Insulation Products Research Articles

An experimental study of spray foam insulation products-evidence of 1,2-dichloropropane and 1,4-dioxane emissions

An experimental study was conducted using SPME-GC-MS and TD-GC-MS to analyse VOC emissions from three spray foam insulation products. Two closed cell and one open cell materials were tested using SPME-GC-MS passive sampling and a range of VOCs were found with 1,2-dichloropropane (1,2-DCP) found in all products. TD-GC-MS analysis of Product 1 (a closed cell foam) and the raw material used for its production (B-side) showed that 1,4-dioxane and 1,2-DCP were both present in the raw material and emitted from the cured foam product. Our findings are currently limited and preliminary, but do seem to indicate that industrial contamination of raw chemicals could be the likely source of these compounds. This could raise the issue of Class 1 and 2B carcinogen VOCs being present in raw polyurethane spray foam insulation (SPF) materials should systematic evidence is provided. As per WHO guidance, it would be a better strategy to remove pollutants at the source. Further research will aim to quantify emission concentrations during application and examine the impact of application strategies.

Cellulose/biochar aerogels with excellent mechanical and thermal insulation properties

Aiming at investigating the use of alternative materials for the production of thermal insulation and, mainly, to replace the carbon structures (graphene and nanotubes), extensively used in the development of aerogels, the present study had the objective to produce cellulose/biochar aerogels and to evaluate their properties. The aerogels were produced from Pinus elliottii cellulose fibers and biochar produced from these fibers. The materials were characterized in their physical, thermal and mechanical properties. They were extremely light and porous, with a density between 0.01 and 0.027 g cm−3 and porosity between 93 and 97%. Several percentages of biochars were added to the cellulose suspension (0–100% w/w). The use of 40 wt% biochar provided a 60% increase in the compressive strength of the aerogel in relation to the cellulose aerogel. Besides that, the addition of this carbonaceous structure did not influence significantly the thermal conductivity of the aerogels, which presented a thermal conductivity of 0.021–0.026 W m−1 K−1. The materials produced in the present research present a great potential to be used as insulators due to the low thermal conductivity found, which was very similar to the thermal conductivity of the air and also of commercial materials such as polyurethane foam and expanded polystyrene.

Determination of thermal and physical characteristics of dead pine wood thermal insulation products

The studies allowed manufacturing dead pine wood thermal insulation materials for the arrangement of premises. Raw materials for their production are wood fibers formed as flat boards. The mechanisms of the thermal insulation process during energy transfer through the material, which makes it possible to influence this process are determined. It is proved that the processes of thermal insulation consist in reducing the porosity of material. So, with a decrease in material density, thermal conductivity decreases, and vice versa. Modeling of the heat transfer process in the swelling of the fireproof coating is carried out, temperature dependences of thermophysical coefficients are determined. Based on the obtained dependences, thermal conductivity for dead pine wood products, reaching 0.132 W/(m·K) is estimated. In case of adhesive bonding of wood products, it decreases to 0.121 W/(m∙K) and when creating wood wool thermal insulation boards it decreases to 0.079 W/(m∙K), respectively. Features of inhibition of the process of heat transfer to the adhesive bonded wood wool material are associated with the formation of pores. This is because in small pores there is no air movement, accompanied by heat transfer. Thermal conductivity of homogeneous material depends on density. So, with a decrease in the material density to 183 kg/m3, thermal conductivity decreases 1.67 times, and vice versa, when using the board, thermal conductivity decreases only 1.1 times. This allows confirming the compliance of the discovered real mechanism of thermal insulation with the revealed conditions for the formation of properties of the inorganic and organic-mineral bonded wood wool material, as well as practical attractiveness of low-quality wood. The latter, in particular, relate to determining the amount of the binder component. Thus, there is reason to argue about the possibility of directed regulation of the processes of formation of wood thermal insulation materials using wood wool and inorganic and organic-mineral binder, which can form a fire-retardant film on the material surface

Development of acoustic insulating materials from recycled textile fiber

Nowadays, there is an increasing demand for recycling materials and hence for greater environmental friendliness. The issue of waste management and recycling is a very actual topic in the society of most developed countries. One area where the vast amount of waste is generated every year is the textile industry. Textile waste (old clothing, fashion accessories, car upholstery, home textiles and other textile products) is most often made up of a combination of different types of natural fibers (cotton, silk) and man-made fibers (polyester, viscose). Thanks to the large amount of this waste and recycling technologies available, the secondary textile fibers are an interesting secondary raw material that can be used for the production of thermal and acoustic insulators. The article describes research results in the development of medium and heavy insulating mats usable in vertical constructions and floating floor structures.

