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69
Factories, Workshops and Workplaces.
Ventilation in Workshops.—Although the powers of the sanitary
authority arc mostly concerned with the number of persons employed
in workshops in order to maintain standards which shall not permit
of overcrowding, there are other considerations which are not laid down
in statutes but to which due regard should be paid. The work of Prof.
Leonard Hill has shown clearly that vitiation of the atmosphere and
the signs of fatigue to which it gives rise are not primarily due to the
C02 of human respiration but to the amount of moisture present together
with a rising temperature and stagnation of the air. He holds that so
long as the air is kept moving and is not fully saturated with moisture
reasonably comfortable conditions can be maintained.
In order to estimate what he terms the cooling power of the air, Prof.
Hill has devised the Kata thermometer. The principles of the working
are similar to those of the wet and dry bulb hygrometer. Both dry and
wet thermometers are heated in warm water to over 100° F., surplus
moisture is shaken off and then is noted how long (by means of a stopwatch)
the level of the spirit takes to fall to a standard mark on the
thermometer (95° F.). If it falls quickly a relatively satisfactory condition
of the air in the room is indicated. Certain standards have been
worked out by Prof. Hill, e.g., 7 dry and 20 wet for schools, 6 dry and 18
wet for workshops in temperatures 60°—65° F.
The Kata thermometer has been used with the object of obtaining
confirmatory evidence as to the state of ventilation in workshops. During
1927 the lady sanitary inspector made 718 observations, 371 with the
djy bulb and 347 wet bulb, in 360 workshops. According to the standard
set by Prof. Hill for workshops—namely, figures of 6 and 18 for the dry
and wet bulbs respectively—it has been found so far that while most of
the workshops were well-ventilated as judged by absence of stuffiness and
satisfactory working temperature, very few came within the standards
mentioned. In those that did the movement of air was almost too
strong. The need for further investigation into the practical application
of the principles is suggested.
Occupations and Workshops.—In the. following tables are shown in
detail the number and variety of work premises on the register at the end
of 1927, the number of inspections made, and the results of such inspections:—