"Scope and Purpose This recommended practice (RP) contains basic requirements for the design@ construction@ operation@ and maintenance of pre-airfield storage terminals located directly upstream of the airport@ hereafter referred to as ""preairfield storage terminals."" Mandatory requirements in this standard are designated by the word ""shall."" Recommendations are designated by the word ""should."" Optional items are designated by the word ""may."" This standard incorporates by reference a number of other standards and recommended practices that need to be referred. The distinction between mandatory@ recommended@ and optional provisions in the referenced documents is not changed by nature of their reference in this standard. The values stated for this standard are in U.S. Customary units."