Bump in the night...

Came back from dinner the other night and found a fire engine and two fire boats at the dock behind us. A 44' Silverton had developed an engine fuel leak, (gasoline) the firemen went aboard and pumped foam into the engine room. At 11:45 our boat took a hit on the swim step as the boat was towed out. No damage but it did startle the Sicilian. As usual I heard nothin' and felt nothin'. Just wonderin' how deleterious the foam is to mechanical stuff.

Hmm, don't know but I'll bet it's less deleterious than fire.

As said... beats the alternative. If I recall from training oh so many years ago... it was mildly corrosive.

Oh its going to be a big repair bill alright! Expect everything metal to corrode to some amount over a long time.

The old protein foam (low and high expansion) was nasty stuff, stunk the high heaven and was very corrosive but the new AFFF (aqueous film forming foam) is more like soap and no more corrosive then the water used in the solution. AFFF was developed by the US Navy for several reasons not the least of them was to not to destroy jet engines when fighting a hot section fire or destroy the mechanical's of a ship fighting a fire.

I was able to use it by the tank full when I was a USAF Firefighter in the late 70's early 80's. Would not want it sprayed in the guts of my boat but as stated beats the alternative.

Not much of the high expansion foam used any more last use was runway foaming now really only used in high cost/loss protection systems like flight deck and hanger deluged systems and they use a very expensive (for obvious reasons)
synthetic HE foam. I doubt that was used by the fire trucks in this case as the cost benefit ratio would make no sense to even carry it.

Been a bunch of years away from it, but that's my take, bumps in the night wake me the heck up.

That's good to know....I know some of the oler boats still have the halon fire bottles and I have been told this is corrosive?

Alaskan Sea-Duction said:

That's good to know....I know some of the oler boats still have the halon fire bottles and I have been told this is corrosive?

Click to expand...

I dont ever remember hearing Halon 1301 as being corrosive. On the contrary, its only used on very expensive equipment where prevention from damage beyond the fire is paramount. Big $$$$$ and leaves no residue. There is another variant of Halon that might be. We NEVER used anything but 1301 in the power plant.

Yes, Halon is expensive. It is no longer used as it is Ozone layer depleting. In the US, if you have an existing system with Halon in it you can keep it until it goes off, then you have to replace it with something else. If you are in the EU (or move equipment to the EU) Halon is not allowed at all (even if it is the existing fire protection system).

If you don't see the Halon system actually discharge, there is no residual evidence that the Halon was discharged on the equipment, other than the low pressure warnings on the supply bottles.

Most systems today are CO2 or water mist.

Halon 1301 and Halon 1211 are/were wonderful fire fighting agents. They are among the banned gasses per the EPA Jan. 1 1994 except for use in Aircraft firefighting systems.

Both worked great with some differences. The flood systems use 1301 as it is self discharging from its own pressure and is lighter and works better inside an enclosed space.

1211 is heaver so it carriers further and is more persistent in an outdoor fire such as may be found in a aircraft engine on the flight deck, it does require a propellant to give it some throw distance from the extinguisher so some of the weight is not agent but a propellant. This is the gas used in handheld extinguishers.

Halon is NOT corrosive and not a hazard to human life even in an enclosed space, it is used in computer and electronic facility's to prevent unnecessary damage to millions of dollars worth of equipment when discharged.

They work by disrupting the chemical chain reaction of the fire and are the reason that the old fire triangle is now a tetrahedron.

Halon 1211 and 1301 is no longer available and systems can only be serviced using the existing gas inside them. No refilling as they are considered a ozone depleting gas. they have been replaced with a less effective gas requiring more agent and a much greater cost. The only 1:1 replacement gas I know of is AF11E there is another product called Halotron 1 that is somewhat of a replacement but not using the same systems you have now.

Halon is still used in aircraft extinguishers.

Keep your FireBoy halon systems protected, replacement cost is a shocker.



Regards,

Actually the AFFF has anti-corrosion chemicals in it. It is more like soap and does dilute and cleans up well with just water. It was just hitting the market the last time I attended a marine fire fighting school. Halon has always been my first choice, wish it did not destroy the ozone layer. I wonder about that because it like C02 was heavier than air. Go figure.
dan

SCOTTEDAVIS said:

... not a hazard to human life even in an enclosed space...

Click to expand...

This is not always true. If the concentration of 1301 is at the recommended amount (I think about 4%) than it is effective against the fire and safe for humans. If the concentration is too high it is hazardous to humans. The Halon system should be sized for the application so that the concentrations are correct. However, it is difficult to ensure that all protected areas have a uniform concentration. There can be places that have a higher than recommended concentration depending on how the gas flows and collects. In most cases the Halon system is designed to initially flood the protected area and then maintain the Halon concentration for many minutes (system contains fast and slow discharge bottles).

From Wikipedia:

Human exposure to Halon 1301 can be toxic, affecting the central nervous system and other bodily functions.

and

It is considered good practice to avoid all unnecessary exposure to Halon 1301, and to limit exposures to concentrations of 7 percent and below to 15 minutes. Exposure to Halon 1301 in the 5 to 7 percent range produces little, if any, noticeable effect. At levels between 7 and 10 percent, mild central nervous system effects such as dizziness and tingling in the extremities have been reported.[3] In practice, the operators of many Halon 1301 total flooding systems evacuate the space on impending agent discharge.

I the situation I worked in, the Halon was discharged into an enclosed area that contained people. If the Halon discharged someone had to go into the affected area and ensure that there were no people overcome and left in the area.

ssobol said:

This is not always true. If the concentration of 1301 is at the recommended amount (I think about 4%) than it is effective against the fire and safe for humans. .

Click to expand...

