Safety of gas tanks

[Guest]

I am opening up a question to the gt40 audience. What is 'explosafe'? how does it prevent explosions. Has anyone experienced fuel tank or engine fires and lived to tell about it? What is the most effective fire extinguishing system for the GT40?null [email protected]

 

[Robert Logan]

Jake,

Explosivesafe is an open cell foam that occupies about 5% of the capacity of the tank. It is used in the aviation world ,I believe, and reduces the sloshing of the fuel.

How safe it is , is dependant on your level of synosism. I believe that the introduction of the stuff in racing was to reduce the movement of the fuel and therefore the "free surface effect" of this large weight. Petrol as well as all other fuels have a rating (name escapes me) which indicates the fuel / air mixture that is explosive. The ratio for pump gas is I think 40 which tells us that 40 parts of air to 1 part of gas and there is a dangerous situation. This clearly shows that the problem is the escape of fuel into the atmosphere and this is what we need to stop. The explosafe would not stop a ruptured tank from releasing its load.

On the other hand a "fuel cell" would if correctly designed and manufactured. These are special rubber style bladders which are inclosed in usually aluminium boxes. They are fitted into all REAL race cars that compete in REAL events and even these are fitted with the explosive safe foam (for free surface effect reasons, me thinks!!!).

As regards fire extuinguishers 4.4 ltrs is what is recommended in top class race cars with an electric or manual activation. We fit both types as options to our road cars and mandatory to our race cars.

Unfortunately I have had one of our cars catch fire after an accident in a race are luckily there were loads of people arround to put it out with little damage. That was the last time one of our cars competed without a full "bomb" style extuinguisher.

Best wishes,

Robert

 

[Howard Jones]

I have installed a 5lb pull system in my car with one discharge under the dash pointed at the drivers lap and the other in the engine bay more or less pointed up at the carb/ fuel pumps area. The whole system cost less than $450 dollars and I feel a lot better for it considering the value of the completed car will be more than $50,000. Of course there is the overwelming safety reasons. I think these cars are just too hot, surounded by fuel and with fuel lines running all over the place along with that they are very hard to get into and OUT of in a hurry not to install a fire system. I intend to get one of those small halon hand-helds also and mount it in front of the other seat for small carb fires if the need presents itself. Think long and hard before you decide not to install a fire system.

[ March 09, 2003: Message edited by: Howard Jones ]

 

I've had three fires racing my Lotus Europa in SCCA racing. I can't say enough about fire safty! Do anything and everything you can to protect yourself!

 

[Jim Glickenhaus]

SPA makes several good systems. They are in Indy as well as UK. They will even demo one for you to show spray pattern. I have a system in all of my cars. There are different systems for carbs and FI.

 

[Mark Worthington]

To respond to the original question, I'll quote from Explosafe's web site:

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>The Explosafe® System is based on a matrix of expanded aluminum alloy foil, slit and expanded to form a mesh of hexagonally-shaped openings. When layered, the mesh results in an open-celled bulk batt which can be cut to sizes and shapes to fit any container/fuel tank.<HR></BLOCKQUOTE>

I believe the GTD tanks were routinely fitted with Explosafe. I am bringing my fuel tanks to these guys on Tuesday for an evaluation of what they can do to retrofit the tanks as full foam-filled, bladder protected fuel cells. Note that, unlike Explosafe, the foam used in racing fuel cells degrades over time and that the design life of a fuel cell is five years.

With that said, I hope you'll agree that this thread won't necessarily be hijacked if we expand the discussion from fuel tank safety to fuel system safety and fire safety. This topic is of high priority to me, because I have a genuine fear of burning to death in the car of my dreams. I believe that one of the "weak links" in the GT40 fuel system, from a safety perspective, is that, in the event of a severe side impact, the tanks (or cells, even) can be compressed which subjects the entire tank and filler-tube system to a hydraulic pressure spike, and that the system will tend to fail at the filler tube. I have been told that it is a good idea to reinforce (i.e., panel and seal) the chassis inboard of the filler tubes to protect the cockpit and occupants in the event of a hydraulic rupture of the filler tubes so that fuel sprays away from the car and not into the interior. I would be very interested in seeing some pictures of how this has been done, preferably in a RF. I would also be interested in hearing other safety issues related to the fuel system and how they might be mitigated during the construction process.

 

[Mark Worthington]

Thanks, Jim. The restoration shop that's going to look at my fuel tanks was recommended by ATL.

 

[David Morton]

To reply to Robert,
This Explosive safe or whatever its name is, is not used in aviation. GTD used it in their alloy tanks and I think the whole set up in GTD cars , and probably some others as well is a sad excuse for properly made bag/foam/kevlar tanks that are available during building a car. I dont know what the answer is except taking the sills off again
and replacing them. Who ever comes up with a sensibly priced option can have my order straight away. There was previous discussion
about side impact protection and fire extinguishers but somebody lept in and started talking about drop down masks and rubbished it. In that discussion I extolled the virtue of Halon extinguishers and nothing yet has replaced the fire knock down of Halon. I will keep the 7.5kg bromochloro difluoromethane system in my car no matter what, and if I need to have something else it will be a dry powder hand held. I live in fear of fires and I've been there, done it,
and the tee shirt got singed.
Dave M

 

[Jim Glickenhaus]

Mark
ATL and Fuel safe will make new kevlar cells to fit that are much safer than the ones you describe. They can be fitted with roll over check valves and robust fuel lines. An onboard system such as a SPA 4.4 liter is also a good idea. They can and will advise on which one is best for you. On the track ALWAYS wear a good suit and baclava. Use a flame arrestor/ Air filter. Mount a kill switch. Enjoy.
Best
Jim

 

[Robert Logan]

Mark,

I have contacted ATL and had a price of US$ 5500 for a tank (hopefully two) but this is way to high for me. The internal panel is a great idea and one we have considered but our race car will have a full safety fuel cell inside the car inside double skinns. More on that later.

Best wishes,

Robert

 

[Mark Worthington]

Robert,

When I spoke with ATL they directed me to a local restoration shop with whom they affiliate; they said they would prefer to supply the bladder bits and leave the fabrication to someone else. I'll post what I learn about this, but I fear it will be seriously expensive.

I would be very interested in hearing and seeing more in regards to how the interior was protected from the filler tube area.