GENERAL a. This specification covers material@ design@ fabrication@ erection@ and testing requirements for vertical cylindrical aboveground@ closed and open-top@ welded steel storage tanks in various sizes and capacities@ for internal pressures approximating atmospheric pressures. b. This specification is designed to provide the oil industry with tanks of adequate safety and reasonable economy for use in the storage of petroleum and its products and those other liquid products commonly handled and stored by the various branches of the industry. It does not present@ nor is it contemplated to establish@ a fixed series of allowable tank sizes; but rather it is intended to permit the selection by the purchaser of whatever size of tank may be required to best meet his particular needs. This specification is for the convenience of purchasers and manufacturers in ordering@ fabricating@ and erecting tanks and is not intended to prohibit purchasers and manufacturers from purchasing and fabricating tanks meeting specifications other than those contained herein; nor is it intended in any way to prohibit purchasers from purchasing tanks from companies not authorized to use the API monogram. c. Appendix A to this specification presents for ready reference design data relating to tanks which may be built according to specifications contained herein. The data presented in Appendix A are for convenience and are not required in order to comply with this specification. d. Appendix D to this specification presents an alternate design basis for tank shells. e. Nothing contained in this specification is to be construed as granting any right@ by implication or otherwise@ for 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. COMPUANCE The manufacturer is responsible for complying with all of the provisions of this specification. The purchaser may make any investigation necessary to satisfy himself of compliance by the manufacturer@ and he may reject any material that does not comply with this specification. It is urged that the purchaser avail himself of this right and furnish his own inspection independently of any supervisory inspection furnished by the manufacturer@ and that the purchaser's inspector follow closely all of the details of field construction and testing herein specified which affect the integrity and safety of the completed structure.