For purposes of this Subpart K, the following definitions apply:
"Airport hydrant fuel distribution system" or "airport hydrant system" means a UST system that fuels aircraft and operates under high pressure with large diameter piping which typically terminates into one or more hydrants (fill stands). The "airport hydrant system" begins where fuel enters one or more tanks from an external source such as a pipeline, barge, rail car, or other motor fuel carrier.
"Field-constructed tank" means a tank constructed in the field. For example, a tank constructed of concrete that is poured in the field, or a steel or fiberglass tank primarily fabricated in the field is considered field-constructed.
Ill. Admin. Code tit. 35, § 731.250