API 650 low-alloy steel tanks allowable longitudinal membrane compression stress in shell

The longer the service life of the API 650 low-alloy steel tanks, the lower the reliability and the prone to failure. Doing a good job in the maintenance of the metal oil tank can ensure the normal use of the oil tank, reduce the wear of the API 650 low-alloy steel tanks body and accessories, and extend the service life of the oil tank. The maintenance of metal oil tanks is mainly to do a good job in the anti-corrosion of the oil tank, the cleaning of the deposits in the API 650 low-alloy steel tanks and the overhaul of its accessories. Regularly inspect and maintain the accessories of the oil tank: valves, oil measuring holes, breathing valves, flame arresters, ladders, foam fire extinguishing generators, etc., and make records. If any damage is found, repair them in time.

Service Conditions and Hydrogen-induced Cracking
When the service conditions might include the presence of hydrogen sulfide or other conditions that may promote hydrogen-induced cracking effects, particularly near the bottom of the API 650 low-alloy steel tanks shell at the shell-to-bottom connections, care shall be taken to ensure that the materials and details of construction of the tank are adequate to resist hydrogen- induced cracking. The Purchaser shall consider restricting the sulphur content of the material to be stored through thickness testing of the steel, laboratory surveillance tests, and the use of internal tank coatings to reduce the possibility of hydrogen-induced cracking.

This specification, in conjunction with API 650 Standard, prescribes minimum standards for the API 650 low-alloy steel tanks design, supply, fabrication, erection, and testing of field erected welded steel storage tanks complete with accessories as specified herein and as shown on attached Datasheets and/or Drawings.