"Halon is a liquefied, compressed gas that stops the spread of fire by chemically disrupting combustion. Halon 1211 (a liquid streaming agent) and Halon 1301 (a gaseous flooding agent) leave no residue and are remarkably safe for human exposure."

What is Halon? How does Halon Work? Is Halon legal? Is Halon Safe?

Everything in moderation.

When the systems discharge you leave, I went to work. Air-pack was not required to be in use but you had to have it on.

Many taxpayer dollars were spent on my training on installed and portable Halon systems. I received the certifications and the T-shirt

I had my Halon fixed engine room system and two hand held extinguishers serviced and refilled in the Dominican Republic in February. Evidently it does not deplete the ozone layer down there. Cost $120.00.
dan

I just had our Halon system, its manual pull, and 7 portables (4 were from our house) "serviced" too -- for $120 -- in Annapolis.

"Service" meant checking the weights and connections, though; no re-charging required or involved.

-Chris

Very interesting thread. Much of what is being said is true and some is outright wrong. I'll set the record straight when I see an outright lie that matters. Halons are called clean agents for a reason........ They are mostly all toxic in higher than say 7% concentrations. There are replacements for 1301 that do not eat ozone such as FM200. You will need to change equipment to use. U.S. signed Montreal Protocol and Halon 1301 can be used/reused but is no longer made. In other countries that did not sign the treaty it is still made and available. Protien foam and AFFF concentrate are both corrosive. Haven't seen protein foam in many years. Fire department most likely used a 1, 3, or 6% AFFF, good wash down with some salt away and engine room corrosion will be OK ...except the flooding is not good.

From the AFFF MSDS sheet: PH of 7-8.5 no longer corrosive. A corrosive inhibitor changing ph characteristics is now part of the chemicals in AFFF.

Halon is not available in St. Lucia or Grenada

Good to know and it would appear i was wrong about Halon...

Alaskan Sea-Duction: I really hate to cause an argument but you may be seriously mistaken in stating that you were "wrong" about Halon. Please read your earlier post. You probably did hear from someone that it was corrosive.

dan

ranger42c said:

"Service" meant checking the weights and connections, though; no re-charging required or involved.

Click to expand...

Yes weight is important (not sure what "connections" the were looking at), but I believe there's also a small explosive "cap" that has to work and is not testable. So you really have no confidence that it will deploy.

refugio said:

Yes weight is important (not sure what "connections" the were looking at), but I believe there's also a small explosive "cap" that has to work and is not testable. So you really have no confidence that it will deploy.

Click to expand...

Connections = automatic engine/genset/blower shut off (I think), and the manual pull. Tested while the bottle itself was out in the cockpit getting weighed.

-Chris

refugio said:

Yes weight is important (not sure what "connections" the were looking at), but I believe there's also a small explosive "cap" that has to work and is not testable. So you really have no confidence that it will deploy.

Click to expand...

In the old days one Halon System manufacturer did have an explosive squib and it was used on sphere shaped containers. Not recollecting any marine systems with pyrotechnic release. Marine systems of the day had electric valves (solenoids).

We had a much older twin engine Tolly that was fitted with an anti-siphon valve at the fuel tank. The valve would shut off the flow of fuel while the engines were not running. Does Silverton not fit their gas powered boats with an anti-siphon valve?

Almost all new fire suppression systems today use heptofleuropropane FM200.

It is breathable sorta, but fire can't live in it, and it wont corrode anything and has no residue.

You can't barbecue on it when done since it's propane

If you pry apart each part of a propane molecule and put a carbon atom, you get FM200.

stu

ancora said:

We had a much older twin engine Tolly that was fitted with an anti-siphon valve at the fuel tank. The valve would shut off the flow of fuel while the engines were not running. Does Silverton not fit their gas powered boats with an anti-siphon valve?

Click to expand...

This was done on carburetor equipped gas engines to prevent gas from flooding the bilge if the float stuck . This was a common problem when fuel sat for a long time and evaporated in the fuel bowl causing varnish and gunk.

Worked OK unless they got stuck and did not open causing a low or no fuel condition that was often overlooked when troubleshooting (don't ask me how I know).

Diesel and other fuel injection engines do not want or need this appendage.

Does anyone know who in the Clear Lake Tx area can test/certify my halon system? I'm sure it has been many years since checked. There is no card in the little pouch hanging on the system. Thanks.

Kevin

Any fuel tank regardless of engine type could benefit from anti siphon valve at the tank.
Say you fuel line broke, and the end flopped down coming from a fuel tank. It is going to siphon out diesel or gasoline regardless of fuel injected or carbureted.

The down side of anti siphon valves, they jam with debris, crud in the tanks. Your pumps just may randomly quit when it gets stuck at that valve, Then you go to investigate and find nothing wrong, because when you turn off and open the line, the crud drains back down into the tank.
i got rid of my anti siphon valves. My fuel lines are all above the tank top and secured in place. Only issue is if the large filter developed a leak it could drain out fuel.

I was thinking an expensive solution, an electric valve that opens when the electric fuel pump runs.

Otherwise, manually turn off a valve so it cant drain fuel .

ulysses said:

Alaskan Sea-Duction: I really hate to cause an argument but you may be seriously mistaken in stating that you were "wrong" about Halon. Please read your earlier post. You probably did hear from someone that it was corrosive.

dan

Click to expand...

It's not every day you see someone calling out another for NOT being wrong.

tallswede said:

Does anyone know who in the Clear Lake Tx area can test/certify my halon system? I'm sure it has been many years since checked. There is no card in the little pouch hanging on the system. Thanks.

Kevin

Click to expand...

The guy I bought my boat from said there wasnt anyone that would deal with halon. If you do hear of someone I would be interested. I have a big ole bottle of the stuff.