There are small ones Automatic gestureswho sometimes pass on for generations and that we often do without thinking about it too much. Many of us, for example, open cold water in the sink before throwing the boiling water of the pasta, for fear that this can damage the exhaust pipes. But does it really make sense to do it? Actually, No: If the plants are in metal it is not a risky practice, these are able to bear very high temperatures. Even in cases where the pipes are in plastic (for example in polypropylene or polyvinylcloride), their merger temperature is of about 170 ° Cmuch higher than the boiling water temperature. In addition, the contact time With the pipes it is very short: the water we drain in the sink is quickly addressed to the drain pipes and the hydraulic system in the wall. Instead, we should be careful of the sink itself, especially if it is made of materials like quartz And granite which are susceptible to temperature changes (thermal shocks) between room temperature and boiling water: they could create themselves crack who in the long run would ruin the material.
Is boiling water risky for the drain pipes?
When the plants are in metal there is no fear, but in the presence of the widespread plastic pipes Many doubts may arise. Polymers like the Polypropylene (Pp) and the Polyvinylcloride (PVC) have melting temperatures around the 170 ° Cmodifiable with the addition of stabilizers. However, the so -called “is really important”Vicat regret temperature“, a temperature to which the polymer begins to lose structural rigidity Until being deformed by a needle during a standard test.
For the Pp The regret temperature is decidedly higher than the PVC because it is of 118 ° C, if pure, but with the addition of iron powder can reach i 150 ° Cmaking this plastic very suitable for contact with hot water. The PVC instead has one lower heat resistancewith regret around the 75 ° C.

In any case, pouring the water into the sink most it will quickly flow towards the wall exhaustwithout creating too many problems for plastics of the exhaust pipes. In fact, these are normally a room temperature before the water drain and this would pass too quickly to be able to warm and regret the pipes: conditions very different from Vicat testduring which the temperature of the object is constant and increased degree per degree until the piece of the piece.
We can therefore continue to pour the cooking water into the sink, as many of us have been doing for decades: above all for domestic usethe plastic pipes are able to resist heat of downloaded waters.
The hot water can also help to eliminate fat residues or organic adhering to the pipes, such as Residues of soap or oils deriving from the washing of the dishes: an advantage for our tubes, less for the sewerswhere these residues can return. This is also one of the reasons why in many states, such as Italy or Finland, the Discharges of industrial plants have maximum temperature limits between the 40 or 45 ° C: especially in the presence of Trappole for Grassithe passage of water at high temperatures would favor the drain of fats that they must instead be captured and treated as a refusal.
The materials of the sinks
And as regards the sink themselves? Heat resistance varies, of course, from one material to another. THE Metal sinksprobably the most common genre in modern kitchens, are certainly able to resist to the heat of the water: thesteellike many other metals and alloys, is a Excellent heat conductor And it is able to quickly distribute the energy on its surface. The melting temperatures are also very distant from that of boiling water: the stainless steel melts over 1400 ° C.

As regards composite materials such as the granite or the quartzthe speech is a little more complicated. These materials are called composites precisely because, in addition to the mineral parts (granite powder and quartz powder), they are composed of percentages of organic resinsnecessary to aggregate and stabilize dust in the desired forms.
These materials are on average heat resistant, aThe point can also be able to endure short contacts with hot pots. Despite this, however, greater caution would be necessary in pouring boiling water into quartz or granite sinks, especially if made of pure material, perhaps distributing it in the entire sink: they are in fact particularly susceptible to temperature changes and in this way they would avoid excessive thermal shocks on a small area, To reduce the risk of formation of cracks and other damage. The use of composite materials with organic resins allows to increase its stability even to thermal shocks, but are still less resistant than stainless steel.
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