The purpose of the IOGP S-742 specification documents is to define a minimum common set of requirements for the procurement of medium-voltage AC contactors, controllers, and control centers in accordance with UL 347, seventh edition, published in November 2020, UL Standard for Safety for Medium-Voltage AC Contactors, Controllers, and Control Centers for application in the petroleum and natural gas industries. The IOGP S-742 specification documents follow a common structure comprising a specification, also known as a technical requirements specification (TRS), a procurement data sheet (PDS), an information requirements specification (IRS) and a quality requirements specification (QRS). These four specification documents, together with the purchase order, define the overall technical specification for procurement.