Seat Belt Expiry Dates

Laurie Callender General Safety, Seatbelts

Recently SFI changed the labelling on their seat belts to show an expiry date and not a date of manufacture. This brings their labelling in line with FIA approved belts which also have an expiry date. For SFI belts the expiry is 2 years and they do this because of the deterioration of the nylon webbing as noted below.
The rate at which the breaking strength of the webbing decreases with outdoor exposure is illustrated in the graph below. The webbing used in motorsports restraints is typically made with DuPont Nylon 6-6 or a similar product. According to the data, the webbing loses about half of its strength in one year.

FIA belts typically have an expiry date of 5 years. The reason for this is that in the main they use Polyester rather than Nylon for their webbing and their testing obviously shows less deterioration due to sunlight etc .
However it goes without saying that belts must always be in good condition and a Scrutineer can still fail seat belts if they find any issues such as fraying, holes etc. Ensure your belts are well looked after and it is highly recommended they be removed from the vehicle after each meeting before the vehicle is washed or has any repair work (welding etc.) carried out.

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