The effect of nearby obstacles in surface condensations on external thermal insulation composite systems: Experimental and numerical study

Abstract

External thermal insulation composite systems are, nowadays, quite common in European buildings, used both in new constructions and refurbishment. Unfortunately, external thermal insulation composite systems can have serious problems of biological growth causing the cladding defacement. Studies carried out in recent years allowed understanding the hygrothermal behaviour of external thermal insulation composite systems. It is known that biological growth is due to high values of surface moisture content, which depends mostly on exterior surface condensation. Despite this existing knowledge, there is little information available about the influence of obstacles near the fac xade on condensation and surface moisture content. In this article, the results of a field test campaign to assess the influence of obstacles on surface condensation are presented. They show that nearby obstacles influence exterior surface temperature during the night and, consequently, surface condensation. Different obstacle configurations have different effects, which may lead to stained patterns on the fac xade due to differential biological growth rates. The effect of nearby obstacles on exterior surface condensation, revealed during the test campaign, addressed the development of a numerical routine to simulate their influence. This routine can be used with any existing hygrothermal model with the ability to simulate explicitly the radiative balance on the Downloaded from exterior surface. It calculates the increase in long-wave radiation due to the obstacle as a function of its geometry and emissivity of its surface. This extra amount of radiation is added to the atmospheric radiation that is an input of the hygrothermal models. The validation of this routine was performed by comparing simulated and experimental results. An example of the practical use of this routine is also presented in this article, with the calculation of the exterior surface condensation on different fac xades covered with external thermal insulation composite systems, with and without nearby obstacles, and its comparison with the coating defacement that they actually present.

Construction Process Technical Impact Factors on Degradation of the External Thermal Insulation Composite System

“…The list of degradation factors was collected through a literature review. The list of shortcomings is based on descriptive instructions, recommendations, harmonized standards, set requirements [38][39][40][41][42][43], studies regarding simulations or material studies made in laboratory conditions [11][12][13][14], field research [2,3,5,7,51,[68][69][70][71][72][73][74][75][76][77][78][79][80], and books on the topic [6,9,10] . Based on these references published between 1996 and 2015, a list of identified on-site degradation factors was created.…”

“…Literature Source Substrate (S) [6,9,10,56,64,68,73] Adhesive (D) [6,7,[9][10][11][12]14,15,46,56,69,73,76] Insulation (I) [6,9,10,13,49,50,58,72,73] Mechanical anchors (A) [6,9,10,40,41] Reinforcement (R) [2,6,9,10,55] Finishing layer (F) [6,[9][10][11]14,69] Additional details (X) [6,9,10,53,62] To reveal questionnaire errors, one declared and one undeclared pre-test were conducted. Similarly, individual pre-testing has been used by other researchers…”

“…Table 1 shows the literature used for the selection of degradation factors and the layer to which the factor is related, whereas entire list of revealed on-site shortcomings for further evaluation is presented in Appendix A. [6,[9][10][11]14,69] Additional details (X) [6,9,10,53,62] To reveal questionnaire errors, one declared and one undeclared pre-test were conducted. Similarly, individual pre-testing has been used by other researchers [81] and shown good results in identifying misinterpretations [82].…”

Modelling the Technical–Economic Relevance of the ETICS Construction Process

“…The list of shortcomings was formulated from descriptive instructions, recommendations, harmonized standards and set requirements [9,[22][23][24][25][26], research regarding simulations or material studies conducted in laboratory conditions [12][13][14], field research [3][4][5]34,[52][53][54][55][56][57][58][59][60][61][62][63][64], and books on the topic [6,10,11]. The selected factors were verified by two experts, who had more than 12 years' experience with ETICS.…”

A Study on Insulation Characteristics of Glass Wool and Mineral Wool Coated with a Polysiloxane Agent

“…Insulation boards are being used in various areas such as modern architecture and other industries, and these insulation boards are manufactured and used in various forms [3]. However, most of insulation is synthetic insulation in a foam type, where porosities are created inside of the product, fiber type insulation which uses glass wool or mineral wool in a nonwoven fabric type made from fabric material and board products which use inorganic binders such as cement with perlite and ceramic ball [4].…”