3. THERMAL INSULATION MATERIALS, TECHNICAL CHARACTERISTICS AND SELECTION.pptx

Building Technology

1. THERMAL INSULATION MATERIALS, TECHNICAL CHARACTERISTICS AND SELECTION CRITERIA

2. Heat transmission modes and technical terms Heat transmission modes It is important to know how heat is transferred in fish holds. Heat is transferred by conduction, convection or radiation, or by a combination of all three. Heat always moves from warmer to colder areas; it seeks a balance. If the interior of an insulated fish hold is colder than the outside air, the fish hold draws heat from the outside. The greater the temperature difference, the faster the heat flows to the colder area. Conduction . By this mode, heat energy is passed through a solid, liquid or gas from molecule to molecule in a material. In order for the heat to be conducted, there should be physical contact between particles and some temperature difference. Therefore, thermal conductivity is the measure of the speed of heat flow passed from particle to particle. The rate of heat flow through a specific material will be influenced by the difference of temperature and by its thermal conductivity. Convection . By this mode, heat is transferred when a heated air/gas or liquid moves from one place to another, carrying its heat with it. The rate of heat flow will depend on the temperature of the moving gas or liquid and on its rate of flow. Radiation . Heat energy is transmitted in the form of light, as infrared radiation or another form of electromagnetic waves. This energy emanates from a hot body and can travel freely only through completely transparent media. The atmosphere, glass and translucent materials pass a significant amount of radiant heat, which can be absorbed when it falls on a surface (e.g. the ship’s deck surface on a sunny day absorbs radiant heat and becomes hot). It is a well known fact that light-coloured or shiny surfaces reflect more radiant heat than black or dark surfaces, therefore the former will be heated more slowly. In practice, the entry of heat into fish holds/fish containers is the result of a mixture of the three modes mentioned above, but the most significant mode is by conduction through walls and flooring.

3. What Is Home Insulation ? Insulation will help you keep the desired temperature in your house all year round, protecting it against cold in winter and excess heat in summer . Insulation is also useful to reduce noise pollution. A well-insulated house is very energy efficient and will need very little additional heating and cooling. How much money you will save by insulating your home will depend on different factors like the type of insulation and the size of your house. Moreover, depending on how old your house is, you will need to incorporate more or fewer insulation measures. The good thing is that you generally don’t need any planning permission for fitting insulation measures and they will eventually pay back so it is a wise investment. Usually, modern houses are built to very good insulation standards, but old houses in the UK need a lot of work to be done. In the last case, there are probably many options to improve the energy efficiency of your house. When too cold, heat can be lost in all directions, so you should think of integral insulation to keep the heat in your house. You can choose to insulate your roof, floors, walls, windows and doors.  The most important thing is the walls since for a typical house the walls will lose around 30 to 40 per cent of the heat. The roof comes in second place, accounting for approximately 25% of heat loss. Then comes windows and doors with 20% and finally, the floor.

4. What Types of Insulation Are There ? 1. Wall insulation Depending on the type of wall you have, you can use: a ) Cavity wall insulation (there is a gap between the inner and outer leaf). An insulator is inserted to the wall through drilling holes which are then refilled with cement . b ) Solid wall insulation (no cavity inside them). If you have solid walls you can choose between internal and external insulation . External insulation typically covers the entire facade of the property while internal is generally applied to inner rooms. 2. Roof insulation a ) Warm loft, insulating immediately under the roof. This is more expensive than cold loft but usually is a better insulator. b ) Cold loft, insulating immediately above the ceiling of the top storey. 3. Window and door insulation Make sure you have  double glazed windows  and doors! This is, having at least two panels of glass some millimetres apart instead of a single glass. Double glazing will also protect you from outer noise, keeping your home warm and silent ! 4. Floor insulation This might be very expensive, make sure if you really need it depending on the type of floor you have. Usually, modern houses have  insulators under the concrete floor surface , but older houses with suspended floors will need some investment. One very accessible alternative for floor insulation is placing good rugs all around. This will also give you a nice feeling when walking !

5. What are the performance terms and what do they mean? Thermal Conductivity / λ (lambda) Thermal conductivity measures the ease with which heat can travel through a material by conduction. Conduction is the main form of heat transfer through insulation.   It is often termed the λ (lambda) value. The lower the figure, the better the performance. Thermal Resistance (R) Thermal Resistance is a figure that connects the Thermal Conductivity of a material to its Width - providing a figure expressed in resistance per unit area (m²K/W) A greater thickness means less heat flow and so does a lower conductivity. Together these parameters form the thermal resistance of the construction. A construction layer with a high Thermal Resistance, is a good insulator; one with a low Thermal Resistance is a bad insulator. The equation is Thermal Resistance (m²K/W) = Thickness (m) / Conductivity (W/ mK )   Specific Heat Capacity The Specific Heat Capacity of a material is the amount of heat needed to raise the temperature of 1kg of the material by 1K (or by 1 o C) . A good insulator has a higher Specific Heat Capacity because it takes time to absorb more heat before it actually heats up (temperature rising) to transfer the heat. High Specific Heat Capacity is a feature of materials providing  Thermal Mass  or  Thermal Buffering  (Decrement Delay).

