We have provided a comparative analysis of the current international computing standards (European Standard EN 13445-3; ASME-Code, Section VIII, Division 2; British Standard (PD 5500: 2009)) that take into consideration only the static loading of flanges and bolts, if the temperatures of the flanges, bolts and sealing gasket are equal to each other and lower than creep temperature. The paper has put forth relations for completion the calculation method for flange joints in situations not taken into consideration by standards, namely: -static loading if flange temperature and bolt temperature are different; -thermal transient loading; -creep stress; -fatigue loading in the general case of a sequence of blocks of normal stresses. Furthermore, relationships have been proposed for the calculation of the maximum allowable difference between a flange and a bolt so as to ensure both the tightness and the mechanical strength of the flange joint.

The paper presents recently published literature research on the tightness and strength of flange joints. These could influence both the calculation and the maintenance of flange joints. Some of the research results have been compared to normative stipulations currently used in the calculation of flange joints. The presentation covers: – the influence of sealing gasket design and screw load on sealing; – the influence of creep on screw relaxation, and thereby on gasket sealing; – cracking in flange joints; – the influence of an additional axial force of flange joints on the rotation and on the deformation of flange joint components; – flanges without sealing gasket; – the influence of the method of flange joint bolt tightening on the uniformity of bolts loading and tightness.