Reinforced Concrete Wall U Value

Cibse guide table a3 1 1980 bulk density.

Reinforced concrete wall u value.

A reasonable r value for a normal concrete slab can be estimated using an r value the thermal resistance per inch of thickness between 0 1 and 0 2 and multiplying it times the slab thickness. From table a4 there is a u correction of 0 01 w m2k which applies to both the following cases. A study at construction technology laboratories ctl found that a lightly reinforced concrete shear wall has over six times the racking load resistance of a wood framed wall. For example a building with material with an r value of r 11 converts to an u value of 0 09 1 r or 1 11 0 09.

For a 6 inch slab r value would be between 0 6 and 1 2. Determine the thickness of the insulation layer required to achieve a u value of 0 21 w m2k if insulation is between the joists and 0 26 w m2k if insulation is between the rafters. For concrete the k value depends on its bulk density and the moisture content in service. The u value is the measure of heat transmittance through a material and the lower the u value the less heat is transmitted through a construction i e.

Reinforced concrete walls resist the compression and tensile forces produced by an earthquake. As we said before the r value measures the thermal resistance of a material. Table 3 shows the approximate percentage of grouted and ungrouted wall area for different vertical and horizontal grout spacings which can be used to. U value has an inverse relationship to r value.

Table 2 lists calculated u factors and r values of various thicknesses of concrete masonry walls for concrete densities of 85 to 135 lb ft 1 362 to 2 163 kg m with various core fills. Reference table for u values u value is the coefficient of transmission i e the transmission of heat through the materials which compose the building s envelope or outer shell.