These include repairs done in individual apartments on request of their owners and renovations carried out throughout the block.Usually in all apartments at the same time they are installed new water meters, corresponding to accepted standards. Plumbers make the readings of the counters and check whether they function correctly and that none of the residents of the block is not he cheat on by their counter just to get lower bills for water consumption. They deal with the replacement of defective meters with new ones, if you notice the occurrence of any irregularities in their operation.
In such a time they can also perform plumbing work in a block of flats.
Plastic Pipes are classified by their ring stiffness.
Stiffness of pipes is important if they are to withstand external loadings during installation.
The higher the figure, the stiffer the pipe! After correct installation, pipe deflection remains very limited but it will continue to some extent for a while.In relation to the soil in which it is embedded, the plastic pipe behaves in a 'flexible' way.
This means that further deflection in time depends of the settlement of the soil around the pipe. Basically, the pipe follows the soil movement or settlement of the backfill, as technicians call it.
This means that good installation of pipes will result in good soil settlement.Further deflection will remain limited. For flexible pipes, the soil loading is distributed and supported by the surrounding soil.
It will exhibit only more deflection while keeping its function without breaking. However, rigid pipes by their very nature are not flexible and will not follow ground movements.They will bear all the ground loadings, whatever the soil settlement.
This means that when a rigid pipe is subject to excessive loading, it will reach the limit for stress values more quickly and break. It can therefore be concluded that the flexibility of plastic pipes is such that it offers an extra dimension of safety.
Buried Pipes need flexibility9Źródło: https://en.wikipedia.org/wiki/Plastic_pipework#Flexibility.