This DVGW Guideline G 409 applies to the conversion of steel gas pipelines for design pressures of more than 16 bar with welded joints for the transmission of gases of the 2nd gas family as specified by DVGW Code of Practice G 260 to hydrogen with at least 98 % by volume (in accordance with standard ISO 14687 of Groups A or D). The design pressure DP of the pipeline remains unaffected. Details on the gas quality of the hydrogen meant for transportation will be included in DVGW Code of Practice G 260 in the near future. After the revised Code of Practice G 260 has been passed into force, it shall be the preferred standard rule for consultation on matters of hydrogen gas quality. Other installation components such as valves, pig traps, regulating stations do not fall under this Guide-line’s purview and must be examined and evaluated separately. A pipeline that transports even small amounts of hydrogen shall, if necessary, already be evaluated sepa-rately. For such cases, this Guideline’s specifications may be applied mutatis mutandis. For gas pipelines made of other material, steel pipes with detachable joints, or gas pipelines with a design pressure lower than 16 bar, this Guideline’s specifications may be applied mutatis mutandis. When planning the conversion of a gas pipeline that transports gases that do not correspond with the specifications of DVGW Code of Practice G 260, this Guideline may be applied mutatis mutandis if the specific characteristics of these gases are taken into account and other applicable regulations, if they exist, are adhered to.

This Guideline G 464 shall apply for the fracture mechanical assessment of steel gas pipelines that already exist or are projected for construction with a design pressure of more than 16 bar for the transportation or distribution of gases of the 5th gas family (hydrogen) as specified by DVGW Code of Practice G 260. This present Guideline G 464 addresses the assessment of an assumed defect; for the assessment of measured defects, the guideline can be applied analogously.

This guideline G 408 shall apply to the conversion of pipelines made from plastic to hydrogen-containing, methane-rich gases (2nd gas family) or hydrogen (5th gas family) in accordance with DVGW Code of Practice G 260 up to an operating pressure of 16 bar and ends with the main shut-off valve, the thematic threshold to DVGW Guideline G 655. This guideline G 408 can also be applied to the conversion of plastic gas pipeline operated with gases that do not conform to the specifications of DVGW Code of Practice G 260 if the gases’ specific characteristics and, if applicable, other existing regulations are taken into account. The respective guidelines on pipeline conversion shall be consulted for networks using different pipeline materials (e.g., plastic and steel).

This guideline G 407 shall apply to the conversion of pipelines made from steel to hydrogen-containing, methane-rich gases (2nd gas family) or hydrogen (5th gas family) in accordance with DVGW Code of Practice G 260 up to an operating pressure of 16th and ends with the main shut-off valve, the custody transfer point to DVGW G 600 (A), respectively to G 614.1 (A) (including the additions detailed in DVGW Guideline G 655). This guideline can also be applied to the conversion of steel gas pipeline operated with gases that do not conform to the specifications of DVGW Code of Practice G 260 when taking into account the gases’ specific characteristics and, if applicable, other existing regulations. The respective guidelines on pipeline conversion shall be consulted for networks using different pipeline materials (e.g., plastic and steel).

For hydrogen transmission within the German gas grid, it is imperative to obtain a clearly defined assessment of steel components for hydrogen suitability and relevant implementation in the DVGW Codes of Practice. Within this context, DVGW Code of Practice G 409 (for the conversion of pipelines to hydrogen transmission) and DVGW Code of Practice G 463  (for the construction of new pipelines), for example, have been specifically aligned to hydrogen as a transmission medium. Both these codes of practice may require a fracture-mechanical assessment of pipelines and pipeline components, with fracture-mechanical parameters beingrequired as input variables. So far, it was only in ASME B 31.12 [3] that these parameters were specified in an international code of practice. They specifically involve minimum fracture toughness (KIc) and the description of crack toughness (da/dN) with hydrogen as a medium. However, the parameters specified in ASME B 31.12 were based on investigations on US materials which are verysimilar, but not identical, to the materials used in Germany and elsewhere in Europe. Furthermore, the conversion of existing older natural gas pipelines (comprising older materials) is of very considerable interest particularly for the scope of application of the DVGW Code of Practice, although a direct transferability of the US investigations was considered to be problematic. Hence, within the context of the DVGW’s extensive SyWeSt H2 research project, fracturemechanical investigations were performed specifically for the pipeline steel grades used in Germany (and, in some cases, elsewhere in Europe) with hydrogen as a medium. The objective of this project was to compare the established fracture-mechanical parameters with the results on which ASME B 31.12 is based for the purpose of validating their application to steel grades used in Germany and, where applicable, drawing up a modified correlation for crack growth.

