Fuel lines into underground storage or dispensing areas shall be drained at the completion of each transfer of fuel unless the following requirements are met:
(a) The valve at the supply source shall be kept closed when fuel is not being transferred.
(b) The fuel line shall be-
(c) Provisions shall be made for control or containment of the entire volume of the fuel line so that leakage will not create a fire hazard.
053-3 Wyo. Code R. § 57.4505