DAIRY AND GENERAL 



system. In case windows are to be used for ventilation they 

 should be hinged at the bottom and open inward from the 

 top. At either side is a galvanized iron shield which pre- 

 vents air entering at the sides of the window and blowing 

 directly on the cattle. 



Flues Must Be Properly Constructed. 



Much of the success of the King system of ventilation 

 depends upon the construction of the flues. Figure 6 shows 

 detail of construction of an outlet flue. The cost of such a 

 flue will average 75 cents a foot of length. If made of gal- 

 vanized iron, the flue should be well insulated, otherwise the 

 moisture passing through the flue will be condensed and 

 fall as water. Insulating a round or square galvanized flue 

 is generally impossible except by a commercial concern. 

 This will increase the cost of installation, 



Build Flue the Right Size. 



In this system the total area of the outlet flues should 

 practically equal the area of the inlet flues. If the windows 

 and doors are not tight the number of inlet flues should be 

 reduced so that their total area should only equal two-thirds 

 of that of the outlet flues, as there will be enough air enter- 

 ing the cracks to furnish plenty of fresh air. 



A convenient size of outlet flue is 18x24 inches or 16x22 

 inches. In figuring the size of flue the number of animals 

 should be carefully considered. The following data taken 

 from King's Physics of Agriculture will be found to be of 

 service in computing the size of inlet and outlet flues. 



Amount of Air Required for Barn Ventilation. 



Horses 71 cubic feet an animal a minute. 



Cows 59 cubic feet an animal a minute. 



Swine 23.2 cubic feet an animal a minute. 



Sheep 15.3 cubic feet an animal a minute. 



Hens 52 cubic feet an animal a minute. 



Assuming that air travels through a flue from a stable 

 at the rate of 290 to 300 feet a minute, the size of outlets and 

 inlets may be determined as follows: 



Total No. of cu. ft. 

 of air required 



x 144 sq. in. = Total cross-sectional area 



300 in 1 sq. ft. sq. in. of inlets or outlets. 



Total cross-sectional 

 areas of outlets 



= Cross-sectional area of each outlet. 



No. of outlets 



Twelve 



