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Architects and engineers call the resulting values either the U-Value or the R-Value of a construction assembly like a wall. Each type of value (R or U) are related as the inverse of each other such that R-Value = 1/U-Value and both are more fully understood through the concept of an overall heat transfer coefficient described in lower section ...
Although the concept of U-value (or U-factor) is universal, U-values can be expressed in different units. In most countries, U-value is expressed in SI units, as watts per square metre-kelvin: W/(m 2 ⋅K) In the United States, U-value is expressed as British thermal units (Btu) per hour-square feet-degrees Fahrenheit: Btu/(h⋅ft 2 ⋅°F)
The construction industry makes use of measures such as the R-value (resistance) and the U-value (transmittance or conductance). Although related to the thermal conductivity of a material used in an insulation product or assembly, R- and U-values are measured per unit area, and depend on the specified thickness of the product or assembly. [note 2]
Based on a typical k-value of 0.007 W/(m·K), the R-value of a typical 25-millimetre-thick (1 in) VIP would be 3.5 m 2 ·K/W (20 h·ft 2 ·°F/BTU). To provide the same R-value, 154 millimetres (6 in) of rockwool or 84 millimetres (3 in) of rigid polyurethane foam panel would be required.
These variables include, building material of the envelope, thicknesses of the building materials, day of the year, time of day, orientation of the surface (e.g. wall or roof, 90 degrees or 180), and wall face orientation (cardinal directions, i.e. N, NW, S, SE, etc.), to name a few.
Kingspan Group plc is a building materials company based in Ireland, trading in over 80 countries with more than 210 factories employing over 22,000 people. The company operates with six divisions; Insulated Panels, Insulation, Light & Air, Water & Energy, and, Data & Flooring, Roof & Waterproofing.
While these curtain wall systems are more energy-efficient than older, single-glazed versions, they are still significantly less efficient than opaque (solid) wall construction. [13] For example, nearly all curtain wall systems, thermally-broken or otherwise, have a U-value of 0.2 or higher, which is equivalent to an R-value of 5 or lower. [14]
Especially valuable is the method of referencing and annotating cables plus their connectors within and outside assemblies. Examples: 1A1A44J5 - Unit 1, Assembly 1, Sub-Assembly 44, Jack 5 (J5 is a connector on a box referenced as A44) 1A1A45J333 - Unit 1, Assembly 1, Sub-Assembly 45, Jack 333 (J333 is a connector on a box referenced as A45) A ...