Plastic pipes and flexibility
Plastic Pipes are classified by their ring stiffness. The preferred stiffness classes as described in several product standards are: SN2, SN4, SN8 and SN16, where SN is Nominal Stiffness (kN/m2). 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. Stresses and strains caused by the deflection of the pipe will occur within the pipe wall. However, the induced stresses will never exceed the allowed limit values.
The thermoplastic behavior of the pipe material is such that the induced stresses are relaxing to a very low level. It has to be noted that induced strains are far below the allowable levels.
This flexible behaviour means that the pipe will not fail. 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 flexibility9
Replacing the defective water meter
Plumbers employed by the cooperative to perform a variety of hydraulic works. 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.
Safety residents of the block in the course of work carried out hydraulic
Plumbers working in a cooperative housing standard working hours from eight hours to the seventeenth or eighteenth. In such a time they can also perform plumbing work in a block of flats. More work done in a block must be well organized in such a way that it can be performed as soon as possible with the greatest respect for the rights of the people to preserve their privacy and quiet in the early morning. The tasks of the executives of the association must also ensure the safety of residents of the block during the works. They can apply to do the second division of water, clean water and sewage network or even replacement of water meters in all areas.