What is the minimum inside diameter of vent openings in the fuel tank?

For fuel tank vent openings, the minimum inside diameter should be 5/16 inch. This size is established to ensure that venting is adequate for the safe release of vapors and positive pressure built up within the tank during operation or temperature changes. A vent that is too small could lead to a potential hazard, as it would not relieve pressure effectively, causing the fuel tank to become over-pressurized and possibly leading to leaks or ruptures. This specification is part of safety measures aimed at preventing fire hazards and ensuring proper fuel system operation in accordance with industry standards.

Larger diameters, while sometimes beneficial, are not the minimum requirement, and smaller diameters could compromise the function of the venting system, increasing risks associated with fuel systems.