6. Density The density refers to the mass (or 'weight') per unit volume of a material and is measured in kg/m 3 . A high density material maximises the overall weight and is an aspect of 'low' thermal diffusivity and 'high' thermal mass . Thermal Diffusivity Thermal Diffusivity measures the ability of a material to conduct thermal energy relative to its ability to store thermal energy. For example metals transmit thermal energy rapidly (cold to touch) whereas wood is a slow transmitters. Insulators have low Thermal Diffusivity. Copper = 98.8 mm 2 /s; Wood =  0.082 mm 2 /s.   The equation is: Thermal Diffusivity (mm 2 /s) = Thermal Conductivity / Density x Specific Heat Capacity

7. Embodied Carbon (aka Emodied Energy) Though not an aspect of the thermal performance of an insulation material, Embodied Carbon is a key concept in balancing the global warming gases in producing the material with the that conserved throughout the lifetime of the insulation. Embodied Carbon is usually considered as the amount of gases released from usually fossil fuels and used to produce energy expended between the extraction of raw material, via the manufacturing process to the factory gates. In reality, of course, it goes much further than that including transportation to site, the energy used in installation through to demolition and disposal. The science of embodied carbon is still evolving - consequently, firm and reliable data is difficult to obtain. Vapour Permeability Vapour Permeability is the extent to which a material permits the passage of water through it. It is measured by the time rate of vapour transmission through a unit area of flat material of unit thickness induced by a unit vapour pressure difference between two specific surfaces , under specified temperature and humidity conditions. Thermal insulation is usually characterised as Vapour Permeable or Non-vapour Permeable. Often referred to, erroneously, as 'Breathing construction', walls and roofs so termed are characterised by their capacity to transfer water vapour from the inside to the outside of the building - so reducing the risk of condensation.

8. INSULATION MATERIALS

9. Polyurethane foam As an insulation, roofing and sealant product, spray polyurethane foams (SPF) can play a major role in insulating and air-sealing homes and buildings – helping to reduce air leakage, which can result in lower utility bills, reduced greenhouse gas emissions and improved indoor air quality by helping to eliminate infiltration of dust and allergens. Strong, durable spray foam also can improve a building’s strength – it essentially increases a building’s resistance to wind uplift, helping to protect a building against severe weather conditions. Polyurethane flexible foam is a popular material used in furniture, bedding and carpet underlay. As a cushioning material for upholstered furniture, flexible polyurethane foam helps make furniture stylish, durable, comfortable and supportive. Both rigid and flexible polyurethane foam can meet fire safety standards and building code requirements for flame resistance. Polyurethane-based binders are used in composite wood products to permanently glue organic materials into oriented strand board (OSB), medium-density fiberboard (MDF), long-strand lumber, laminated-veneer lumber and even strawboard and particleboard. Polyurethane elastomers are rubber-like materials that can be created with a wide variety of properties and molded into almost any shape. Depending on the intended use, polyurethane elastomers can provide resistance to abrasion, cuts and tears; temperature extremes; mold, mildew and fungus; and negative effects of aging. The low weight of elastomers and their machinability, make elastomers a great choice for dozens of applications in building and construction.

10. Expanded polystyrene EPS possesses ideal physical and mechanical properties for most insulating needs. As a result of its manufacturing process, aging does not effect the long-term thermal resistance (LTTR) of EPS. Due to its flexibility and versatility, it can be cut into sheets, slabs, or any desired design to meet specific building code requirements, as well as customized designs. EPS is used as insulation in walls, roofs, and foundations, and serves as an integral component of structural insulated panels (SIPs), insulated concrete forms (ICFs), and exterior insulation and finish systems (EIFS). From humble beginnings, EPS has grown into one of the most versatile insulating materials in construction today. Sheathing is available in many different materials, but it was not until the energy crisis of the 1970s that rigid foam insulation found any prevalence as sheathing. With its versatility, ease of installation, and consistent performance benefits, EPS foam- insulating sheathing has become an industry standard. The sheathing is non-structural, and is primarily used as an exterior insulator, both below and above grade (though it can be used throughout the structure in roof, floors, and ceilings). Different densities help provide the R-value required to meet local building energy codes. EPS sheathing is used in renovations as well as new construction because of its compatibility with wood and steel framing, and masonry. The boards are installed vertically over the exterior sides of the studs, with the vapor retarder facing the heated side of the structure. It can be fastened with nails, screws, and/or staples (depending on the framing surface), while spot adhesive is the norm for masonry substrates.

