Right now, as you read this, at a small laboratory outside Sacramento, Calif., a technician is very likely dropping heavy things onto a helmet, or dropping a helmet filled with heavy things onto something blunt and immovable. After that, he’ll pull on its straps and HANS anchors in an effort to dislodge them, try to shoot a hole in the face shield with a BB gun, and then, for good measure, he’ll attempt to set fire to its key components.

It’s all in a day’s work at the Snell Foundation, testing the helmets we wear while we’re out enjoying HPDE, Time Trial and racing.

Like so many good things, the Snell Foundation’s mission was unfortunately born from tragedy. When a popular racer named Pete Snell died in the 1950s from head injuries sustained in a crash — while wearing the standard helmet of the time — Dr. George Snively suggested using donations collected in Snell’s honor to create a nonprofit organization to push for better head gear to protect racers. In 1957, the Snell Foundation was founded.

This was the helmet of used by racers in the mid to late 1950s, the one worn by Pete Snell when he was killed in a crash. It’s still on display at the Snell Foundation offices in Sacramento, Calif.

At that time, there was no standard, no testing, and head impacts were the most lethal injuries. They still are, but thanks to a small cadre of technicians outside Sacramento subjecting helmets to all manner of torture, head injuries are far less frequent and helmets are manufactured to a higher standard that advances with forward march of technology.

“Back then, nobody knew how to set a standard because there was no standard for helmets at all in this country, and nobody knew how to evaluate the performance of a helmet,” said Hong Zhang, director of education for the Snell Foundation. “So they started doing a lot of pioneering work in this area.”

This photo shows Dr. Snively during the early days testing helmets at the Snell Foundation in 1960.

Zhang began to work for the Snell Foundation when it had offices on Long Island in New York. She was in graduate school, majoring in education and writing her dissertation, and needed some part-time income to help pay the bills. She worked with Dr. Snively’s wife on Snell’s education program and translating documents from the Chinese factories making the bicycle helmets at the time. Snell no longer evaluates bicycle helmets, but Zhang ended up staying on at Snell, and even moved from Long Island when the foundation centered all its testing and operations at the Sacramento headquarters. Now the director of education, Zhang gave Speed News a tour of the facility and demonstrated how the foundation tests helmets.

“I just loved the work the foundation does. My parents were physicians and I later was like, ‘Hey, mom and dad, don’t push me doing anything else,’” Zhang said. “I’m probably saving more lives than you have combined in your lifetime. So, that’s how I ended up staying with the foundation for so long.”

It’s important to note that helmet manufacturers send their products to Snell on a voluntary basis. When manufacturers approach Snell to obtain Snell standard, they must submit a small batch, usually six to seven helmets, identical, and for each size configuration. Snell tests helmets in cold and hot conditions, room temperature, wet and dry. Snell also buys helmets throughout the year and tests them randomly and independently.

“They don’t know when and where we are going to obtain that random sample to bring back for the identical criteria tested,” Zhang said. “So if it all passed, everybody’s happy, they get the report, they reimburse the cost of the helmet and the testing fee. And that helmet stays on our certification list. It’s published on the website. Everybody can see it’s in good standing, but if the helmet does not meet the standard in any item of the tests performed, I would immediately bring three more identical samples and have them tested. And if any one of the three fails, then that means this helmet is decertified immediately because it’s a systematic problem. So, the factory will be notified, this helmet is decertified. Stop shipping, and let’s do the investigative work.”

Lab technician Dominic Ferlo shows the magnesium alloy head forms used inside the helmets for impact testing.

It doesn’t happen often that a helmet is decertified or recalled, but there is no wiggle room. If a helmet tests outside the range in a particular test, it is announced that the Snell Foundation no longer certifies it.

“That helps the consumer, the racer, to really have a peace of mind with that label,” Zhang said. “Somebody is looking over the shoulder of the manufacturers, that all these helmets that carry a label means it has already passed the test in the first place and also still remains under monitoring for compliance throughout the year.”

