External Insulation System Research Articles

Analysis of Thermal Performance of a New Regenerated Glass Pumice External Wall Insulation System in Hot Summer and Cold Winter Zone

The thermal performance of a new regenerated glass pumice board as external wall thermal insulation material was analyzed in this paper. Considering the roles of solar radiation and air convection, and selecting Wuhan city as an example of the hot summer and cold winter zones, the temperature field distributions of the external building walls in different orientations in summer and winter seasons were numerically simulated by using the finite element software ANSYS. The thermal performance of regenerated glass pumice exterior wall external insulation system including the heat transfer coefficient and the temperature distribution was evaluated. The simulation results demonstrate the good thermal insulation performance of the regenerated glass pumice as a new kind of external wall materials, and the feasibility of the application of this environmentally friendly material to the wall insulation system in energy conservation building is also promoted.

Thermal Optimization Strategy of External Wall in Low-Rise Light Steel Keel Structure Based on the Theory of Thermal Bridge

Light steel keel structure is the most mature structure system in low-rise light steel structure residence. Exterior wall skeleton belongs to dense ribbed structure, so its thermal problems of exterior wall are more prominent. From light steel keel structure composition and exterior wall structure, based on the theory of thermal bridge, thermal performance of external wall is analyzed and thermal optimization measures of external wall in low-rise light steel keel structure are put forward. Specific measures are as follows: Firstly, finding the optimum balance point between the structure steel consumption and thermal performance; Secondly, punching in the steel skeleton webs to improve steel column; Thirdly, arranging the non-metal heat blocking between metal components; Finally, choosing external insulation system of outer wall. These measures are not only conducive to eliminate thermal adverse effects, but also can provide valuable theoretical basis for energy consumption analysis of low-rise light steel keel structure residence.

Experimental study and advanced CFD simulation of fire safety performance of building external wall insulation system

Large scale fire tests of building external wall insulation system were conducted. In the experiment, thermal-couples were mounted to measure the insulation system surface temperature and the gas temperature inside rooms at the second and third floors. Photos were also taken during the fire tests. The measurement provides information of the ignition and fire spread of the external insulation system which consists of surface protection layer, glass fibre net, bonding thin layer, anchor and the load bearing wall. Comprehensive simulations of the fire tests were carried out using an advanced CFD fire simulation software Simtec (Simulation of Thermal Engineering Complex) (1, 2), which is now released by Simtec Soft Sweden, with the turbulent flow, turbulent combustion, thermal radiation, soot formation, convective heat transfer, the fully coupled three dimensional heat transfer inside solid materials, the 'burn-out' of the surface protection layer and the pyrolysis of the insulation layer, etc, all computed. The simulation is compared with experimental measurement for validation. The simulation well captured the burning and fire spread of the external insulation wall. With strategic implementation of building energy conservation, external wall insulation system has been widely used in China. Thin plaster external thermal insulation systems (TPETIS), with advantages such as light weight, low thermal conductivity, wall structure protective, simplicity in construction and etc., have become the most widely used type of wall insulation system. Typical insulating materials used in TPETIS are EPS (Expanded Polystyrene), XPS, (Extruded Polystyrene) PUR (Polyurethane) and PIR (Polyisocyanurate). In recent years, however, a number of serious fire accidents of high-rise building are related to TPETIS. This has drawn people's high attention to the fire safety of TPETIS. The fire performance of TPETIS is mainly affected by factors such as ignition source, system structure and combustion property of the insulation materials. For ignition source factor, Lee (3-5) has analyzed of the spreading mechanism of window fires (the external wall insulation system fire is usually started by window fires) and proposed a new length scale for correlating window fire's flame height, plume temperature and heat flux. Himoto (6) considered pressure gradient effect of window fire plume, and proposed a model for predicting the trajectory of window flame ejected from a fire compartment. For system structure factor, Oleszkiewicz (7) pointed out that laterally projecting structure of building facade can reduce radiant heat flow by 90%, and the vertical extending structure can increase radiation heat flux by 50%. For TPETIS, he also proposed fire-barrier belts to be used between every one or two floors. In recent years, a number of scientists (8-10) have carried out a number of window and corner fire experimental studies and indicated that the systems with improved structure (such as additional This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Experimental Research of Foaming Concrete Performance with Different Fly Ash

