scope:

Std. 12-C covers general specifications, including chemical and physical properties by reference to ASTM standards; together with permissible working stresses in welded tank joints and in reinforcement of openings, with complete details on erection, inspection, testing, repairs during construction, on welding, including definitions of joints, and qualification procedure for welding operators and for welding procedures.

While Std. 12-A on Riveted Tanks provides scope rate details drawings, these are not necessary in the case of Std. 12-C on Welded Tanks, although the printed specification contains explanatory sketches, showing types of joints, etc. Std. 12-C permits the manufacture of tanks of any size, consistent with current practice, and in that respect differs from Std. 12-A (Riveted Tanks), which definitely fixes. the. .diameters and heights of riveted tanks. Tanks under Std. 12-C may have any width of shell plates, with minimum of 72", and in any desired combination of. wide and narrow courses. Plate-thickness limits are included.

Std. 12-C gives complete specifications, including sketches, on appurtenances. such as shell and roof manholes and nozzles, draw-off elbows and sumps, and platforms, stairways and walkways for all welded Oil storage tnks.

The API monogram is permitted by licensed manufacturers under Std. 12-C, Fourth Edition, by means of a standard name plate, the same as stipulated in Std. 12-A, to be placed on the reinforcing plate, or shell plate immediately above the manhole.