API Std 650 duplex stainless steel tanks toughness requirements of plates

API 620 Crude Oil Tank Pneumatic Pressure
An air pressure equal to 1.25 times the pressure for which the vapor space is designed shall be applied to the enclosed space above the water level. In the case of a double-wall tank with an open-top inner tank, where the air pressure acts against the outer tank and the inner tank is thus not stressed by the air pressure, the inner API Std 650 duplex stainless steel tanks may be emptied of water before the pneumatic pressure test begins. The test pressure shall be held for 1 hour.

Floating roofs shall comply with API standard 650, Appendix C (Attachment 01) or with the API Std 650 duplex stainless steel tanks requirements as layed (laid )down in the national Chinese specifications SH3046-92 and GBJ128-90.

The longer the service life of the API Std 650 duplex stainless 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 Std 650 duplex stainless 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 Std 650 duplex stainless 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.