Connecting pipe sewer systems made of PVC or PP by push-fit method is one of the easiest ways to make a sewage system. However, in order not to forget about the basics, we invite you to read the article below, which will refresh your knowledge in this area and provide some practical tips.
The process of connecting push-fit pipes.
Before proceeding with assembly, first check whether the end of the pipe or fitting is chamfered. In the vast majority of cases, the phase is carried out at the factory, but there are cases where the pipe is not chamfered. This is the case, among others when cutting pipes. Then we chamfer the pipe end on a 5 mm section at an angle of 15 °. We check that the gasket has been correctly seated in the groove, fitting or pipe. We make sure that all the joined elements are dry, clean and free of dirt and dust, and that at the bare end of the pipe or fitting there are no deep scratches that could prevent the creation of a watertight joint using the seal. We evenly spread the lubricant around the bare end of the pipe or fitting. We do not use oils or greases.
Standard seals used in sewage systems are made of SBR (styrene butadiene rubber), which degrades when exposed to contact with mineral lubricants and oils. Sometimes it is also worth lubricating the seal itself with a dedicated lubricant, if the amount of factory grease is insufficient to overcome the first resistance during interference. On the other hand, the amount of lubricant on the seal should not be exaggerated. Particularly here is the passage of grease between the seal and the groove of the cup. Upon encountering the first resistance, the gasket may slip out of the groove and roll up. Therefore, if possible, after making the connection, it is worth looking inside, if the use of a large amount of lubricant did not translate into the use of less interference force.
We put the connected elements straight in line with each other. Press the bare end of the pipe or fitting completely into the socket. When inserting a plastic pipe with a length of 2 m or longer, we mark the bare end of the pipe at the front of the socket, and then retract it by 10 mm to leave room for its elongation due to thermal expansion. The lack of a gap may result in pressure of the bare end of the push-fit pipe against the notch of the socket under the influence of hot sewage flow and, as a consequence, failure (the crack of the socket and leakage). After further assembly work, we re-check to ensure that the designated expansion gap has been maintained.
In some low-noise systems (e.g. Wavin AS), in addition to flare pipes, there are also non-flare pipes. The connection of these pipes is carried out using a socket socket with system expansion compensation. In this case, the push-fit pipe in the muff does not need to be retracted by the aforementioned 10 mm, unless excessive use of the lubricant has allowed the bare end of the push-fit pipe to be pushed into the plastic ring stop in the middle of the muff.