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SCIENCE 



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



ditioning. The task of applied science is 

 to find out the best elements in a natural 

 environment and to select the good without 

 the bad. 



Only as we succeed by the application of 

 the methods of research in disentangling 

 and measuring the various factors involved 

 in atmospheric influence shall we be able to 

 establish sound standards for the practical 

 art of ventilation. 



C.-B. A. "WiNSLOW 



New York City 



SOME ENGINEERING PROBLEMS IN 

 VENTILATION 



In the study of ventilation the engineer- 

 ing problems have not been overlooked. 

 The criticisms directed against artificial 

 ventilation have accomplished the double 

 purpose of spurring to greater effort those 

 who have been investigating the physio- 

 logical problems relating to this subject and 

 of causing the ventilating engineer to in- 

 vestigate the mechanical features of his 

 work, with the intent of determining 

 whether ventilation systems as installed 

 meet all of the demands of good ventilation 

 as now understood and whether they oper- 

 ate at a maximum of mechanical efficiency. 



A careful review of the results in both 

 fields is of surprising interest. The sani- 

 tarian formerly told us that carbon dioxide 

 was a poison, that insufficient ventilation 

 meant insufficient oxygen for breathing 

 purposes and that we were endangered by 

 ' ' crowd poison ' ' when in a mass of people. 

 But little was said of temperature, less of 

 humidity and nothing of air movement. 

 We all believed that the chemistry of the 

 air was vital. 



The sanitarians, as a result of much ex- 

 perimentation, beginning about ten years 

 ago, have proven to the satisfaction of all 

 that there were other factors within the 

 reabn of ventilation of much greater impor- 



tance than the chemistry of the air, notably 

 its temperature, humidity and air move- 

 ment, that is, the physical condition of the 

 air. 



The effect of excessive temperatures and 

 humidities is especially well understood, as 

 is the demand for constant air movement 

 for the elimination of bodily heat and mois- 

 ture. Less is scientifically known of the 

 effect of cold and the effect of low humidi- 

 ties. The solution of these two problems 

 is of vast importance. 



Some there are who disregard altogether 

 air quality, pinning their entire faith on 

 proper temperature, humidity and air 

 movement. Such a position is not justified 

 by any reliable data now available. The 

 cumulative effect of long exposures to stag- 

 nant air must be studied before safe con- 

 clusions may be drawn. Attention may be 

 directed to the fact that in the experiments 

 of the New York State Commission on Ven- 

 tilation stagnant air decreased the appetite 

 of the subjects 13 per cent. Is it not safe 

 to assume that this is indicative of other, 

 and possibly more serious, results. The 

 report of Professor Winslow on the first 

 year's work of the commission well states 

 that this is "an observation which for the 

 first time offers scientific evidence in favor 

 of fresh air as compared with stagnant air 

 of the same temperature and humidity." 

 A final determination of the importance of 

 air quality involves extended experimenta- 

 tion. 



"Window ventilation has been put forward 

 as a panacea for all of ventilation's ills. 

 But how little we scientifically know of its 

 worth or its difficulties, especially those of 

 air distribution, drafts, stagnant areas, 

 temperature regulation, humidification, 

 dust and economics. 



But real advances have been made in 

 solving the long-standing question of what 

 constitutes good ventilation. The solution 



