SFI 3.3 Racing Undergarments

What SFI 3.3 Undergarments Actually Do

A racing suit certified to SFI 3.2A/5 provides two layers of fire-resistant protection across your torso, arms, and legs. Adding SFI 3.3 certified undergarments underneath that suit effectively increases the total layer count — giving you a third layer at the skin level that dramatically extends the time available to exit the car safely in a fire scenario.

Thermal Protection Performance and why it compounds

The SFI Foundation rates fire-resistant gear using Thermal Protection Performance (TPP) values — a measure of how long a material takes to cause a second-degree burn under defined heat exposure. A quality SFI 3.2A/5 suit carries a TPP value that provides meaningful protection time on its own. When you add SFI 3.3 certified Nomex undergarments underneath, the combined TPP of the two layers is significantly higher than either layer alone. The improvement is not additive in a simple sense — the dead air space between layers also contributes to insulation — but the practical result is a driver who has considerably more time to get out of the car before sustaining serious injury.

What SFI 3.3 covers

SFI Specification 3.3 covers driver accessories including undergarments (tops and bottoms), socks, gloves, and shoes. For undergarments specifically, the specification requires the outer layer of each piece to pass flame resistance testing. Pieces meeting SFI 3.3 certification carry the SFI conformance label and can be presented at tech inspection as compliant protective equipment.

The difference between SFI 3.3 and non-certified base layers

Some drivers wear standard moisture-wicking athletic underlayers beneath their suit, reasoning that comfort is the main purpose of a base layer. This is incorrect from a safety standpoint. Non-certified synthetic fabrics can melt and bond to skin in a fire event, making injuries significantly more severe. Nomex and other aramid fiber materials used in SFI 3.3 certified undergarments do not melt — they char in place, maintaining a protective barrier. If your series requires undergarments, they must carry SFI 3.3 certification. If your series does not require them, wearing certified undergarments anyway is one of the highest-value safety investments a driver can make.

EPIC SFI 3.3 Undergarment Products

EPIC Racewear supplies the full range of SFI 3.3 certified undergarment components required for a complete base layer system.

Nomex long-sleeve top

The long-sleeve Nomex top covers the torso and arms beneath your race suit, adding a complete upper body layer of fire-resistant protection. The soft knitted Nomex construction sits comfortably against the skin without bunching or restricting movement, and the lightweight material does not add significant bulk beneath a fitted race suit. Moisture-wicking properties help manage heat and perspiration during long stints.

Nomex pants

Nomex racing pants cover the lower body and extend to the ankle, sitting beneath your race suit legs and above your racing socks. The same soft knitted Nomex construction used in the top ensures consistent fit and comfort. The waistband and leg openings are designed to layer cleanly with both the suit above and socks below, avoiding gaps in coverage at the transition points.

Nomex socks

Racing socks are the undergarment component most frequently overlooked. SFI 3.3 certified Nomex socks provide foot and ankle coverage that works with your certified racing shoes to eliminate the gap between the shoe’s Nomex lining and your skin. Without certified socks, that gap exists regardless of how good your shoes are — skin-level heat exposure at the ankle and foot is a real risk in a fire event. EPIC’s SFI 3.3 Nomex socks are lightweight, breathable, and sized to fit comfortably inside a racing shoe without adding pressure or bulk.

Who Needs SFI 3.3 Racing Undergarments?

Series where undergarments are required

Many Canadian and American sanctioned racing series require SFI 3.3 certified undergarments as mandatory equipment. NASCAR Pinty’s Series, NHRA classes with fire suppression requirements, and a number of provincial oval and road racing series mandate full undergarment systems alongside the suit. Check your series technical regulations or contact your sanctioning body to confirm whether undergarments are required in your class before your first race of the season.

Series where undergarments are recommended

Even in series where undergarments are not explicitly mandated, wearing SFI 3.3 certified Nomex base layers is strongly recommended by safety professionals and sanctioning bodies alike. The cost of a full undergarment set is modest relative to the protection benefit — and the protection benefit is most significant in exactly the kind of incidents that drivers do not plan for.

Oval track racing

Dirt oval, asphalt oval, late model, modified, and stock car classes across CASC Ontario and regional Canadian oval track associations frequently require or recommend full undergarment systems. Scrutineers at tech inspection check for certified undergarments in many of these classes — having a complete SFI-certified system including top, pants, and socks means no conversation at the tech line.

Drag racing

NHRA regulations for drivers in classes with fire suppression requirements typically mandate SFI 3.3 certified undergarments as part of the complete safety package. At faster elapsed times and higher vehicle classifications, the safety requirements are more stringent — undergarments are part of the base equipment list, not an upgrade. EPIC supplies undergarments to drag racing drivers competing across Canada and the United States.

