A Practical Guide to Fire Suppression Systems


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A Practical Guide to Fire Suppression Systems

Whether you spend your weekends racing your car around the local track or exploring the back country in your Jeep, fire safety is a topic that all too often only gets the attention it deserves after a fire incident has occurred. In both competitive and recreational motorsports, an on-board fire suppression system can add precious time for vehicle occupants to make a safe exit and improve the odds of sparing the vehicle from major damage.

So perhaps you have decided that it’s time to outfit your vehicle with a fire suppression system but don’t know where to begin? An internet search for race car fire suppression will return an overwhelming menu of equipment options, from extinguishing agent types to bottle sizes to activation styles and industry approvals.

SPA Technique is one of the leading fire suppression equipment manufacturers in the motorsports industry with a variety of high-quality systems and components to choose from but selecting the system that best fits your needs is a big decision, so let’s start with fire suppression fundamentals.

What is a Fire Suppression System?

An on-board fire suppression system is a collection of components intended for fixed installation in a vehicle which will typically consist of the following items:

  • Storage bottle filled with a specified weight of extinguishing agent.
  • Activation device(s) which trigger release of the bottle contents manually and/or automatically.
  • Spray nozzles specifically designed to produce an optimum spray pattern for the selected extinguishing agent.
  • Tubing, fittings, and mounts to plumb the system from bottle to nozzles.

Keep in mind, the primary purpose of a fire suppression system is to extend the time you have available to exit a burning vehicle. Having an improved chance to save the car should be thought of more as an added benefit.

Equipment Considerations

Before selecting a fire suppression system, it’s important to think about the goals for your installation and the characteristics that are most important to you. Like many things in motorsports, selecting the best fire suppression system for your vehicle is a matter of balancing functionality and performance with physical packaging and budget constraints.

If you are counting ounces on your race car to keep weight to a minimum, racing in extreme cold temperatures, or if your vehicle is loaded with sensitive high-tech electronics, these factors will affect which systems are most appropriate to consider.

Sanctioning Bodies

If you are a racer or competitor, the first place to start is the rulebook for the sanctioning body in which you compete. Many sanctioning bodies will specify requirements for industry approvals, extinguishing agent types, and/or minimum weights of extinguishing agent although this is not always the case. For instance, most off-road racing sanctioning bodies state in their rulebooks simply that “on-board fire suppression systems are strongly encouraged” (handheld fire extinguishers, however, are almost always required). Where specific requirements are not provided or for recreational applications, there is more flexibility in terms of system selection.

Industry Approvals

There are two major safety approval agencies in the world of motorsports that we will come across time and again; US-based SFI and Europe-based FIA. Both organizations set out fire safety test criteria that suppression systems must pass to bear their logos. In general, FIA tests are more rigorous than SFI although this should not imply that one is any less effective than the other.

        
      • SFI 17.1: This standard defines acceptable performance for SFI approved suppression systems (other than Indycar systems which conform to SFI 17.2). Tests primarily consist of igniting a 20” square pan of fuel which the fire suppression system must adequately extinguish without re-ignition for a defined period. A list of SFI approved systems can be found here

      SFI Testing

      • FIA Technical List 16: This standard defines acceptable performance in fire tests using a mock vehicle engine bay and cab. Systems that pass FIA tests are said to be FIA “homologated” and must follow strict adherence to the equipment options and installation guidelines exactly as tested. While FIA Technical List 16 homologated systems are available in a variety of agents and activation types, the options are more limited than those for SFI approved systems. A list of all systems homologated to this standard can be found here.
      • FIA Technical List 52: Also referred to as FIA 8865-2015, this is an even more rigorous test using a mock vehicle like Technical List 16 but with greater demands on fire suppression capability and prevention of re-ignition. A list of suppression systems homologated to this standard can be found here.

      FIA Fire Test Apparatus

        Firefighting Agents

        In general, the two types of extinguishing agents that should be considered for an on-board fire suppression system are AFFF low expansion foam or a gaseous agent such as Novec™ 1230. Each has advantages and disadvantages depending on application.