Low-density foam concrete is inorganic silicate material that can replace traditional organic materials for external wall insulation system. Based on the analysis of structure formation mechanism of foaming foam concrete prepared with chemical method, investigation by a large number of comparative tests and quantitative analysis, quantitative relationship of compressive strength, tensile strength, and blowing agent dosage quantitative of 3d, 7d and 28d foaming concrete are analyzed. The relationship between blowing agent and foam concrete strength and thermal conductivity variation is revealed by the research of doped fly ash concrete strength, improved workability mechanism. And further, independent sealing pores, high mechanical strength of pore wall, pore structure approximate to sphere and pore diameter with similar and small size were all favorable factors for higher strength of foam concrete.

Experimental Research of Foaming Concrete Performance with Different Blowing Agent

Low-density foam concrete is inorganic silicate material replace to traditional organic materials for external wall insulation system. Based on the analysis of structure formation mechanism of foaming foam concrete prepared with chemical method, investigation by a large number of comparative tests and quantitative analysis, quantitative relationship of compressive strength, tensile strength, and blowing agent dosage quantitative of 3d, 7d and 28d foaming concrete are analyzed. The relationship between blowing agent and foam concrete strength and thermal conductivity variation is revealed by the research of doped foaming agent concrete strength, improved workability mechanism. And further, independent sealing pores, high mechanical strength of pore wall, pore structure approximate to sphere and pore diameter with similar and small size were all favorable factors for higher strength of foam concrete.

The Surface Characteristics of Exterior Wall External Insulation System with Foamed Glass in Weathering Resistance Test

A weathering resistance test was made to exterior wall external insulation systems with foamed glass decorated with coating and facing brick in this paper. The results show that the change of ambient temperature has large effect on the external insulation systems. Because of the phenomenon of stress concentration, there are many cracks in the windows position. On the other hand, the system decorated with facing brick has much less cracks than the system with coating, and its surface layer has no hollowing. So from the perspective of weathering resistance, the exterior wall external insulation systems with foamed glass decorated with facing brick is better than the system decorated with coating.

Thermal Performance Analysis for a New External Wall Insulation System

Based on the existing quality problems of external wall insulation system, a new external wall insulation system was developed through the rational use of closed air layer’s thermal insulation performance. Considering three kinds of ways of heat transfer-- convection, conduction and radiation and using the coefficient of air equivalent thermal conductivity to obtain the thermal resistance in the air layer, compared with the thermal resistance at different thicknesses in the new system using polyurethane and polystyrene board of insulation material with two different thicknesses, the authors can get the most optimal model. This paper takes the extreme value of indoor and outdoor temperature in summer as the temperature loads of this model and uses ANSYS simulation to obtain its heat flow density, gradient and temperature field, and in the meanwhile, undertakes a comparison with the present form of external wall insulation in the new code. Data indicates that in the same index of energy saving, this system can not only meet the needs of the code, but also reduce the requirement of heat insulator, as well as greatly improve anti-cracking and waterproofing ability. Thus, the new system follows the direction of the development in this field.

Energy Efficiency Analysis of Internally and Externally Insulated Apartment Buildings

Apartment buildings are the most common type of residential buildings in Korea, where hot water heating pipes are installed in the floor structures. An internal insulation system (IIS) has been applied to the outside walls of most Korean apartment buildings, so there are many cases in which the layer of insulation is disconnected by structural components at the wall-slab joints. These joints become thermal bridges where heat transfer increases. An external insulation and finish system (EIFS) is a possible solution to this problem. In this study, the surface temperature distributions of actual apartment buildings with an IIS and an EIFS were investigated with an infrared thermal imaging camera. Annual heat losses and gains through the wall-slab joints with an IIS and an EIFS were calculated by three-dimensional transient heat transfer simulations in which hot water heating was excluded and included, respectively, in order to evaluate not only the heating and cooling loads, but also the heating efficiency when the building is actually heated. The results show that the amount of heat transfer through the wall-slab joints with an IIS is considerable, even though additional insulation is installed under the slab, and the EIFS significantly reduces the heating and cooling loads and improves the heating efficiency.

