Thermal insulation (both heat – preservation and cold – preservation) materials are a type of lightweight, porous, loose materials with low thermal conductivity. Thermal insulation materials used to prevent heat dissipation from buildings, equipment, and pipelines are called heat – preservation materials, while those used in refrigeration and low – temperature applications are called cold – preservation materials. With the continuous development of building energy conservation, the heat – preservation and heat – insulation of building structures, as an important part of building energy conservation, have become a new field of research and application of energy – saving building technologies in China. According to relevant statistics, building energy consumption accounts for about 28% of the total social energy consumption. Therefore, vigorously developing new energy – saving building materials based on thermal insulation materials has practical and far – reaching significance for the sustainable economic and social development of China in the 21st century.
Generally, the roofs and walls of energy – saving buildings need to be thermally insulated. There are three types of wall insulation forms: internal wall insulation, external wall insulation, and sandwich wall insulation. Inorganic thermal insulation products are mostly selected for internal wall and sandwich wall insulation, while both inorganic and organic materials can be chosen for external wall insulation.
Thermal insulation materials with different properties should be selected for different building structures. For example, in bamboo and wood structures, the use of organic thermal insulation materials is prohibited; in lightweight steel and steel – structure buildings, inorganic thermal insulation materials should be preferentially selected; in concrete – structure buildings, both inorganic and organic thermal insulation materials can be used.
The following are the top ten thermal insulation materials widely used in the construction field.
01 Mineral Wool
Mineral wool mainly refers to rock wool, slag wool, glass wool, aluminum silicate wool and their products. It has characteristics such as low bulk density, low thermal conductivity, non – flammability, heat resistance, frost resistance, corrosion resistance, insect – proof, and good chemical stability.
Since the 1950s, mineral wool has been mainly used for industrial thermal insulation. Now it is widely used in various types of buildings and has formed a relatively complete product system. Product types include felts, boards, pipe shells, blocks, pads, ropes, etc. Mineral wool is the main thermal insulation and sound – proof material for industry and construction in China. It has good application prospects in heating buildings in the western and northern heating regions of China, especially in rural and poor areas.
02 Cotton Insulation Made from Recycled Blue Jeans
Cotton insulation is a kind of thermal insulation material obtained by treating waste cotton fabrics (such as jeans) with non – toxic, fire – proof, and insect – repellent boron. Cotton insulation not only wins honors in terms of environmental and health safety but also has better properties than many other thermal insulation materials.
Cotton insulation is suitable for maintaining the indoor temperature of houses in cold climates. It is in the form of flat plates, and its installation method is similar to that of fiberglass thermal insulation materials. When installing cotton insulation, there is no need to wear a respiratory mask or safety equipment, and there is no warning label required by the product.
03 Reflective Insulation
Reflective building thermal insulation materials are mainly composed of resins with good transparency and high – reflectivity fillers. Commonly used high – reflectivity fillers are hollow glass microspheres. Glass microspheres, also known as multi – functional hollow additives, have round or nearly round particles. Their surfaces are smooth, hard, and dense glass bodies, which hardly absorb various liquid media, can well reflect incident waves such as light and heat, and have low density, low thermal conductivity, and good heat – transfer isolation performance.
Reflective building insulation is usually used in roof rafters, walls, or floor joists. By using the high – reflection effect of the material on light and heat, most of the energy from the sun shining on the material is reflected instead of being absorbed. At the same time, due to its very low thermal conductivity, it has good thermal insulation performance and prevents heat conduction through the material.
04 Radiant Barriers
Radiant barrier building thermal insulation materials refer to materials that increase the thermal radiation in the building area. They emit the sunlight and heat absorbed by the building into the air in a certain wave, thus achieving the effect of heat insulation and cooling, making the surface temperature of the building lower than the surrounding environment temperature. Different from other thermal insulation materials, radiant barrier materials can only slow down the heat transfer efficiently but cannot block it.
Radiant barrier thermal insulation materials are usually installed in attics to reduce heat intake in summer and heat loss in winter. The use of radiant barrier thermal insulation materials in buildings in regions with hot summers and warm or cold winters can effectively improve the living thermal comfort.
05 Spray Polyurethane Foam
Spray polyurethane foam is a kind of thermal insulation foam plastic. Taking advantage of the characteristics of fast on – site molding and strong self – adhesion of polyurethane, it is directly sprayed and formed on the building exterior wall in liquid form, combining the high – efficiency of the spraying process and the excellent thermal insulation performance of polyurethane foam materials.
