For non-pressure parts, e.g. for supporting lugs, skirts, saddles, baffles, brackets, and similar parts welded to pressure vessels, material shall be used which are supplied to material specifications covering at least requirements for the chemical composition and the tensile properties. These materials shall not limit the operating conditions of the material to which they are attached.
Note: The essential safety requirements on materials specified in Annex I section 4.1 and section 7.5 do not apply to this material, but the heat affected zones of a weldment of this parts to the pressure equipment well.
The review of the chemical composition and mechanical properties by the manufacturer is required to be able to assess the suitability of the material.
The welded-on non-pressurised parts must not have a negative effect on the safety of the pressure equipment, either through the material used or through the welding to the pressure equipment.
The use of unsuitable welded-on material can cause damage due to
- Unsuitable welding consumables
- Cracks in welds or heat-affected zone (HAZ)
- Corrosion
- Cracks due to dynamic loads
- Damages caused by PWHT or other treatments
- Breakage due to loads, e.g. with skirts, lifting lugs
Comparisation of non-pressure parts vs. Components what contributing to the pressure resistance
Compared to the non-pressure parts described above, there are also the components what contributing to the pressure resistance of the pressure equipment. These are components that do not come into direct contact with the fluid or internals (also “non pressure”), but which contribute to ensuring the pressure resistance or stability of the pressure equipment through additional reinforcements:
| Non-pressure parts | Components what contributing to the pressure resistance | |
|---|---|---|
| Parts/Components | Pressure Vessel supporting parts a) Lugs; b) Skirts; c) Saddles; d) Baffles; e) Brackets; and f) Other similar parts; | a) Reinforcing plate for a nozzle; b) Reinforcing plate/forging for other vessel openings; c) Stiffened rings for cylindrical shells; d) Stiffened rings for conical shells; e) Internal stiffening rings; f) Heating/cooling channels; |
| Material requirements | Check for suitability by manufacturer e.g. weldability, corrosion resistance | Essential safety requirements on materials specified in PED Annex I section 4.1 and section 7.5 |
| Material certificate EN 10204 required | Chemical composition and the tensile properties; Certificate of compliance 2.1 EN 10204 | Test report 2.2 EN 10204 for Category II, III and IV |
| Inspection and testing | Welds and HAZ in acc. to EN 13445 part 5 | Welds and HAZ in acc. to EN 13445 part 5 |
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The EN 13445 series comprises European standard for unfired pressure vessel
