Pastatų atitvarų medžiagų sąlyčio zonos drėgminės būsenos prognozavimas

Abstract

Remiantis eksperimentinio tyrimo rezultatais, pasiūlyta patikslinti medžiagų sąlyčio zonoje vykstančių drėgminių procesų matematinį modelį. Kapiliariniam įgėriui silpnėjant, prasideda kitas sąlyčio zonos drėgminio būvio etapas – kondensato „išspaudimas“ į šiltinamąją medžiagą ir galimas jo judėjimas dėl gravitacijos. Didinant apšiltinimo efektyvumą iš esmės keičiasi drėgmės perdavimo mechanizmas.

In this article the temperature and moisture behaviour in contact area of two different materials is investigated. According to experimental investigation results an inadequacy of practical data in comparison with calculated data with non-stationary heat and moisture exchange programme WUFI (made in Germany, Holzkirchen) has been found. Therefore the experiment consisted of two stages. In the first stage it was shown that the importance of vapour permeability of insulating wall is bigger in comparison with data of temperature field distribution in the mentioned wall. In the second stage it was shown that effectiveness of insulating material changes the of moisture behaviour in contact area of two different materials. It is experimentally estimated and analytically grounded that insulation from the inside of building external wall with thermal resistance up to 1,2 m2·K/W, the thickness of the additional thermal insulation (mineral wool) has to be no less than 40 mm if vapour barrier is not applied. If thickness of additional insulation material (mineral wool) is increased up to 10 cm, it is necessary to install a vapour barrier, with a vapour resistance value sd no less than 3,6 m. In a contact area of two materials (mineral wool products and external wall) where water vapour condensation starts, the moisture behaviour is changed: capillary active and insulated from the inside outside wall material (ceramic brick masonry) does not absorb in time the condensed moisture (water) and it could move down under the influence of gravitation forces or it could freeze, if there is a negative temperature. According to presented mathematical model, it was established that ceramic brick masonry insulated from the inside by 10 cm thick mineral wool boards, the ceramic brick masonry absorb in time only 0,34 kg/m2. In a contact area of two materials, 0,4 kg/m2 of unabsorbed moisture is left.