11. Expanded perlite Perlite is a common name for amorphous volcanic silicate/alumina rock which can be expanded when rapidly heated at 900–1200 °C. Utilization occasions of perlite have made the product adjustable to abundant applications in construction, petrochemical industries, industrial, chemical and horticultural. In construction, expanded perlite (EP) can be used as a part of cement or aggregate in traditional cementitious materials or as a source material for geopolymers . EP in construction deals good thermal and sound insulation, good fire resistance and low density. Subsequently perlite seems to be a very important material. In this paper, the author reviews the effect of EP which used as a part of building material on fresh properties and hardened properties of traditional cementitious materials, geopolymers as well as other binders. Furthermore, different additives which used to improve some properties of EP matrices have been reviewed.

12. Fibreglass Typically manufactured in two different forms — pre-cut batts and rolls, and blown-in loose-fill — fiberglass building insulation is used primarily for thermal and acoustical purposes in wall cavities, attics and other critical open spaces in building assemblies. One of its key advantages is value. Fiberglass insulation has a lower installed price than many other types of insulating materials and, for equivalent R-Value performance (i.e., thermal resistance), it is generally the most cost-effective option when compared to cellulose or sprayed foam insulation systems . Thermal performance and energy efficiency Fiberglass insulation helps make buildings more thermally efficient by better retaining the desired temperature of enclosed spaces, whether they are heated or cooled. Its thermal performance reduces utility costs for building owners, conserves non-renewable fuel sources and provides greater occupant comfort (when used in conjunction with appropriately sized heating and cooling equipment ). Moisture resistance When exposed to moisture, fiberglass insulation neither absorbs nor holds water. If fiberglass insulation does get wet during or after installation, installers should visually inspect it on all six sides for contamination. If the material appears free of visible defects, installers must dry it thoroughly to restore its full R-Value. Once the area surrounding the insulation has also been inspected, cleaned and fully dried, the fiberglass insulation can be reinstalled and will regain its original R-Value.

13. Fibreglass Fire resistance Made from sand and recycled glass, fiberglass insulation is naturally non-combustible and remains so for the product's life. It requires no additional fire-retardant chemical treatments. Many building codes also recognize fiberglass insulation as an acceptable fire stop in wood- and steel-framed wall assemblies. Acoustic control Fiberglass insulation is a naturally sound-absorbent material that significantly reduces sound transmission in wall, ceiling, floor and HVAC assemblies. The first inch of fiberglass insulation in a building cavity can increase an assembly's sound transmission class (STC) value by three or four points in some constructions. Each additional inch can further increase the STC rating by two points. Recycled content Between 1992 and 2000, the fiberglass insulation manufacturing industry recycled more than 8 billion pounds (3.6 billion kg) of pre- and post-consumer glass containers, eliminating the need for millions of cubic feet of landfill space. Fiberglass insulation has significant recycled content, with some batt, roll and loose-fill insulation products containing up to 80 percent recycled glass 4 . The other main ingredient in fiberglass insulation, silica sand, is an abundant, naturally renewing resource, limiting environmental impact in the manufacturing process.

14. Cork Insulation 1. Cork for roof insulation It is very simple to hammer the cork boards onto the slats of your roof construction. These panels are lightweight and easy to saw. For this reason, they are perfectly suitable for roof insulation. The cork insulation boards are available in different thicknesses. The thicker the sheet, the better it insulates. To insulate a roof with cork, it is recommended to use boards with a thickness of approximately 6 inches. In order to avoid heat loss due to thermal bridges, one can apply the boards diagonally across each other. This way, the insulation will be more efficient in these difficult zones . 2. Cork insulation for floors Cork insulation boards can easily be glued onto a concrete subfloor. Especially if the floor of your house exists of a carpeted floor, cork boards are the best floor insulation materials. Moreover, these boards are hard-wearing and feel warm . 3. Cork granules Cork granules are easy to work with. They usually have a size between 1 and 10 millimeter . Because of this, they are perfectly applicable in gaps (for example gaps between the ceiling and the floor of the story on top). Cork granules are frequently used to insulate cavity walls as well .

15. Comparison of the various insulants Some of the more common materials used for insulation are compared in Table 5.6 with their relative insulating values and the advantages and disadvantages of particular types. In general, the more expensive materials, such as the polyurethane foams are more efficient insulators for given thicknesses. Using the “R” system of grading, it is possible to arrive at equivalent “R values” for a variety of insulating material types. Some designers indicate that the thermal conductance coefficient (l) for shore-based chill and ice stores should not exceed 0.26 kcal m -2  h -1  °C -1  (equivalent to an R-value = 18.8 ft 2  h °F Btu -1 ). However , the setting of this value depends basically on the energy costs, therefore it may be reduced if, in the future, energy costs increase. TABLE 5.6 Common insulating materials, “R” values, advantages and disadvantages