Failure Analysis and Suggestions of Composite Insulators

In this paper, the development of composite insulators at home and abroad was firstly introduced. Then several common failure forms and mechanisms of composite insulators were systematically expounded, which mainly included the failure of sheds and sheaths, brittle and decayed fracture of cores. In addition, the fracture of composite insulator cores had been the greatest threat to the safe operation of transmission lines. At last, to provide a reference for the operation and maintenance, some suggestions and measures for design, production and installation of composite insulators were put forward from practice.

Investigation of the Extrusion Process Influence on the Thermophysical, Rheological Properties and Operational Characteristics of Insulating Polymers

In this work, we carried out complex experimental studies of the thermophysical and rheological properties of the initial and secondary (after extrusion) polymer compositions based on low, medium and high density polyethylene, intended for the cable insulation production. On the basis of the obtained experimental data, a comparative analysis of the numerical study results of the flow processes in the extruder metering zone with a constant technological regime was carried out. Changes in the graphics of maximum and average temperature values along the length of the channel are received.

The influence of compression pressure on thermal expansion, bulk density, and Young’s modulus of electroporcelain mixture up to 1100 °C

The production technology has a significant impact on physical and mechanical properties of ceramic materials. The common manufacturing processes are pressing, extrusion, or casting. Porcelain products are often formed by pressing, which increases their mechanical properties. Therefore, samples made from electroporcelain mixture for production of high-voltage insulators are studied using pressing with five different compression pressures from 70 MPa up to 110 MPa. Young’s modulus, thermal expansion, and bulk density are investigated during firing in temperature interval from 25 to 1100 °C. All measurements are carried out in the same temperature program with a heating rate of 5 °C min−1 in static air atmosphere. The influence of pressing and heating on Young’s modulus, thermal expansion, and bulk density of electroporcelain mixture is examined.

Contribution of Polish agrotechnical studies on Cannabis sativa L. to the global industrial hemp cultivation and processing economy

Summary Industrial hemp (Cannabis sativa L.) attracts increasing interest of growers, in relation to both industrial and medical purposes. Construction is the most promising area of the economy for hemp, and specifically, the fast-growing production of insulation and bio-composite materials. The most significant factors affecting the final yield of hemp seeds and biomass include: climatic factors, i.e. influence of weather conditions that determines the content of cannabinoids in plants; genetic predisposition of the variety used as well as agrotechnical factors. The article provides information on the botanical characteristics of fiber hemp, hemp cultivation area, Polish monoecious varieties of industrial hemp, hemp's agricultural requirements, including: the demand for macroelements (nitrogen, phosphorus, potassium, calcium); choice of soil, pioneer crop, and field preparation; sowing timing and density; harvest time; water conditions; heat and light requirements for hemp. The review article is focused mainly on the results of studies carried out at the Institute of Natural Fibres and Medicinal Plants, data of the Agency for Restructuring and Modernization of Agriculture (ARiMR), Research Centre for Cultivar Testing (COBORU), European Industrial Hemp Association (EIHA), published in 2008 - 2018.

Innovative Thermal Insulation Products for a Circular Economy

The depletion of non-renewable resources is followed by severe ecological and social impacts, and the heavily usage of raw, virgin resources leaves significant, long lasting footprints. In order to move into a more sustainable economic system, a recently more frequently discussed approach for overcoming the current linearity of product lifecycles is the concept of circular economy (CE). The transition to a more circular economy, where the value of products, materials and resources is maintained and circulated (by recycling activities) in the economy for as long as possible, is an essential contribution to the EU’s efforts to develop a sustainable, low carbon, resource efficient and competitive economy. In this context, ecological solutions consisting of materials which helps carbon sequestration and necessitates small amounts of energy for production are becoming increasingly popular from buildings construction point of view, namely: the raw material is cheap and in large quantities; have low thermal conductivity; are from a renewable source. The paper presents an analysis of some innovative thermal insulating products made from renewable or recycled resources (recycled plastics, low quality wool, straw, cellulose), their thermal conductivities over a temperature interval and acoustics coefficients (αs, αw), the purpose being to inform the market in order to increase the present level of technical knowledge and to facilitate the implementation of high energy efficiency buildings with products from recycled materials or using industrial by-products.

