This article presents a some of standards on steel materials and welding consumables specified in EN 14015:2004 and a some of Vietnamese standards (TCVN) on steel materials and welding consumables that can be used for flat-bottomed cylindrical tanks for storing liquids at ambient temperature or above. At the same time, the calculation method and numerical example for the calculation of the tank wall, earthquake effects, tank anchorage and over stability are presented in accordance with EN 14015:2004, in order to supplement the regulations when calculating the tank according to EN 1993-4-2 and EN 1998-1-1 and in accordance with some current Vietnamese standards. Keywords: Welded steel tanks, EN 14015:2004.