ДСТУ ЕN 12952-3:2025 Водотрубні котли та допоміжні установки. Частина 3. Проєктування та розрахунок деталей, що працюють під тиском (EN 12952-3:2022, IDT)



ДСТУ EN 12952-3:2025
(EN 12952-3:2022, IDT)

Водотрубні котли та допоміжні установки. Частина 3. Проєктування та розрахунок деталей, що працюють під тиском

 
   
 
 
     
Не є офіційним виданням.
Офіційне видання розповсюджує національний орган стандартизації
(ДП «УкрНДНЦ» http://uas.gov.ua)

Contents

European 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 Other design requirements

5.6.1 General

5.6.2 Access

5.6.3 Drainage and venting

5.7 Design, calculation and test pressures

5.7.1 Design pressure

5.7.2 Calculation pressure

5.7.3 Calculation pressure for pressure differences

5.7.4 Hydrostatic test

5.8 Metal wastage

5.8.1 Internal wastage

5.8.2 External wastage

5.8.3 Requirements

5.8.4 Stress corrosion

5.8.5 Mechanical requirements

5.9 Attachment on pressure parts

5.9.1 Load carrying attachments

5.9.2 Non load carrying attachments

6 Calculation temperature and nominal design stress

6.1 Calculation temperature

6.1.1 General

6.1.2 Circulation boilers

6.1.3 Once-through boilers, superheaters and reheaters

6.1.4 Hot water generators

6.1.5 Temperature allowances for unheated components

6.1.6 Headers

6.1.7 Unheated components

6.1.8 Components protected against radiation

6.1.9 Components heated by convection

6.1.10 Components heated by radiation

6.2 Maximum through-the-wall temperature difference and maximum flue gas temperature for heated drums and headers

6.2.1 Maximum through-the-wall temperature difference

6.2.2 Headers exposed to flue gas

6.2.3 Allowable deviations

6.3 Design stress

6.3.1 General

6.3.2 Rolled and forged steels

6.3.3 Austenitic steels

6.3.4 Non-alloy and low-alloy cast steel

6.3.5 Nodular graphite cast iron

6.3.6 Design stress for welded connections operating under creep condition

6.3.7 Design stress for test pressure

7 Cylindrical shells of drums and headers under internal pressure

7.1 Shell thickness

7.1.1 Requirements

7.1.2 Required wall thickness including allowances

7.2 Basic calculation

7.2.1 Required wall thickness without allowances

7.2.2 Different thickness

7.2.3 Fabrication tolerances

7.3 Combined stress in drum or header shells

7.3.1 General

7.3.2 Stress from longitudinal loads

7.3.3 Longitudinal bending stress

7.3.4 Evaluation of ligament stress for inclined ligaments in drums

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

8.1.1 Requirements for the ligament efficiency of the main body with openings and branches

8.1.2 Effective lengths for calculation of efficiencies of components

8.1.3 Conditions for isolated openings

8.1.4 Requirements for design of branches

8.1.5 Requirements for the design of reinforcing pads

8.2 Efficiency factor, calculation by way of approximation, and maximum diameter of unreinforced openings

8.2.1 General

8.2.2 Allowable efficiency and maximum diameter of unreinforced opening

8.2.3 Isolated openings

8.2.4 Adjacent openings

8.3 Design of openings and branches in cylindrical shells (efficiency and reinforcement)

8.3.1 Symbols and abbreviations

8.3.2 Requirements for application

8.3.3 Design of isolated openings and branch connections

8.3.4 Design of adjacent openings and branch connections

8.4 Bolted connections

8.4.1 General

8.4.2 Symbols and abbreviations

8.4.3 Calculation of bolt diameter

8.4.4 Calculation of bolt load

8.4.5 Calculation temperature tc

8.4.6 Design strength value K

8.4.7 Safety factor S

8.4.8 Quality factor q

8.5 Screwed and socket welded connections

8.5.1 Screwed connections into the belt

8.5.2 Screwed socket connections

8.5.3 Socket welded connections

9 Headers and plain tubes of rectangular section

9.1 General

9.2 Symbols and abbreviations

9.3 Required wall thickness

9.3.1 General

9.3.2 Minimum wall thickness at the centre of one side

9.3.3 Minimum wall thickness at the corners

9.3.4 Minimum thickness at a line of openings

9.3.5 Minimum wall thickness at staggered opening arrangement (diagonal pitch)

9.3.6 Minimum wall thickness at isolated openings

10 Ends and spherical shells

10.1 Symbols and abbreviations

10.2 Spherical shells and dished heads

10.2.1 General

10.2.2 Calculation formula

10.2.3 Openings in dished ends and spherical ends

10.3 Unstayed flat ends

10.3.1 General

10.3.2 Thickness of circular unstayed flat ends

10.3.3 Thickness of non-circular and rectangular unstayed flat ends

10.4 Flat unstayed closures

