(a) All LPG facilities within the State of New York are to be constructed, operated and maintained, except as otherwise provided in this Part, in accordance with Standard for the Storage and Handling of Liquefied Petroleum Gases at Utility Gas Plants, ANSI/NFPA 59 (as described in section 10.3 of this Title) (referred to in this Part as NFPA 59), and such codes, specifications and standards referred to in the NFPA 59. Those provisions of the NFPA 59 or associated references that have been indicated to be optional by phraseology, including “should,” “preferably,” “may” or “such as” (illustrative only), are mandatory in accordance with the intent of the NFPA 59 except where an obvious contradiction occurs.