Road racing and circuit events

ASN Canada FIA affiliated series and provincial road racing clubs vary in their undergarment requirements by class. Formula car, GT, and endurance racing classes frequently mandate full base layer systems. Confirming requirements with your club’s technical regulations before ordering is always recommended.

Safety teams

Fire suppression crew members operating at sanctioned events often work in close proximity to vehicles and fuel — arguably a higher risk exposure than a driver in a cockpit. SFI 3.3 certified undergarments for safety team members are available through EPIC’s safety teams section with the same quality and certification as driver undergarments.

Wearing and Caring for SFI 3.3 Undergarments

Layering order

The correct layering sequence for a complete SFI driver safety system is: SFI 3.3 certified socks first, then SFI 3.3 certified undergarment pants and top, then the SFI rated race suit, then SFI 3.3/5 certified gloves, then SFI 3.3/5 certified shoes. This order ensures that every transition point between pieces is covered by at least one layer of certified material, and that the undergarments are properly positioned to provide base-layer protection beneath the suit.

Washing and maintenance

SFI 3.3 Nomex undergarments should be washed in cool or warm water using a gentle detergent without bleach or fabric softeners. Bleach degrades Nomex fibers and reduces fire resistance. Fabric softeners coat the fibers and can reduce their ability to wick moisture and breathe. Air drying is recommended over machine drying to preserve the integrity of the material and the SFI label. Inspect undergarments before each use for tears, worn seams, or areas of significant abrasion — damaged undergarments should be replaced rather than repaired.

When to replace undergarments

SFI certifications on undergarments do not carry an expiry date in the same way that some helmet ratings do, but material condition matters. Undergarments that have been involved in a fire event, regardless of how minor, should be replaced. Significant wear, thinning, or damage to the Nomex material reduces its fire resistance regardless of certification status. Replacing undergarments as part of a regular safety gear review — alongside your suit inspection — is good practice.

Complete Your SFI Safety System with EPIC Racewear

SFI 3.3 undergarments work as part of a system. Every piece of that system is available from EPIC Racewear, produced from Walkerton, Ontario and shipped across Canada and the United States.

SFI 3.3/5 racing gloves cover your hands with two-layer Nomex construction and full custom design options — matching your suit and completing upper body protection at the contact points.

Custom SFI 3.3/5 racing shoes complete the foot and ankle protection layer. Paired with SFI 3.3 Nomex socks, they eliminate every gap in lower body coverage from ankle to toe.

Racing suits certified to SFI 3.2A/1, SFI 3.2A/5, SFI 3.4, and FIA 8856-2018 form the outer layer — the visible custom piece that carries your team colours and sponsor branding while providing the primary fire protection barrier.

Together, these components form a complete, certified driver safety system built by a single Canadian manufacturer, designed to work together, and produced to consistent quality standards. Contact the EPIC Racewear team to order undergarments individually or as part of a full kit package. All orders ship to Canadian provinces and to the United States from Walkerton, Ontario.

Frequently Asked Questions

Are SFI 3.3 undergarments required for racing in Canada? Requirements vary by series and class. Many sanctioned oval track, drag racing, and road racing series in Canada and the United States require SFI 3.3 certified undergarments as mandatory equipment alongside your race suit. Check your specific series technical regulations or contact your sanctioning body to confirm requirements for your class. Even where not required, SFI 3.3 undergarments are strongly recommended by safety professionals.

What is the difference between a Nomex undergarment and a regular base layer? SFI 3.3 certified Nomex undergarments are made from aramid fiber materials that resist burning and do not melt under heat exposure. Standard synthetic athletic base layers can melt and bond to skin in a fire event, significantly worsening injuries. Nomex undergarments char rather than melt, maintaining a protective barrier between the skin and heat source. Only SFI 3.3 certified undergarments meet the requirements of sanctioning bodies that mandate base layers.

Do I need a full set — top, pants, and socks? For complete protection and to meet the requirements of most series that mandate undergarments, yes. A top and pants without certified socks leaves the ankle and foot without Nomex coverage at the skin level, even if your racing shoes have a Nomex lining. The full set — top, pants, and socks — ensures there are no gaps in coverage between your skin and the certified material above it.

How do SFI 3.3 undergarments improve the protection of my race suit? Wearing SFI 3.3 undergarments beneath your race suit adds a complete additional layer of fire-resistant material at the skin level. The combined thermal protection of the undergarment and suit layers together is significantly higher than either piece alone, and the dead air space between layers contributes additional insulation. The practical result is meaningfully more time for a driver to exit the vehicle safely in a fire scenario.

Do EPIC Racewear undergarments ship across Canada? Yes. EPIC Racewear is based in Walkerton, Ontario and ships SFI 3.3 certified racing undergarments to all Canadian provinces as well as to the United States. All orders are produced in Canada and ship from the Ontario facility.