630 



SCIENCE 



[N. S. Vol. XLI. No. 1061 



Stagnant Air," the curator of a large col- 

 lege building at once called upon the chief 

 of the investigating staff to ask if he would 

 be justified in stopping his fans. Such a 

 conclusion as this is^ of course, quite un- 

 justified and most unfortunate in its ef- 

 fects. No scientific investigations can con- 

 tradict or minimize the well-established 

 results of experience as to the bad effects 

 of poor ventilation and the beneficial re- 

 sults of fresh air. What physiological re- 

 search has done is to show why bad air is 

 bad — primarily on account of its high 

 temperature and lack of cooling air move- 

 ment, sometimes combined with high hu- 

 midity. In our experimental rooms we can 

 separate the factors of stagnation and 

 overheating, but in practise an unventi- 

 lated room (if at all crowded) is an over- 

 heated room. Ventilation is just as essen- 

 tial to remove the heat produced by human 

 bodies as it was once thought to be to re- 

 move the carbon dioxide produced by hu- 

 man lungs. 



Even the quantitative standards of air 

 change established on the old chemical 

 basis serve very well on the new physical 

 one. For example, according to Petten- 

 kofer's classical figure, which is a very low 

 one, an adult gives off 400 British thermal 

 units per hour. Let us assume that this 

 heat must be removed by air entering the 

 room at 60° and leaving it not above 70°. 

 One B. T. U. raises the temperature of 

 about 50 cubic feet of air by 1°, or the 

 temperature of 5.0 cubic feet of air from 

 60° to 70°. Hence our average adult pro- 

 ducing 400 B. T. U. will require 2,000 cubic 

 feet of air per hour at 60° to keep the sur- 

 rounding temperature from rising. An 

 ordinary gas burner produces 300 B. T. U. 

 per candle-power hour ; therefore each such 

 burner requires 1,500 cubic feet of air per 

 candle power. These calculations, of 

 course, ignore direct heat loss through walls 



and ceiling which with a zero temperature 

 outside may carry off the heat produced by 

 50 or 100 people. Ventilation provisions 

 must, however, be based on the least, rather 

 than on the most, favorable conditions. In 

 crowded auditoria every bit of the 2,000 

 cubic feet of air is needed, and in many 

 industrial processes where the heat pro- 

 duced by human beings and illuminants is 

 reinforced by the friction of machinery and 

 the heat from solder pots, furnaces, man- 

 gles, pressing irons and a host of other 

 sources, even more will be required. 



Furthermore, the recent studies of the 

 New York State Commission suggest that 

 there may, after all, be certain deleterious 

 effects resulting from the chemical composi- 

 tion of the stagnant air of occupied rooms, 



STAeHAMT AIR STACflAMr 



Fig. 7. Average Calorific Value of luncheons 

 eaten witli ample supply of fresh air and with no 

 fresh air supply. In .both summer and fall ex- 

 periments the same conditions as to temperature 

 and humidity prevailed through each series. 



