How to limit evaporation of liquid contents from API standard 650 self-anchored storage tanks

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 standard 650 self-anchored storage tanks), then no design or evaluation for ALE is required by these provisions for the inner or outer tank.

One of the most widely used design codes is the API 650 Standard, from the American Petroleum Institute. The main objective of this standards API standard 650 self-anchored storage tanks is, through the requirements contained in its various sections, to facilitate the purchase and construction of vertical, aboveground, welded fabricated tanks assuring that required safety regulations are met.

Define the welding sequence of API standard 650 self-anchored storage tanks bottom plate: the welding sequence of metal vertical storage tank shall be carried out according to the procedure required by the welding scheme. Spot welding shall be consistent with the formal welding requirements, and no spot welding shall be carried out for the weld not welded. Back bar should be added to prevent deformation when welding the full length seam of middle plate, butt joint of edge plate and turtle shell joint.