API 650 duplex stainless steel tanks sheel openings

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 650 duplex stainless steel tanks), then no design or evaluation for ALE is required by these provisions for the inner or outer tank.

Before pressure testing, thoroughly flush the API 650 tank floating roof primary drain hose system. Supply API 650 duplex stainless steel tanks blind flanges, gaskets, and bolting (for other types of blanking covers as may be required) necessary for testing.

The construction period comparison of mechanical cleaning and manual cleaning for vertical storage tank, API 650 duplex stainless steel tanks. The API 650 duplex stainless steel tanks mechanical cleaning period is short, and the construction period is not affected by the size of the storage tank and the amount of sludge in the tank, and the cleaning equipment operates 24 hours a day. The manual cleaning of the API 650 duplex stainless steel tanks has a long construction period, which is easily affected by the external environment, and the number of workers is limited by the size of the storage tank and the amount of sludge.