Evaluation of the contributions to the effective thermal conductivity of an open-porous-type foamed glass

Abstract Sustainable development focused on energy and material savings is driving attempts to decrease the thermal conductivity of heat insulation materials. Foamed glass is one of the most sustainable thermal insulation materials and has unique, load-bearing properties. In this study, contributions to the effective thermal conductivity were quantified for an open-porous-type foamed glass. Foamed samples were prepared by heating a mixture of waste flat glass, the foaming additives carbon and Mn3O4, and the nucleation agent TiO2. The density of the foamed glass was 117 kg m−3 (total porosity 95.8 vol%) with a closed porosity of only 5.8 vol%. The latter was minimized by promoting partial crystallization. The thermal conductivity was 54.3 mW m−1 K−1 at atmospheric pressure. Fitting the pressure dependence of the thermal conductivity gave a base thermal conductivity of 26.7 ± 0.4 mW m−1 K−1, and a gaseous contribution of 27.7 ± 0.5 mW m−1 K−1 with a pore size of 0.77 ± 0.07 mm. Thus, the base thermal conductivity, which is attributed mainly to the thermal conduction in the solid phase, is much higher than in the case of fibrous glass insulation products.

CONVECTIVE DRYING OF HEAT INSULATION BASALTO- BENTONITE PRODUCTS

The paper presents the results of the experimental study of air convective drying of flat basalt-bentonite heat insulation products of various thickness and density. Were considered products with the thickness of 50 and 100 mm, and the density of from 100 to 225 kg / m 3. The effect on the intensity of the process temperature and the average speed of the drying agent was studied. The temperature of the drying agent varied in the range from 100 to 180 ° C with its average moisture content of 20-25 grams of moisture / kg of dry air. The average speed of the drying agent ranged from 1 to 10 m / s. For insulating products there are periods with constant and falling drying speed. In the considered range of product thicknesses, both the first and second critical moisture content are observed. It is noted that with decreasing thickness of the heat insulation product, the values of critical moisture content increase. The influence of the thickness and density of the heat insulation product on the kinetic characteristics of the drying process has been established. The dependence for the drying rate in the first period, as a function of temperature and speed of the drying agent, is given. Using the method of V. Krasnikova constructed generalized curves of air convective drying, established the values of the reduced moisture content and the relative coefficients of drying. A generalized dependence is obtained for calculating the time of air convective drying of heat insulation basalto-bentonite products of various thickness and density. It is noted that the rational organization of the process allows to achieve a 2-3-fold reduction in specific energy consumption per unit of evaporated moisture. The study serves as the basis for the development of energy-efficient heat technology modes of convective drying of basalt-bentonite insulation products and its hardware design.

Thermal Properties of Insulation Boards Made of Tree Bark & Hemp Residues

Two disparate waste materials were mixed to identify the likelihood of constructing insulation boards. Treebark and Hemp (cannabis) residues were combined in different proportions and with two dissimilar typesof glue. The thermal conductivity (λ) for all boards was measured. Diverse methods of processing the finalboards demonstrated altered thermal properties based also on the different density (low and medium).The results have validated the possibility of exploiting local waste materials to produce an eco-friendly,low priced insulation product with competitive (λ) compared to the market products. All materials werecollected within a small range to the laboratory (< 100 km). The energy requirements and the carbonfootprint of these boards were kept low compared to traditional chemical insulation materials.

