API Std 650 liquid-storage tanks heat-affected zone

The safety inspection of atmospheric storage tank, API Std 650 liquid-storage tanks is divided into external inspection, internal and external inspection and comprehensive inspection. External inspection shall be conducted at least once a year, internal and external inspection shall be conducted at least once every three years, and comprehensive inspection shall be conducted at least once every six years. The safety inspection of large atmospheric storage tanks, API Std 650 liquid-storage tanks requires special attention: the parts where the liquid level often fluctuates, the parts that are susceptible to corrosion, and the parts that are deformed and worn during use should be checked.

Hydrostatic Test
The API Std 650 liquid-storage tanks product shall be vented to the atmosphere when it is filled with or emptied of water. During water filling, the elevations of at least four equidistant points at the bottom of the tank shell and on top of the ringwall or slab shall be checked. Differential settlement, or uniform settlement of substantial magnitude, requires an immediate stop to water filling. Any further filling with water will depend on an evaluation of the measured settlement.

According to API standard 650, the stairs used for API 650 petroleum storage tanks or thermal insulation tanks should be double longitudinal beams supported by a minimum of ribs. If the gap between the API Std 650 liquid-storage tanks tank shell and the stringer of the API 650 petroleum storage tank exceeds 200mm, handrails should be provided on both sides of the stairs. Unless otherwise specified, according to API Std 650 liquid-storage tanks ASTM A123, the following accessories shall be hot-dip galvanized. The damaged zinc coating should be repaired with zinc alloy.