94 



VETERINARY HYGIENE 



90 square inches and also a minimum outlet area of 90 square 

 inches. 



Table showing the inlet and outlet capacity that should be 

 allowed per animal with wind blowing at 3 miles per hour : 



Animal. 



Square Inches of Inlet and also of Outlet required 

 if total CO 2 content in the Air is not 

 to exceed 



METHODS OF VENTILATING BUILDINGS. The customary and 

 most efficient method of ventilating animal houses is to make pro- 

 vision for the escape of the foul air at the highest level possible, and 

 to let the fresh air in at a lower level. This may be accomplished 

 in a variety of ways by the use, for preference, of the most simple 

 fittings such as will involve the least necessary attention. It should 

 be borne in mind that in buildings with a loft or upper floor there 

 is difficulty in securing ventilation at the roof, although, where pos- 

 sible, this difficulty should be overcome by the use of ventilating 

 shafts between the byre or stable ceiling and the roof. These 

 shafts may pass vertically to the roof ridge, or if there is objection 

 to breaking up the floor space above, the shafts may be arranged 

 to pass up the wall of the loft and follow the inner contour of the 

 roof to the highest point. At their termination they require a cap, 

 louvred outlet, or extraction cowl. In buildings with a loft where 

 outlet shafts are for some reason considered to be inconvenient, 

 the exchange of air must depend upon a system of cross ventilation. 



There is no doubt that the best animal houses are those without 

 an upper flat or hay loft and open to the roof. This gives good 

 air-space and simplifies the ventilation. 



INLETS. These may be in any of the following forms : IV all 

 windows, Tobin tubes, direct inlet pipes or boxes, air bricks or 

 gratings and hit-and-miss zvindows. 



