Abstract
Various Heat-Air-and-Moisture models may give divergent results for the same case, due to differences in assumptions, simplifications, or approximations. Inter-model comparisons have been ...used as ‘peer review’, but common limitations and/or mistakes may remain concealed. Recent validation efforts, confronting simulations with measured datasets, use limited materials, configurations, and boundary conditions. A thorough and stepwise assessment is still lacking. In this study, dedicated hygrothermal experiments on four wall assemblies (comprising calcium silicate board, mineral wool, wood fiber board and vapor barrier in different configurations) are conducted in a hot box-cold box at KU Leuven, Belgium as a benchmark. Temperatures, relative humidity, heat fluxes and moisture mass are monitored while the thermal and hygric properties of the materials from the same batch are measured. One dimensional simulations in WUFI and DELPHIN are employed to reproduce the experiments in three stages: (1) “similar” materials (with the closest properties) from respective databases provide realistic trends but also significant deviations; (2) “same” materials (attained by mathematical translation) give better agreement but uncertainties in material properties and simplifications still have great influence; (3) monitored datasets are employed to compare with simulated results using measured material properties, based on which a collaborative inter-model blind-box validation has been initiated.
Abstract
External Thermal Insulation Composite System (ETICS) facades are widespread and cost-effective building solutions in many climates. However, they are frequently found to deteriorate ...prematurely. In addition to other possible defects, several buildings were found with horizontal cracks on the facade between every floor level. Because of the fire safety requirements of multi-storey buildings, EPS insulation has been divided by mineral wool fire breaks at each floor level. The service life of the system usually ends up with horizontal cracks appearing at the lower level of the wool belt. This study aimed to determine the damage mechanism. One deteriorated facade was opened to explore possible construction technology errors and specimen were analysed in the laboratory. Temperature and RH were measured in situ inside the walls at different positions. It turned out that built in moisture of concrete was still drying out after three and a half years. Moisture content of concrete was found to be between 0.046 to 0.063 m
3
/m
3
behind EPS insulation and 0.047 to 0.074 m
3
/m
3
behind MW insulation - slightly higher than hygrothemal model was predicting. A possible solution was proposed to alleviate the similar problem in the future with application of waterproofing membrane behind mineral wool.
Sound insulation of slabs in dwellings Miškinis, Kęstutis; Bliudžius, Raimondas; Buska, Andrius
Journal of physics. Conference series,
12/2023, Volume:
2654, Issue:
1
Journal Article
Peer reviewed
Open access
Abstract
The well-being and sleeping quality of people in dwellings depends on appropriate sound insulation efficiency of building structures. In individual apartments, airborne sound is produced by ...people talking and music playing, and impact sound is produced by people walking and falling of various objects on the floor. The inter floor slab separating the individual dwellings is intended for airborne and impact noise insulation, so special attention is paid to its design and installation. Since the composition of this structure is primarily determined by the structural requirements, the improvement of the sound insulation performance is mainly carried out by developing the damping interlayer materials. The stone wool plate has been modified reducing the fiber intertwining to obtain a more uniform fiber directivity, thus reducing its dynamic stiffness. Therefore, the aim of this study was to investigate the sound insulation efficiency of inter floor slabs with a new modification of stone wool damping interlayer in comparison with currently used mineral wool products. The experimental measurements in 50-5000 Hz frequency range were performed in construction site (real structures), the single-number quantities – weighted standardized level difference (D
nTw
) and weighted normalized impact sound pressure level (L‘
nW
) with living adaption term (C) were determined and compared. The research results demonstrated that the modified stone wool with reduced fiber intertwining and lover organic content used for damping interlayer enables to improve living sound insulation of inter floor slab comparing with existing stone wool materials.
Abstract
Aerogel-based coating mortars with thermal conductivities ranging from 30 to 50 mW/(m·K) are an emerging type of thermal insulation coating mortar. They are intended for retrofitting ...uninsulated building envelopes due to their thermal performance which is comparable to conventional thermal insulation materials such as mineral wool. Meanwhile, their long-term hygrothermal performance and the reliability of the material properties are not fully demonstrated since these normally are declared based on single-cycle laboratory measurements. This paper presents laboratory measurements to determine the capillary water absorptivity of a commercial aerogel-based coating mortar after three consecutive wetting and drying cycles. The effect of the chosen drying (elevated versus room temperature) and sealing condition (sealed versus unsealed samples) on the measurement results were also assessed. The results show that the capillary water absorptivity of the samples increased after each repeated wetting and drying cycle regardless of the drying and sealing conditions. After three cycles, the measured capillary water absorption was more than five times higher than the initial measurement. Future research should investigate the causes of the observation and whether it applies to other aerogel-based coating mortars.
•Chemical composition of 88 mineral wool samples is reported.•Glass wool composition is similar to soda-lime silicate glass.•Stone wools have composition similar to basalt, but variation is ...observed.•Cr, Ba, Ni, Cu, Zn, and Pb are present in mineral wools, but in low concentrations.•Organic resin within mineral wools may cause NH3 emissions during their processing.
