Shelf Life

Safety equipment service life expectancy is based on quantitative testing—most often conducted by either SFI or Snell. Both are privately funded, independent entities with no direct connection to any sanctioning body or manufacturer, so you don’t have to wonder if there’s a relationship between expiration dates and safety equipment manufacturers’ desires to sell you more stuff.


SFI Foundation

The black-and-white SFI tag is ubiquitous in motorsports. SFI was founded by SEMA to establish standards for specialty and racing equipment. SFI is now a separate entity from which more than 70 sanctioning bodies around the world have incorporated their standards into rules.

A committee sets the specifications for SFI certification. Experts from all facets of the industry comprise the technical committee, providing a comprehensive cross-section of knowledge. This diverse expertise and open participation ensures that standards are established fairly. SFI uses more than 100 specifications, from driver safety items to drag racing wheels to shift cover boots.


Snell Foundation

William “Pete” Snell was a well-liked race car driver whose died when his substandard helmet failed him during a 1956 sports car crash. In 1957, a group of scientists, racing colleagues and Snell’s friends formed the Snell foundation whose goal is to improve helmet effectiveness through research and testing, and to develop objective standards. Snell tests thousands of helmets each year and maintains its objectivity by remaining independent of helmet manufacturers and government.



This is the biggest hot button in racing safety. Most sanctioning bodies use SFI Specification 16.1, which defines a driver-restraint assembly, outlines basic design dimensions and requirements, and explains the testing procedures in detail. After a harness has met Specification 16.1, the manufacturer can affix an SFI certification tag that displays the date of manufacture. SFI specifies that driver restraints must be regularly maintained and inspected, and must either be replaced or rewebbed by the original manufacturer—and only the original manufacturer—and recertified every two years.

Nylon webbing is susceptible to degradation through exposure to the elements, particularly ultraviolet rays. Says SFI’s Arnie Kuhns, “The best-defined case of a finite service life in safety equipment is the driver restraint harness.” New polyester webbing is less susceptible to decline.

Harnesses weaken over time, and in the case of nylon, at an alarming rate, whether they are used or not. Testing data clearly supports this standard. “The webbing used in motorsports restraints is typically made with DuPont Nylon 6-6 or a similar product,” Kuhns says. “The webbing manufacturers supplied the test data that the committee used to set the service life standard. As the graph shows, [nylon] webbing loses approximately half its strength in one year and 75 to 80 percent of its strength in just 24 months. By the end of the third year, it is nearly worthless.”

Given such rapid deterioration, replacing nylon webbing at regular intervals is essential. SFI-certified harnesses are tested to withstand a 70-g crash. SFI determined that crashes in Indy car and NASCAR races routinely produce 70 to 75 g’s. “Our eventual goal is to protect a driver in a 100-g crash,” Kuhns says. “We’re not there yet, but we are making steady progress.”

The beauty of an SFI-certified harness is that a $65 model meets the same standards as a $400 model. The cheaper version may not have the same fancy buckles or dazzling colors, but it will still save your ass when you need it. Says Kuhns, “Driver restraints are the cheapest and most important piece of safety equipment in a race car.”



Most sanctioning bodies require the SFI Spec 3.2A standard for driver uniforms. A black-and-white SFI patch on the left shoulder is the manufacturer’s guarantee that the suit meets or exceeds the specification.

Spec 3.2A uniforms are graded into six levels of protection. (A common misconception is that the SFI rating represents the number of fabric layers.) Says Kuhns, “Suit specs are designed around the human body’s tolerance for heat.” SFI Spec 3.2A uses multiple tests to rate capability to retard radiant heat and direct flame.

The Thermal Protective Performance (TPP) measures the time a wearer can be exposed to an 1,800°F heat source applied to the outside of the garment before incurring a second-degree burn. A second-degree burn causes some skin blistering, but is generally not severe enough to require skin grafts. TPP tests can evaluate multiple and single-layer garmets.

The radiant-heat test is significant because most racer burns are caused by heat transfer rather than direct flame. Multiple layers of fabric insulate to keep heat from the skin longer because each layer creates air gaps that have to heat up. The extra seconds gained with each layer are vital to a driver trying to escape from a burning car.

The wide range of materials and manufacturing techniques employed makes it possible for garments with different numbers of layers to have the same performance rating. But here is what you need to know: The higher the TPP value, the higher the garment rating and the more time before a second-degree burn.

SFI Rating TPP Value Time to 2nd Degree Burn
3.2A/1 6 3 Seconds
3.2A/3 14 7 Seconds
3.2A/5 19 10 Seconds
3.2A/10 38 19 Seconds
3.2A/15 60 30 Seconds
3.2A/20 80 40 Seconds

Table courtesy of SFI Foundation

Three to five layer suits (3.2A/10, /15 & /20) have five-year recertification periods. Inner layers of multi-layer uniforms sometimes deteriorate or fall to the end of the sleeves or bottom of the legs. (Suits are often quilted to prevent this.) Recertification involves the manufacturer opening up the suit and inspecting the condition and position of the Nomex insulation, after which they can either recertify the suit or recommend replacement.

The second major test included in spec 3.2A is the After-Flame test, which measures time to self-extinguish when subjected to a direct flame. To pass, this time must be 2.0 seconds or less. The flammability test evaluates single layers of fabric only, and includes cuff material. Each layer of a multiple-layer suit is subjected to the after-flame test separately. Spec 3.2A includes tests for thread and zipper heat resistance and multiple layer thermal shrinkage resistance.

To optimize the protection of a driver suit, get one that fits; a suit that’s too tight will compress the air gaps and allow heat to reach skin faster. Fire-resistant underwear doubles the minimum protection time of all single-layer suits, and it is beneficial even with multiple-layer garments. (Underwear undergoes the same TPP and flammability tests as uniforms.)

