"These rules are intended to cover the design and construction of large@ welded@ low-pressure@ carbon steel@ aboveground storage tanks which have a single vertical axis of revolution and are operated at metal temperatures not greater than 200 F and with pressures in their gas or vapor spaces exceeding those permissible under API Standard 650: Welded Steel Tanks for Oil Storage (formerly API Standard 12C)@ but not exceeding 15 psig. Provision is made for installations in areas where the lowest recorded one-day mean atmospheric temperature is as low as -50 F. Appendix R covers low-pressure storage tanks for refrigerated products from + 40 F to - 60 F. These rules may be used for tanks intended either for holding or storing liquids with gases or vapors above the surface of the liquid or for holding or storing gases or vapors alone@ but do not apply to ""lift-type"" gas holders. Although these rules are not intended to cover horizontal tanks@ they are not intended to preclude the application of appropriate portions hereof to the design and construction of horizontal tanks designed in accordance with good engineering practice@ in which the details not covered by these rules are no less safe than the design and construction provided herein for tanks of the shapes expressly covered."
API STD 620-1970 history
2013API STD 620-2013 Design and Construction of Large@ Welded@ Low-pressure Storage Tanks (TWELFTH EDITION; ADD 1: November 2014)
2008API STD 620-2008 Design and Construction of Large@ Welded@ Low-pressure Storage Tanks (Eleventh Edition; Incorporating Addendum 1: March 2009; Addendum 2: August 2010)
2002API STD 620-2002 Design and Construction of Large@ Welded@ Low-Pressure Storage Tanks (Tenth Edition; Addendum 1: June 2004)
1996API STD 620-1996 Design and Construction of Large@ Welded@ Low-pressure Storage Tanks (Ninth Edition; Includes Addendum 1: December 1996 and Addendum 2: December 1997)
1990API STD 620-1990 Design and Construction of Large@ Welded@ Low-pressure Storage Tanks (Eighth Edition; Incorporating Errata: August 1992)
1982API STD 620-1982 Recommended Rules for Design and Construction of Large@ Welded@ Low-Pressure Storage Tanks (Seventh Edition; Incorporating Revision 1@ April 1985)
1978API STD 620-1978 Recommended Rules for Design and Construction of Large@ Welded Low-Pressure Storage Tanks (SIXTH EDITION)
1970API STD 620-1970 Recommended Rules for Design and Construction of Large@ Welded@ Low-pressure Storage Tanks (Fourth Edition)
1966API STD 620-1966 Recommended Rules for Design and Construction of Large@ Welded@ Low-Pressure Storage Tanks (FIFTH EDITION; SUPP 3: August 1975)
1963API STD 620-1963 RECOMMENDED RULES FOR DESIGN AND CONSTRUCTION OF LARGE@ WELDED@ LOW-PRESSURE STORAGE TANKS (SECOND EDITION)