THE MECHANICS OF VENTILATION. 54T 



tlon ol gas, therefore=148x 0.43=192.6 cubic feet. Each person produces 

 O.G cubic feet of the same gas per hour. Production from respiration, then 

 =960 cubic feet. Total amount of carbonic acid per hourz=:960-|-192.6z=: 

 1152.6 cubic feet. 



Assume the heat from a single person to be 475 units per hour, and the- 

 heat from combustion of a cubic foot of gas to be 750 units: We have 



1600x475=760000 heat-units per hour from the audience; and from the- 

 lights 



448 x750=336000 heat-units per hour, making a total production per 

 hour of 



1096000 heat-units. 

 Suppose the air supply to be at a temperature of 62° and equal to 200Q 

 cubic feet per hour for each person, the amount per hour will be 

 1600X 2000=3200000 cubic feet. 

 The amount of heat required to raise a single cubic foot of air 1° at au 

 original temperature of 60° or thereabouts is 



0.0766X 0.238=0.01815 units. 

 The increase in temperature of the air supply, due to the heat from 

 lights and people will be found as follows : 

 3200000 

 =246154 pounds of air per hour, and 



1096000 



— ^ =:4.4=:number of heat-units to each pound of air 



246154 



A single heat-unit raises one pound of air through 

 1.0000 



^4°. 2 actual temperature. 



0.238 

 The increase of actual temperature of the whole supply will therefore be 



4.2 x4.4=18".48. 

 On the supposition that the adjustment of supply to exhaust is proper- 

 ly made the air on leaving the hall must have a temperature of 

 62°+18°.48=80°.48. 

 The exit per second will equal 

 3200000 



=888 cubic feet. 



3600 

 Assuming the velocity of exhaust in vertical flue to equal 20 fee-t pei" 

 second, we have for area of said flue 



888 



=44.4 square feet, 



20 

 or what would be preferable, two flues each with area of 22.2 square feet. 

 Assume farther that the inflowing air shall have a velocity of 4 feet per 

 second, the area of inlets will be 



888 . 



=222 square feet, 



4 