Experimental Study on the Smouldering Combustion of Mineral Wool Insulation in Chimney Penetrations

A large number of fires have been caused by metal chimney penetrations in recent years. One factor that has contributed to these occurrences is smouldering combustion within mineral wool, which is often used as insulation in metal chimneys and their penetrations. Based on reaction to fire performance mineral wool is typically classified as a non-combustible material and in European standards it belongs to category Euroclass A1. However, mineral wool insulation products contain organic material, which smoulders and generates heat at temperatures between 200°C and 500°C. Experimental research indicates that this additional heat may increase the temperature in the chimney penetration materials over 100°C for a limited period of time. The European fire classification of materials does not set requirements to control mineral wool smouldering and limit the subsequent heat release. This experimental study examined the smouldering of mineral wool insulation products specified for chimney penetrations and the heat release generated during the smouldering combustion. The aim of the study was to determine the actual level of temperature increase within the chimney penetration and to estimate the effects of the increase with regard to fire safety. The study also reviewed how the smouldering potential of an insulation material could be considered in the fire classification of products.

Existence and stability of heat and fluid flow in the presence of nanoparticles along a curved surface by mean of dual nature solution

This study examines the possible existence and stability of the heat transfer solutions due to unsteady nanofluid flow over a curved surface. Alumina oxide (Al2O3) is considered as one of the important nanoparticles due to its potential use in various fields like purification of water, ceramics and insulation products. It is considered that the small quantity of nanoparticles is incorporated in the Ethylene Glycol to form the nanofluid. Mathematical form of the problem is obtained by using the fundamental laws of motion and heat transfer. These equations are modified for the presence of solid concentrations in an ordinary liquid. The complicated coupled unsteady system is transformed into non-dimensional form by the use of relevant transformations. The solution of nonlinear problem is produced by the use of numerical scheme, available in the form of BVP4C package in MATLAB. In the case of surface shrinking towards the surface, a reverse flow situation is also developed, and requires careful selection of solution by examining the stability of solution. Detailed stability analysis is carried, and critical values are determined for the possible existence of dual solutions. Moreover, various parameters variation is also analyzed by plotting graphs and tables. The numerical values are also calculated for the reduced Nusselt number and skin friction values caused due to variation in various flow parameters. Results have shown that for the curved shrinking surfaces, one should expect multiple solutions for a set of parameter values like mass suction, curvature, nanoparticles volume fraction and unsteadiness. The isotherms suggest linear decay of heat away from the surface.

Comparison of four commonly used high temperature vulcanized silicone rubber formulas for outdoor insulator and their regional adaptability

ABSTRACTHigh temperature vulcanized silicone rubber (HTVSR) insulators are widely used in transmission lines. In this article, four formulas [fumed silica and precipitated silica as reinforcing agent, alumina trihydrate (ATH) and alumina as flame retardant, and Fe2O3 and Fe3O4 as colorant] widely used in the production of HTVSR insulators were investigated by performing a series of laboratory experiments. The surface morphologies of silicone rubber, mechanical characterization (hardness, tensile property, and tear strength), electrical properties (volume resistivity, dielectric property, and breakdown strength), hydrophobicity and its transfer property, and thermal property of these four formulas were analyzed. According to the test results, the formula composed of fumed silica, Fe2O3 colorant, and alumina trihydrate (ATH) were excellent in mechanical properties because of more secondary structures, more bound rubber, and uniform dispersion. Therefore, it can be used in strong wind and bird pecking regions. Due to the absence of crystal water, the formula composed of fumed silica, Fe2O3 colorant, and alumina was observed to be excellent in thermal stability and electrical properties, making it suitable for the regions with high temperature and humidity. The formula composed of precipitated silica, Fe3O4 colorant, and ATH was found to be excellent in hydrophobicity transfer characteristics because of more raw rubber and satisfactory performance could be expected when it was applied in polluted regions. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47477.

