Technical drawing of ASME B16.11 90° elbow with socket welding ends. A: center-to-bottom of socket; B: socket bore diameter; D: bore diameter of elbow; C: socket wall thickness; G: body wall thickness; J: socket depth.
The technical drawing of ASME B16.11 90° elbow with NPT threaded ends. A: center-to-end of threaded elbow; H: outside diameter of band; G: minimum wall thickness; B: minimum length of perfect length; L2: length of useful thread.

ASTM A213 Gr. TP316L seamless tubes can be further classified as TP316L boiler tubes, TP316L superheater tubes, and TP316L heat exchanger tubes, according to the service it is used for. The tubing is usually specified by outside diameter and minimum wall thickness, or average wall thickness. Sometimes the wall thicknesses are specified by Birmingham Wire Gauge (B.W.G) numbers.