This specification covers vertical@ cylindrical@ welded@ above-ground@ steel tanks for oil storage@ including allowable plate and joint stresses@ qualification procedures for welding@ and chemical and physical properties of materials@ including electrodes. This specification also includes stipulations on appurtenances@ such as manholes@ nozzles@ stairs@ etc.@ together with stipulations on inspection@ including sectioning methods for testing welded joints. This specification is designed to provide the industry with tanks of adequate safety and reasonable economy@ which can be built in any sizes required to meet the needs of the several branches of the industry subject to the physical limitations imposed hereinafter and by recognized field erection practices. 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 meet best his particular needs. Appendix A to this specification presents for ready reference typical data relating to tanks which may be built under this specification. Data presented therein are for convenience and are not mandatory. 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. Compliance. 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 may reject any material that does not comply with this specification.