Engine/Generator Bay Operating Temperatures

[gulfquest2]

After reading the fire stories recently posted here, I have become
much more aware of my fire extinguisher status onboard. After
servicing my factory ABC units, I thought about installing automatic
units in both the engine bay and the generator bay.

Does anyone have an idea of the temperature ranges in these bays under
worst case scenarios (short of fire, that is...)? The automatic units
I have are preset to go off at 212 degrees Fahrenheit and I am
concerned that the presets are too low especially when driving in the
Southwest in summertime. Doees anybody have any ideas?

Allen & Conny Cranford
'00 43LXi, "Lone Wolf"
Tampa Bay, FL

[Gary Smith]

Allen,
Take a look at the RV fire suppression system shown on
http://www.rvsafetysystems.com/index.htm.

Gary
SOB

[Pete Masterson]

Since the EGT gauge often reads 300 to 400 degrees, the exhaust system probably gets well above 212 much of the time.

I note that I have a couple of fire sensors in my engine compartment -- and one, near where the exhaust pipe passes by goes off if the engine is simply warmed up. A previous owner disconnected it. The dealer re-connected it just before I bought the coach --- and it went off during our test drive. When I replaced the radiator core, the shop (unknown to me) reconnected it. It went off while I was on the freeway heading home. (One that's on the other side of the engine causes no headaches, if it's working.) I must say having a light come on up front reading "engine fire" is not very comforting!

Well, lets just say too, I'm not very impressed with temperature sensors and I sure wouldn't trust one to set off a fire extinguisher with all the resultant mess it would make -- at least not without a fair number of tests to ensure that it only went off when it was -really- necessary. So, start out with some temperature sensors or use an IR thermometer to try to get some reasonable vaules for various places in the engine compartment. Then install the sensors (but not the extinguishers) and continue testing. Once you're satisfied that the extinguishers aren't going to discharge unexpectedly, then it might be worthwhile for peace of mind.*

It occurs to me that fires raise the temperature very quickly -- so something above 500 or 600 degrees ought to be more appropriate than something around 200 where the exhaust system can easily exceed that level.

None the less, I note that my operating manual suggest "concern" if the EGT gets up to 1200 degrees -- which suggests that even 800 or more might be "normal" (although I've never seen it above around 550-600 while climbing I-70 over 10,000 ft. in Colorado). How much cooler the exhaust is once it gets past the EGT sensor is something I'm not sure about.

*It's also a question of just how common engine fires are... They do happen on occasion -- and I've seen one or two on the road in the Bay Area -- but there are some 5 million automobile trips per day in the SF area, so one or two engine fires observed over a 30+ year period suggests that it's pretty rare. And I've never seen a bus with an engine fire.

Pete Masterson

'95 Blue Bird Wanderlodge WBDA 42

El Sobrante CA

"aeonix1@mac.com"

On Feb 20, 2008, at 1:05 PM, gulfquest2 wrote:

After reading the fire stories recently posted here, I have become 

much more aware of my fire extinguisher status onboard.  After 

servicing my factory ABC units, I thought about installing automatic 

units in both the engine bay and the generator bay.  

Does anyone have an idea of the temperature ranges in these bays under 

worst case scenarios (short of fire, that is...)?  The automatic units 

I have are preset to go off at 212 degrees Fahrenheit and I am 

concerned that the presets are too low especially when driving in the 

Southwest in summertime.  Doees anybody have any ideas?

Allen & Conny Cranford

'00 43LXi, "Lone Wolf" 

Tampa Bay, FL

[Ryan Wright]

I, too, have thought about onboard / pre-routed fire extinguisher
systems. However, I don't think I'd want an automatic unit. A manually
activated system would be preferred. That way, one could verify a fire
was in progress before unleashing the extinguishing compound.

Granted, you can grab your own extinguisher and run back there, but if
you get an alarm at 70mph and see smoke in your rear-view camera, you
could hit the "extinguish" button and get a head-start on fighting it
- or simply give you more time to get stopped and get out. On the
other hand, if you just get an alarm but don't see any source of
flame, you can hold off on activating the system until you've verified
there really is a fire in progress. I'd imagine that would save the
hassle and expense of an automatic system screwing up.

I don't know a lot about engine fires, but I'd imagine water is
effective. Might be a neat idea to route your water pump through
nozzles into the engine bay. Depending on where and how you aimed
them, they may be effective in a fire without making a mess or
damaging anything if activated accidentally.

-Ryan
'86 PT-40 8V92

On 2/20/08, gulfquest2 wrote:
>
> After reading the fire stories recently posted here, I have become
> much more aware of my fire extinguisher status onboard. After
> servicing my factory ABC units, I thought about installing automatic
> units in both the engine bay and the generator bay.
>
> Does anyone have an idea of the temperature ranges in these bays under
> worst case scenarios (short of fire, that is...)? The automatic units
> I have are preset to go off at 212 degrees Fahrenheit and I am
> concerned that the presets are too low especially when driving in the
> Southwest in summertime. Doees anybody have any ideas?
>
> Allen & Conny Cranford
> '00 43LXi, "Lone Wolf"
> Tampa Bay, FL

[Pete Masterson]

Since an engine fire is likely to involve grease, oil, and fuel, water will tend to spread the fire (as these materials float on water). Dry powder, Halon, CO2 or other chemical extinguishers will smother the fire (cut off the air supply) and are preferred. 

Pete Masterson

'95 Blue Bird Wanderlodge WBDA 42

El Sobrante CA

"aeonix1@mac.com"

On Feb 21, 2008, at 11:11 AM, Ryan Wright wrote:

<snip>

I don't know a lot about engine fires, but I'd imagine water is

effective. Might be a neat idea to route your water pump through

nozzles into the engine bay. Depending on where and how you aimed

them, they may be effective in a fire without making a mess or

damaging anything if activated accidentally.

<snip>

[Ryan Wright]

Which basically leaves dry powder. I was going to mention halon or CO2
but I can't see them being the least bit effective - you'd have to
shut the engine down and come to a complete stop before activating the
system. Otherwise, there's too much air being pulled through there.

-Ryan

On 2/21/08, Pete Masterson wrote:
>
>
> Since an engine fire is likely to involve grease, oil, and fuel, water will
tend to spread the fire (as these materials float on water). Dry powder, Halon,
CO2 or other chemical extinguishers will smother the fire (cut off the air
supply) and are preferred.
>

[Gary Smith]

Better yet, a foam. Look for Cold Fire (a product). Take a look at the RV
fire suppression system shown on http://www.rvsafetysystems.com.
Gary
----- Original Message -----
From: "Ryan Wright"
To:
Sent: Thursday, February 21, 2008 7:27 PM
Subject: Re: [WanderlodgeForum] Engine/Generator Bay Operating Temperatures


> Which basically leaves dry powder. I was going to mention halon or CO2
> but I can't see them being the least bit effective - you'd have to
> shut the engine down and come to a complete stop before activating the
> system. Otherwise, there's too much air being pulled through there.
>
> -Ryan
>
> On 2/21/08, Pete Masterson wrote:
>>
>>
>> Since an engine fire is likely to involve grease, oil, and fuel, water
>> will tend to spread the fire (as these materials float on water). Dry
>> powder, Halon, CO2 or other chemical extinguishers will smother the fire
>> (cut off the air supply) and are preferred.
>>
>
> ----------------------------------------------------
> This message has been processed by Firetrust Benign.
>
>
>
> E-mail message checked by Spyware Doctor (5.5.0.178)
> Database version: 5.09260
> http://www.pctools.com/spyware-doctor/
>

[Pete Masterson]

Probably true. I'd take a look at aircraft fire suppression systems to see what they use, since such systems work with a _lot_ of airflow.

OTOH, I'm not convinced that an engine fire is all that likely. Some decent sensors should be sufficient. It's a balance of the cost of the event vs. the chance that it would happen. Of course, chances for an individual are 100% or 0% and none of us want to be in the 100% group. 

Careful inspection of the vehicle and systems may actually be a better way to avoid problems. It might be more cost effective, for example, to spend the money on a new radiator core (thereby avoiding an overheating incident that leads to a fire) rather than spending the money on a fire suppression system. 

Blue Birds are pretty safe vehicles. Since they're all (or mostly) steel, the chance of the fiberglas burning (which it does with a vengeance, once started) isn't an issue. I saw photos a year or two back of a 'bird that had an exhaust fire. (The coach was for sale on eBay as a salvage vehicle, as I recall.) Serious damage, to be sure, but one that appeared repairable by a dedicated owner/builder -- but I'm sure the insurance company didn't appreciate paying for the loss. I imagine that the vehicle was "totaled" since the cost of repair was probably more than the vehicle was worth -- but that's an insurance determination -- not an issue of practicality. (I'm sure one of the bus nuts that would do a home-conversion might have found that coach a great starting point for a half-done conversion.)

