EN 13445 European Standard for Unfired Pressure Vessels
The European Standard EN 13445 was formally approved in April 2002 after continuous development in over 13 years.
The EN 13445 standard consist of the following parts:
- EN 13445-1 General
- EN 13445-2 Materials
- EN 13445-3 Design
- EN 13445-4 Fabrication
- EN 13445-5 Inspection and testing
- EN 13445-6 Vessels and pressure parts constructed from spheroidal graphite cast iron
- EN 13445-7 Guidance on the use of the conformity procedures
- EN 13445-8 Additional requirements for pressure vessels of aluminium and a aluminium alloys (under approval)
Some benefits of the EN 13445 standard includes:
- EN 13445 is giving the presumption of the essential safety requirements of the Pressure Equipment Directive 97/23/CE (so called PED). By other rules the manufacturer has to demonstrate separately the safety level required by PED.
- Very competitive against other standards.
- Comprehensive, the standard has a wide scope. In example, section 16 for None Pressure Loads includes a number of different methods for vessel supports (saddle and ring supports for horizontal vessels, and skirt, leg, ring and bracket supports for vertical vessels).
- Covers a number of special cases (nozzles located in knuckle radius of dished ends, multiple and eccentric openings can be located in flat ends, no restrictions on nozzle size if pads are not included, etc.).
- Includes alternative method for design of flanges to Annex G. This method considers additional axial forces and moments, forces due to thermal expansion, creeping factor of gasket, non-linear elastic response of the gasket etc.
- Includes alternative method for design of tubesheets to Annex J.
- The standard is logical and easy to use.
VVD software – EN13445
Ohmtech started to develop the EN 13445 standard in 1998, in close cooperation with Polartest in Finland (notified body in Finland). The software have been extensively tested and validation documentations includes feedback from over 80 different companies supplying us with several hundred calculations. Our reference list includes over 70 different notified bodies, and we are cooperating with several notified bodies and major vessel fabricators in the further software development. The VVD software has also been certified by a Notified Body. Today our EN13445 software module is almost complete with all sections included (ref. table below) covering both design and rerating of pressure vessels and shell & tube heat exchangers.
Conditions of applicability in each section of the EN13445 standard are checked and verified by the software. In cases where numbers are unavailable or the condition of applicability only is stated by words, the text will be printed together with the calculation results and summarized in a separate section.
The EN material library included with the VVD software includes material properties for all the 388 materials listed in EN13445 part 2 Table A.2-1. In addition to values for proof strength at elevated temperature, the database also includes the tensile strength properties at elevated temperatures for austenitic steels to allow a reduction in the safety factor from 1.5 to 1.2 (ref. EN13445-3 Table 6-1). Properties for material densities, modulus of elasticity, and thermal expansion coefficient are also included. The material database also includes material libraries to ASME, BSI and NGS material standards (over 3000 different materials are included).
Included Sections of EN13445 in the VVD software
|6||Derivation of allowable stresses.|
|7||SHELLS UNDER INTERNAL PRESSURE|
|7.4||Cylindrical and spherical shells|
|7.6||Cones and conical ends|
|7.7||Nozzles which encroach into the knuckle region|
|8||SHELLS UNDER EXTERNAL PRESSURE|
|8.5||Cylindrical shells (including design of light and heavy stiffener rings)|
|8.8||Vessel ends (spherical, ellipsoidal and torispherical ends)|
|9||OPENINGS IN SHELLS|
|9.5||Isolated and openings in shells|
|9.6||Multiple openings (groups of openings)|
|9.7||Openings close to a shell discontinuity|
|10.4||Unpierced circular flat ends welded to cylindrical shells|
|10.5||Unpierced bolted circular flat ends|
|10.6||Pierced circular flat ends|
|10.7||Flat ends of non-circular or annular shape|
|11.5||Narrow face gasketed flanges|
|11.6||Full face flanges with soft ring type gasket|
|11.7||Seal welded flanges|
|11.8||Reverse narrow flanges|
|11.9||Reverse full face flanges|
|11.10||Full face flanges with metal to metal contact|
|12||BOLTED DOMED ENDS|
|12.5||Bolted domed ends with narrow face gaskets|
|12.6||Bolted domed ends with full face joints|
|13||HEAT EXCHANGER TUBESHEETS|
|13.4||U-tube tubesheets heat exchangers|
|13.5||Fixed tubesheets heat exchangers|
|13.6||Floating tubesheets heat exchangers|
|13.7||Ligament efficiency and effective elastic constants of
|13.8||Maximum permissible tube to tubesheet joint stress limit|
|13.9||Maximum permissible buckling stress limit of tubes|
|13.10||Design of tubesheets flange extensions|
|14||Expansion bellows (also including fatigue evaluation)|
|15||RECTANGULAR PRESSURE VESSELS|
|16||ADDITIONAL NON-PRESSURE LOADS|
|16.4||Local loads on nozzles in spherical shells|
|16.5||Local loads on nozzles in cylindrical shells|
|16.8||Horizontal vessels on saddle support|
|16.9||Horizontal vessels on ring support|
|16.10||Vertical vessels on bracket support|
|16.11||Vertical vessels with leg support|
|16.12||Vertical vessels with skirt support|
|16.13||Vertical vessels with ring support|
|16.14||Global loads, tall tower analysis including any combinations of external loads (wind, blast, seismic, internal&external pressure, weight, etc).|
|17||SIMPLIFIED ASSESSMENT OF FATIGUE LIFE|
|17||Simplified assessment of fatigue life|
|18||DETAILED ASSESSMENT OF FATIGUE LIFE|
|18||Detailed assessment of fatigue life|
|20||REINFORCED FLAT WALLS|
|21||STAYED FLAT WALLS|
|Annex E||Procedure for calculating the departure from the true circle
of cylinders and cones
|Annex F||Allowable external pressure for vessels outside circularity tolerance|
|Annex G||Alternative design rules for flanges and gasketed flange
|Annex H||Table H-1 Gasket factors m and y|
|Annex I||Load cases of heat excganger tubesheet design|
|Annex J||Alternative method for design of heat exchanger tubesheets|
|Annex M||In service monitoring of vessels operating in fatigue or creep range|
|Annex O||Physical properties of steels|
|Annex S||Creep rupture strength|
For more information regarding the EN 13445 standard: EN 13445 Help Desk