HEAT-LOSS FROM A SOLID GROUND FLOOR

Heat losses from solid uninsulated ground floors are often calculated using Macey's formula which involves the floor length and breadth, and the thickness of the wall surrounding it. The origins of the formula are examined. It is shown that in deriving it, an assumption is implicitly made that a semi-circular section of the floor beneath the wall is composed of perfectly insulating material. Further, the adjustment which is used to make the formula apply to a floor of finite length leads to an internally inconsistent expression. Procedures are advanced that tend to correct for both these defects. An exact expression has been advanced by Delsante, Stokes and Walsh against which five simplified forms can be tested and one of them is compact and provides 1 % accuracy.