Experimental Study of Shear Capacity under Different Temperatures

The external wall insulation system exposed to the building surface, in summer temperature of outside surface can reach 50 °C -70 °C, this article designs a new external wall insulation system shear strength test of test equipment to study at different temperatures decorative panels sandwich insulation fiber reinforced concrete shear performance, the results show that: with increasing temperature, fiber reinforced concrete decorative panels sandwich insulation ultimate shear capacity has reduced to varying degrees, damage patterns cut from the extruded plate destruction into the adhesive surface of shear failure.

Research on Fireproofing and Insulation System of Polyurethane Foam and Moulding Board with Glazed-Hollow-Bead Mortar

In this paper, a new insulation system of polyurethane foam and moulding board with glazed-hollow-bead mortar is designed. According to the principle of the temperature gradient and the spreading and releasing stress in different layers, the fire prevention and aging resistance performance of polystyrene board in external insulation system are improved. Performances of fireproofing and insulation motor of different ingredients, such as glazed hollow bead, fly ash, polymer emulsion powder, quicklime and fiber were tested in the lab, and the reasonable mix ratio of the mortar was obtained. Moulding board of glazed-hollow-bead mortar was deigned and manufactured. To quickly construct and improve quality of the new insulation system, fixed moulding board system was manufactured, board of glazed-hollow mortar and fixed board system were gained.

Energy Saving Measures of Building Integration and Cost Analysis Based on 65% Standard

It is difficult to reach the request that 65% standard of building energy in china and the goal of China’s science and technology development in 2020 using traditional outer insulation technology. The several combinations of ordinary concrete (1) and bearing ceramsite concrete (2), styrofoam board of external thermal insulation for external wall (3) and cement-based glazed hollow bead insulation system (4) are made thermal calculations and cost analysis separately in this paper based on a practical project of Jiaozuo city. The results indicate that the combination of (2)+(4) is the best one, which reduces the energy saving rate, labor intensity, transportation weight, project cost by 74%, 20%, 30%-40% and 10% respectively.

An improved approach for the application of Trombe wall system to building construction with selective thermo-insulation façades

An improved Trombe wall is proposed to adapt to building construction with selective thermo-insulation façades (internal and cavity wall insulation, but not external wall insulation system). The case study is conducted in Xining, Capital city of Qinghai province in China, where the general building façades are mostly selective thermo-insulation façades to fight against the severe cold. A numerical analysis is undertaken to show the effects on the improvement of the building’s thermal environment by comparing the improved Trombe wall system with the classical Trombe wall system. The operating efficiency of the improved Trombe wall can be up to 33.85%, an increase of 56%. The results show that the improved Trombe wall works more effectively than the classical Trombe wall system in utilizing solar energy for the sample building.

Decay of Wood and Wood-Based Products Above Ground in Buildings

Abstract This paper is an overview of what we know about occurrence of wood decay above ground within buildings. It presents information concerning under what conditions decay may become established. In laboratory tests involving optimum moisture and temperature conditions for decay fungi, and direct contact with large quantities of specific well-developed decay fungi, substantial decay in small specimens of untreated wood of nondurable species can occur in a few weeks. The simultaneous occurrence of optimum conditions for decay and high degree of inoculation with mature decay fungi is probably very rare in buildings. However, spore germination also proceeds rapidly at optimum moisture and temperature conditions. For most decay fungi, optimum moisture conditions mean moisture contents above fiber saturation (usually around 25 to 30% mc,) but well below the waterlogged condition. Optimal temperatures for most decay fungi are in the range of 21 to 32°C. Untreated wood and wood-based products will not decay if intermittently wetted for short periods to moisture contents above fiber saturation or if wetted to such levels for periods of a few months when temperature is low. However, little is known in quantitative terms about decay development under fluctuating conditions. Moisture and temperature conditions are not expected to fluctuate appreciably behind external insulation and finish system (EIFS) claddings. Given this, we can find nothing in the research literature that would contradict the 20% wood moisture content rule for this application.

Wind loads on permeable roof-blocks in roof insulation systems

Similar to the wind-exposed outer layer of many roofing systems, the roof-blocks in external roof insulation systems are wind permeable. This paper describes the wind loading mechanism on blocks with relatively thick air-layers underneath. The experiments are carried out for both a prototype and a scale model to investigate the effects of gaps between blocks and of air-leakage device. Furthermore, a numerical analysis based on the unsteady Bernoulli equation to obtain the internal pressure distribution under a known external pressure field is presented.