API Std 650 carbon steel tank convective spectral acceleration parameter

Aftershock Level Earthquake (ALE)
This design case shall be applicable only when regulations or project documents specifically require the tank system to be designed or evaluated for aftershocks.
If the outer tank is not designed as a secondary containment (i.e. it serves as vapor barrier and pressure boundary only and is not constructed of API 620 material suitable for the inner tank API Std 650 carbon steel tank), then no design or evaluation for ALE is required by these provisions for the inner or outer tank.

Before pressure test, the main drain hose system of API 650 petroleum storage tank floating roof should be thoroughly flushed. Provide blind flanges, gaskets and bolts required for the API Std 650 carbon steel tank test (other types of covers are also required if necessary). Covers for maintenance shall be provided in accordance with the interfaces specified by API 650 petroleum storage tanks, and these seals shall remain in place after the test; and for those interfaces that are not provided for maintenance covers, the covers can be removed after the API Std 650 carbon steel tank test.

The safety inspection of atmospheric storage tank, API Std 650 carbon steel tank 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 carbon steel tank 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.