API Std 650 horizontal tank hydrostatic test

The mechanical seal of floating roof API Std 650 horizontal tank relies on mechanical force to press the sealing steel plate tightly against the tank wall, so that it can slide on the tank wall and avoid gap as far as possible. However, mechanical seal has high requirements for the geometry of storage tank and poor adaptability, so mechanical seal is rarely used in newly built floating roof API Std 650 horizontal tank.

The impact tests for API 620 welded storage tanks used pipe (including structural members made of pipe), bolting, and forgings, shall be in accordance with ASTM specifications ASTM A333 (seamless only) pipe, ASTM A36 Mod 1 plate, ASTM A131 Grades CS, D, and E steel plate, ASTM A633 Grade A CSA G40.21 Grades 38WT, 44WT and 50WT high-strength low-alloy structural steel plate, ASTM A350 carbon and low alloy steel forgings, and ASTM A320 Grade L7 bolts.

Welding certification is regulated by Section 10 of the American Society of Mechanical Engineers (ASME). For both API Std 650 horizontal tank storage tank API 650, non-destructive inspection is required, but third-party inspection is not required.