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
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.
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.
They will bear all the ground loadings, whatever the soil settlement.
Circulating hot water can be used for central heating.
Sometimes these systems are called hydronic heating systems.15 Common components of a central heating system using water-circulation include: A supply of fuel, electric power or district heating supply lines A Boiler (or a heat exchanger for district heating) which heats water in the system Pump to circulate the water Radiators which are wall-mounted panels through which the heated water passes in order to release heat into rooms. The circulating water systems use a closed loop; the same water is heated and then reheated.A sealed system provides a form of central heating in which the water used for heating circulates independently of the building's normal water supply. Heating systems in the United Kingdom and in other parts of Europe commonly combine the needs of space heating with domestic hot-water heating.
These systems occur less commonly in the USA.In this case, the heated water in a sealed system flows through a heat exchanger in a hot-water tank or hot-water cylinder where it heats water from the regular potable water supply for use at hot-water taps or appliances such as washing machines or dishwashers.