CHAPTER 7 COMPETITOR VEHICLES AND VEHICLE SAFETY Appendix 4- Fuel and Fuel Systems
1. General
1.1. Permitted Fuel All Competitors must use Permitted Fuel( see definition Chapter 8 and Chapter 1 App. 1) except subject to prior written authority having been given by the ASN where permitted otherwise under Event Official Documents and Championship Regulations.
1.2. Fuel Tanks and Pipes Every effort should be made to isolate fuel tanks and pipes from the Driver / Passenger compartment.
1.3. The risk of fuel spillage from accident damage can be reduced by use of Safety Fuel Cells or by bag type tanks or by coating metal tanks with GRP.
1.4. Tanks should be located so that they are given maximum protection by the structure of the Vehicle.
1.5. Where applicable the entire fuel tank area‘ Licked’ by the open air-stream must incorporate a crushable structure as below.
1.6. Vents should be designed to avoid spillage if the Vehicle becomes inverted. 1.7. Fuel Fillers should be designed and located to reduce risk of damage.
1.8. Filler caps should not be liable to open in the case of an accident. Simple screw caps are effective. The positive locking of the fuel filler cap( s) is recommended.
1.9. The filler pipe to the tank should be of minimum possible length and not protrude beyond the bodywork.
2. Tank Fillers, Vents and Caps
2.1. Tank fillers and caps must not protrude beyond the bodywork or be situated within the Driver / Passenger compartment. The caps must have an efficient locking action to reduce the risk of opening during an accident and to ensure closing after refuelling.
2.2. Air vents must be at least 250mm to the rear of the cockpit and must be designed to prevent the escape of fuel should the Vehicle be inverted. It is recommended that a non-return valve is incorporated in the vent system.
3. Crushable Structure
3.1. The crushable structure should be a sandwich construction based on a fire-resistant core of minimum crushing strength 25lb / sq in. It is permitted to pass water pipes through this core.
3.2. The minimum thickness of the sandwich construction must be 10mm.
3.3. The fore and aft fuel tank area, however, must provide for a crushable structure of at least 100mm thickness at its thickest point and over a length of at least 350mm after which it may be generally reduced to 10mm. The position of this widest point to be at the constructor’ s discretion.
3.4. The sandwich construction must include two sheets of 1.5mm thick aluminium sheet having a tensile strength of 14 tons / sq in and minimum elongation of 5 %.
4. Safety Fuel Cells
4.1. The FIA approved standard for Safety Fuel Cells is FIA Standard FT3-1999, FT3.5-1999 and FT5-1999. Fuel cells complying with this standard are only manufactured by authorised companies and bear the FIA Homologation Label on each cell.
4.2. No other cells are approved by the FIA.
4.3. At International Status Events. Under FIA Regulations the homologation expires once the cell is five years old. The validity of this homologation may be extended for a further two years if the cell is inspected and recertified by the original manufacturer.
Motorsport UK 2025 National Competition Rules Version 11
Chapter 7 Appendix 4- Fuel and Fuel Systems 260