The provisions of this section apply for calculating evaporative emission credits related to fuel tank permeation. You may generate credits only if you are a certifying equipment manufacturer. This may include engine manufacturers that make engines with complete fuel systems as described in § 1054.2 .
Emission credits (kg) = (STD-FEL) * (Total Area) * (UL) * (AF) * (365) * (10-3 )
Where:
STD = the emission standard, in g/m2 /day.
FEL = the family emission limit for the family, in g/m2 /day, as described in paragraph (b) of this section.
Total Area = The combined internal surface area of all fuel tanks in the family, taking production volume into account, in m2 .
UL = 5 years, which represents the useful life for the given family.
AF= adjustment factor. Use 1.0 for testing at 28 °C; use 0.60 for testing at 40 °C.
40 C.F.R. § 1054.706