid that high temperature zone. Although the turbo is probably the most likely source of ignition, it seems to me the passenger side of the engine is the primary source of fuel for a fire. Does the head on the side of the engine need to be more in the radiator area or is the location a good compromise between the radiator and the passenger side of the engine?
Nice way to not worry about an engine fire. I booked marked and it might wind up on my to do list. With our coach the tank would have to be mounted externally probably in the un finished storage box behind drivers side rear tires.
Mark,
Your extinguishers look good but unless you have a heat sensor that will warn you on the dash, the extinguishers will empty with the engine on fire. The wind from the coach's speed really feed any fire. The engine could care less if it's on fire as long as the ECU or fuel lines don't burn. The big coach I posted the video on had a fire from a hydraulic hose failure. Unless the driver is alerted and pulls over, the coach could be easily lost.
Nice to have another extinguisher to take to the back to knock down any residual fire.
Pierce
Yep, I remember that post and also your saying something to this effect. I have two 10-lb dry chemical extinguishers on board.
Do you have suggestions for engine heat / smoke / fire alarm systems?
Edit: Fireboy - Xintex makes a system marketed to the boating crowd. (http://www.fireboy-xintex.com/wp-content/uploads/2014/07/FR1000+FR2000.pdf) It has remote heat sensors that trigger at 170 deg F. Would that be too sensitive for our engine compartments?
Pierce, how about a pressure switch on hose connection to fire extinguisher, that closes an audible alarm. Even better if it uses a relay to 'latch' alarm that will continue after extinguisher pressure ends.
Mark,
The smoke detector on your link would work.
Curious what the trigger temp for the extinguisher heads. I don't see an on/off valve. How did you pressurize system after installation?
Yes, I can see your concern about the 170 degrees being too low. The closed engine compartment on a hot day after climbing a grade and then shutting down might exceed 170 but I'm only guessing.
They do make sensors for higher temps.
Yes, an alarm triggered by the extinguisher using a pressure switch could work.
Best is to visit or call a fire extinguisher company. They are in all cities as businesses have to recharge their extinguishers on a regular basis. They will be able to tell you exactly your best options.
Fire, especially on the road is extremely dangerous and with the engine at the back, it may go undiscovered until it's too late to do anything but stop and get out of the coach. An initial warning of abnormal temperatures or smoke gives the operator time to pick a spot to pull off and stop. If the reason for the alarm is a fire, the stationary vehicle is much easier for the fire extinguishers to put the blaze completely out and much less hazardous for the occupants. The high fire loading of the petroleum based construction makes immediate action imperative.
An interesting quote on residential or business sprinkler heads: "Sprinkler heads are individually activated by fire. Residential fires are usually
controlled with one sprinkler head, and 90 percent of all fires are controlled
with six or fewer heads. A study conducted in Australia and New Zealand
covering 82 years of automatic sprinkler use found that 82 percent of the fires
that occurred were controlled by two or fewer sprinklers. "
The chance of a sprinkler head failure is one in sixteen million.
Pierce
Hey Steve. The trigger temp is 286 F. The advertisement said that the unit would ship with a ball valve but it didn't. It shipped with the heads already attached and pressurized. That's made the installation more difficult.
This seems to make a good case for the 170 deg F head. Installing separate heat and smoke sensors as independent alarms could be interesting. If, say, the vehicle is stationary and the heat sensor alerts but the smoke sensor doesn't alert, then certainly you check out the heat alarm but perhaps not the same reaction as if the smoke sensor alerts? The Fireboy-Xintex FR-2000 has two alarm zones. One could wire one zone for smoke and the other for heat.
As Barry points out, another type of alerting is a buying a foam tank with a pressure switch. When a head discharges it triggers an alarm in the remote panel and the panel alarm latches until silenced. If I had this to do over I would consider that option. Perhaps one downside to this would be that it only alerts after the event? No early warning??
I like those odds.
Nascar uses these . There is a trunk system @ around 180 degrees and engine system at around 300. They time out for Nascar and they sell them cheap . Check "Roush sales" for one.
You could use a pressure switch in the hose or head and have it trigger a relay with a horn. The can /system would have to be unloaded to fit the switch , and the switch might be prone to leak.
Aircraft might also use a similar system but definitely uses a dash indicator.
I always have an BA fire bottle near me when the door is 20ft away.
Regardless of what kind of detector is used, as I mentioned before, an early warning allows you to pull out of traffic, park, do a calm evacuation and then explore the problem without having to consider your family's safety. Do a mental picture of looking in the mirror, seeing smoke and then trying to collect your thoughts to make all the correct decisions while pulling off the road. Difficult at best.
The oxygen supplied from vehicle movement is any fire's best friend and will greatly hinder the capabilities of any type of fire extinguisher.
Pierce
On our fire suppression system, my installer at the time produced a audible detector panel that not only shows which detector activated the alarm but also produce a 125 decibel siren to alert us of a problem. Unfortunately, the owner of the company has since sold the company and along with his departure this great system is no longer available.
A shut off is a must for any fire suppression system. You will need to recharge these systems over a period of two years and without the shut off, you have a real issue. Some systems built today without a shut off also have non-rechargeable cylinders. While they are cheaper, in the long run you have to spend more money in the long run.
Consider also installing foam unit where the hydro hot unit is as well as the generator. Since these units use fuel too, they can produce a nasty fire as well.
