Manholes and special constructions

man1For sewage pipelines a variety of manholes and special constructions for inspection, regulation and combination are necessary. Therefore, we have in our delivery programme for profile pipes manholes and special constructions with different functions, made of polyethylene and polypropylene. By using these materials, there is the possibility to have a nonstop welding of the sewer system – from the start to finish. Different material properties like reaction on subsidence will be considered for the complete system.



man2Usually PKS manholes consist of a bottom part made of polyethylene or polypropylene and will be completed by prefabricated concrete parts. In this case the ferro-concrete manhole rings carry off the traffic load directly to the manhole wall. The bottom part which contacts the sewer or ground water is made of a noncorrosive polyethylene or polypropylene. Depending on load the manhole can also be manufactured completely in PE 80, PE 100 or PPR. The manholes will be furnished with a step in and step irons. PKS manholes themselves have an electro fusion socket and spigot end for a direct connection to the PKS pipes. The manhole is designed according to the corresponding requirement. PKS manholes distinguish themselves by a clear, inspection friendly inner surface, low weight and a very low roughness. In case of manholes with high traffic load, the manhole should have to the top with a plate of ferro-concrete to spread the traffic load. This plate carries the traffic load in the underground, so that no axial load can act on the manhole.



For sewer pipelines DN 300 up to DN 800 inspection manholes are used. Here you have the complete cross section of the sewer pipe within the entrance manhole. The entrance manhole is in this case: DN 1000 for PKS pipes DN 300 up to DN 500, DN 1200 for PKS pipes DN 600 and DN 1500 for PKS pipes up to DN 800. The channel of the inspection manhole is fabricated with a lifted, sure footed berm and sloped to the bottom. The upper part has concrete manhole rings. Through this an individual adaption to the later terrain is possible. The height of the inspection manhole depends on the maximum ground water level. Generally, the passage from the PKS manhole to the concrete manhole rings should be higher than the ground water level.



Tangential manhole

For bigger sewer pipelines from DN 600 the tangential manole is used. Here the sewer pipe is outside the centerline of the entrance manhole and under the manhole bottom. Therefore, it is possible to design the entrance manhole as standard in DN 1000. As upper part of the manhole a ferro-concrete cover plate has to be installed to take off the load. The passage to the concrete cover plate should also be higher than the maximum ground water level.



Advantages of PKS manholes

  • Manhole diameter up to DN 3500 made of a modern PE 100 material.
  • Clear and inspection friendly inner surface made of PE 100, manufactured in a co-extrusion process
  • Manhole depths deliverable according to customer requirement.
  • Channel in all bendings and dimensions possible:
    – Inspection manhole from DN 100 up to DN 2400
    – Tangential manhole from DN 600 up to DN 3500
  • Low pressure losses due to low frictional resistance.
  • Inlayed EPDM-sealing in manhole wall for passage to prefabricated elements of ferro-concrete.
  • Safety steps- or ledder according to customs requirement.
  • Quality controlled, tight and welded construction  to DVS.
  • Static design following with evidence of buoyant force guarantee.
  • Design of a CAD-drawing for each construction.
  • Connection to the sewer pipe system PKS via easy electro fusion welding possible.
  • Special constructions: Pump manhole, leakage controlled construction and landfill manholes, drainage- and infiltration manholes, storage tanks with throttle manholes, geothermal manholes and distributors.



Plastic pipes made of polyethylene are successfully installed in canalisation for more than 35 years. Spiral pipes made of the modern material PE 100 can be used for all intents and purposes in an innovative sewer pipe system – also for storm water tanks. To guarantee a constant inflow for waste water treatment, it is necessary to install containment volumes in the sewage network. These containment volumes must be able to reserve the flow after rain and release then constantly. For special constructions also the use of an overflow basin is required.




With the profiled sewer system (PKS) made of PE different constructions can be realised. Manholes with formed pipe connection can be manufactured up to a dimension of 3,5m in our workshop. There is also the possibility to have separate pipe- and manhole components which can be delivered as complete construction, pre-assembled in our workshop with a storage up to 100m³. The connection of each pipe and construction can be done at site up to 2,3m via integrated electro fusion socket. For bigger dimensions extrusion welding is used.






In the early 1980s, FRANK developed and patented the FRANK puddle flange, a sealing system in use today in millions of buildings and structures all over the world. The original.

The FRANK puddle flanges, suitable for all standard pipes in steel, plastic, stoneware, concrete and cast iron from d 32  to d 3200, have been specifically designed for the pressure-tight installation of pipelines in concrete walls, foundation plates and manholes. FRANK puddle flanges are pressure-tight water, diffusing media such as gases (e.g. radon) and hydrocarbons (e.g. oil, petrol). The FRANK puddle flange is an extremely flexible product available in a range of versions. A perfect solution for any application! Easy to install. Cost-effective alternative to conventional sealing systems.

Protection against radioactive gas, Radon-resistant, gas-tight puddle flanges from FRANK
Radon is a naturally occurring radioactive gas and comes from the natural radioactive decay of uranium and thorium. These metals occur naturally in bedrock and the release of radon therefore depends on the local geology. You cannot see, smell or taste radon. The gas diff uses through the soil and is released into the atmosphere where it is found in very small concentrations. Outside of buildings, radon is therefore not a problem. The gas can however enter buildings, for example through cracks and joints, defective foundation plates in the basement or the ground floor, or along cable and pipe ducts. In this case, the radon concentration builds up gradually, often exceeding the limit values recommended by the German Federal Office for Radiation Protection. Tight foundations, solid constructions and special ventilation measures help keep the radon concentration in buildings low. When installing pipes and cable ducts through building walls, we therefore recommend using the special orange FRANK puddle flanges which are tested for radon-tightness.