This document ISO 17885 specifies the requirements for mechanical fittings for joining plastic piping systems for the supply of gaseous fuels, the supply of water for human consumption and other purposes, as well as for industrial application. It provides a unified set of test methods to check the performance of the fittings, depending on their intended use. It is the responsibility of the purchaser or specifier to select the appropriate fitting, taking into account their particular requirements and any relevant national guidance or regulations and installation practices or codes.

This Guideline W 403 has been elaborated by the project group on ?Decision support for the rehabilitation of water pipe nets? of the Technical Committee on ?Water distribution operation and asset management? and serves as a decision support for the rehabilitation of water distribution systems. Professional circles have long used the term ?rehabilitation? to refer to the improvement of technical infrastructures. The publication in 1997 of DVGW guideline W 401, ?Decision support for the rehabilitation of water pipe nets?, instituted this term also into the national water supply. The condition of water distribution systems greatly influences the adequate quantity, necessary pressure and perfect quality of the drinking water supply. System condition‑based rehabilitation (condition‑based maintenance, cf. DVGW W 400‑3 (A)) serves to meet these requirements, at the same time improving the safety of supply and economic efficiency with a focus on the holistic approach of condition‑based, riskoriented maintenance. High‑quality supply and a good system condition in accordance with the DVGW Technical Rules can be ensured only if water leakage and system failure rates as well as the risks emanating from a water distribution system or affecting it remain at low levels. Low failure rates coinciding with high water losses do not indicate high‑quality supply but rather the presence of pipe damage not yet discovered because of e.g. unfavourable soil conditions. While increased inspection activities designed to reduce water losses may be a first step towards detecting and markedly reducing local water losses, system failure rates and risks as well as water losses may be kept at permanently low levels in the long term only if the pipe system is subjected to purposeful rehabilitation work. This holistic approach of condition and risk‑based maintenance is also important in the context of international standardisation. While the installation and development of pipeline systems is almost complete, the renaturisation and optimisation of networks has become necessary in many places in order to respond to changing societal conditions. Consequently, networks are subject not only to aging as well as wear and tear but also to adaptation processes, requiring water utilities to focus increasingly on the growing need to rehabilitate existing water distribution facilities. Rehabilitation will thus become essential in asset management, with ever more stringent requirements on the design and execution of rehabilitation. The evolution of the Technical Rules must pay heed to this fact, as reflected by the publication of the Technical Rules on Water distribution systems (TRWV, Water Distribution Facilities, W 400 series), in particular DVGW W 400‑3 (A) and DVGW W 490 (H) published in September 2006 and January 2007, respectively, which already describe fundamental rehabilitation principles. The inclusion of sophisticated technical processes in DVGW Codes of Practise GW 320 et seq. documents state‑of‑the‑art rehabilitation solutions for technical water infrastructure. DVGW Code of Practise W 402, ?Network and failure statistics?, which will supersede DVGW W 395 (M) and is currently available as a yellow paper only, will provide an important new basis for planning rehabilitation measures.This Guideline W 403 translates the above‑mentioned statistics and analyses into actual rehabilitation activities. The fact that it has been combined with W 402 illustrates the growing future importance of highly detailed and meaningful data acquisition and maintenance processes for water utilities.As the contents of DVGW W 400‑3 (A) form the basis of this Guideline, it has been deliberately structured along the lines of DVGW W 400‑3 (A). The revised version of DVGW W 401 (H) also describes the characteristics of water distribution systems used in the long‑distance water supply. This Guideline offers advice ‑ but no technical rules ? on how to introduce a rehabilitation strategy and elaborate rehabilitation planning. A clear distinction is being made between these afore‑mentioned activities and ongoing service activities (inspection and maintenance). The suggested method is meant to be universally applicable, regardless of the structure of a given water distribution system. Criteria shall be weighted according to the original local conditions prevailing in each case. Any empirical numeric values given are mere support values; concrete href= https://shop.wvgw.de/507926 >here. specific values. This Guideline supersedes DVGW Guideline W 401:1997‑09.

For the purposes of this Standard GW 381, the term ?minimum requirements? implies that further requirements canensue from technical rules and legal provisions and/or that the ordering party may stipulate further requirements,in particular in the presence of special features or needs for protection or other constraints. Theoptional criteria shall, without claiming to be exhaustive, be considered guidance for the ordering partywho shall decide on the need for further requirements.If a company consists of several units, this technical rule applies to the units in charge of undergroundconstruction and, without exception, to independent subsidiaries as well. A subsidiary shall be assumed tobe independent if, in effect, it actually controls most operations and/or if the head office of the company isunable to provide the supervision of the staff and the construction sites as required.

This standard W 551-2 applies to the operation and maintenance of drinking water installations in buildings. It stip-ulates the requirements on the management of technical and microbiological irregularities that may ad-versely affect hygiene in drinking water installations.

This Standard W 1003 relates to the piped supply of public water under normal operating conditions. Covering the different technical aspects and value-added steps, it provides an integral overview of how to de-scribe, analyse and assess the resilience and security of supply in water supply areas.

This Technical Rule GW 350 in conjunction with DIN EN 12732 applies to the manufacture, testing and Evaluation of welds on steel pipelines and installations which serve to supply the general public with gas within the meaning of the Energy Industry Law (EnWG) or which are part of the associated energy installations on factory premises and in the area of operational gas use and which are to be operated with the gases ofthe 2nd gas family according to DVGW Standard G 260 or DVGW Standard G 262. It also applies to pipes in operation.For steel pipelines and installations for gases which do not comply with the provisions of the above DVGW standards, this technical rule may be applied mutatis mutandis taking into account the specific properties of the gases and any other existing provisions.

W 270 Technical Standard 11/2007

W 551 Code of Practice 04/2004

GW 301 Technical Rule ‑ Standard 01/2021

DVGW Information WATER No. 108 02/2021

GW 10 Technical Standard 06/2018

W 249 Technical Rule ? Standard 07/2012

W 202 Technical Rule ? Standard 03/2010

W 129 Technical Rule ? Standard 04/2012

W 127 Technical Rule ? Standard 03/2006

W 126 Technical Rule ? Standard 09/2007