U Value Of Concrete Wall

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.

U value of concrete wall.

Coverage charts for masonry units. Therefore the overall wall element u value 1 r 1 4 16 0 24 w m 2 k. F btu 1 23 m k w an estimate of the building envelope energy use for this structure is approximately 27 800 btu ft 87 7 kwh m as shown in figure 1. Cellulose blown wall 3 70 vermiculite 2 13 air entrained concrete 3 90 urea terpolymer foam 4 48 rigid fiberglass 4 lb ft3 4 00 expanded polystyrene bead board 4 00 extruded polystyrene 5 00 polyurethane foamed in place 6 25 polyisocyanurate foil faced 7 20 construction materials concrete block 4 inch 0 80.

U values of typical building methods u values overall coefficient of heat transmission indicate the heat flow through materials the higher the figure the higher the heat loss. If we increase the r value of the wall to r14 by adding additional insulation while holding the other envelope variables constant the building envelope energy use drops by only 2 5 which is not in. While the values do vary for each particular material and method of construction the following table gives general figures for some common modes of construction. U value has an inverse relationship to r value.

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. The u value can be calculated as. For a 6 inch slab r value would be between 0 6 and 1 2. So the lower the u value the better.

In addition perlite loose fill insulation cuts installation costs since it is lightweight and pours easily and quickly in place without need for special installation equipment or skills. U value 0 11w m2k 0 2w m2k. Wall 1 with u value of 0 3 w m2 k will lose heat at half the rate of wall 2 which has a u value of 0 6 w m2 k. Some systems offer the option to increase the internal insulation and can provide a u value as low as 0 11w m2k with a wall thickness of 335mm.

As calculation of u values can be time consuming and complex particularly where for example cold bridging needs to be accounted for numerous online u value calculators have been released. U 1 1 5 8 m 2 k w 0 25 m 1 7 w mk 3 13 w m 2 k. Example u value concrete wall. Are u values important in the building regulations approved document part l.

Calculating the inverse of that 1 r would give you a u factor in the range of 1 67 to 0 83. Insulation is essential in all construction for energy conservation. A concrete wall with thickness 0 25 m and conductivity 1 7 w mk is used for the default values in the calculator above. The insulation is typically expanded polystyrene and having insulation inside and out gives a u value of at least 0 2w m2k with a wall thickness of 250mm.

The original cost of installing perlite loose fill insulation can be recovered quickly due to substantial reductions in heating and air condition energy consumption. If this school is built using single wythe concrete masonry walls with cell insulation only and a resulting wall r value of 7 hrft 2.