Processing engineered polymer pipes made of polypropylene: What should you pay attention to? __

15. December 2022 3 min.

Due to its technical and ecological properties, polypropylene is a popular material for piping systems. Polypropylene pipes also impress with their good and simple processing during installation on the construction site.

Safe and stable connections are achieved by various welding methods. Such methods create stable and secure connections between individual PP pipes and their fittings: Leaks and the escape of liquids are avoided. 

In this article, we will introduce you to various welding methods and explain what else you should look out for.

Processing PP pipes: Welding methods 

There are different welding methods for processing plastic pipes made of polypropylene. The diameter of a pipe determines which method of welding to choose.

In the following, we present some welding methods:

  • Pipe diameter 16 mm to 63 mm:
    Socket welding can be performed with a hand welder for a quick and secure joint. Socket welding involves joining pipes with fittings.
  • Pipe diameter 50 mm to 125 mm:
    Even with this diameter, you can use a manual welding device for socket welding. But you can also carry out the process with a welding machine.
  • Pipe diameter 160 mm to 450 mm:
    Butt welding machines are used for both vertical and horizontal welding. With butt welding, pipes are joined surface to surface without additional parts.
  • For hard-to-reach areas:
    For pipes located in hard-to-reach areas and with pipe diameters between 20 mm and 250 mm, the electric socket welding process ( also called electrofusion) is suitable. With this process, special sockets with incorporated heating wires are electronically heated and fused to the pipe.
  • Horizontal and vertical welds can be created using the saddle welding process and branches can be made with weld-in saddles. Material and time requirements are reduced with saddle welding and this welding method proceeds in the same way as socket welding: pipes are joined with fittings, each with a matching radius.

If you want to learn about welding methods in detail, take a look at our YouTube channel. Furthermore, you will find more information around the processing methods of aquatherm green, aquatherm blue, and aquatherm red on the respective overview pages.


Hints for the processing of plastic pipes

Before starting the welding process you should familiarise yourself with and consider the following aspects:

DVS guidelines: rules and regulations for welding of PP pipes.

When welding plastics, it is important to observe the following guidelines issued by the German Welding and Allied Processes Association (DSVDVS):

  • DVS 2207-11: Welding of thermoplastics, hot plate welding of PP pipes, pipe sections and sheet.
  • DVS 2208-1: Welding of thermoplastics - Machines and equipment for hot plate welding of pipes, pipeline parts of sheets.
  • DVS 2212-1: Testing of plastic welders test groups I and II.
  • DVS 2281: DVS training course - plastics welders in test group I.
  • DVS 2282: DVS course - Plastics welders in test group II


Ambient temperatures and conditions for plastics welding

Temperatures and ambient conditions are critical to plastic welding. Therefore, be sure to protect your work environment from adverse weather conditions. 

If you want to weld outdoors, you should bear in mind that you need an environment in which you can carry out all the necessary steps without compromising quality - regardless of the outside temperatures. In this regard, observe the specifications of the plastic pipe manufacturer. In addition, the parts to be joined must have the same temperature level and test welds guarantee that the welding process is exactly as desired.

With regard to the condition of the pipe, make sure that frost, ice, and moisture are removed during welding preparations. You should also keep molded parts free of frost and moisture.

The cleanliness of tools, surfaces and the environment.

The cleanliness of tools, surfaces and the environment is very important: the tools you use for welding must be free of contamination and checked for cleanliness before assembly.

If necessary, clean contaminants thoroughly with a non-fibrous paper. Also make sure that the surfaces to be welded are clean and dry. Contamination, dust, and moisture can have a negative effect on the final result. The same applies to the environment in which you are working: This should be clean and dry.


Processing PP pipes: You now know what you need to consider

Do you know all the DVS guidelines? What ambient temperatures and conditions are ideal for welding? Are tools and surfaces clean? If so, then nothing stands in the way of processing your PP pipes.

On our product pages you can get an overview of the respective welding methods. If you prefer practical experience, we recommend attending one of our seminars in which we will familiarise you with the aquatherm products and their properties.

Trainings at aquatherm