Leaktight recommendations from SMP

Jul 17, 2007

A publication last year of a European study of the performance of various pipe systems, respectively pipe materials for municipal sewage systems under special consideration of the ecological range of effect during the service life, caused quite some stir amongst those involved with sewer systems.

This study, to which often is referred as the SMP study (Sustainable Municipal Pipes study), amongst others concluded that plastic pipes suffer significantly less damages which cause leaks than other materials. No wonder it caused a stir.
For RondLeiding magazine this was an important reason to interview Mr Robert Stein from Stein & Parnter GmbH in Bochum (Germany), the company which performed the above mentioned study. Stein & Partner is a highly experienced and knowledgeable engineering corporation where the underground infrastructure is concerned.

Stein & Partner GmbH
Stein & Partner GmbH (hereafter: “Stein”) considers its USP to be the knowledge and expertise on all aspects which deal with underground infrastructure: not only sewer systems, but also tunnels and fully equipped underground transport systems.
Stein is neutral, which means they look for the best solution for each problem, regardless of any possible material. Next to neutrality of course they want to be considered reliable and knowledgeable. As proof of the latter the many translations of their guidance documents can serve, even into Japanese!
Stein is active in 3 areas: Research & Development, Auditing - mainly of situations where an assessment of damage has to be made -, and knowledge transfer.
Stein differs from similar engineering offices because of its focus on the complete infrastructure: this goes beyond pipes!
This philosophy is best explained by their slogan “the future is in the underground”. Most knowledge about sewer systems is concentrated in the Stein subsidiary “Stein Consult GmbH”. This is also where the SMP study has been performed.

An important part of Stein’s message is that too often the value of the underground infrastructure is underestimated. Many owners and users of underground pipe systems have no idea of the value of the infrastructure they own and/or use. And this explains why often important and necessary investments never take place or at least are postponed!

And this is all the more important where in the future the interdependency of all what is part of the underground infrastructure will only grow: changes (repairs, maintenance etc.) of certain parts of the sewer system should only be allowed when the consequences for the whole system are known.

This is where Stein sees much room for innovation: making the whole network more efficient. And as part of this innovation new design of pipes should allow for a more efficient use of pipe systems and their applications.
Obviously this will require additional funds. And these will not be found if owners and users of the underground infrastructure are not fully aware of the value of these systems.

In order to maintain the value of the underground infrastructure good maintenance is paramount. And good maintenance requires good planning. This is why Stein is proud of a software programme they developed themselves: Status.

Status allows for the planning of maintenance, expansion and renewal of underground pipe systems, while considering a great variety of parameters.
Unfortunately the underestimation of the value of underground networks has also as a consequence that not much relevant data are directly available. Fortunately there often is more information available than the owner of the net is aware of, and Stein is able to convert this information into useable data.

However, it is Stein’s clear conviction that regular sewer inspection, a/o to gather more data, is imperative. This is why they support that sewer inspection should be mandatory, like for instance in Germany.
And the more data are collected, the more specific circumstances can be considered in the planning software.

Plastics vs. concrete
Obviously BureauLeiding is very interested in learning about Stein’s opinion on plastic pipes. Before addressing this issue Mr Stein repeates that Stein is neutral: there is no preference for methods and/or materials; Stein is only focussing on what is best for the underground infrastructure.
According to Robert Stein, managing director of S&P consult, the question is not about a preference for a specific material. It is his strong conviction that the emphasis should be on the design of the pipe system, the construction of the pipe system and the maintenance of the pipe system.
For most applications the choice for a specific material will be clear on the basis of the specific advantages. When choosing a material a few criteria should be considered: the material should be durable, functionally safe and leak tight. Further the whole pipe system should be sustainable. With the latter is especially meant that it should be possible at all times during its lifetime to inspect the system, to repair it and to maintain it.

Having said that, Stein nevertheless sees some clear advantages of plastic pipes:
  • - the large number of possible forms of the various parts of plastic pipes. This allows for flexible and efficient design and installation. However, a warning is in place as well: the industry has to be careful for the “l’art pour l‘art” principle: changes should be functional and not only a marketing tool. If the customer cannot be convinced of the added value of a different shape or form, he might loose confidence in plastics altogether.
  • the lower number of joints that are needed for plastic pipes and thus a lower risk of leakage, and in addition to this the possibility that the weld of the joint is made of the same material as the pipe itself.
  • easier handling of plastic pipes during installation.

As mentioned before it can be said that SMP on the basis from data from Germany, the Netherlands and Sweden concludes that plastic pipes have less damages which affect tightness than other materials. However, SMP does not analyse the cause. Further it has to be considered that attention for tightness of the sewer pipe system is relatively new (approx. the last 15 years). It was always thought that a sewer pipe system would make itself watertight. Now more recent information show that this is not the case, waterthightness has become more important.

According to Stein, SMP can surely be considered a European study for the simple reason that it is the largest research in this field ever, and because of the fact that data from several countries is used.

Stein very much hopes that this first study of its kind will be the basis for discussion and further research in this area.

The study itself, and a summary written by Stein can be downloaded from the BureauLeiding website.

Waste Water quality
When discussing sewer systems it is inevitable not to discuss what is supposed to go through these pipes. And in this respect the (changing) quality of waste water quality is of quite some interest.
The most dramatic changes over the last decades concern the chemical cocktail of the waste water and the raise of temperature. Stein is convinced that the current emphasis on environmental impact will cause a stable situation for the near future, which will most likely change in to an improvement a bit further down the line.

BureauLeiding considers this to be good news, because it means that the life time predictions which were recently established, were based on a truly “worst case scenario”, and thus allow for even more optimistic interpretation.

At the end of the interview Mr Stein urges us not to forget how intelligent water is. Water will always find its way! To design (sewer) systems which sufficiently consider this a holistic and material-neutral approach is required, which considers most of all the water tightness of the system and the proper and correct installation.

More information on Stein & Partner GmbH can be found on:
The full SMP study and a summary written by Stein Consult can be downloaded on www.bureauleiding.nl.

This text is an unofficial translation of the Dutch text which is intended for RondLeiding, a magazine edited by BureauLeiding, the Dutch trade association of plastic pipe manufacturers.
The interview was conducted in German.

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Roger Loop (Bureau Leiding)




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