China
Africa
Explore chapters and articles related to this topic
Foam in Insulation
Published in S. T. Lee, Polymeric Foams, 2022
Xiangmin Han, Barbara Fabian, Bruce Kline, Chase Boudreaux, Nigel Ravenscroft
Polyisocyanurate insulation foam (ISO, PIR, polyiso) is produced from the chemical reaction between isocyanate (e.g. methylene diphenyl diisocyanate, MDI) and polyester polyol. A blowing agent such as pentane and other ingredients such as a catalyst, surfactant, and flame retardant are mixed into the reactants. The heat produced in this chemical reaction makes the blowing agent vaporize, and foam cells are created along with the curing of reactive resins. ISO building insulation is combined with facers tailored to match the end use. For example, foil faced ISO is most commonly used as wall sheathing in residential construction or in masonry cavity wall construction. Faced polyiso insulation foam usually exhibits a higher R/inch. The facing material and polymer matrix slow air diffusion into the foam and pentane diffusion out of the foam.
Insulation materials
Published in Arthur Lyons, Materials for Architects and Builders, 2019
Polyisocyanurate foam (PIR) is usually blown with pentane. It is used as a roof insulation material since it is more heat-resistant than other organic insulation foams, which cannot be directly hot-bitumen-bonded. Polyisocyanurate is also appropriate for use in wall and floor insulation. PIR is combustible (BS 476-4: 1970) with a Class 1 Surface Spread of Flame (BS 476-7: 1997) but is more fire-resistant than polyurethane foam and it can be treated to achieve a Class 0 rating. Polyisocyanurate foam boards have a fire classification of Class F, but the Building Regulations permit their use in wall cavities within masonry leaves of at least 75 mm thickness (BS 4841: 2006). Polyisocyanurate tends to be rather friable and brittle. Certain proprietary systems for insulated cavity closers use PVC-U-coated polyisocyanurate insulation. Such systems offer a damp-proof barrier and can assist in the elimination of cold bridging, which sometimes causes condensation and mould growth around door and window openings. In situ formed polyisocyanurate foam, described in BS EN 14315: 2013, is delivered as a two-component sprayed mix that subsequently expands to fill the void space. (The thermal conductivity of polyisocyanurate foam is usually in the range of 0.023–0.025 W/mK.)
Water vapour by diffusion of PIR and mineral wool thermal insulation materials
Published in Mohamad Al Ali, Peter Platko, Advances and Trends in Engineering Sciences and Technologies III, 2019
N.I. Vatin, I.I. Pestryakov, Sh.T. Sultanov, O.T. Ogidan, Y.A. Yarunicheva, A.P. Kiryushina
Typically, air-based insulating materials do not exceed the thermal resistance of still air. However, some foam insulations such as the polyurethane encapsulate fluorocarbon gas instead of air within the insulation cells to obtain higher thermal resistance than the air. PIR plate based on polyisocyanurate, as the thermal insulation material with the lowest the indicator of heat conductivity, has been extensively used in the USA and Western Europe for a long time, more than 10 years. In North America, the roof insulation market shows that polyisocyanurate is the most widely used roof insulation, covering more than 50% of all commercial new or re-roofing applications. This is probably due to the often nominal double of thermal resistance of the polyisocyanurate when compared to fiberglass or rock wool insulation. These last products have generally a larger market share for vertical building elements and in several European countries.
Design and evaluation of passive downdraft cooling systems: outcomes from built prototypes of single stage and hybrid downdraft cooling towers
Published in Architectural Science Review, 2021
The shaft and outlet for each tower were built as one piece from identical materials. The structural frame was made from 25-gauge steel track typically used for drywall construction. The outer layer was made from 2-inch-thick polyisocyanurate rigid insulation panels with reinforced aluminium foil facers on two sides that has a total thermal resistance value of 13 ft2°Fh/Btu. The towers were mounted onto a structural insulated base made from 2-inch-thick polyisocyanurate rigid insulation sandwiched between two layers of 1/2-inch-thick plywood. Each enclosure was mounted onto the metal grating that covers the roof floor using four 3/32-inch wire ropes that span from the tower top corners down to the floor. The structural base was covered on the inside with PVC liner up to 1 ft high. Figure 3 shows photos of the experiment setup while under construction.
Embodied energy data implications for optimal specification of building envelopes
Published in Building Research & Information, 2020
Shahaboddin Resalati, Christopher C. Kendrick, Callum Hill
The Global Building Thermal Insulation market is accounted for $24.65 billion in 2015 and is expected to reach $34.41 billion by 2022. Mineral and glass wool insulation account for largest market share globally with plastic foam witnessing highest growth (Trent, 2019). According to Trent (2019), the Insulation materials with the highest market share within the construction sector are the following materials: Expanded Polystyrene (EPS), Polyurethane Foams (PU), Extruded Polystyrene (XPS), other Plastic Foams, Phenolic Foams (PF), Polyisocyanurate Insulation (PIR), Mineral Wool (MW), Glass Wool (GW). This study therefore included these materials in addition to two other types including Cellulose based insulations (CEL) and novel materials at the verge of upscaling such as Vacuum Insulation Panels (VIP) for the analyses.
Analytical study on sandwich shells considering partial degree of composite action
Published in Mechanics of Advanced Materials and Structures, 2023
An Chen, Defa Xu, Jiaxu Shi, Jing Sun
The following assumptions are adopted to develop the analytical model:Materials of the sandwich shells are isotropic and linear elastic, which indicates that, if concrete is used, the compressive stress should be less than 0.5fc’, where fc’represents the compressive strength of concrete [19].Each layer of the sandwich shell is symmetric with respect to the connector, i.e., torsion can be neglected for each layer.The tangential shear deformation is predominately caused by the flexible shear connectors. Therefore, the shear deformation caused by the two layers are neglected, i.e., the same curvature change is assumed for the inner and outer layers.The material used in the functional layer depends on the expected function of the sandwich structure, e.g., vibration and noise reduction, thermal insulation, etc. Existing materials are commonly used, including Expanded Polystyrene (EPS), extruded polystyrene (XPS), Polyurethane (PUR), Polyisocyanurate foam (PIR), Phenolic Foam (PF), etc. The stiffness of these materials is generally low compared with that of concrete. Therefore, the contribution from the functional layer is neglected in the analytical model.All shear connectors have the same properties.