11 Tubes

11.1 Symbols and abbreviations

11.2 Thickness of straight boiler tubes

11.2.1 Required wall thickness with allowances

11.2.2 Required wall thickness without allowances

11.2.3 Minimum thickness

11.2.4 Circumferentially butt welded tubes

11.3 Thickness of tube bends and elbows

11.3.1 General

11.3.2 Required wall thickness with allowances

11.3.3 Required wall thickness without allowances

11.3.4 Departure from circularity of tube bends

11.4 Flexibility of integral tubing systems

11.4.1 General

11.4.2 Analysis

11.5 Structural attachments to tubes

11.5.1 General

11.5.2 Attachments welded on tube bends

11.5.3 Length of attachments

11.5.4 Limit of intensity in the case of radial loading

11.5.5 Calculation of intensity in the case of radial loading

11.5.6 Strength of welds

11.6 Fitting and joining of heated tubes

11.6.1 Fitting of tubes

11.6.2 Joining of heated tubes

11.7 Joining of unheated tubes

11.7.1 General

11.7.2 Flanges and bolting

11.7.3 Butt welded joints

11.7.4 Screwed or screwed and seal welded joints

11.8 Standardized fittings

12 Pressure parts of irregular shape

12.1 Hydrostatic test for determining the allowable internal pressure

12.1.1 General

12.1.2 Proof test to produce yielding

12.1.3 Proof test to destruction

12.2 Numerical methods

12.2.1 General

12.2.2 Methods

12.2.3 Evaluation of stress

13 Fatigue

13.1 General

13.1.1 Procedure

13.1.2 Fatigue loading

13.1.3 Calculation of fluctuating stress

13.1.4 Fatigue assessment

13.2 Symbols and abbreviations

13.3 Exemption rule for fatigue analysis

13.3.1 General

13.3.2 Materials

13.3.3 Loadings

13.3.4 Temperature differences during transient operating conditions

13.4 Stress analysis for fatigue calculation

13.4.1 Principal and equivalent stresses

13.4.2 Temperature of a load cycle

13.4.3 Protection of the magnetite layer

13.4.4 Allowable circumferential stress range at the inside corner of a bore

13.4.5 Circumferential stress caused by pressure at the inside corner of a bore

13.4.6 Stresses on the branch caused by external forces and moments

13.4.7 Thermal stresses

13.4.8 Upper and lower limit of the circumferential stress at the inside corner of a bore

13.4.9 Admissible through-the-wall temperature differences

13.4.10 Allowable temperature transients

13.4.11 Components with oblique and/or non-radial branches

13.5 Example calculations

Annex A (normative) Calculation of tube bends and elbows

A.1 General

A.2 Symbols and abbreviations

A.3 Calculation

A.3.1 Required wall thickness

A.3.2 Calculation of the wall thickness

A.3.3 Calculation of stress

A.3.3.1 The strength conditions for the intrados of the bend shall be:

A.3.3.2 The strength conditions for the extrados of the bend shall be:

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.4.1 General

B.4.2 Uniaxial stress state

B.4.3 Multiaxial stress state with principal stress directions constant

B.5 Correction factors for taking into account the influences of surface finish and weldments

B.6 Controlling stress range

B.6.1 General

B.6.1.1 Controlling stress range

B.6.1.2 Elastic range

B.6.1.3 Partly elastic range

B.6.1.4 Fully plastic range

B.6.2 Correction factor

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 number of load cycles

C.3 Calculation of the admissible temperature gradient

Annex D (informative) Physical properties of steels

D.1 General

D.2 Symbols and abbreviations

D.3 Physical properties

D.3.1 Density

D.3.2 Differential coefficient of linear thermal expansion

D.3.3 Heat capacity

D.3.4 Thermal diffusivity

D.3.5 Poisson's ratio

D.4 Physical properties of steels

D.4.1 Data sheet (tables)

D.4.2 Graphs

D.4.3 Polynomials

Annex E (informative) Consideration of external wastage due to flue gas exposure

E.1 General

E.2 Symbols and abbreviations

E.3 Wall thickness of straight tubes in accordance to Clause 11

E.3.1 Required wall thickness with allowance

E.3.2 Required wall thickness without allowances

E.3.3 Circumferentially butt welded tubes

E.4 Wall thickness of tube bends and elbows in accordance with Clause 11

E.4.1 Required wall thickness with allowance

E.4.2 Required wall thickness without allowances

E.5 Wall thickness of tube bends and elbows in accordance with Annex A

Annex F (informative) Significant technical changes between this European Standard and the previous edition

Annex ZA (informative) Clauses of this European Standard addressing essential safety requirements of the Pressure Equipment Directive 2014/68/EU

Bibliography