Endurance racer Stephen Cox shares his chilling first-person testimony (in two parts) that his car caught fire at 125 mph. He was amazed that the smoke made it almost impossible to see belts and window nets come off.
Fire is not specific to any particular racing series. When Ryan Blaney’s car caught fire in his 2018 Coca Cola 600, his crew chief asked if the fire suppression system was activated.
“Dude, I tried to get out of there. I didn’t look for the pin. I didn’t see it anyway,” Blaney told him.
The next-gen car had more than its share of fires in its first season. Tyler Reddick experienced his first next-generation fire during his March test in Kansas. During the season, the fire affected Chris Buescher, Joey Logano, Cole Custer, Chase Briscoe, JJ Yehley, Kevin Harvick (all Ford drivers), and Alex Bowman.
After the Indianapolis race, NASCAR mandated an insulating shroud around the right exhaust pipe. Officials theorized that the contact displaced the pipe and set fire to the foam inside the door panel.
However, the fire continued.
Driver frustration is no different.
After a fire knocks out championship contender Harvick From the Darlington Playoff Race, NASCAR issued more technical changes. These changes are based on new theories. This means that small pieces of rubber inside the car will catch fire.
What caused the fire?
Knowing how fire starts is the key to stopping it.
Fire is a chemical reaction between fuel and oxygen in the presence of heat. The engine uses spark plugs to burn gasoline. Your body oxidizes glucose and fat in a similar reaction to sustain your metabolism.
Sustaining a fire requires all three elements—fuel, oxygen, and heat—in sufficient amounts to sustain the chain reaction that sustains the flame. The fire stops when one or more of the three components are reduced or eliminated.
Air is about 21% oxygen. Rolling someone over the fire in the ground or in a blanket separates the fire from the oxygen. This is the same reason you put out a grease fire by banging on the lid of a pot.No oxygen, no fire.
By cooling the water, the heat component is removed. But for the same reason that you can’t put out a gasoline fire with water, you can’t put out an oil fire with water. Liquids such as gasoline and thinner do not mix with water.
NASCAR uses chemical fire extinguishing agents on board vehicles and in containers carried by safety personnel. These chemicals devour oxygen. The fuel cell area requires a thermal fire extinguisher, but the driver’s fire extinguishing system is manually operated.
How firefighting clothes work
The number 0 rule of motorsport safety is: This means not only avoiding fires, but protecting people in the event of a fire.
No fire resistant material. The driver’s fire suit protects the driver by providing insulation, being a poor source of fuel, and blocking oxygen.
Quilting traps air between layers of fire protection clothing. Air is an excellent insulator, reducing the amount of heat that penetrates your fire suit.
Most fire protection clothing is made from Nomex or Nomex blends, but there are more and more material choices. Nomex may not be as strong as its sibling Kevlar, but Nomex doesn’t burn. Carbonization forms a layer of carbon around the fibers as shown in the diagrams and photos below.
Carbon is an excellent insulator that provides additional protection from heat. Char is not flammable, so it is not fuel for fires.
Finally, the expanding Nomex fibers close the fabric’s weave holes (see picture below). This prevents oxygen and flame from reaching the driver’s skin.
From head socks to shoes to underwear, all driver gear must be fire resistant. Even patches must comply with standards established by the SFI Foundation. This gear gives the driver about 10 extra seconds before getting his second degree burn.
If you want to learn more about fire protection, check out this video I made with the National Science Foundation.
car firefighting suit
With enough heat and oxygen, any substance will burn or melt. Carbon fibers are stable to very high temperatures, but the resins and adhesives that hold carbon fiber composites together are flammable at low temperatures.
NBC Sports analyst Steve Letarte details the latest NASCAR-mandated changes in the video below. The first fix seals where rubber debris could enter the car. The second modification replaces part of the resin right-side door panel (the area closest to the exhaust pipe) with stainless steel.
The only thing I would add to the video is that the smaller pieces of fuel ignite more easily. But marbles — rubber crumbs and truck grit — have a lot of surface area. That means there are plenty of places to start burning. That may be why the problem isn’t known until the actual race on a track with a lot of rubber.
NASCAR has proposed another optional fix. It’s an intumescent paint. This paint is an amazing piece of material science and fun to say.
Intumescent (in-to-MESS-scent) often means expanding in the presence of heat. Research into intumescent paints began after 9/11 and the World Trade Center steel melted in surprising ways. Intumescent coatings are now required in many commercial buildings. It is also commonly seen in drag racing.
Intumescent paint works similarly to Nomex. Heat causes the paint to expand, but to a much greater extent. The video below shows an example of intumescent paint used in construction.
Also, like Nomex, char is not a fuel. The examples below use regular cardboard with and without protective paint.
NASCAR limits the paint area to where the exhaust passes near the body panels and right side foam. The team also has the option of painting the door foam.
There is a slight weight penalty, but not as great as the result of being knocked out of the playoff race due to fire.
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