2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 51 



INTRODUCTION 



The following is a report submitted to the New York Commission 

 on Ventilation, covering experiments conducted by the Smithsonian 

 Institution under a grant of $1000 from the Commission. 



The raison d'etre of the experiments here described is explained in 

 the following quotation from A Preliminary Note on Radiant Body- 

 heat and the School Ventilation Problem, by T. J. Duffield, Execu- 

 tive Secretary, New York Commission on Ventilation : 



Satisfactory temperature conditions in the classroom can be established and 

 maintained only when the loss of body heat from each pupil is not interfered 

 with by similar processes of his neighbors or other bodies. In the class- 

 room, the pupil loses heat by evaporation, convection (including conduction), 

 and radiation. It is only through thorough consideration of each of these 

 types of body heat loss that we can hope to determine logical standards of 

 floor and air space per pupil for classrooms. 



The heat required to evaporate the moisture both in the lungs and from 

 the body surface is a real loss as far as the pupil is concerned, but the 

 heat-loss by evaporation does not enter into the problem of ventilation, because 

 the heat has disappeared in the form of latent heat of vaporisation. Modern 

 ventilation — using that term in the strict sense — can cope successfully with 

 the problem of removing the cowi'ected heat, which, under normal conditions 

 of school-room construction and occupancy, is transferred by coMuction to 

 the air which surrounds the body. The air, thus heated, expands, rises and 

 may be readily removed and replaced by cooler air. In these ways, two of 

 the three forms of body heat loss are accomplished, but concerning the third 

 form — radiation — very little experimental work appears to have been done 



.... The heat loss by radiation can be cared for only if artificial sources 

 of radiant heat in the classroom are properly shielded, and if adequate 

 floor space per pupil in the seating section is provided. 



Just what the area of this space should be is a matter requiring further 

 study, but, by reason of the different factors affected, it is evident that the 

 provision of additional air space by making ceilings higher cannot compensate 

 for inadequate floor space. The amount of body heat loss by radiation and 

 the thermal gradients for pupils of different average ages must be investigated 

 before standards of floor space in classroom design can be established 

 scientifically and logically. 



After a conference with Dr. C. G. Abbot. Secretary of the Smith- 

 sonian Institution, the New York Commission on A'entilation in June. 

 1927, made a grant of $1000 to the Institution to carry out a study 

 of body heat loss by radiation. The prosecution of this study was 

 delegated by Dr. Abbot to the writer. In a letter dated July 20, 1927. 

 Mr. Duffield, Executive Secretary of the New York Commission on 

 Ventilation, says : 



Our problems, as we appreciate them are two : 



(i) We want to know the amount of body heat loss by radiation and its 

 relation to the total under various conditions of air temperature, and if they 



