API 650 welded storage tanks internal floating roof loads

The manufacturing requirements of bottom plate of vertical metal tank, API 650 welded storage tanks are as follows: 1. In order to compensate welding shrinkage, the layout diameter of tank bottom is 5-2mm than the design diameter; 2. The butt joint of edge plate of tank bottom shall be machined automatically or semi-automatically; 3. The distance between any two adjacent welding joints on the tank bottom plate and the distance between the butt joint of edge plate and the longitudinal weld of bottom ring wall plate shall not be greater than 200 mm.

For all API 620 crude oil tank other materials, the impact test temperature shall be at least 30°F colder than the design metal temperature. Alternately, materials impact tested at the design metal temperature or lower with Charpy impact test energy value of 25 ft-lb (average), 20 ft-lb (minimum) are acceptable for design metal temperatures above –40°F. API 650 welded storage tanks materials with an energy value of 30 ft-lb (average), 25 ft-lb (minimum) are acceptable for design metal temperatures of –40°F or lower.

API standard 650, Welded Tanks for Oil Storage, Thirteenth Edition, has been published to ensure the safety, sustainability, and environmental performance of API 650 welded storage tanks oil storage tanks. The updated standard will help continue operational excellence and trust between operators and manufacturers.