72 



KADI \TI()N MIOLOGY 



and infant wards of hospitals where essential discipline of personnel is 

 possible. Sut'h an nltraviolet l)arrior obviously also provides general air 

 disinfection b}' virtue of the circulation of room air through it. Because 

 of its p()siti\-e functioning, the ultraviolet l^arrier has somewhat the same 

 psychologic as well as engineering appeal as ultraviolet air disinfection in 



110° 100° 90° 80° 70° 60° 50° 



120° 



300 400 500 600 



PER CENT OF BARE LAMP INTENSITY 

 ■"10° 



1 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 

 DISTANCE FROM FIXTURE, ft 



(6) 

 Fig. 2-13. (a) Spatial distribution of ultraviolet from typical bactericidal tubes and 

 open reflectors, (b) Isointensity lines in milliwatts per square foot in a plane perpen- 

 dicular to the center of the G30T8 tulie of Fig. 2-9. 



air ducts; the door opening becomes a duct from one room to another in 

 spite of its unconventional cross section compared with its length. 



The variation in ceiling height and the difference in exposures per 

 day in patient and service rooms of hospitals have led to two distinct 

 types of commercial equipment, an open type for use under high ceilings 

 and where there may be personnel exposure of about 8 hr per day (Fig. 

 2- 13a) and a louvered tj^pe for use under low ceilings and where there may 

 be continuous exposure (Fig. 2-14a). Figures 2-13a and 14?> suggest a 

 possible way to provide energy intensities of 15-20 m\v/sq ft in the upper 

 third or fourth of a room. 



