"This specification covers sizes@ materials@ plate thicknesses@ and design factors for light-weight all-welded steel production tanks@ together with stipulations on cleanouts@ walkways@ and stairways. Unless otherwise state@ all detailed requirements for design@ welding procedure@ constructional details@ testing@ inspection@ etc.@ shall conform to API Std. No. 12-C: ""API Specification on All-welded Oil-Storage Tanks."" 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."