        AFFF:

        • What It Is: Short for “Aqueous Film Forming Foam”, AFFF is a low expansion foam which produces a stable, heat-resistant, and self-sealing blanket to smother a fire and prevent re-ignition by preventing oxygen contact with fuel.
        • When To Use It: Because AFFF sprays much like a liquid and is less subject to wind drift, it is an excellent choice in open cockpit vehicles such as tube-chassis off-road buggies. It is also generally safe for human contact which makes it a good choice for use in closed cabin  rally and track racing cars as well.
        • What To Watch Out For: AFFF agents are water-based which means that freezing is a concern in cold environments. However, not all AFFF agents are the same. While some options are subject to freeze at 32˚F, others feature additives to modify freezing points as low as -40˚F. As you would also expect with a foam solution, the aftermath of system activation will leave the protected area wet. Spent foam can easily be rinsed off with minimal corrosion effects but in a vehicle loaded with high-tech electronics, a gaseous agent may be preferable for this reason.
        • Types:
          • FireAde AFFF-AR: This agent is used in SPA Technique’s FIA Technical List 16 homologated FireSense systems. The “AR” stands for Alcohol Resistant which prevents foam breakdown by alcohols in an alcohol-fueled fire. However, AFFF-AR is manufactured as a concentrate and mixed with water at time of bottle filling. This means that due to being composed of mostly water, it should not be stored or used in environments below 32˚F (0˚C) due to risk of freezing.
          • FireAde Climate Control: This agent is used in SPA Technique’s SFI 17.1 approved FireSense systems. It is a premixed low temperature AFFF solution that includes proprietary additives (not antifreeze) which reduces the freezing point to -40˚F (-40˚C).
          • 4Fire: Like FireAde Climate Control, 4Fire is a low temperature AFFF agent offered in SPA Technique’s SFI 17.1 approved FireSense+ systems and is suitable for use down to -22˚F (-30˚C). While it is slightly more expensive than a comparable FireAde SFI 17.1 system, 4Fire has shown to exhibit better fire-out properties during testing.
        AFFF Spray Pattern

        Novec™ 1230:

        • What It Is: Novec 1230 is the trade name of a gaseous firefighting agent manufactured by 3M. Developed as a next-generation halon alternative with zero ozone depletion potential, it is a unique material which is stored as a liquid but vaporizes rapidly into a gas when sprayed. This rapid vaporization removes heat from a fire and cools the combustion zone to the point that the fire extinguishes.
        • When To Use It: Even in liquid form, Novec 1230 is non-conducting and safe for contact with sensitive electronics. This along with the fact that it leaves no residue after discharge means Novec is an excellent choice in cars with high-end electronic equipment at the tradeoff of being a more expensive system to initially purchase and service compared to AFFF systems. It is available in both SFI 17.1 approved and FIA Technical List 16/52 homologated SPA Extreme systems.
        • What To Watch Out For: Although Novec has a low environmental impact and is considered to be non-toxic to humans in the concentrations necessary for extinguishing fires, activation of the suppression system with occupants in the vehicle will result in inhalation of the vapor which can result in minor toxicity exposure. Additionally, because Novec vaporizes into a gas, it will be more subject to wind drift and potentially less effective than AFFF when used in an open environment. Also worth noting is that Novec has a freezing point of -162˚F although since it extinguishes a fire by means of rapid cooling, it becomes less effective in very cold air temperatures and may exhibit limited fire extinguishing capabilities below -40˚F.

        What to Avoid:

        • Halon/Halotron: Halons or “halocarbon” based extinguishing agents are rapidly vaporizing clean agents with negative environmental impact compared to Novec 1230 and may cause respiratory irritation or increased risk of cardiac arrhythmia when inhaled in high doses.
        • Dry Chemical Powder: Aside from the fact that SFI does not approve dry chemical fire suppression systems, powders leave messy residue that is difficult to clean and causes corrosion of electronics and exposed metals. Dry powders also irritate the respiratory system when inhaled and may cause coughing and difficulty breathing.

