NEN EN 12952-3 : 2012

Foreword
1 Scope
2 Normative references
3 Terms and definitions
4 Symbols and abbreviations
5 General
   5.1 Purpose
   5.2 Dimensions of pressure parts
   5.3 Strength of pressure parts
   5.4 Design by analysis
   5.5 Cyclic loading
   5.6 General design requirements
   5.7 Design and calculation pressures
   5.8 Metal wastage
   5.9 Attachments on pressure parts
6 Calculation temperature and nominal design stress
   6.1 Calculation temperature
   6.2 Maximum through-the-wall temperature difference
       and maximum flue gas temperature for heated drums
       and headers
   6.3 Design stress
7 Cylindrical shells of drums and headers under internal
   pressure
   7.1 Shell thickness
   7.2 Basic calculation
   7.3 Combined stresses in drum and header shells
   7.4 Boiler drum supports
   7.5 Other stresses in cylindrical shells
8 Openings and branches in cylindrical shells of drums
   and headers and integral tubes
   8.1 General
   8.2 Efficiency factor, calculation by way of approximation,
       and maximum diameter of unreinforced openings
   8.3 Design of openings and branches in cylindrical
       shells (efficiency and reinforcement)
   8.4 Bolted connections
   8.5 Screwed connections
9 Headers and plain tubes of rectangular section
   9.1 General
   9.2 Symbols and abbreviations
   9.3 Required wall thickness
10 Ends and spherical shells
   10.1 Symbols and abbreviations
   10.2 Spherical shells and dished ends
   10.3 Unstayed flat ends
   10.4 Flat unstayed closures
11 Tubes
   11.1 Symbols and abbreviations
   11.2 Thickness of straight boiler tubes
   11.3 Thickness of tube bends and elbows
   11.4 Flexibility of integral tubing tube systems
   11.5 Structural attachments to tubes
   11.6 Fitting and joining of heated tubes
   11.7 Joining of unheated tubes
12 Pressure parts of irregular shape
   12.1 Hydrostatic test for determining the allowable
        internal pressure
   12.2 Numerical methods
13 Fatigue
   13.1 General
   13.2 Symbols and abbreviations
   13.3 Exemption rule for fatigue analysis
   13.4 Stress analysis for fatigue calculation
   13.5 Example calculations
Annex A (normative) Calculation of tube bends and elbows
    A.1 General
    A.2 Symbols and abbreviations
    A.3 Required wall thickness
    A.4 Calculation
Annex B (normative) Fatigue cracking - Design to allow
        for fluctuating stress
    B.1 General
    B.2 Conditions
    B.3 Symbols and abbreviations
    B.4 Cyclic stress range and mean cyclic stress in the
        case of uniaxial and multiaxial fluctuating stress
    B.5 Correction factors for taking into account the
        influences of surface finish and weldments
    B.6 Controlling stress range
    B.7 Permissible stress range with a known number of load
        cycles
Annex C (informative) Examples of calculating the effects of
        fatigue
    C.1 General
    C.2 Calculation of the admissible of load cycles
    C.3 Calculation of the admissible temperature gradient
Annex D (informative) Physical properties of steel
        D.1 General
        D.2 Symbols and abbreviations
        D.3 Physical properties .
        D.4 Physical properties of steels
Annex ZA (informative) Clauses of this European Standard
         addressing essential requirements or other provisions
         of the Pressure Equipment Directive
Bibliography

Defines the requirements for the design and calculation of water-tube boilers as defined in EN 12952-1.