API Std 650 stainless steel storage tanks subsurface investigation and construction

The factors affecting the "small breathing" loss of API Std 650 stainless steel storage tanks are: 1. It is related to the change of temperature difference between day and night. The greater the change of temperature difference between day and night, the greater the loss of "small breathing"; on the contrary, the smaller the change of temperature difference between day and night, the smaller the loss. 2. It is related to the sunshine time of the oil storage tank. The longer the sunshine, the more the "small breathing" loss; otherwise, the less the loss.

All API Std 650 stainless steel storage tanks fillet welds shall consist of a minimum of two passes. The ends of the fillet welds shall be 2 in. from the rat hole, and these welds shall be deposited by starting 2 in. from the rat hole and welding away from the rat hole. An acceptable alternative to stopping fillet welds 2 in. short of the rat hole would be to weld continuously through the rat hole from one side of the stiffener to the opposite side. All craters in fillet welds shall be repaired by back welding.

API 650 vertical tanks meet American Petroleum Industries (API) standards in design, material, fabrication, and testing of aboveground welded steel API Std 650 stainless steel storage tanksstorage tanks for use in industrial applications.