Instances of counterfeit Snell decals fitted to the outside of helmets are almost nonexistent, but the only thing that really verifies a helmet is Snell-rated is the sticker inside the helmet, under the padding. And that’s also where your safety inspectors look. Labels are never shipped to anyone but helmet manufacturers.

Snell standards for auto racing helmets are updated every five years. SA 2010, SA 2015, SA 2020 and the forthcoming SA 2025, for which testing is already under way. Once a new standard has been announced, as happened in 2020 and will happen again in 2025, helmets meeting the old criteria can still be sold. They are still safe, but any new helmets produced must meet the latest standards set forth by Snell.

The board of directors for the Snell Foundation, which meets at least twice a year, establishes the criteria. The board is comprised of doctors, mechanical and biomechanical engineers, biodynamicists and, of course, an attorney, who all monitor the scientific publications for the latest research.

Hong Zhang shows the rig used to drop-test helmets. The head form that fits inside the helmet is made from magnesium alloy.

The regimen of tests Snell puts helmets through is comprehensive and enormously destructive. As mentioned before, they test them hot, cold, at room temperature wet and dry. They perform four different impact tests on the shell, test the face shield, test flame and fire resistance on the strap, liner, shell and face shield, perform pull tests on straps for strength and positional stability and test the integrity of the anchors for head and neck devices. Lab technicians essentially are always looking for new ways to beat the daylights out of them.

“So, all of this, every single one, you cannot have one single failure on all these multiples, like six, seven helmets. And if any one of them fails, the whole set is rejected,” Zhang said.

Shell Impact Testing

Early helmet impact testing at the Snell Foundation.

The most important part of the helmet is the shell, which encapsulates the head with varying recipes of impact-absorbing foam and padding. In impact testing, the helmet is strapped to a magnesium alloy head form appropriate to the size of the helmet, then dropped onto an “anvil,” a small steel immovable sphere fastened to the concrete floor. Snell conducts the tests in a few different ways, dropping it on anvils of different shapes at different orientations, and then dropping a heavy pointed object onto it.

Fitted with accelerometers to measure forces in three dimensions, the head forms are made from K1A, a highly pure form of magnesium alloy used because it reduces “noise” in the measured data. It doesn’t vibrate as much as aluminum or steel. Impacts are measured in milliseconds and g forces.

“So a flat anvil is diametrically opposed to a curved surface. They do different things and you’re hoping you’re catching most of the stuff in between that someone might hit their head on,” said lab technician James Easley. “So again and again, it’s not trying to repeat something that’s a reality. It’s trying to give a scope of what the helmet can do under these circumstances.”

In the sharp-object drop test, lab technician Dominc Ferlo dropped the point of the object directly onto a vent in a helmet’s shell to see if it would penetrate. And there is no hiding failure because directly beneath the point of impact is a copper disc that irrefutably proves any penetration. Part of the purpose of any Snell tests is to have a protocol established so that the tests are measurable, repeatable and equitable for all manufacturers involved.

The sharp object test simulates, well, a sharp object impacting the shell. In this test, lab technicians aimed the point of the instrument right at a vent opening. The helmet passed because the shell maintained its integrity and the copper disc showed no signs of penetration. This test is brutal.

It might seem like enough if shell testing stopped there, but it doesn’t. Snell technicians also measure deflection on impacts to the chin bar, another possible occurrence in a crash. Technicians orient the helmet appropriately on the testing rig, then drop the weight onto the chin bar while measuring its defection during and after the impact. The data is measured in millimeters of deflection over milliseconds of the impact. The one tested while we were touring the facility passed easily.

Face Shield Testing

It is highly unlikely for racing drivers to be shot in the face shield with a BB gun from 3 feet away, but it’s nice to know your Snell-rated helmet will protect you from such an incident. That is how Snell tests the face shields, with a good old Crossman BB air rifle. They shoot it three times in the face shield, in fact. A passing helmet will not allow penetration.

