Engineers at the SFI Foundation are good at breaking things — and, as a result, racing drivers across the world are safer because of it.
Originally an offshoot of SEMA, the SFI Foundation has grown into an independent nonprofit organization that develops and administers “standards, certifications and testing criteria for use in motorsports. SFI strives to equally serve the manufacturers, consumers, sanctioning bodies, racers and government agencies through fairness, efficiency and respect.”
Well, fairness to everything but the equipment they test, and they tear up a lot of it. SFI Foundation tests equipment for every kind of car racing, from drag racing to sports car racing at professional and amateur levels to equipment used for boat racing and even tractor pulling.
The SFI Foundation has more than 85 specification programs, which are used internationally by 100 member sanctioning bodies and more than 300 companies that make racing equipment. SFI doesn’t certify equipment, per se, but rather establishes the safety criteria that equipment needs to meet and tests it to see if it meets those criteria.
“Really, the standards are managed by committees which are formed by the manufacturers, sanctioning body officials, outside safety people,” said Mike Hurst, technical manager for the SFI Foundation. “So, you wouldn’t say I’m the author of the standards, I’m more like the editor of the standards.”
To get an SFI label on a racing product, it requires successful testing and ongoing quality control. SFI conducts secret purchases of parts to make sure they continue to conform, and revisits the standards every two years. Manufacturers enter into a contract with SFI to agree to these terms, they test, and then the manufacturer certifies that the part meets SFI certifications by putting the SFI label on it. SFI Foundation is funded primarily by the sales of those labels, which cost about 1 percent of the suggested retail price of a product.
The organization got its start in the late 1970s by testing bellhousings and clutches on drag-racing cars, which were failing at the track and sending discs and flywheels through the floors of the cars, and injuring drivers. One of the later pieces of equipment that needed specification and testing was the supercharger restraints.
Before the supercharger containment systems were developed, when a Top Fuel drag car would backfire, the blower housing would rupture and send metal bits flying. When a supercharger struck and killed a television cameraman, the NHRA came up with some initial calculations for the forces these containment mechanisms would need to withstand, and SFI went to work with the sanctioning body and various manufacturers to come up with a spec and products that would do the job. SFI also uses some of the protocols established by the Society of Automotive Engineers, and does biomechanical testing at the Center for Advanced Product Evaluation in Indiana for products like head and neck restraints and karting rib protectors.
During a tour of the SFI Foundation labs, its technicians and engineers demonstrated a few of the testing procedures and equipment used to validate driver safety gear and car safety equipment. It was a pretty eye-opening experience.
Driver Safety Gear
Before any driver’s suit can be fitted with an SFI label, the technicians and engineers at the lab subject it to burn tests and the thermal protective properties test, which measures the amount of time it takes for the heat energy to transfer through the materials, through the sample, and into the sensor. Technicians measure the thickness and the ounces per yard of the material and then plug that information into the computer before burning the sample.
Suits, gloves, shoes, you name it, all go through this testing, in the form of raw materials — right down to the thread used for stitching and the zippers — and in finished form. The machine used to test the materials actually uses an open flame and a red-hot electrical element. When the test is over, the material has to put itself out to pass.
“After 12 seconds, the flame goes out and then there’s a timer here that measures what we call the after-flame time,” said SFI Foundation technician Joe Musick. “And so that’s the time that it takes for the material to self-extinguish. So, the actual passing certification, the material has to have an average after-flame time of under 2 seconds with an average char length of less than 6 inches.”
The burn tests are intense. For racing gloves, they test all the raw materials in the same manner as they would with the suits, then test different sections on the gloves, including burn tests on each individual finger. They are nothing if not thorough.
Car Safety Equipment
Racing harnesses face lots of different kinds of testing. The lab has a machine that simulates ultraviolet radiation to test for the sun’s effects on materials used for harnesses and window nets. In the old days, they would just nail samples of webbing to a piece of plywood they had up on the roof. The accelerated weathering tester is faster and more controlled.
“So, it does a few hours — what is it like 8 hours? — of UV and then that shuts off and there’s a humidifier that kicks on and a heater, like it’s a damp, humid night in Florida,” said Hurst. “And then that kicks off and the bulbs kick on again and it continuously cycles.”
And that friends, is why window nets expire. Window nets also undergo load tests two other procedures. One test uses a heavy steel ball to examine the likelihood of human hand being able to penetrate the mesh. The second procedure tests the overall strength of the net by dropping a 175-pound weighted bag on it.
That is not the end of it, though. SFI also tests the abrasion resistance of harness straps with a clever machine specially built to rub things the wrong way. It’s basically a reciprocating drum wrapped with sandpaper, which is more abrasive than anything in a racecar.
SFI also tests the tensile strength of harness webbing on a machine that has a lot of uses. The United machine uses screw jacks to pull and jaws that tighten as the pulling load increases. When they tested a particular harness strap, it needed to withstand 3,750 pounds of force, and by the time it broke, it was measured at more than 12,000 pounds. After the strap finally broke, it was warm to the touch.
They also test the full harness assemblies on a proprietary machine, which has hydraulic rams that pull the harnesses over a leather-covered form that approximates the lap and shoulders of a driver. The rams are run on computer technology that SFI engineers developed specifically for the purpose of testing. This is where the hardware such as anchors, latch-and-link assemblies and cam locks all pass or fail.
For testing seats, SFI built another rig, with more hydraulic rams and linear variable differential transformers to measure deflection in a seat. Certification 39.1 puts 2,000 pounds of force on seats used in NASCAR. The carbon and aluminum honeycomb construction used is so strong it only deflected a half inch — then popped right back.
“We use that computer and then an LVDT to measure the deflection on the other side,” Hurst said. “The computer runs the RAM out to the force level and we measure the deflection on the far side of the seat with an LVDT.”
For engine parts, such as harmonic balancers, flexplates and clutches, the SFI technicians and engineers use an electric motor to spin the components up to 10,000 rpm. SFI has sold labels for balancers and flexplates in excess of a million each. The failures are often violent, which is why the spin-test machine is fitted with a heavy-duty cage around it.
“We’ve got a bunch of adapters and different noses for the cranks and that spec is required in NHRA and NASCAR for the harmonic balancer because that was another problem years ago,” Hurst said. “On a standard balancer the rubber between the hub and outer ring would fail and the outer ring would come right off. So, you have this ring spinning at 10,000 rpm. This ring of cast iron and it would take off and just go anywhere.”
The SFI Lab maintains an inventory of all the tested parts through each test cycle. They keep hundreds and hundreds of tested samples, including NASCAR shifter boots. Yes, there’s an SFI spec for them, too. Why?
If you blow an engine at 200 mph and there’s a fire, the high-pressure area under the car will push the flames and burn through a rubber boot. NASCAR also likes to ensure the boots are built to a certain spec because some teams were hiding zippers and Velcro on the shifter boots because you can pick up 30 to 40 pounds of downforce with a “leaky” shifter boot. The leak reduces air pressure inside the driver compartment of the car. So the specs aren’t just for safety. They also can be to ensure parity.
It’s just another day at the SFI Foundation. Tearing things up. Saving lives.