On Fri, 03 Oct 2008 15:23:29 EDT, you wrote: >Isn't air (especially O2 one of the 3 legs of the fire triangle? Wouldn't it >be better to cut off all the air instead of intriducing more? Curious as I am >always intrigued by Norm's ideas. > >Noel
I was thinking about this too. You are correct about the legs of the fire triangle. One leg is fuel (the boat itself OR the diesel in the fuel tanks - diesel is not flammable, but it certainly is combustible or it wouldn't work as fuel), one is oxygen and one is heat. So when we want to put out a fire we want to cut one or more fire legs off. When we use water to put out a fire, the water cools, and also may act to cut off the oxygen. A CO2 or foam extinguisher or a freon bottle cuts off the oxygen. Fire breaks or non-combustible insulation act to reduce fuel. In the case of an electrical or fuel fire we don't usually use water. Fuel will float on the water and keep burning. But at the same time we don't want to allow the fire more oxygen so it can burn better. It is true that smoke obscures the fire, but that's often (IMHO because I am not an expert on this) because there's not much air there. There will probably also be (with the smoke) some carbon monoxide, which is more dangerous than the smoke. Opening up the engine room to air may make the fire easier to see, but it may also make it flare up and get hotter and more aggressive. It will be a challenge to see whether you can put out a much bigger fire fast enough when you can see it. I have a picture of a man trying to fight a large house fire with a garden hose. At some point the fire will get too big to fight. I would prefer to enclose the fire and cut all ventilation off if possible. We have a freon extinguisher in our engine room, but it is smaller than Norms is. Also with such an extinguishing system, you would not be able to go into the space at all as if the fire didn't have air, neither would a firefighter. > >From: Arild Jensen >Norm a question here. Would it make more sense to suck out the smoke >or bring fresh air into the Engine room full of smoke? > >Pushing air into the compartment would mean some of the smoke might get >pushed into the rest of the boat such as through the open E/R hatch. > >Seems to me that pulling air from the interior of the vessels and >pushing the smoke directly outboard might be more effective. And of >course if there is any toxic components in the smoke, you get it away >from the boat faster. >Arild >Norm of Bandersnatch wrote: > >> I picked up on the fire issue. >>> snip >>To this end I have almost completed fabrication and installation of a >> large vent, 4" x 20", with a automotive radiator fan to blow air into the >> engine room to allow me to enter the space whilst clearing it of most of >> the smoke so can get to the fire. >> Norm > >> S/V Bandersnatch _______________________________________________ Liveaboard mailing list [email protected] To adjust your membership settings over the web http://www.liveaboardnow.org/mailman/listinfo/liveaboard To subscribe send an email to [EMAIL PROTECTED] To unsubscribe send an email to [EMAIL PROTECTED] The archives are at http://www.liveaboardnow.org/pipermail/liveaboard/ To search the archives http://www.mail-archive.com/[email protected] The Mailman Users Guide can be found here http://www.gnu.org/software/mailman/mailman-member/index.html
