PVC windows. Technical class and scope of application.
Which windows for a single-family house and which for an apartment in a block of flats? Searching for the correct answer to such questions will always lead you to the technical class obtained through the window. Since no universally binding set of requirements and applications of windows has been formulated in Poland so far, we will present to readers selected fragments of ITB Instruction 480/2012, which constitute a proposal for the scope of use of windows depending on the technical class obtained by them.
Technical window class and requirements.
What distinguishes two seemingly the same PVC windows from each other is the level of specific functional properties called by the Institute of Building Technology in Instruction 480/2012 a “technical class”. It is not at all the case that an investor from Pcim should use windows of the same technical class in his home as the investor from Świnoujście, and an investor from Gorzów the same as the investor from Pacanów. Although the windows of all these people can be built of profiles with the same number of chambers, they can be equipped with the same glazing and fittings, but what should be different is the technical class, i.e. the level of performance. The need to vary the levels of performance of PVC windows not only results from the individual needs of each investor, but also results from … objective reasons, which above all include the location of the object in which they are to be used.
The specific role played by a window in a building, consisting in separating the stable indoor climate of the rooms from changing external atmospheric conditions resulting from seasons, wind, rain and temperature differences should encourage investors to carefully watch the windows for their resistance to the adverse effects of these phenomena. Due to the fact that different weather phenomena in different parts of Poland occur with varying intensity, it is necessary to use windows with different functional properties, of different technical class.
Air, water, wind
Air, water, wind are a certain mental shortcut regarding the window’s functional properties. The three title concepts relate to the resistance of each window to air permeability at variable pressure of wind pressure, its tightness during rainfall and resistance to deformation caused by impact (pressure and suction), wind. We have previously signaled that in various regions of Poland certain weather phenomena occur with varying intensity, which necessitates the use of windows with different levels of performance there. Below we present tables derived from Instruction 480/2012, in which the Building Research Institute gives the values of minimum requirements in the scope of these three functional properties depending on the location of the object in a specific wind load zone, the location of the object relative to sea level, the category of terrain and the height of building windows in the walls building. To make it easier to read the values given in the tables, we remind you the normal division of Poland into wind load zones and the division of land into categories.
Instruction 480/2012 is a relatively new document, published five months ago. Despite the passage of time, he did not cause industry discussion, although he should, because there is something to discuss. Without going into a polemic with the contents and values of technical classes contained in the Instruction, it seems to us an important document in that for the first time investors and architects find a reference to the minimum levels of so many window performance properties at the same time, and they learn that: ” Windows cannot be worse than … ” The ball is now on the side of producers and sellers who should prove that their windows are not worse than the requirements of ITB. “They are not worse” is not enough. Windows available on the market should have a technical class much better than the minimum ITB requirements! Our recent consumer PVC window test showed this. Thanks to it, it is known that even the best window is “like new” only at the time of purchase, and its use by the user causes a gradual, sometimes very significant, loss of the initial technical class. Adding to this the adverse impact of weather conditions, it turns black and white, that when buying windows with a relatively low technical class, such as on the border of ITB requirements, we will quickly get into trouble, not to mention the lack of satisfaction with the purchase.
With this impact of weather conditions on windows, and in particular temperature differences, it is interesting. Few investors and architects know that window resistance to climatic influences can be determined before purchasing it. You will admit that it would be good to know in advance whether the window you are buying will make a “banana” or not? And if you already have a “window banana”, does it fall within the limits of deflections recognized by the ITB as acceptable, or does it exceed them? If this interested you, then from our next article you will learn what about the “window bananas” and window resistance to climatic influences says Instruction 480/2012.
Author: UPVC Windows Costs