The Purpose and Function of Insulation
Purpose and Function of Insulation
Building insulation is any object in a building used as insulation for any purpose. While the majority of insulation in buildings is for thermal purposes, the term also applies to acoustic insulation, fire insulation, and impact insulation (e.g. for vibrations caused by industrial applications). Often an insulation material will be chosen for its ability to perform several of these functions at once.
Insulation is an important economic and environmental investment for buildings. By installing insulation, building use less energy for heating and cooling and occupants experience less thermal variability. Retrofitting buildings with further insulation is an important climate change mitigation tactic, especially in geographies where energy production is carbon intensive. Local and national governments and utilities often have a mix of incentives and regulations to encourage insulation efforts on new and renovated buildings as part of efficiency programs in order to reduce grid energy use and it’s related environmental impacts and infrastructure costs.
Thermal insulation usually refers to the use of appropriate insulation materials and design adaptations for buildings to slow the transfer of heat through the enclosure to reduce heat loss and gain. The transfer of heat is caused by the temperature difference between indoors and outdoors. Heat may be transferred either by conduction, convection, or radiation. The rate of transmission is closely related to the propagating medium. Heat is lost or gained by transmission through the ceilings, walls, floors, windows, and doors. This heat reduction and acquisition are usually unwelcome. It not only increases the load on the HVAC system resulting in more energy wastes but also reduces the thermal comfort of people in the building. Thermal insulation in buildings is an important factor in achieving thermal comfort for its occupants. Insulation reduces unwanted heat loss or gain and can decrease the energy demands of heating and cooling systems. It does not necessarily deal with issues of adequate ventilation and may or may not affect the level of sound insulation. In a narrow sense insulation can just refer to the insulation materials employed to slow heat loss, such as: cellulose, glass wool, rock wool, polystyrene, urethane foam, vermiculite, perlite, wood fiber, plant fiber (cannabis, flax, cotton, cork, etc.), recycled cotton denim, plant straw, animal fiber (sheep’s wool), cement, and earth or soil, reflective insulation (also known as radiant barrier) but it can also involve a range of designs and techniques to address the main modes of heat transfer – conduction, radiation, and convection materials.
Most of the materials in the above list only retain a large amount of air or other gases between the molecules of the material. The gas conducts heat much less than the solids. These materials can form gas cavities, which can be used to insulate heat with low heat transfer efficiency. This situation also occurs in the fur of animals and birds feathers, animal hair can employ the low thermal conductivity of small pockets of gas, so as to achieve the purpose of reducing heat loss.
The effectiveness of reflective insulation (radiant barrier) is commonly evaluated by the reflectivity of the surface with airspace facing towards the heat source.
The effectiveness of bulk insulation is commonly evaluated by its R-value, of which there are two: metric (SI) (in units of K x W−1 x m2) and US customary (in units of °F x ft2 x h/BTU). For example, in the US the insulation standard for attics, is recommended to be at least R-38 US units. The equivalent standard in the UK are technically comparable. Newer buildings have to meet a higher standard than those built under previous versions of the regulations. It is important to realize a single R-value or U-value does not take into account the quality of construction or local environmental factors for each building. Construction quality issues can include inadequate vapor barriers and problems with draft-proofing. In addition, the properties and density of the insulation material itself are critical. Most countries have some regime of either inspections or certification of approved installers to make sure that good standards are maintained.
The History Of Thermal Insulation
The history of thermal insulation is not so long compared with other materials, but human beings have been aware of the importance of insulation for a long time. In the prehistoric time, human beings began their activity of making shelters against wild animals and heavy weather, human beings started their exploration of thermal insulation. Prehistoric peoples built their dwellings by using the materials of animal skins, fur and plant materials like reed, flax, and straw, these materials were first used as clothing materials, because of their dwellings were temporary, they were more likely to use the materials they used in clothing, which were easy to obtain and process. The materials of animal furs and plant products can hold a large amount of air between molecules which can create an air cavity to reduce the heat exchange.