Follow the manufacturer’s instructions to maintain your uniform’s integrity. “Proper care of the suit ensures long service life and maximum protection,” says Bob Weiss, operations manager for Pyrotect. “Wash your suit in cold water with Woolite and allow it to air dry. I like to wrap a heavy towel around the hanger to simulate the shape of the driver’s shoulders.”

Gasoline, oil, or grease can be absorbed into fabric and provide fuel in a fire. Non-flammable fluids soaked into a suit could produce steam when exposed to heat and cause liquid vaporization burns.

No matter what type of suit you have, if you are involved in a fire, ditch the suit and get a new one. Even the smallest singe creates a weak spot. Pyrotect’s Bob Weiss sums it up best: “You can always buy another race car, but for you, it’s a one-shot deal.”



Most sanctioning bodies recognize Snell and/or SFI helmet certifications. Snell Standards are updated about every five years to reflect advances in engineering and materials. “Snell tests all manufacturers’ helmets confidentially and is aware of the advances that manufacturers are making,” says Snell Foundation’s Hong Zhang. “We have a really good idea of their innovations and what is possible to integrate into the next specification.”

According to Snell, a helmet’s most critical elements for automotive applications are:

  • Impact management—how well the helmet protects against collisions.
  • Positional stability—whether the helmet will be in place, on the head, when it’s needed.
  • Retention system strength—whether the chin straps are sufficiently strong to hold the helmet throughout a head impact.
  • Extent of protection—the area of the head protected.
  • Flame resistance—whether the helmet will withstand exposure to direct flame.

Helmets that meet requirements for all five elements are identified with the Foundation’s current certification label, the orange “SA2005”. Those meeting requirements for the first four elements but not tested for flame resistance are identified by the Foundation’s light blue “K2005” certification label.

Snell continuously purchases and tests samples of currently certified helmets. If a currently certified helmet fails, the manufacturer must take corrective action to Snell’s satisfaction. Failing that, Snell revokes certification and requests the return of its serialized certification decals.

The energy input used to test helmets has not changed in more than 15 years. To pass Snell’s certification standard, the helmet must allow no more than 300 gs to pass through to the users head. By comparison, US DOT specifications allow for 400 g’s.

Though Snell is usually the most recognized name in helmet testing, SFI has a helmet program as well. Kuhns says the Snell and SFI standards for adults are nearly identical. SFI also tests helmets.

Because they are designed to absorb energy through destruction, namely liner crush and shell delamination, helmets have finite service lives. When the shock-absorbing materials (usually expanded polystyrene) dry out, the foam padding breaks down and shell materials begin to delaminate. All of these severely compromise the helmet’s ability to dissipate shock.

Both foundations recommend helmet replacement intervals of no more than five years. Frequent use can accelerate this slightly, but both Zhang and Kuhns recommend following your helmet manufacturer’s replacement guidelines. Says Bell’s Kyle Kietzmann, “Bell Racing’s position is that a helmet should be replaced every five years or anytime it is involved in a serious crash.”

This doesn’t mean you can ignore the helmet for five years, however. “Naturally,” says Kietzmann, “it should be inspected regularly, and any delamination of the shell should deem the helmet retired.”

Impact Racing founder Bill Simpson offers a more proactive approach. “A professional racer who is wearing his helmet several hours per day, several days per week, should consider replacing it every season,” he says. “If you use it only once a month or so, buy a new one every two to three years. We still see few Snell 80 helmets in the field, which is crazy.”

Kietzmann also offered this warning: “While custom helmet painting can be done with any automotive type finish, special care must be taken to prevent the helmet’s interior from solvent and fumes, which will greatly accelerate deterioration.”


Fuel Cells

Entry-level plastic fuel cells are governed under SFI Spec 28.1. This type of cell is commonly seen in lower level stock car racing. Better fuel cells consist of an impact-resistant rubberized bladder filled with explosion-suppressant foam baffling. This type of cell is certified by SFI under Spec 32.1. The bladder is enclosed and supported by a steel, aluminum, or composite container. The container supplies a means of secure mounting, and functions as a flame shield. Additional safety features frequently include rollover check valves and a leak-tight cap and fittings.

According to ATL’s Justin Hoyt, “Major racing sanctioning bodies have determined the safe use-life of flexible fuel bladders as five years when exposed to normal use and wear. After [that], a cell bladder needs to be recertified or replaced, and recertification’s are good for two years.”

Modern anti-explosion foams offer good gasoline resistance and rarely need replacing during the fuel bladder life. However, oxygen-bearing fuels do affect safety foam, which should be inspected several times per year, and replaced every two years.

“As in all things, there are ways to handle a product that will contribute to its integrity or detract from it,” Hoyt says.

Safety equipment wears out. But because it often shows no outward signs of deterioration, conspiracy theorists suggest that service life dates and updated standards are but a marketing ploy. The truth is that state-of-the-art safety equipment is vital when the worst happens. If you think the price of a new harness is too high, compare it to the cost of a failed one.

Aero Tec Laboratories
45 Spear Road Industrial Park
Ramsey, NJ 07446


Bell Racing Company
116 E. Neal St.
Rantoul, IL 61866


Impact Race Products
1650 Northfield Drive
Building A-100
Brownsburg, IN 46112


3227 14th Ave.
Oakland, CA 94602


SFI Foundation, Inc.
15708 Pomerado Road
Suite N208
Poway, CA 92064


Snell Memorial Foundation
3628 Madison Avenue,
Suite 11
North Highlands, CA 95660


By Chris Endres