          Bottle Size

          • For SFI 17.1 systems, regardless of if they are AFFF or Novec, bottles are offered in 5 lb and 10 lb sizes. These describe the weight of extinguishing agent held in each bottle.
          • For FIA homologated systems, AFFF bottles are offered in a 4.0-liter fill capacity (approximately 10 lbs). Novec bottles are described by fill weight in kilograms and are offered in sizes of 2.25, 2.5, 3.0, and 4.0 kgs (5.0, 5.5, 6.6, and 8.8 lbs, respectively). Note that for rally racing specifically, FIA requires a minimum size of 4.0L AFFF or 3.0 kg Novec. 
          The bottle size dictates the number of spray nozzles included with each system. Typically a 5 lb system will include 2 spray nozzles and a 10 lb system will include 4 nozzles. In the absence of minimum weight requirements from a racing sanctioning body, it’s good to follow the mantra “bigger is better” and select the largest bottle that you have the space, budget, and/or weight allowance to accommodate.

          Fire Suppression Activation OptionsActivation Types

          Most activation devices will be fitted directly on the head of the storage bottle and will activate the system by one of three general methods:
          • Mechanical
            • Mechanical activation types use a pull cable to trigger release of firefighting agent. They can be mechanical-only, such as the most economical Lever Valve option, or can be combined with a thermal bulb for mechanical and automatic operation in an integrated (Universal) head.
          • Electrical
            • Electrical activation types feature a stand-alone electrical controller powered by its own 9V battery (to be replaced once per season) along with two push button switches to trigger release of the firefighting agent when either button is pushed. All electrical activation heads also include a thermal bulb.
          • Automatic
            • Automatic heads are always used in conjunction with a mechanical or electrical activation. They feature a thermal bulb which bursts at a set temperature to release agent. Standard bulbs will burst at 175˚F although other temperature bulbs are available for special applications.

          While the choice between mechanical or electrical activation is mainly a matter of preference, the choice to use an automatic thermal bulb is an important consideration, especially for those racing at higher speeds or in higher risk motorsports where a major accident could mean the possibility of being unable to manually activate the suppression system.

          Remote Automatic Head

          SPA Technique also offers remote automatic heads which allow the thermal bulb to be installed in a different location away from the bottle itself. The only drawback to this option is the fact that the tubing between the bottle and remote activation head always needs to remain pressurized so in vehicles where the bottle may need to be removed on a regular basis, a small amount of bottle pressure will be lost each time and will therefore require service sooner.

            Servicing

            To maintain SFI or FIA approval on any installed fire suppression system, bottles need to be serviced at an authorized service center every 2 years. Service consists of emptying and inspecting bottles and activation heads, replacing any worn components, and re-filling/re-charging. Each bottle includes a label with its original fill date and date of required service.

            Radial Dynamics is an authorized service center for all SPA Technique AFFF systems or you can use the SPA Technique service center lookup to find the service center nearest to you: https://spatechnique.com/pages/service-centers-dealers

            Conclusion

            Now that you have an understanding of the options available, it's time to select equipment that's right for you and your vehicle.

            If you still have questions, need help selecting the right equipment, or just want to verify that the selection you've made is the best match, all you have to do is Contact Us and as an authorized and trained dealer, Radial Dynamics can guide you in making the most appropriate choice. 


            About the Author

            Eric Amato

            Eric received his Bachelor's in Mechanical Engineering from Umass Amherst in 2008 and has since dedicated his career to fluid mechanics. Inventor of the patented Vortex Steering Reservoir, he is an IFPS Certified Fluid Power Hydraulic Specialist and owner and founder of Radial Dynamics. In his free time, you can find him either racing his buggy, traveling, practicing photography, or working with his wife on their apple orchard in western Massachusetts.