Final Report G 202333 09/2024

Content of DVGW Final Report G 202333

In connection with the new construction or conversion of high-pressure gas pipelines, proof of the suitability of the materials used must be provided as part of extensive fracture mechanical tests in accordance with DVGW regulations - depending on the design and the materials used. This currently applies both to the high-pressure range and formally to the low-pressure range. In order to simplify the previously required process, the DVGW initiated the BAG464 research project, with the aim to identify a boundary for the sensible application of fracture mechanical assessment. 

As part of the project, fracture mechanical assessments were carried out for typical design parameters for both the distribution network and the transport network. The investigations identify an area in which - taking conservative boundary conditions into account - fracture mechanical assessments do not provide any added value for the safe design of the pipelines. 

The identified range fulfils several criteria for safe design and shows, that in particular for a maximum allowable operating pressure (MOP) p ≤ 16 bar, a fracture mechanical assessment only needs to be carried out in very rare exceptions. For MOP 12 bar < p ≤ 16 bar, no fracture mechanical assessments are required up to and including DN 200. For larger diameters, individual case analyses must be carried out. Below MOP p ≤ 12 bar, no fracture mechanical assessments are generally required, if the described boundary conditions are met - regardless of the pipe outside diameter and steel material. 

For high-pressure gas pipes with MOP p > 16 bar, however a fracture mechanical assessment can only be dispensed with in a few exceptions. These exceptions are limited to smaller pipe diameters and/or smaller MOP.

Table of Contents

• 1 Task definition
• 2 Basic procedure for carrying out fracture mechanical tests
• 3 Analysed Materials
• 4 Results of the fracture mechanical evaluation
• 4.1 Design according to DVGW Code of Practice G 462, DIN EN 12007-3, p ≤ 16 bar
• 4.2 Design for stations in accordance with DVGW Code of Practice G 491, DIN 30690-1
• 4.3 Design according to DVGW Code of Practice G 463, DIN EN 1594, high-pressure range p > 16 bar
• 5 Conclusions and outlook
• 6 References
• 7 List of Figures
• 8 List of tables
• 9 List of symbols
• Annex 

Important normative references

G 464 Guideline

German Version

DVGW-Forschungsbericht G 202333

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