Later, human beings’ long life span and development of agriculture determined that they needed a fixed place of residence, earth-sheltered houses, stone houses, and cave dwellings began to emerge. The high density of these materials can cause a time lag effect in thermal transfer, which can make the inside temperature change slowly. This effect keep inside of the buildings warm in winter and cool in summer, also because of the materials like earth or stone is easy to get, this design is really popular in many places like Russia, Iceland, Greenland.
Organic materials were the first available to build a shelter for people to protect themselves from bad weather conditions and to help keep them warm. But organic materials like animal and plant fiber cannot exist for a long time, so these natural materials cannot satisfy people’s long-term need for thermal insulation. So, people began to search for substitutes which are more durable. In the 19th century, people were no longer satisfied with using natural materials for thermal insulation, they processed the organic materials and produced the first insulated panels. At the same time, more and more artificial materials start to emerge, and a large range of artificial thermal insulation materials were developed, e.g. rock wool, fiberglass, foam glass, and hollow bricks.
The Significance Of Thermal Insulation
Thermal insulation can play a significant role in buildings, great demands of thermal comfort result in a large amount of energy consumed for full-heating for all rooms. Around 40% of energy consumption can be attributed to the building, mainly consumed by heating or cooling. Sufficient thermal insulation is the fundamental task that ensures a healthy indoor environment and against structure damages. It is also a key factor in dealing with high energy consumption, it can reduce the heat flow through the building envelope. Good thermal insulation can also bring the following benefits to the building:
Preventing building damage caused by the formation of moisture on the inside of the building envelope. Thermal insulation makes sure that the temperatures of room surface don’t fall below a critical level which reduces humidity to prevent the growth of mold. According to the Building Damage reports, 12.7% and 14% of building damages were caused by mold problems. If there is no sufficient thermal insulation in the building, high relative humidity inside the building will lead to condensation and finally result in mold problems.
- Producing a comfortable thermal environment for everyone in the building. Good thermal insulation allows sufficiently high temperatures inside the building during the winter, and it also achieves the same level of thermal comfort by offering relatively low air temperature in the summer.
- Reducing unwanted heating or cooling energy input. Thermal insulation reduces the heat exchange through the building envelope, which allows the heating and cooling units to achieve the same indoor air temperature with less energy input
Insulation is an important economic and environmental investment for buildings. By installing insulation, building use less energy for heating and cooling and occupants experience less thermal variability. Retrofitting buildings with further insulation is an important climate change mitigation tactic, especially in geographies where energy production is carbon intensive. Local and national governments and utilities often have a mix of incentives and regulations to encourage insulation efforts on new and renovated buildings as part of efficiency programs in order to reduce grid energy use and it’s related environmental impacts and infrastructure costs.
The Definition Of Thermal Insulation
Thermal insulation usually refers to the use of appropriate insulation materials and design adaptations for buildings to slow the transfer of heat through the enclosure to reduce heat loss and gain.] The transfer of heat is caused by the temperature difference between indoors and outdoors. Heat may be transferred either by conduction, convection, or radiation. The rate of transmission is closely related to the propagating medium. Heat is lost or gained by transmission through the ceilings, walls, floors, windows, and doors. This heat reduction and acquisition are usually unwelcome. It not only increases the load on the HVAC system resulting in more energy wastes but also reduces the thermal comfort of people in the building. Thermal insulation in buildings is an important factor in achieving thermal comfort for its occupants. Insulation reduces unwanted heat loss or gain and can decrease the energy demands of heating and cooling systems. It does not necessarily deal with issues of adequate ventilation and may or may not affect the level of sound insulation. In a narrow sense insulation can just refer to the insulation materials employed to slow heat loss, such as: cellulose, glass wool, rock wool, polystyrene, urethane foam, vermiculite, perlite, wood fiber, plant fiber (cannabis, flax, cotton, cork, etc.), recycled cotton denim, plant straw, animal fiber (sheep’s wool), cement, and earth or soil, reflective insulation (also known as radiant barrier) but it can also involve a range of designs and techniques to address the main modes of heat transfer – conduction, radiation, and convection materials.