Evaluation of Kalalani vermiculite for production of high strength porcelain insulators

The present work has evaluated Kalalani vermiculite as a potential raw material for the production of high strength porcelain insulators. Three porcelain compositions were prepared to contain 0, 20 and 30 wt% of Kalalani vermiculite. Porcelain samples were fabricated using a semi-drying method. The chemical, mineralogical phases and microstructural characterization of the raw materials were carried out using XRF, XRD, and SEM techniques, respectively. Water absorption, bulk density, dielectric and bending strengths were performed on porcelain samples fired up to 1300?C. However, at the sintering temperature of 1250?C, the porcelain sample with 20 wt% of Kalalani vermiculite gave the dielectric strength of 61.3 kV/mm, bending strength of 30.54 MPa, bulk density of 2.21 g/cm3 and low water absorption value of 0.21 % which is the prerequisite properties for high strength porcelain insulators. It was therefore concluded that Kalalani vermiculite has the potential to be used for the production of high strength porcelain insulators

Use of waste production of crystalline silicon in the production of vacuum insulation

The purpose of the study is to consider the possibility of using microsilica - waste of aluminum production, as filler in a vacuum insulation panel. The properties of silicon dioxide powder have been studied, and compositions and manufacturing technology of vacuum thermal insulation panels on its base have been developed. Differential thermal analysis of powders is carried out; the curves of differential thermal analysis and thermogravimetric analysis, x-ray phase analysis are obtained. The microstructure of the samples is investigated. The thermal conductivity of the manufactured panels is measured. The test results suggest that for the manufacture of low–vacuum insulation panels of microsilica powders, waste production of crystalline silicon can be used. The use of waste in the future can become the basis for the production of high-quality vacuum insulation with low cost.

The use of the ash of thermal power plants for the production of efficient porous insulation

The article presents the results of research related to the use of ash from thermal power plants for the production of porous heat insulating materials. Using the method of differential - thermal analysis, the optimal values of the composition of the raw mix and the thermal regimes of the formation of the porous structure were found. It is shown that it is possible to obtain a new ash-based binder and thus replace up to 70% of cement in the production of thermal insulationthe properties of the new material are similar to the properties of foam concrete.

Snow insulation and conservation systems

Various aspects of application of polyethylene foam implemented for roof thermal insulation within the frame of one of the sports venues and, closely, the realization of insulation systems for cold conservation on the territory of public sports facilities, particularly for snow storage conservation within ski resorts have been regarded in this article. Additional demands are placed on thermal insulating material for suchlike constructions. Apart from high thermo technical properties, the material should involve hermeticity, lightness, easy mounting and maintenance, durability, bacterial and fungal resistance and temperature differential resistance. The examination results concerning properties and particularities of application of non-cross-linked polyethylene foam within the scope of production of insulation coatings protecting the snow from melting are given in the article. It has been established that being the part of insulation system polyethylene foam preserves the accuracy of mechanical and thermo physical characteristics. Taking all functional particularities of insulation systems implementation into consideration, the principles of protection and conservation of snow covering have been developed being realized on the mountainsides and plateaus of ski resorts. Polyethylene foam rolls have been connected in a butt joint and mechanically fixed. As a result, a seamless insulating coating - thermal blanket has been formed, which covered the entire mountainside. Maintenance of insulation system is performed during the off-season between March and September in the period of stable positive temperatures.

Thermal Assessment of a New Bio - Based Insulation Material

In recent times, the building sector is moving towards new approaches to energy - efficient design "low energy consumption". The development of bio - based thermal insulation materials contributes to such approaches; their implementation in the building gives a good result in a reduction of energy demand. Moreover, another beneficial environmental portion such as the reduction in the depletion of non - renewable resources and in waste generation. Using thermal insulation in the building envelope can substantially reduce the building's thermal load and consequently its energy consumption. Thermal insulation is organic or inorganic material, manufactured to reduce the propagation of the heat by a combined heat transfer (i.e., conduction, convection, and radiation). More advanced insulation materials have been recently developed. However, most of the available insulations are not eco - friendly and may require a huge amount of energy and complex manufacturing processes to be produced. Some commercialized bio - based therm al insulation materials are currently available, such as industrial fibers hemp, flax, kenaf. Also, recently some researches are conducted to develop thermal food - crop by - product insulation from palm date, pin apple leaves and rice husk. However, productio n cost and lower thermal resistance are the main correlated issues. A new cheap bio - insulation material with huge commercialization potential and environmental footprint is proposed. The main idea of running a project is to develop a new material, which is environmentally friendly insulation from grain. The early experiments of the insulation product showed a similar or even better thermal performance that could compete with common insulation materials such as polystyrene.