VENTILATING 



127 



escape more rapidly when the ventilators 

 are opened, as there is but little obstruc- 

 tion and the opening is at the highest part 

 of the house. There is also less tendency, 

 when ventilators are used on one side of 



Fig. 68. Two methods of hanging ventilator sash 



the roof only, for unfavorable winds to 

 blow directly into the house. 



The practical disadvantages of this meth- 

 od of hanging is that the ventilator sash 

 are more likely to be torn off by severe storms 

 than when hinged at the top, and also that 

 it is more difficult to prevent leakage at 

 the ridge. The prevailing tendency is to 