To ensure that the test is measurable, repeatable and equitable among helmet manufacturers, Snell certifies the air rifle once a year. Given the rigors of a test like that, it’s a safe bet that small chunks or rubber or pebbles or stones are no match for the face shields in certified helmets, even at speeds exceeding 100 mph.

Snell lab technician Dominic Ferlo takes aim for the first of three shots fired at a helmet’s face shield.
Helmets don’t always pass the face shield test. Here is one that allowed full penetration when shot with a Crosman air rifle.

Strap Testing

Of course, a helmet doesn’t do anyone any good if it doesn’t stay on, which is why Snell tests the chin straps in a few different ways, the first of which is the retention test.

Lab technician James Easley subjects a helmet’s chin straps to the retention test. A weight fastened to the chin strap, then dropped. The equipment measures deflection in millimeters and time in milliseconds.

Flame Resistance

Lab technician Dominic Ferlo sets a flame to the helmet’s strap. Note the back of the shell was also tested for burn resistance.

Helmets used for automobile racing must be resistant to fire and Snell also has a rigorous testing regimen for that. Lab technicians apply open flames to the helmet’s straps, face shield, its shell and inner liner. To achieve a passing score, all the materials tested must either not catch fire, or self-extinguish if they do.

Head and Neck Anchors

One of the most important helmet safety features of the last 25 years has to be the advent of the head-and-neck support devices, which strap beneath the shoulder harnesses in the car and attach to the sides of the helmet. This keeps the weight of the helmet tethered to the body in a crash and greatly reduces risk of a basal skull fracture.

The whole system is rendered moot if the anchors on the helmet aren’t up to the task, and in the Snell tests the helmet must withstand forces that boggle the mind. The first “pull” is on both anchors at 7,000 Newton-meters. Then the helmet is rotated and one of the M6 terminals is tested at 3,500 Newton-meters. When those two tests are complete, the helmet is returned to the original orientation to test both anchors, which must withstand 14,000 Newton-meters of force for 5 seconds.

That’s more than 10,000 pound-feet.

“It’s a slow pull. It’s not a dynamic load. It’s not a static load, but it’s not really a dynamic load either,” said Snell executive director Stephen D. Johnson. “When you think of a dynamic load, it would be instantaneous or very quickly. This is a very slow pull, and what they’re looking for is to see if this thing basically pulls apart at any point during the test.”

As technology advances, so too will Snell’s testing and standards, and the next published standard is due for release in 2024 as SA 2025. When that happens, the technicians at Snell will begin testing a new crop of helmets from manufacturers the world over. One thing is certain, when those new standards are published, the testing that follows will be as comprehensive as those outlined above.

“The challenge is not really to surpass the Snell requirements. Say the bar is set up this high, there’s no benefit to go beyond that by a lot, unless they’re not confident about their quality control,” Zhang said. “The challenge is how to meet the Snell standard consistently with the least material, reduce the bulk and the weight and the cost.”

One good example of the march of technology is the use of carbon fiber, which is ideal for helmet manufacturers because the material has that rare and prized quality of being strong and light. It comes at the right time, because fiberglass helmets had essentially reached the peak of the material’s usefulness. To make them any stronger would have meant making them perhaps larger or heavier, which is less safe, not more.

“So basically we had reached a pinnacle in the industry with fiberglass and materials that were readily available and affordable where we couldn’t ask anymore because the helmets would’ve gotten bigger,” Johnson said. “Because the use of these materials like carbon fiber and things like that are getting more common, they’re getting better at it and it’s getting more affordable. They are working toward reducing the peak accelerations you see, and the strength of the helmet and how they perform. So it is working that way, and future standards will start to look at how do we make them not only lighter and better, but more protective and things like that.”

Hong Zhang welcomes Speed News to the Snell Foundation headquarters in Sacramento, Calif.


Images courtesy of Brett Becker and Snell Foundation

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