DAIRY AND GENERAL 



to open and close so as to prevent drafts in the barn and to 

 keep the stable from becoming too cold during the extreme 

 winter season. A register, similar to those used for hot-air 

 furnaces, may be installed in place of the damper. 



The foul air flues are made of galvanized iron, insulated, 

 or of paper and lumber. The design of these flues is of the 

 greatest importance to the success of the ventilating system. 



Fig. 4. Inlet Flue in Stone Wall. 



Vitrified sewer tile or galvanized iron pipe may be used to provide the 

 air passage in masonry wall. 



They should be as straight and smooth as possible for every 

 turn or bend reduces the carrying capacity of the flue. If it 

 is necessary to pass around a bend, the flue should be en- 

 larged so that its capacity will not be reduced. The ventilat- 

 ing flue acts as a chimney and should, therefore, rise above 

 the highest part of the building in order to receive the full 

 force of the wind. The velocity of the wind, as well as the 



Ten 



