Here the picture is quite different. An industrial or scientific process may, perhaps, be performed properly only if it is carried out in an environment that has values of temperature and humidity lying within well defined limits. A departure from these limits may spoil the work being done. It follows that a choice of the inside design condition is not based on a statistical survey of the feelings of human beings but on a clearly defined statement of what is wanted.
Thus, a system might be specified to hold 21°C ± 0.5°C, with 50 per cent saturation ±21 per cent, provided that the outside state lay between 29.5°C dry-bulb, with 21°C wet- bulb and — 4°C saturated.
Posted in Engineering Fifth Edition