An update of DVGW technical regulations for Network inspection and DVGW W (A): Water Loss in Pipeline Networks; Determination. Dvgwarbeitzblatt w testing method according to section 3. Dvgw innovation and setting standards in the gas and water sectors. Application of dvgw technical . But there are news -the new W guidelines, issued by the DVGW (Deutsche Vereinigung des Gas-und Wasserfaches e.V., which translates to German.
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An update of DVGW technical regulations for Network inspection and water losses activities, procedures and assessments, issued last September, has adopted the Infrastructure Leakage Dvbw ILI as the principal technical performance indicator for Water Losses.
ILI is the performance indicator developed by International Water Association IWA in for the specific purpose of more rational national and international comparisons of technical leakage performance management between systems with dvyw characteristics. An informative paper by Liemberger on many aspects of the previous W regulations will, it is understood, be updated soon.
The updated documents xvgw by Deutsche Vereinigung des Gas- und Wasserfaches e. Network Input is used instead of System Input. However, W has followed a consistent approach for over 20 years in clearly stating that:.
Bulk Metering Error is often one of the largest sources of random error in calculations of real losses.
W recommends that, for the assessment of network input volumes, decentralised measurements are in general more suitable. For example, a meter could be aligned to the actual range of use of a pump in a way that the meter measures most reliably in the upper operating range.
Central measurement points e.
Dvgw w pdf file download
For the best possible assessment of metering errors, the actual flow conditions and the actual failure curve need to be determined. If there is no information available and a meter dimensioning according to DVGW W A is assumed, then the sum of metering errors should be set to zero. Apparent Losses customer meter rvgw, theft etc: This is a very low limit compared to other international Guidance, and presumably reflects high metering standards which require customer meters to be replaced every 6 years.
Dvggw Loss qvr is retained because it is traditional in Dvyw, even though it is not considered equal to ILI. The W update also mentions that operating pressure influences real losses with reference to the UARL equation and recognises the need to control pressure transients.
There is no further mention of pressure management as a means of reducing leak flow rates, burst frequency on mains and services, and annual real losses. This needs to be read together with WA. However, the following 3 classes for Water Losses in terms of ILI are shown in Table 2a, where they are related to recommended minimum network inspection rates.
Table 2a not reproduced here has 6 detailed footnotes relating to interpretation of inspection frequencies, which will be discussed in more detail in an upcoming paper by Liemberger. Classification of Failure Frequencies with Water Emission: Translation of documents dvgq result in unintended errors of interpretation or emphasis.
This blog was jointly prepared by Allan Lambert and Joerg Koelbl; any opinions expressed are their own and intended as constructive comments on this welcome initiative by DVGW.
German DVGW endorses ILI –
Anyone wishing to draw the attention of the authors to such items in this Blog, please Contact Us. Technical rules for Water Supply Systems; Part 3: Operation and Maintenance; Supplement 1: Inspection and Servicing of Distribution Systems.
However, W has followed a consistent approach for over 20 years in clearly stating that: