Wash. Admin. Code § 51-52-1305
1305.7 Vent piping. Liquid fuel vent pipes shall terminate outside of buildings at a point not less than 5 feet (1524 mm) from building openings and not less than 15 feet (4572 mm) from outdoor air intakes. Outer ends of vent pipes shall terminate in a weatherproof vent cap or fitting or be provided with a weatherproof hood. Vent caps shall have a minimum free open area equal to the cross-sectional area of the vent pipe and shall not employ screens finer than No. 4 mesh. Vent pipes shall terminate sufficiently above the ground to avoid being obstructed with snow or ice. Vent pipes from tanks containing heaters shall be extended to a location where oil vapors discharging from the vent will be readily diffused. If the static head with a vent pipe filled with oil exceeds 10 pounds per square inch (psi) (69 kPa), the tank shall be designed for the maximum static head that will be imposed.
Liquid fuel vent pipes shall not be cross connected with fill pipes, lines from burners, or overflow lines from auxiliary tanks.
EXCEPTION: | Liquid fuel vent pipes may terminate outside the building at a point not less than 2 feet from the fuel oil equipment combustion exhaust outlet. |
Wash. Admin. Code § 51-52-1305