Despite mineral wool waste is only a small fraction of total construction and demolition waste (CDW) by mass, it requires large transportation and landfilling capacities due to its low bulk density, and its utilization remains low compared to other CDW types. It is essential to understand the physical and chemical properties of this waste fraction in order to utilize it, e.g. as fiber reinforcement in composites or as supplementary cementitious material. Here, we provide a chemical and physical characterization of 15 glass wool and 12 stone wool samples of different ages collected from various locations across Europe. In addition, the chemical compositions of 61 glass and stone wool samples obtained from the literature are presented. Glass wool samples show little variation in their chemical composition, which resembles the composition of typical soda-lime silicate glass. Stone wool presents a composition similar to basaltic glass but with variability between samples in terms of calcium, magnesium, and iron content. Potentially toxic elements, such as Cr, Ba, and Ni, are present in mineral wools, but in low concentrations (<0.2%). Both wool types contain organic resin, which may decompose into smaller molecular fragments and ammonia upon heating or contact with alkaline solution. Mineral wool wastes have relatively similar length and width distributions, despite the age and type of the mineral wool. Overall, both mineral wool waste types have homogenous chemical and physical properties as compared to many other mineral wastes which makes their utilization as a secondary raw material promising.
External Thermal Insulation Composite Systems (ETICS) are the most common technical solution to improve the thermal efficiency of existing buildings. In the light of the applicable regulations, ETICS ...are kits that apply only one type of thermal insulation material. All typically used ETICS introduced into the market classify as non-combustible. Despite that, the emerging recommendations in some countries point to the need for the introduction of barriers of non-combustible material such as mineral wool (MW) around the openings and horizontal isolation barriers around the building between different floors to prevent fast fire spread. That raises an important question: Do MW partitions significantly improve the fire safety of the building and balance other aspects such as the sustainability and durability of such combined insulation materials with different properties? Here, we assessed the impact of MW partitions in EPS-based ETICS on the spread of the fire according to the requirements of BS 8414-1: 2020. Four different variants were investigated. The study showed slight differences in average temperatures and the size of the polystyrene melting area for various insulation variants with the introduced horizontal MW partitions. The introduction of MW partitions shows no significant benefits or improvement of fire safety of the investigated ETICS.
•Enhancement of flame retardancy and smoke suppressant of natural fibre Elium® composite laminates using intumescent thermal resistive mats containing expandable graphite was performed ...successfully.•While higher expansion ratios of EG particles in the composite lead to greater flame resistivity and reduction of smoke, the modulus decrease proportional to the increase of EG exfoliation ratio.•The bending strength of composites was found to increase as compared to that of the Control composite and the glass transition temperature was seen to increase with EG of lower expansion ratios in the coating material.
This investigation studied the utilization of intumescent thermal resistive mats to provide surface protection to the core natural fibre-reinforced Elium® composite structural integrity. The intumescent mats contained flame retardant (FR) i.e. expandable graphite (EG) with four different expansion ratios and alumina trihydrate (ATH). All natural fibre thermoplastic composites were fabricated using a resin infusion technique. The impact of char thickness and chemical compositions on the flammability and smoke properties was investigated. It was found that surface protection significantly reduced the peak heat release rate, total smoke release, smoke extinction area and CO2 yield, and substantially enhanced UL-94 rating, time to ignition and residual char network, depending on the EG exfoliation ratio, ATH and mineral wool fibre. The glass transition temperature increased for the FR composites containing EG with lower expansion ratio. Inclusion of intumescent mats increased the strength of the composites while it had a negative effect on the modulus.
•Rock wool and glass wool were used to manufacture lightweight aggregates (LWAs).•The new LWAs exhibited technological properties analogous to the commercial ones.•Glass wool allows LWAs to be ...obtained at temperatures of 500 °C below the usual.•Life Cycle Assessment has shown significant environmental benefits of the new LWAs.
Waste recycling is one of the key elements to mitigate the environmental problems that threaten our society. Mineral wool is currently the most widely used insulation material in the European Union, so the amount of waste generated in the demolition and restoration of buildings has increased alarmingly. This work investigates for the first time the use of glass wool (GW) and rock wool (RW) as a component in the manufacture of lightweight aggregates, showing that both can be suitable raw materials considering the density (1.3–1.5 g/cm3) and mechanical strength (2–6 MPa) obtained. In addition, the use of GW would help to reduce the firing temperature significantly (700 °C) compared to that normally used in the manufacture of these materials (around 1200 °C), which would imply significant energy savings. Considering that thermal insulation materials and lightweight aggregates are among the most widely used materials in the construction sector, the work presented here also evaluates the environmental impact associated with the manufacture of lightweight aggregates with RW and GW in comparison with the traditional process, using the Life Cycle Assessment (LCA) methodology. A significant environmental improvement has been observed in almost all the analyzed impact categories of the artificial aggregates manufactured with mineral wool with respect to traditional LWAs.
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