Recently, the Typhoon has been rampant, which brings a lot of inconvenience to people's life and work. Due to the high humidity, there may be water seepage in doors and windows, water accumulation inside the structure, and moisture returning to the wall body of the hole, water tightness refers to the ability of closed doors and windows to prevent rainwater leakage under the simultaneous action of wind and rain. If the water tightness of the outer windows is not good, in the case of violent wind and rainstorm, rainwater will penetrate into the room through the window with the help of wind. Roland Sini doors and windows have already put forward a comprehensive solution to the problem of leaking doors and windows.
What is the watertightness of doors and windows?
The ability of doors and windows to resist rain
Before explaining the watertightness, let's clarify a misunderstanding of the concept.
Many people think that when it rains, the rain falls vertically, which is like people walking on the road holding umbrellas to avoid being caught in the rain. Buildings have roofs, naturally, rain can be avoided indoors.
In fact, this is a very wrong concept. Because the rain and wind in nature are always accompanied. The national standard tests the watertightness of doors and windows are also measured in the form of "wind and rain. (We will talk about the details below)
Let's take a look first. How can "wind and rain" happen in real life?
Apart from normal natural phenomena of wind and rain, for buildings and doors and windows, the influence of water tightness will mainly occur in the following two situations. One situation is that when the typhoon comes, everyone must experience it. When the typhoon comes, the Thunder and Thunder will flash and the storm will naturally be "wind and rain. Another situation is that with the high-level effect brought by urbanization, the wind in nature will change with the height away from the ground, and the wind speed will become faster and faster, when the slight breeze felt on the ground reached the top of the 20-storey building, it was found that it was difficult to stand firm, which was the phenomenon that the wind speed was constantly plus-sized with the change of height. Therefore, looking at the light rain and the wind, when I arrived at the high-rise residential building, it was "the wind and rain.
Therefore, when we determine the watertightness of doors and windows products, we must use the state of "wind and rain" to determine the performance level of the products. At this time, we need to introduce a concept called: severe leakage pressure difference.
What is the severe leakage pressure difference?
Pressure difference when serious leakage occurs on outer door and window specimens
About Severe leakage pressure difference (? P), the definition of national standard is: the pressure difference when the outer door and window specimen has serious leakage. (Well ~~~ does it look quite understandable ~~ well, well, I still can't understand ~~)
Well, let's turn it into a normal language to explain. In short, when the wind is stronger, the pressure on doors and windows will be greater. This is like when you walk with an umbrella and wind on rainy days, the stronger the wind, the more difficult it is to walk.
So, how much pressure difference will be in this severe leakage? Architectural experts in our country have already given the answer.
As mentioned just now, there are mainly two kinds of wind and rain. Let's first look at the situation when the first typhoon comes. The place where there are many and violent typhoons in China is South China, while Okinawa is the place where Japanese typhoons are most willing to visit. Take the two places as an example, let's take a look at the situation when the typhoon comes.
Although the above chart is a bit complicated, it is not difficult to see from it that when the typhoon comes to the surface, under normal circumstances, the difference of severe leakage pressure (? The maximum value of P) is about 700PA.
Influence of floor height on severe leakage pressure difference
Next, let's take a look at the difference between floor height and severe leakage pressure (? P). The following figure explains why the height of the floor affects the size of the wind in a scientific way, but this...... Well, well, it's still difficult to understand. It doesn't matter. We have already listed the situation of typical cities from south to north, and everyone can see it clearly.
The generation of wind is the result of the combined action of pneumatic gradient force, friction force and Coriolis force. Near the surface, the influence of Coriolis force is very small. Wind is mainly dominated by pneumatic gradient force and friction force. Influenced by buildings, topography and vegetation, the friction force is relatively large. Therefore, the wind speed increases with the increase of height, when the friction force decreases, the wind speed will increase accordingly, and the wind direction will deflect under the influence of Coriolis force.
Finally, we combine the typhoon with the height of the building to see that the water tightness of doors and windows that the 100-meter-high residence must achieve when the typhoon comes: Severe leakage pressure difference (P)
It is based on this principle that in the national standard (GB/T 7106-2008), The watertightness of doors and windows is graded, and the watertightness of the highest level in the country is grade 6, that is, p≥700pa.
In addition, by simulating this natural environment of wind and rain, the watertightness of doors and windows is detected, and finally the watertightness of doors and windows is determined.
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