Plastic & cast-iron pipes
Existing cast-iron pipes
Pipes in drainage systems are mostly made of cast iron. This was completely dominant up to the beginning of the 1960’s, when plastic pipes entered the scene. But a lot of cast-iron pipes are still installed. Plastic pipes, for example, don’t meet fire requirements, which is necessary in buildings with sectioned fire cells. Cast-iron pipes have a material thickness of around 4 mm with a tolerance of +- 1 mm. Large variations in quality occur.
Corrosion
During corrosion, iron reacts to the acid in water and in the air, and the cast iron is slowly broken down. One can reckon with a cast iron pipe corroding, on the average, 1 mm every 10 years. There are, however, great variations. This means that the cast iron can be unaffected with 3 mm thickness in some parts where other parts of the same plumbing system can be affected to a significantly higher degree.
It is very difficult to evaluate the condition of pipes. If small dark brown dots are starting to be seen on drainpipes where they are visible, it is high time for repairs. Embedded pipes can have rust damage that has gone through the pipe without causing visible water damage. But when the pipes are cleaned, deposits consisting of grease etc. loosen, and leaking becomes a fact.
Existing plastic pipe
The first plastic pipes were whitish pipes of the HT type. With time they became brittle, and the ends of the pipes are most vulnerable. They can be repaired with our method. An advantage of all plastic pipes is that deposits from gray water don’t stick to them in the same way as they do in cast iron pipes. Cleaning is easier to manage.