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Influence of Variable Moisture Conditions on the Value of the Thermal Conductivity of Selected Insulation Materials Used in Passive Buildings
The interest in passive construction that has low demand for thermal energy continues to grow every year. It is related to both the reduction in maintenance costs of buildings and the growing environmental awareness in societies. Passive houses are characterised by very good thermal insulation properties of their external partitions. This paper presents the results of tests on the thermal conductivity for three different types of building materials, assuming their use as thermal insulation. The materials were subjected to water absorption tests during long-term immersion. The purpose of this study was to simulate water absorption caused by long-term water exposure. The tests were carried out on a perlite concrete block, a sheet of polyurethane foam applied by spraying and expanded clay in a loose form in three different fractions. The tested insulation materials were selected due to their different form, structure, and porosity characteristics, which largely determined the value of the thermal conductivity. A perlite concrete block is a new, innovative product, of which manufacturer’s data are not yet available as the product is currently at the stage of detailed research. The results were analysed statistically and used in graphs to show the dependence of the value of the thermal conductivity on moisture content of the samples. The purpose of this study was to indicate the importance of the proper incorporation of insulation materials into buildings, their storage before construction and use in the post-construction phase. Building standards for passive houses place high demands on materials used. In order to fully enjoy the advantages of passive buildings, i.e., lower energy consumption and benefits for the natural environment due to lower consumption of energy generated from non-renewable energy sources, it is necessary to use certified building materials and ensure proper use of objects. The studies quoted in this paper indicate to what extent the influence of moisture content negatively affects the properties of insulation materials in external partitions.
Analiza cech materiałowych bloczków z perlitobetonu poddanych działaniu czynników atmosferycznych
Obecnie, w przypadku dużych inwestycji budowlanychoraz zmian klimatycznych obejmujących gwałtowne zjawiskapogodowe, trudno jest wypracować w harmonogramieprac budowlanych odpowiedni termin wykonywania prac. Gwałtowneulewy zdarzają się w miesiącach uznawanych wcześniejza odpowiednie do wykonywania niektórych prac budowlanych.W artykule poruszono zagadnienia stosowania zawilgoconychmateriałów podczas budowy przegród ściennych oraz wpływunadmiaru wilgoci na ich dalsze użytkowanie na przykładziebloczków z perlitobetonu. W pracy odniesiono się do wcześniejwykonanych badań dotyczących badania wilgoci, współczynnikaprzewodzenia ciepła, wytrzymałości oraz pokazano prototypowysposób odwzorowania niekorzystnych warunków atmosferycznychdla ściany z bloczków z perlitobetonu poddawanychsystematycznemu zawilgoceniu
Application of Experimental Studies of Humidity and Temperature in the Time Domain to Determine the Physical Characteristics of a Perlite Concrete Partition
These days, the use of natural materials is required for sustainable and consequently plus-, zero- and low-energy construction. One of the main objectives of this research was to demonstrate that pelite concrete block masonry can be a structural and thermal insulation material. In order to determine the actual thermal insulation parameters of the building partition, in situ experimental research was carried out in real conditions, taking into account the temperature distribution at different heights of the partition. Empirical measurements were made at five designated heights of the partition with temperature and humidity parameters varying over time. The described experiment was intended to verify the technical parameters of perlite concrete in terms of its thermal insulation properties as a construction material used for vertical partitions. It was shown on the basis of the results obtained that the masonry made of perlite concrete blocks with dimensions of 24 × 24.5 × 37.5 cm laid on the mounting foam can be treated as a building element that meets both the structural and thermal insulation requirements of vertical single-layer partitions. However, it is important for the material to work in a dry environment, since, as shown, a wet perlite block has twice the thermal conductivity coefficient. The results of the measurements were confirmed, for they were known from the physics of buildings, the general principles of the formation of heat and the moisture flow in the analysed masonry of a perlite block. Illustrating this regularity is shown from the course of temperature and moisture in the walls. The proposed new building material is an alternative to walls with a layer of thermal insulation made of materials such as polystyrene or wool and fits into the concept of sustainable construction, acting against climate change, reducing building operating costs, improving living and working conditions as well as fulfilling international obligations regarding environmental goals.