In conjunction with DIN EN 1594, this Technical Rule G 463 applies to the planning and construction of steel high pressure gas pipelines with a design pressure of more than 16 bar for supplying gas to the general public as well as to connected energy facilities on company premises and in the field of commercial gas application of gases of the 2nd and 5th gas family as defined by DVGW Code of Practice G 260. The scope of application has no upwards limitation in terms of the technical parameters nominal diameter and design pressure. This Technical Rule can be applied mutatis mutandis to the construction of high pressure gas pipelines which do not conform to the specifications of DVGW Code of Practice G 260, provided that the specific characteristics of the gases or, if applicable, other already existing technical sets of rules are taken into account.

This standard G 493-2 encompasses personal and professional requirements for companies providing maintenance for gas plants and installations that fall within the scope of DVGW G 495 (A), as well as biogas injection and refeeding plants as specified by DVGW G 265-2 or hydrogen injection plants as specified by DVGW G 265-4 (M).Companies which, within the context of comprehensive plant management, either as original operators or as contractors, are responsible for the maintenance of energy plants, and possess the required personal qualification and organization according to DVGW G 1000 (A), may conduct the maintenance of gas plants without certification as defined by this standard within the network which they have the abovementioned responsibility for. The prerequisite for the maintenance without certification as mentioned above is that the expert and tech-nical conditions detailed in this standard are met by the company’s own workforce or by service providers with a TSM certification or other corresponding certifications. The company shall appoint the experts re-sponsible for maintenance in writing. The fulfilment of these conditions can be verified e.g. during a TSM review according to DVGW G 1000 (A).

Code of Practice GW 315 provides essential information on how to avoid damaging to existing supply systems during construction operations. It applies to all construction work  and regulates the requirements for construction contractors and operators of supply systems.

This Technical Rule G 260 specifies the requirements for the quality of fuel gases used in the supply of the general public with gas and sets the parameters for gas delivery, gas transportation, gas distribution, gas storage, operation of gas plants/systems and gas appliances for commercial and industrial gas applications as well as for development, standardization, and testing. Gases transported in separate pipelines which are not used in the supply of the general public, or are used as energy carrier or resource, and/or are used in special gas appliances are not subject to the scope of this Technical Rule.

G 452‑3 Technical Information ‑ Guideline 03/2021

G 452‑2 Technical Rule ‑ Standard 08/2020

This Technical Rule G 280 applies to all gases covered in DVGW Codes of Practice G 260 and G 262 respectively Standards DIN EN 16723-1 and -2 as well as DIN EN 16726 and all gases used for the supply via pipeline system of the general public and other consumers with a comparable level of safety. When using sulfur-containing odorants, the fact shall be taken into account that the entailed increase of the sulfur content in the gas is undesirable for some applications, such as its use as basic material in the chemical industry. Industrial companies using natural gas exclusively on company premises can forego odorization if the operator utilizes other measures to maintain the industrial gas plant or system’s safety. When switching from one odorant to another, special attention shall be paid to Section 9. The calibration of measuring devices for odorant control requires test gases which are detailed in Section 10.

G 473 Guideline 01/2018

G 497 Technical Rule‑Standard 02/2019

This document DIN CEN TR 17797 is written in preparation of future standardization and provides guidance on how injection of H2 into the gas infrastructure can impact processes from the input of gas into the on-shore transmission network up to the inlet connection of gas appliances.

This Standard shall also apply, mutatis mutandis, to gas mixing plants that supply process gas to trade and industry and to industrial gas mixing plants for in‑house mixed‑gas supply.Gas mixing plants are frequently integrated into gas measurement and pressure reduction stations, which latter shall meet the specifications of DVGW Standards G 491 and G 492. In other words, most of the requirements specified in these Standards will also apply to gas mixing plants. All other requirements that go beyond the scope of G 491 and G 492 are described in this Technical Rule at hand, which first and foremost complements DVGW Standard G 491.