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.
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.
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.
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.
The principal causes of explosions, in fact the only causes, are deficiency of strength in the shell or other parts of the boilers, over-pressure and over-heating.
Deficiency of strength in steam boilers may be due to original defects, bad workmanship, deterioration from use or mismanagement." "Cause.-Boiler explosions are always due to the fact that some part of the boiler is, for some reason, too weak to withstand the pressure to which it is subjected.This may be due to one of two causes: Either the boiler is not strong enough to safely carry its proper working pressure, or else the pressure has been allowed to rise above the usual point by the sticking of the safety valves, or some similar cause" Boiler explosions are common in sinking ships once the superheated boiler touches cold sea water, as the sudden cooling of the superheated metal causes it to crack; for instance, when the SS Ben Lomond was torpedoed by a U-boat, the torpedoes and resulting boiler explosion caused the ship to go down in two minutes, leaving Poon Lim as the only survivor in a complement of 54 crew.Źródło: https://en.wikipedia.org/wiki/Boiler_explosion#Causes_of_boiler_explosions.