by Bill Strong
At Charlotte, a new team showed up to tech with a new build and was ready to get their car inspected. I did a quick once over on the car since I built the cage for them. I noticed that they had removed the heater core of the BMW. This car has one large hole under the dash that extends under the hood of the car. Without covering this hole, it would help make the interior cooler at race speeds. It would also allow oil, fuel, and fire into the interior if something catastrophic happened during the race. After explaining to the guys the error in their build we set out on how to fix it, which turned out to be super easy. Simple construction flashing along with a sealant to keep fumes and flames from finding those small holes into the interior at speed.
The simple fix was to get some metal flashing material, some self-tapping screws or pop-rivets, and some fireproof caulking. The caulking sold for fireplace and flue install works awesome. It is sold in tubes or a can of expanding foam. We also pointed out some of the smaller openings like threaded bosses that were used to screw things into the firewall. Those would just need a squirt of foam or caulk to fill the gap.
Now to remind everyone, using this caulking is not a requirement per the BCCR. It is a good practice that is proven to work at keeping fire and fuel/oil mist from working its way into the interior of the race car. this can give your driver more time to get out of the car. Now covering the holes in the firewall and fuel tank/firewall is required by the BCCR.
This was tested in my Opel GT at the VIR 12-hour race in 2017 when the engine caught fire during the red flag for another incident. The fire block we used was the expanding foam, and as soon as the fuel fire hit it, it expanded more keeping the fire from the interior. We had also put a layer between the firewall and the blanking off covers we used to plug holes.
In the back of the car we also use the expanding foam to fill in the gaps between the fuel cell firewall holes where the cage down bars goes into.
Anything you can do to keep fire and fumes out of the drivers’ area will help keep your driver safer longer.
3M Fire-Barrier Caulk is available online or at your favorite home improvement stores like Lowes or Home Depot.
Use 3M 10.1 fl. oz. Fire-Barrier Caulk to guard against damage from fire, smoke, and toxic gasses. This latex sealant withstands flames for up to 4 hours and expands when exposed to heat. Dries to red color, no mixing required.
No-sag, non-halogen formula
Protects against fire for up to 4 hours
Expands when exposed to heat to protect against smoke and toxic gasses
Dries to the touch in 15 minutes
Firestop tested up to 4 hours in accordance with ASTM E 814 (UL 1479) and CAN/ULC S115
Fire resistance tested for static construction joint systems in accordance with ASTM E 1966 (UL 2079)
Helps minimize sound transfer
This product qualifies as an intumescent fire caulk
Just a reminder of how fast fires can start.