Sheffield 8 Sep 2017

Friday 8th September 2017, 09:45 – 15.30

Registration Process

(following the 15th International CCWI Conference,

5th to 7th September, University of Sheffield)

Realistic modelling of pressure-dependent leakage in water pipes. Applying FAVAD concepts to testing of pipe samples, with fast-track practitioner approach in distribution systems; practical prediction of pressure:burst frequency relationships.

Hosted by: Professor Kobus van Zyl, University of Cape Town;

Allan Lambert, Water Loss Research & Analysis Ltd, UK


The FAVAD concept (May, 1994) states that leak flow rates include both fixed area and variable area leaks. The N1 Power Law approximation assumes leak flow rate varies with average pressure PavN1 (0.5 ≤ N1 ≤ 1.5). Both FAVAD and N1 are widely used internationally in laboratory tests on pipe samples and in distribution systems as a logical conceptual basis to explain, analyse and predict diverse relationships between average pressure and leak flow rates. Kobus and Allan will explain how their collaborative research (including a Journal of Hydraulic Engineering paper currently in press) provides new insights into application of these concepts, improving theoretical and practical predictions of the influence of pressure on leak flow rates, including low and negative pressures (intrusion flows). Allan will then summarise practical methods for predicting reductions in pipe burst frequencies by reduction of excess pressure.


Why you should attend:  

Researchers involved or interested in leakage modelling:

o   Understand the evidence for the FAVAD approach to leakage modelling

o   Use the leakage number to convert between Power and FAVAD equation parameters

o   Modified EPANET code for FAVAD leakage modelling (code to be provided to delegates)

Leakage Practitioners needing a fast-track approach for distribution Zones:

o   understand and check how N1 varies with average zone pressure in any system

o   fast-track an N1 test result into a zonal FAVAD pressure:leak flow rate equation

o   implications for assessment of daily leakage from night flows and Night-Day Factors

o   update on practical pressure: burst frequency relationships from international studies


09.30     Registration

09.45:    Opening Remarks: Richard Collins (Sheffield University)

10.00     Pressure and Leak Flow Rates: FAVAD full hydraulic approach (Prof. Kobus van Zyl)

11.00     Tea/coffee Break

11.15:    Leakage Practitioner Fast Track approach for distribution Zones (Allan Lambert)

12.15     Questions and Discussion

13.00     Lunch

13.45     Targeting pressure management to reduce burst frequency: Case Studies (A.L)

14.45     Questions and Discussion

15.30     Finish

Workshop Prices:            £160 + 0% VAT per person; 50% discount for students.

Any profits from the Workshop will be used to assist in the running costs of the free to all  website

Registrations may not be accepted after 24th August 2017

Allan Lambert

Allan Lambert has 55 years’ experience in the UK and international water industry, split in almost equal parts between Water Resources/Hydrology, and Non-Revenue Water management, with experience in more than 40 countries. A Past President of the British Hydrological Society and special advisor on water resources and leakage to the UK Government during the 1995-1996 drought, he developed Component Analysis (Background and Bursts Estimates) when he was Technical Secretary to the UK National Leakage Control Initiative in 1992-1994. He chaired the 1st IWA Water Loss Task Force (1995-1999) which developed the Best Practice IWA Water Balance and Performance Indicators. A Fellow of the IWA, he has been researching and applying the many benefits of pressure management for over 20 years, after being inspired by John May’s ideas in 1994. As a leading international authority in leakage management, over the last 4 years he has developed the LEAKSsuite website to disseminate his knowledge, free-to-all, to over 20,000 users in 175 countries. Readers of Water & Wastewater International magazine voted Allan in the top 25 for global thought leadership in the water industry in 2016 and 2017.

Kobus van Zyl

Kobus van Zyl is a professor in the Department of Civil Engineering at the University of Cape Town. He has been involved in research on the behavior of leaks in distribution systems for more than 15 years using a range of techniques that include hydraulic, FEM and CFD modeling, mechanics theory, laboratory studies and field work. He collaborates closely with leakage practitioners and has published 11 peer-reviewed papers on the behaviour and modelling of leakage in distribution systems. He is a professional engineer, an associate editor of the ASCE Journal of Water Resources Planning and Management and a member of the Editorial Board of the Urban Water Journal. He currently chairs the ASCE Environmental and Water Resources Institute’s standing committee on Water Distribution Systems Analysis.