Pete Masterson

'95 Blue Bird Wanderlodge WBDA 42

El Sobrante CA

"aeonix1@mac.com"

On Feb 21, 2008, at 4:27 PM, Ryan Wright wrote:

Which basically leaves dry powder. I was going to mention halon or CO2

but I can't see them being the least bit effective - you'd have to

shut the engine down and come to a complete stop before activating the

system. Otherwise, there's too much air being pulled through there.

-Ryan

On 2/21/08, Pete Masterson <"aeonix1@mac.com"> wrote:

 Since an engine fire is likely to involve grease, oil, and fuel, water will tend to spread the fire (as these materials float on water). Dry powder, Halon, CO2 or other chemical extinguishers will smother the fire (cut off the air supply) and are preferred.

Yahoo! Groups Links

<*> To visit your group on the web, go to:

    http://groups.yahoo.com/group/WanderlodgeForum/

<*> Your email settings:

    Individual Email | Traditional

<*> To change settings online go to:

    http://groups.yahoo.com/group/WanderlodgeForum/join

    (Yahoo! ID required)

<*> To change settings via email:

    "WanderlodgeForum-digest@yahoogroups.com" 

    "WanderlodgeForum-fullfeatured@yahoogroups.com"

<*> To unsubscribe from this group, send an email to:

    "WanderlodgeForum-unsubscribe@yahoogroups.com"

<*> Your use of Yahoo! Groups is subject to:

    http://docs.yahoo.com/info/terms/

[Gregory OConnor]

It may be a good Idea to study the best way to open the engine bay
while there is a fire inside or where to chop at it for it to fall
off (my 94pt is fiberglass door) The locks and linkage may not work
after some flames and heat distort them. Water can then be used to
hose the insulation under the skin. I have put engine fires out
with water even used a bucket and sand.


GregoryO'Connor
94ptRomolandCa


--- In WanderlodgeForum@yahoogroups.com, "Ryan Wright"
wrote:
>
> I, too, have thought about onboard / pre-routed fire extinguisher
> systems. However, I don't think I'd want an automatic unit. A
manually
> activated system would be preferred. That way, one could verify a
fire
> was in progress before unleashing the extinguishing compound.
>
> Granted, you can grab your own extinguisher and run back there,
but if
> you get an alarm at 70mph and see smoke in your rear-view camera,
you
> could hit the "extinguish" button and get a head-start on fighting
it
> - or simply give you more time to get stopped and get out. On the
> other hand, if you just get an alarm but don't see any source of
> flame, you can hold off on activating the system until you've
verified
> there really is a fire in progress. I'd imagine that would save the
> hassle and expense of an automatic system screwing up.
>
> I don't know a lot about engine fires, but I'd imagine water is
> effective. Might be a neat idea to route your water pump through
> nozzles into the engine bay. Depending on where and how you aimed
> them, they may be effective in a fire without making a mess or
> damaging anything if activated accidentally.
>
> -Ryan
> '86 PT-40 8V92
>
> On 2/20/08, gulfquest2 wrote:
> >
> > After reading the fire stories recently posted here, I have
become
> > much more aware of my fire extinguisher status onboard. After
> > servicing my factory ABC units, I thought about installing
automatic
> > units in both the engine bay and the generator bay.
> >
> > Does anyone have an idea of the temperature ranges in these
bays under
> > worst case scenarios (short of fire, that is...)? The
automatic units
> > I have are preset to go off at 212 degrees Fahrenheit and I am
> > concerned that the presets are too low especially when driving
in the
> > Southwest in summertime. Doees anybody have any ideas?
> >
> > Allen & Conny Cranford
> > '00 43LXi, "Lone Wolf"
> > Tampa Bay, FL
>

[Ryan Wright]

On 2/21/08, Pete Masterson wrote:
>
> OTOH, I'm not convinced that an engine fire is all that likely. Some decent
sensors
> should be sufficient. It's a balance of the cost of the event vs. the chance
that it would
> happen. Of course, chances for an individual are 100% or 0% and none of us
want to be
> in the 100% group.

Right. You know I was thinking more about this, too, and really the
only purpose I can see for a fire suppression system back there is to
give one more time to get out. Once the engine's on fire, it's almost
preferable if the thing burns to the ground. If you really think about
it, who wants a fire damaged coach? Sure your insurance will pay to
fix it but you've just destroyed the resale value. I know I wouldn't
want a coach that had been on fire at one point in time. The smell may
linger for years and major repairs often come with annoying problems
due to repair shops cutting corners or general lack of knowledge.

-Ryan