The analysis of negative temperatures influence on air permeability of modern PVC windows was made. For this purpose, complex tests of several types of PVC windows with different profile thicknesses were performed in the laboratory. The determination of the windows air permeability was made under standard conditions (+20 °C) and negative outside temperatures (-5°C, -15°C, -25°C, -35°C, -45°C). For the windows air permeability determination at negative outdoor temperatures was created the special test stand. It was found that at negative temperatures there is a significant decrease in the windows air permeability is observed. However, this process occurs differently for PVC windows with different profiles thickness, this process also depends on the outdoor temperature. The research results are proposed to be used to calculate the buildings heat balance. This will increase the calculations accuracy, since this will use the windows air permeability data, determined not under standard conditions (as it is now), but under real winter conditions. The further research directions of the issue are given.
The PVC windows application experience in various climatic conditions shows that at their operation the windows profile deformations can be observed. One of the reasons for these deformations is the climatic loads influence on the windows – wind pressure, solar radiation, negative outside temperatures. The profile elements deformations affect the window tightness and the normal window hardware operation. The calculated loads combinations on windows in winter and summer were analyzed. For window as external element of building is more critical winter loads combination – the combined effect of wind pressure and negative temperature. The work was done the analysis of the effect of negative temperatures and wind pressure on the PVC window deformation. The studies were performed in laboratory conditions on the basis of two testing centers. Three PVC Windows with different profile thickness were tested. The temperature deformation of the casements and mullions profiles of this windows were analyzed. These deformations have to take into account in the static calculations. But the engineering methods creation for calculating windows for the wind and temperature loads effect requires additional research. They are associated with the study of the joint work of the windows constituent elements (profiles, insulating glass units, hardware).
Аннотация. Работа посвящена вопросу изучения теплотехнических характеристик современных оконных блоков из ПВХ профилей при отрицательных температурах наружного воздуха, а также оценке их соответствия требованиям действующих нормативных документов. Для исследования были отобраны типовые конструкции оконных блоков, массового применяемые в строительстве. Лабораторные испытания показали, что под воздействием перепада температур наружного и внутреннего воздуха, соответствующего зимним условиям эксплуатации, профильные элементы оконных блоков приобретают значительные деформации. Температурные деформации профилей ПВХ, а также снижение эластичности уплотнительных прокладок приводят к снижению теплозащитных качеств оконных блоков. Эффект проявляется в повышении их воздухопроницаемости, а также в снижении температур на внутренних поверхностях их профильных элементов. Это приводит не только к повышению инфильтрационных теплопотерь через данный класс светопрозрачных конструкций, но и нарушению нормируемых параметров микроклимата в помещении. Установленный экспериментальным методом эффект снижения теплотехнических характеристик оконных блоков из ПВХ профилей при отрицательных температурах наружного воздуха не учитывается существующими методиками расчета, что говорит об необходимости их корректировки.
The PVC windows using experience in the climatic conditions of the Russian Federation shows that their profile elements are subject to temperature deformations under the influence of the temperature gradient of outdoor air and indoor air. This physical phenomenon is observed both in the summer and winter operation period. In this article we study the influence of external air negative temperatures into the sound insulation of PVC windows. The research was performed on a standard PVC window in a climate chamber with acoustic equipment. The PVC window sound insulation measurements were carried out at the following temperatures inside the cold compartment of the climate chamber+20 °C, 0°C, -5°C, -20°C (at a constant temperature in the warm compartment of the chamber + 20°C). It is established that the reduction of PVC windows sound insulation begins to occur only at outdoor temperatures below 0 °C. The sound insulation of PVC window at an outdoor temperature -20°C is 3 dB lower than the sound insulation of the same window, determined under standard conditions (+20 °C). Obviously, existing methods of calculation of sound insulation of PVC windows it is necessary to adjust in terms of operational ambient temperatures and design features of the windows.
The paper analyzes the temperature and humidity conditions of the roof space of buildings with translucent roofs in the winter period of operation. The work is based on the generalization of data from a number of field observations and monitoring of translucent roofs of atrium buildings in Moscow. It is established that the temperature and humidity regime of the sub-roof space of atrium buildings with translucent roofs in the winter period of operation has a significant impact on the load-bearing capacity and durability of the translucent filling of coatings (insulated glass units), as well as snow loads on translucent roofs. At the same time, an analysis of existing approaches to the design and calculation of translucent roofs atrium buildings has shown that the issue considered in this work is often not taken into account when assigning their design solutions, which further complicates their normal operation. It is established that when performing strength calculations of roof insulated glass units it is necessary to take into account the design conditions of the transitional spring-winter period, which is characterized by low outdoor temperatures and high solar activity. The thermal regime of translucent roofs of atrium buildings also has a significant impact on the formation of snow cover on similar structures, which is manifested in a different nature of the distribution of snow loads on translucent roofs, as well as on the amount of snow loads, which are several times less than the loads on similar deaf insulated roofs.
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