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