Coverage. This specification describes optimum requirements for assemblies designed for the unattended automatic custody transfer (ACT) of liquid hydrocarbons@ such as crude oil and condensate@ at rates below 11@000 U.S. barrels (1750m3) per 24-hour day@ in field applications at less than 500 psig (3447 kPa) operating pressure. One design configuration illustrating acceptable locations for the transfer pump@ positive displacement liquid meter@ monitor probe@ sampling system@ piping@ valves and controls is presented in Fig@ 1.1 and 1.2. Although this specification contains only one design configuration@ it is recognized that other component arrangements are possible. Any design that meets the requirements of this specification is acceptable by agreement between purchaser and fabricator. Appendix A contains specification data sheets for a standard API LACT Unit. Two identical data sheets are shown@ one with U.S. Customary units and the other with metric units. Required ACT system elements not described in this specification include the surge tank@ electrical power and instrument gas supply@ signals to start and stop the pump@ piping and valves. Compliance with the provisions of this specification may result in an approach to accuracy or may establish safeguards not necessary under all conditions. By agreement between the purchaser and fabricator@ non mandatory portions of this specification may be waived. The compulsory verb form shall has been used where a deviation from the requirements may adversely affect the satisfactory operation of a system designed for optimum operation under typical producing conditions. This specification presents the concurrence of the industry on current system requirements for ACT@ There is equipment now in the design or field- .proving stage that may further improve the art of ACT@ Such developments are encouraged and every effort should be made to expedite their reduction to practice and standardization. Policy. American Petroleum Institute (API) specifications are published as an aid to procurement of standardized equipment and materials. These specifications are not intended to inhibit purchasers and producers from purchasing or producing products made to specifications other than API@ and nothing in any API specification is intended to in any way inhibit the purchase of products from companies not authorized to use the API monogram.* Nothing contained in any API specification is to be construed as granting any right@ by implication or otherwise@ for the manufacture@ sale@ or use in connection with any method@ apparatus@ or product covered by letters patent@ nor as insuring anyone against liability for infringement of letters patent. API specifications may be used by anyone desiring to do so@ and every effort has been made by the Institute to assure the accuracy and reliability of the data contained in them. However@ the Institute makes no representation@ warranty@ or guarantee in connection with the publication of any API specification and hereby expressly disclaims any liability or responsibility for loss or damage resulting from their use@ for any violation of any federal@ state or municipal regulation with which an API specification may conflict@ or for the infringement of any patent resulting from the use of an API specification. The use of the API monogram is a warranty by the manufacturer to the purchaser that the manufacturer has obtained a license to use the monogram and@ further@ that the product which bears the monogram conforms to the applicable API specification. However@ the American Petroleum Institute does not represent@ warrant@ or guarantee that products bearing the API monogram do in fact conform to the applicable API standard or specification. This specification is tentative and the API monogram shall not be applied to LACT units fabricated in accordance with the specification until the tentative classification has been removed. *The API monogram??AP ??is a registered trademark of the American Petroleum Institute.