Norlite

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INFORMATION

Norlite, LLC
628 S. Saratoga Street Cohoes, NY 12047
(518) 235-0030 (phone) (518) 235-0233 (fax) info@norliteagg.com

Structural Concrete

Thermal Insulation

With the many improvements being made in heating and air conditioning equipment for residences, commercial and office buildings, hotels, industrial buildings and the like, it is becoming increasingly important for architects and engineers to have ready access to information on the thermal insulation properties of building materials. Since the mechanical engineer designs the heating and cooling plant on the basis of the total hourly heat transmission through the exterior parts of the building, optimum efficiency in economical structural design requires analysis of relative heat loss through the elements of the structure.

Since thermal insulation varies inversely with density, lightweight concrete has better thermal insulation properties than normal-weight concrete. The thermal conductivity, k, for lightweight concrete is usually between 2.5 and 3.6 Btu per hour per inch thickness per square foot per degree Fahrenheit for oven-dry concretes weighing 80 to 100 Ibs. per cubic foot. The corresponding k value for normalweight concrete is generally between 9.0 and 12.0, depending upon the density of the concrete.

The table below shows R-values for Solid Concrete (Normally Dry)

Concrete
Type
Denisty
(lbs/ c.f.)
Per Inch Thickness of Concrete
2 4 6 8 10 12
Insulating
Lightweight
20 1.43 2.86 5.72 8.58 11.44 14.3 17.16
30** 1 2 4 6 8 10 12
40 0.83 1.66 3.32 4.98 6.64 8.3 9.96
50 0.67 1.34 2.68 4.02 5.36 6.7 8.04
60 0.52 0.04 2.08 3.12 4.16 5.2 6.24
70 0.45 0.9 1.8 2.7 3.6 4.5 5.5
Structural
Lightweight
80 0.37 0.74 1.48 2.22 2.96 3.7 4.44
90 0.3 0.6 1.2 1.8 2.4 3 3.6
100 0.24 0.48 0.96 1.44 1.92 2.4 2.88
110 0.19 0.38 0.76 1.13 1.51 1.89 2.27
120 0.14 0.28 0.57 0.86 1.14 1.43 1.71
Normal-
Weight
130 0.11 0.22 0.43 0.65 0.87 1.09 1.31
140 0.083 0.16 0.33 0.5 0.67 0.83 1
145*** 0.075 0.15 0.3 0.45 0.6 0.75 0.9
150 0.065 0.13 0.26 0.39 0.52 0.65 0.78


Conductivity, (k), Btu in./hr. sq. ft. F R(l/k)

NOTE: Typical increases in conductivity and density, from the PCA Development Bulletin D114. General Relation of Heat Flow Factors to the Density of Concrete.

Conductivity