The user divides the distribution network into different groups of mains. A remaining life probability distribution is defined for each group on the basis of the triangular distribution. This distribution is chosen because, in contrast for instance to a normal or a Weibull distribution, it fits in with the perception and experience of the experts working in the water companies. The triangular distribution is determined on the basis of three points in time:

• t1: the time at which the first mains must be replaced on the basis of their condition.
• t2: the time at which the largest part of the mains must be replaced on the basis of their condition.
• t3 : the time at which the last mains must be replaced on the basis of their condition.

The combination of the groups with the mains’ installation year results in a forecast of the number of mains to be replaced . By entering the average cost figures per pipe diameter, the user can then make an estimate of the investments involved.

Within the Dutch water sector’s joint research programme, working in close collaboration with the water companies, the distribution network was divided into 22 groups, and values for t1, t2 and t3 were established for each group. If a water company has not made its own division, it can make use of these values. See BTO 2011.038 and the LESAM article.

What can you do with it?

The tool assists water companies in making investment forecasts for the replacement of mains, which are both well structured and founded on the best information possible.

Implementation of the tool involves the following steps:

1. Data collection: 

• a. Enter the following pipe characteristics in an Excel file:
  - material
  - diameter
  - installation date
  - length.
  Other characteristics can also be used to distinguish the groups. In this case, a separate input file should be used. For example, you can load a file with mains installed in peaty soils and one with mains installed in sandy soils.
• b. Divide the mains into groups on the basis of their t1, t2 and t3 values.
• c. Enter the other data, including costs.

2. Conduct the calculation
3. Presentation of the results: the figures can be used in reports and the associated data can be copied to an Excel file.

There are several forms of support available to ensure that you optimise your use of the tool, and that you are updated on all the latest developments. Specifically, you can make use of the following options to suit your particular situation:

• A short introductory – or more elaborate – course on the Mains Investment Planning for you, your clients and other stakeholders.
• Expanded or modified functionalities to create tailored solutions.
• Consultancy services.
• Access to Mains Investment Planning-related projects or research.

Mentioned in: 2 Publications
Enrolled in: 1 Country

• Beuken R.H.S. and G.A.M. Mesman (BTO 2011.038).
  "Technische levensduur voor groepen leidingen, naar een onderbouwing van het investeringsbeleid."
  Nieuwegein, KWR Watercycle Research Institute. In Dutch
• Beuken R.H.S., L. Pinheiro, P. Horst, G.A.M. Mesman (2011).
  "Enabling investment planning by defining remaining life probability distributions for water mains." 
  Proc IWA LESAM 2011 Mulheim.