Finally, when I was driving buses, I had one engine fire while driving. At first I did not know I had a problem but quickly the engine died and I pulled over and safely unload 49 passengers. Let me say that when a foam unit is used, there is so much foam used that any wind from driving made very little difference to the amount of foam needed. The foam covered the entire engine, smothering out a fuel line fire and saving the bus. Luckily, I had shut off the bus before going back to see why the engine died which in turn shut off the electric fuel pump. I was surprised to see foam all over the ground and back of the coach before opening the engine doors. Once I had opened the doors, I could not even see the engine at first. Thank goodness for the foam and this is why from day one when I bought my Foretravel I had the fire suppression system installed. FOT took many pictures of my unit and really took an interest in what I had. If you are hunting around for a great fire suppression system, then check out the marine market for they use them a lot.
Bob
AFFF foam is great stuff and the residual foam after use is no big deal. With the remote air intake, the engine may continue to run like in the case of the video I shot. Nice you have the audible alarm.
https://www.youtube.com/watch?v=dX6sJ91fK-U
Pierce
Back in a previous life I worked on military aircraft. The fire suppression systems I remember used hydrofluorcarbon or Halon extinguishing agents. The fire sensors where photo cells similar to the flame sensor used in the AquaHot burner. The pilot was given a visual and audio alarm and then had to decide if he wanted to manually activate the extinguishing agent. False alarms were not uncommon. Never had an occasion to see if these systems really worked.
Interesting system shuts engine down and provides alert at detection and deployment of extinguisher. (http://www.fireboy-xintex.com/engineshutdownorder/)
You are supposed to have automatic engine shutoff whenever you have an automatic extinguisher system. With a diesel, you need a shutoff valve for the intake also in case there is a flammable fluid spraying in the engine compartment that would keep the engine running.
You could hook the pressure switch/relay to the fuel stop solenoid and shut off the engine . Downside is the engine stops and you are parking right now. Knowing the engine is on fire but still running gives you a few more seconds of options. The engine will continue to run pretty much under water as long as the fuel keeps running.
Thanks for all the input and discussion. I know the configuration of the tank and hoses without a shutoff valve or pressure switch wasn't the ideal product selection, but it was free. After thinking about all of your comments above, I plan to install the cockpit alarm, external horn, and some smoke and heat detectors. Thinking about adding smoke and heat detectors to the basement, refrigerator compartment and the interior.
I'm on the fence about the engine auto shutdown. I agree it would be ideal to pull off the road prior to engine auto-shutdown. Any more thoughts on auto-shutdown?
Because the system needs to be recharged every 2 years, maybe that would be the time to get the plumbing on the tank redone to add a pressure switch and a cutoff valve so the lines can be reinstalled more gracefully?
Only the race systems needs to be re certified every few years. The common check is to unhook the bottle and give it a shake test. It should feel as tho it has some fluid inside, no rock solid.
FWIW any of the AFFF systems are water based and will freeze.
The auto shut down seems like a good idea. Reality is that all those behind you are well aware of the fire before you are and will give enough room . IMHO.
Good to know! I saw a couple of youtube videos where the tank is mounted in the engine compartment. Seems like a plus to mount it inside the coach from a freeze protection point of view.
Also good to know. Thanks!
An automatic shutdown can be a good idea as well as a bad one too. Consider driving down a freeway and the coach shuts down due to a fire while you are in the middle lane of the road. Now you must exit the coach onto the highway. Just cause there is a fire going on, do you think the motorists are going to all stop in all lanes or look for ways to go around you? Now here you are in the middle of road, trying to get out of the coach with cars flying seriously close to you. Better off with an alarm where you can steer the coach to side of the road and escape safely. Automatic shut offs are great for boats where you have lots more room.
Bob
I have had all three of my foam units either have been mounted of the engine or in compartments for over ten years now. We have been in very cold weather and never had a freeze up. Last year, we had all three tanks removed and refilled. It was exciting to see these units in action as we discharged them outside the coach for a refill.
Bob
Great comments about automatic shutdown. I did note the item on the link I posted addresses the issue via:
Override switch for restart or control of auto-shutdownThis would appear to address the "middle lane of the expressway" concern which would certainly be real!
Maybe the aircraft and commercial bus units have some sort of antifreeze solutiion. That would make sense as frozen stuff wont eject. Check the man and get back to us. The racer units have a warning about freezing.
Great point about freezing. When we refilled our foam units for their first recharge, the agent did include a chemical to prevent freezing. I had never in the first five years of use in our coach finding these units freezing up. I am coming up to my next five year cycle in a few months - equalling a total now of ten years our foam system has been in our coach. Never a problem with them and I found my units similar to the ones we used in our buses. I think since these units are never exposed directly to cold windy nights and tucked up high enough from the ground, they do not freeze up. Naturally the foam unit in the hydro hot cabinet is keep toasty warm with the hydro hot running.
Bob
No manual came with the unit but here's an email convo with the Amazon vendor:
[Mark]: Can this unit be mounted where it is exposed to freezing temperatures? Will it still work below freezing?
[Vendor]: Yes, there is room in the container for freezing expansion. The foam inside turns slushy when it is exposed to freezing temperatures. Heat of engine running will warm it up and it will thaw. The unit will deploy once the ambient temperature near the heads reach 286 degrees.[Mark]: For 24/7 protection should it be kept from freezing?
[Vendor]: Yes