scope:

This recommended practice should be considered as a guide on new tank installations and maintenance of existing tanks. It contains recommendations for good practices in (a) the collection of well or lease production, (b) gauging, (c) delivery to pipeline carriers for transportation, and (d) other production storage and treatment operations. In particular, the spill prevention and examination/inspection provisions of this recommended practice should be companion to the spill prevention control and countermeasures (SPCC) to prevent environmental damage.

This recommended practice is intended primarily for application to tanks fabricated to API Specifications 12B, D, F, and P (sometimes called the API 12 series in this document) when employed in on-land production service; but its basic principles are applicable to atmospheric tanks of other dimensions and specifications when they are employed in similar oil and gas production, treating, and processing services. It is not applicable to refineries, petrochemical plants, marketing bulk stations, or pipeline storage facilities operated by carriers. Tanks fabricated to API Standard 650 or its predecessor (API Standard 12C) should be maintained in accordance with API Standard 653.

This document recommends maintenance practices based on the estimated corrosion rate life of various tank components. Corrosion rate life of tank components will vary widely with location, environment, service, type of fluid, and corrosion mitigation techniques elected by the owner/operator. Recommendations for specific corrosion mitigation techniques are not within the scope of this document. For such recommendations, see publications of the National Association of Corrosion Engineers (NACE) (see Section 2).

This document contains some specific safety recommendations applicable to tanks. For complete safety recommendations, see publications of the API Committee on Safety and Fire Protection.

The schematic drawings included in this publication are examples only of some features described in the document. Numerous variations in piping systems and tank components are known to give satisfactory service. Unusual grades of crude, particularly heavier grades, may cause the owner/operator to elect other equally satisfactory practices.

Lease automatic custody transfer (LACT) operations are covered in API Specification 11N, and in the API Manual of Petroleum Measurement Standards, Chapter 6.1.