1.1 General
This European Standard defines a Calculation method for bolted, gasketed, circular flange joints. Its purpose is to ensure structural integrity and control of leaktightness. The following equations use gasket parameters based on definitions and test methods specified in EN 13555.
1.2 Requirement for use of the Calculation method
Where permitted, the Calculation method is an alternative to design validation by other means e.g.
- special testing
- proven practice
- use of standard flanges within permitted conditions.
1.3 Validity
1.3.1 Geometry
The Calculation method is applicable to the configurations having:
- flanges whose section is given or may be assimilated to those given in Figures 4 to 12
- four or more identical bolts uniformly distributed
- gasket whose section and configuration after loading can be assimilated by one of those given in Figure 3
- flange dimension which meet the following conditions:
a) 0,2 ≤ bF/ eF ≤ 5,0 0,2 ≤ bL/ eL ≤ 5,0
b) eF ≤ max {e2 dB0 pB x }
c)
NOTE For explanations of symbols see clause 3.
NOTE The condition bF/ eF ≤ 5,0 need not be met for collar in combination with loose flange.
NOTE The condition is for limitation of non-uniformity of gasket pressure due
to spacing of bolts. The values 0,01 and 0,10 are to be applied for soft (non-metallic) and hard (metallic)
gaskets respectively. A more precise criterion is given in annex A.

NOTE Attention may need to be given to the effects of tolerances and corrosion on dimensions reference should be made to other codes under which the calculation is made, for example values are given in EN 13445 and EN 13480.
The following configurations are outside the scope of the Calculation method:
- flanges of essentially non-axisymmetric geometry, e.g. split loose flanges, web reinforced flanges