Engine shutdown on extinguisher discharge (ESRS)

[Express 390]

How suppression gases work is complicated and I have not researched it. I have heard that bulky CO2 systems deprive a fire of O2 but Halon sucks the heat out of it. Originally thought to be safer for crew members, Halon had its own problems. A distinction is made between gas and diesel engines. I had a depleted factory option Halon bottle and found that the only replacement that would fit in the space available was FM-200. I don't know what effect the discharge of a standard powder extinguisher would have had but it would have been messy!

Halon suffocates the flame

 

[Arminius]

Wiring change: As to the SPDT override switch behind the dash; center terminal is attached to the pressure switch-green/white wire terminal on the ESRS box; one side terminal is attached to the ground connection on the ESRS box; the other (normal position) has the free lead from the green LED. This way the green LED will go out when the extinguisher discharges and the motor quits. Throwing the override switch will start the engine but not re-illuminate the light.

 

[Arminius]

I think I should clarify in case the lack of a display/override switch and the substitution of a concealed SPDT switch confused. If you are confused, you should definitely ignore the SeaRay green light and install the ESRS manufacturer's display/override switch. The simplest way is to use a holesaw to bore a mounting spot near the box on the dash. An alternate spot might be on the fore/aft bulkhead I used to secure the box. Another alternative might be to extend the three factory display leads and position the display/override switch just aft of the throttle/shift lever.

 

[NotHerDecision]

Halon suffocates the flame

Express 390

I haven’t really been keeping up with the thread but I’ve now noticed your comments a couple of time regarding Halon. Halon breaks the chain reaction of a fire. Typically to extinguish a fire you need to remove something from the ‘fire triangle’ ignition, oxygen, fuel. But halon adds a fourth component and breaks the triangle.

You describe it as removing the oxygen or suffocating the fire but that is what CO2 extinguishers do,not halon. This is why halon is safe for humans.

Just want clarify this because folks tend to go back and read these threads many times in the future and CSR tends to be a reliable place for information.

josh

 

[Arminius]

Clarification: For me this is a winter hobby upgrading a lake bowrider without a potentially entrapping cabin. For others it could be a deadly serious business subject to Coast Guard inspection. 34 divers were burned to death on the MV Conception on Labor Day, a vessel that reportedly had Halon suppression in its engine compartment. The report on the kitchen equipment and other potential causes is not yet in. If maritime regulation resembles the building code, my project was not compliant and one questions the original SeaRay option. The Code states that the installation instructions of a device are incorporated by reference into the Code. Failure to follow the instructions is a Code violation. The instructions on the Halon substitute bottle did not mandate an ESRS box for a gas engine. If the blower did not dissipate the gas, maybe it would kill the mixture sensitive gas engine. The ESRS box is mandated for diesel installations because the diesel is resilient and could continue running despite aspirating Halon. Halon is converted to phosgene at high temperatures and the exhaust would be emitting WW1 poison gas. While I did this at home, any serious installation might be better left to professionals. The problem with the original SeaRay option is that the boat operation manual requires the blower to be in operation at all times and this would suck out any suppression gas and fan the flames!

 

[Express 390]

Express 390

I haven’t really been keeping up with the thread but I’ve now noticed your comments a couple of time regarding Halon. Halon breaks the chain reaction of a fire. Typically to extinguish a fire you need to remove something from the ‘fire triangle’ ignition, oxygen, fuel. But halon adds a fourth component and breaks the triangle.

You describe it as removing the oxygen or suffocating the fire but that is what CO2 extinguishers do,not halon. This is why halon is safe for humans.

Just want clarify this because folks tend to go back and read these threads many times in the future and CSR tends to be a reliable place for information.

josh

I have to say you are right I looked it up prior i got some bad info Thanks, i should of researched before the quick post

 

[NotHerDecision]

That’s why these forums are so great!

 

[Arminius]

I installed a Seafire display/override switch which matches the ESRS box described above, including color coded wiring. The manual override switch has been removed.

 

[Nater Potater]

...I also read a few comments that state that a crimp connector on a 14AWG wire should be able to withstand a pulling apart force of 30 lbs.

Coming into this kind of late, but there are regs set by NASA for such matters. As NASA-STD 8739.4 reads "...the tensile strength of the crimp connection shall be no less than 60 percent of the tensile strength of the wire." For 14 gauge copper, that's 65 pounds for the wire, with a pullout of 39 pounds or greater from the crimp. If the pullout is anything less, you don't have enough compressive force on the junction to properly break down any native oxide, leading to the potential for high resistance and heat buildup. Bad!
If you can find them, the double-crimp connectors have a second, thin barrel that grabs the wire's insulation to help spread the load in attempts to avoid a hinge point next to the crimp. McMaster-Carr has a limited assortment of such, and the ratcheting crimp pliers. These things are quite expensive, but do a great job at crimping to just the right amount, and will probably outlive most of us.

 

[techmitch]

Coming into this kind of late, but there are regs set by NASA for such matters. As NASA-STD 8739.4 reads "...the tensile strength of the crimp connection shall be no less than 60 percent of the tensile strength of the wire." For 14 gauge copper, that's 65 pounds for the wire, with a pullout of 39 pounds or greater from the crimp. If the pullout is anything less, you don't have enough compressive force on the junction to properly break down any native oxide, leading to the potential for high resistance and heat buildup. Bad!
If you can find them, the double-crimp connectors have a second, thin barrel that grabs the wire's insulation to help spread the load in attempts to avoid a hinge point next to the crimp. McMaster-Carr has a limited assortment of such, and the ratcheting crimp pliers. These things are quite expensive, but do a great job at crimping to just the right amount, and will probably outlive most of us.

"native oxide"... Big fan of the heat shrink crimp connectors with the epoxy sealer of which employs the added support of "spreading the load" not to mention the corrosion protection.

 

[Arminius]

NASA huh? On aerospace, I recall the Army's THAAD theatre defense SAM was a disaster failing test after test. Manufacturer recalled and redesigned it and it became a model of reliability. Aviation Week said electrical junctions had been found to be the weak link and were "eliminated." Soldering is the only "mission critical" way to go.

 

[Nater Potater]

I recall the Army's THAAD theatre defense SAM was a disaster failing test after test.

Last time I checked, a SAM missile didn't live long enough to suffer long-term vibration issues with solder joints.