Investigations using a 1/12 scale model representing one bay of a
factory have shown that, where the area or the fire is small and its heat
output is known, use can be made of Bernoulli's theorem and the theory of
turbulent plumes to calculate the rates of discharge of heat and air through
a vent and beneath a curtain extending from the ceiling, the temperatures
near the ceiling and the depth of the layer of hot air. Formulae are given for
the effect on these quantities of varying the size of the vent and the
depth of the curtain. Some of the effects of the shape and position of
the vents are also discussed.