Why do you use Krah pipes? An interview with a civil engineer
We wanted to do an interview with an engineering company to find out the crucial points to use our pipes for their projects. Therefore, we have contacted the in Germany well known engineering office Müller GmbH Co. KG in Grünberg, Hessen. On a wednesday morning, I met Dipl.-Ing. Maik Ginsberg in his office to have a coffee and a chat with him. He has been working with Polyethylene pipes for over 20 years. In his engineering office in Grünberg, he plans projects for sewage systems, drinking water, tanks, water treatment plants and road construction.
Which kind of projects do you work with?
I work with large diameter pipes, mostly in the sector of canal construction, drinking water canals, tanks, water treatment plants and road construction. Which requirements do you have for modern sewer pipe systems and which on suppliers?
First of all, the most important feature for sewer pipe systems is the tightness, which is given by plastic pipes with a welded socket. Other important features concern the installation and handling. Especially for large diameter pipes the weight is a key factor - that‘s where plastic pipes come in handy. In terms of requirements for suppliers it is especially important that they stick to the stated delivery terms, which can be achieved by pre-fabricated pipes that only have to be connected together.
How important are storm water retention tanks for you?
Depends on the factors, which volume of water do we have, what kind of receiving water do I have? Can I drain off enough, do I have to install storage space? It must be designed accordingly. With today‘s punctual heavy rainfall events, there is an increasing need for a buffer so that the water bodies are not completely polluted. It is noticeable that more reservoir channels are being installed. There are also demands from the licensing authorities to install more. The significance is growing all the time.
How do you estimate the follow-up costs of leaks in sewers?
Leakage is bad in any pipe. The first goal is to lay the pipes in such a way that we do not have any leaks. In the case of completely welded pipes without rubber gaskets that can become leaky, we have produced a homogeneous product without any foreign material (rubber gasket), theoretically nothing can happen. If it is properly welded, nothing can happen.
Which pipe materials do you use for water and sewage projects?
Depends on the client. There are municipalities where we specify this, but some operators also have specifications. Water: cast iron and Polyethylene, in our area we were a bit heavy on cast iron because we have the Buderus cast iron here. When I started here 20 years ago, Polyethylene was only rarely used, water pipes were all made of cast iron. That has now changed, the proportion of Polyethylene is currently increasing.Sewage: mainly plastic pipes, but not always just Polyethylene. Polypropylene or PVC are also used. A small niche product, although this is becoming more and more common, is a combination of concrete and plastic pipe. Here in Hessen, a new system has been developed, Polyethylene pipe wrapped in concrete. This is very much in vogue at the moment. In terms of cost it is somewhat more expensive than Polyethylene, but the advantage is its high stability. The problem with our bending soft pipes is the deformation. This is always controlled by the calibration, which gives the 6% short- and long-term deformation. If you have a client who really pays attention to this, it is difficult to keep to this. The pipe doesn‘t mind, but explain this to someone: it‘s crooked now, but it still works.
How long have you been using Polyethylene pipes in your projects?
For 20 years, since I came here. The Polyethylene pipe was introduced here via Alexander. The older colleagues had nothing to do with it. When I started here, a bit of fresh wind came in, and with it the Polyethylene pipes.
Where do you see advantages and disadvantages in Polyethylene pipes?
Advantages: Handling due to low weight, sustainability due to the long service life, tightness through welding or sleeves, if it is done sensibly, nothing can happen. Disadvantages: partly with higher nominal diameters the long welding time and cooling time, because this is a downtime factor on the construction site. In the case of large storage ducts, this is already reflected in the long minute times. I am not allowed to do anything else on the pipe during this time, neither backfill it nor attach the next pipe. This also partly cancels out the price advantage. On the one hand, I come cheaper because I have a cheaper pipe, but on the other hand I have to charge the working time of the column, which almost cancels it out again.
In your opinion, has the cost structure for sewage systems changed?
With larger pipes, we have lower wall thicknesses, correspondingly less excavation and less disposal. Today, the disposal factor is the factor that has a considerable impact on the cost structure due to the grouping into the storage classifications at the Arbeitsgemeinschaft Abfall. This saves excavation, disposal costs and backfill material due to the smaller trench width. What are your customers‘ current expectations of pipe systems?Durability, tightness, low cost, low maintenance (less deposits).
Corona - how does Corona change your current plans?
Is there more or less planning, is there less money from the municipalities?No. At the moment it is not visible. Of course, it‘s impossible to predict what the future holds. At the moment the municipalities receive subsidies from the federal states and the federal government because of the defaulted trade taxes and so on. At some point, the federal government won‘t have anything left or will have to bring it back in. But at the moment nothing has hit us, we do not notice anything yet.
What project are you currently working on?
Currently we are planning and building a reservoir sewer with 1800 DN ID large capacity profiles and an elevated drinking water tank with a capacity of 600m3 in Hessen.
Thank you very much for your time and your interesting answers. Finally, I have an important question: Do you have a dog?
Hm... no! Okay, nice to know! We hope that your company will get through the Corona crisis well and wish you and the company all the best!
Jenny, Krah Pipes