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Project SC300 Road Racer: Part 13 - Updating for Proper Fire Safety

by Erik Jacobs

 

Since we were starting to button up our Project SC300, it seemed logical to attack the fire system.

Before we do that, though, let’s take a moment to talk about fire systems. But, even before that, let’s talk about safety standards bodies. As some of you know, there are two major certification organizations when it comes to safety equipment. In the US, the SFI Foundation, Inc. (SFI) is the most commonly known. For those that follow motorsports outside of the US, the FIA is widely recognized. Both the SFI and FIA certify products from manufacturers to various safety standards. We’ll talk more about SFI and FIA in an upcoming safety feature. But, suffice it to say, FIA is an “international” certification, while SFI may or may not be recognized by your sanctioning group if you are outside the US.

At this point in time, there are basically two types of fire systems available for motorsports use: foam and liquified gas. Both types are effective at combating and extinguishing fires, but each has certain pros and cons that you should be aware of before you decide to make a purchase. First, let’s talk about liquified gas systems.

Liquified gas systems involve a compressed liquid that, when the system is opened, rapidly turns into a gas as it leaves the nozzles. This gas is what extinguishes an active fire, usually by depriving the fire of oxygen required to continue combustion, essentially by displacing the oxygen. You are probably familiar with Halon, as it used to be a common material used in fire fighting. Developed jointly by the U.S. Army and Dupont in the 1950s, Halon has been replaced over the years by other compounds, mostly due to Halon’s toxicity as well as its effects to the ozone layer.

Today, within the liquified gas systems, there are two widely used compounds. FE36, also from Dupont, is the SFI-certified compound, and it is not FIA certified. FE36 evaporates almost instantly at ambient temperatures and atmospheric pressure, is much less toxic than Halon, and has no ozone depletion effects. The other compound available is Novec, from 3M. It, too, is non-toxic and has no ozone depletion effects. However, it is a quite slowly evaporating liquid at ambient temperature and atmospheric pressure. It also is certified by the FIA, but not the SFI.

The alternative to the liquified gas systems are the foam systems. You will usually see the designation AFFF, which stands for Aqueous Film Forming Foam. These systems utilize a pressurized liquid that, when released, comes out as a soapy, filmy liquid that coats everything it comes into contact with.

The primary benefit to an AFFF system is prevention from reignition. While a gas system may instantly put out an active fire, a gas system does not stop smoldering nor does it eliminate sources of combustion. AFFF, in contrast, because it coats everything, can prevent sources from causing things to ignite and can cool hot things. While this prevention from reignition is a benefit, it comes with the cost of having to clean the vehicle thoroughly with water after the system is used. AFFF is minimally corrosive, but should be cleaned soon after contact with components.

All fire systems have a 2-year recertification timeline. To maintain their legality, the bottles need to be sent to an authorized facility to get recertified. The recertification process is essentially a refill and an inspection. If the system passes, it receives a new date label and is valid for another two years.

In addition to the recertification process, pressure tests must be done every 5 years. This is a more involved process that validates the structural integrity of the bottle. And, ultimately bottles are timed out after 10 years. At the 10 year mark, a new bottle will need to be purchased. Don’t forget, shipping the bottles around typically involves a hazmat shipping fee. Isn’t racing fun?

OK, now on to our installation. One note before we get started: other than the techniques used in the installation of the system, this article is not recommending any particular product or system type. The correct system for you to use is highly dependent on the rulebook for the series you are participating in, assuming you are subject to the rules of a sanctioning body.

If you think about an on-track emergency, one of the first things that the track safety workers do is to approach the driver to evaluate them. That means that any safety equipment designed for a track safety worker to operate should probably be near the driver. As our external fire system actuator was “incorrectly” mounted on the passenger side, we decided that it was appropriate to move it.

 

Rerouting the pull handle meant that it needed to be detached from the fire bottle’s handle.

Mechanical fire systems generally involve a pull handle that is a lot like a throttle cable. Pulling the handle pulls the metal cable inside the sheath, and that metal cable is attached to the handle of the fire bottle. When the cable is pulled, it pulls in the handle of the fire bottle, which is just like squeezing it. This activates the extinguisher.

 

Tom whips up a quick bracket since the other one won’t work.

The bracket for the passenger side was a flat piece bolted into the A-pillar. We wanted to move the pull over to the driver side right behind the driver’s head. The easiest mounting location would be directly on the roll bar behind the seat. This meant a curved bracket.

 

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Comments
spdracerut
spdracerutlink
Wednesday, January 31, 2018 9:11 AM
Interesting about the 3M Novec fluid. They have different formulations within that product line and some of the fluids are used for direct cooling of electronics as it's a dielectric fluid. Good call on having a nozzle by the turbo; I remember a long time ago, a time attack car burned down because the fire was in the turbo area and they unfortunately had nozzles on either side of it, but not in the turbo area itself.
Crousti
Croustilink
Thursday, February 01, 2018 10:25 AM
The often overlooked problem with the foam extinguishing is that users really need to clean everything. The engine was on while the extinguisher was used ? Well ... now you can disassemble your engine and intake system entirely to clean it. And i mean it; the last time i saw it happen, the guys found foam everywhere (intercooler of course, but also turbo compressor and turbine, head, valvetrain, oil pan, combustion chamber ... the stuff goes everywhere).

And you want to remove the engine to clean the bay anyway because, again, it goes everywhere.
thoraxe
thoraxelink
Thursday, February 01, 2018 12:46 PM
That's a great point, @crousti.

I had actually had a fire in my 240SX way back when. Even a minor engine bay fire did quite a lot of damage. The track workers used chemical extinguishers which are actually quite corrosive.

Not only did we do a full engine-out, but we also replaced all of the brake hard lines just in case. We probably should have replaced the brake and clutch master as well, but they seemed to hold up. If I had to do it again, I'd replace them both.

Also one thing to think about -- if you are going to pull your extinguisher, TURN OFF THE CAR!
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