The thermal insulation performance of polyurethane foam is the best among all synthetic materials at present. It also has excellent wear resistance and water – resistance, and is currently recognized internationally as an ideal thermal insulation material. Its thermal conductivity is low, about half of that of EPS, and it is the material with the lowest thermal conductivity among thermal insulation materials at present.
At present, in developed countries and regions such as Europe and the United States, the use of polyurethane materials as thermal insulation materials for building roofs, walls, ceilings, floors, doors, and windows accounts for 49% of the building thermal insulation materials; while in China, this proportion is less than 10%.
06 Extruded Polystyrene
Extruded polystyrene foam plastic (extruded polystyrene, XPS) is a new type of thermal insulation material developed in foreign countries in the 1950s and 1960s. It has characteristics such as low thermal conductivity, low water absorption, and high compressive strength, thus having excellent and lasting thermal insulation functions, unique vapor – resistance permeability, extremely high compressive strength, and being easy to process and install. The production process of XPS is to heat – extrude melted polystyrene resin or its copolymer and a small amount of additives and blowing agents in a specific extruder, extend them through a pressure roller, and cool them in a vacuum forming area (some processes do not require vacuum forming).
The applications of XPS in the construction field mainly include:
- Thermal insulation material in composite walls;
- Underground wall foundations of buildings;
- Internal and external roof insulation;
- Roof thermal insulation;
- Places such as highways, airport runways, and parking lots that need to prevent road frost heave and require high compressive strength;
- Low – temperature storage equipment such as cold storage.
07 Expanded Polystyrene
Expanded polystyrene (EPS) is a polystyrene material with a continuous closed – cell honeycomb structure formed by polystyrene resin and other additives through a vacuum extrusion process. EPS has a closed – cell rate of over 98%, so it has obvious thermal insulation effect, a persistently very low thermal conductivity, and a persistent thermal resistance retention rate. The thermal resistance retention rate of this material is over 85% after 55 years.
Compared with XPS, in terms of the economic effect of thermal insulation materials, EPS is more economical than XPS. The thermal insulation material market in China started relatively late. When organic thermal insulation materials began to be widely used in the construction industry, the most widely used material was EPS. With the development of the economy and the more excellent performance of XPS, a large part of the future EPS market may be replaced by XPS.
08 Poly isocyanate Insulation
Poly isocyanate is a plastic composed of closed – cell foam. The gas inside the foam has low conductivity, and the R – value is between R – 5.6 and R – 8. Over time, the gas will leak, thus reducing the R – value.
Poly isocyanate insulation materials come in several different forms: liquid, sprayed foam, and rigid foam boards. It can also be made into composite insulation boards with different facing arrays. Generally speaking, direct foam is cheaper and has better performance than installing foam boards because liquid foam can cover all surfaces.
09 Cellulose Insulation
Cellulose insulation material, mainly composed of recycled paper such as newspapers, is also called paper cellulose insulation material. Compared with other types of thermal insulation materials, cellulose insulation material has the following advantages:
- Stable thermal performance;
- Low energy consumption;
- Recyclable;
- Excellent fire – proof performance;
- Waste utilization and environmental – friendly
Cellulose insulation material is widely used in developed countries in Europe and America, mainly in attics and wooden – frame structure buildings. Its installation and use technologies mainly include the following: Loft Installation (also known as loose filling), Wall Cavity Installation, Hot Roof Installation, Factory Panel Filling.
Cellulose insulation material rarely appears in the Chinese building energy – saving market. The main reason is the difference in building characteristics between China and foreign countries. Most of the residential buildings in Europe and America are low – rise buildings with wooden structures, and almost all of them have sloping roofs. In contrast, most of the buildings in Chinese cities and towns are medium – and high – rise buildings with reinforced concrete frame structures.
10 Fiberglass Insulation
Fiberglass refers to fibrous substances formed by melting glass at high temperatures. The diameter is about 10 microns. It has the characteristics of good insulation, strong heat resistance, good corrosion resistance, high mechanical strength, and non – flammability. It can significantly improve the energy efficiency of buildings and is inexpensive.
There are two types of fiberglass: loose – fill fiberglass insulation material and fiberglass insulation material (with different densities, widths, and lengths, in the form of flat plates or rolls).
Fiberglass insulation materials are commonly found in air pipes, water pipes, roofs, walls, and floors.分享
