SAW TOOTH ROOFS 185 



the fan and changing the air every 15 minutes with cool air in hot 

 weather. 



The floor is built of heavy plank and finished maple laid on sleep- 

 ers which are bedded in cinders. The walls are made of heavy tile and 

 the openings are closed with iron fire doors. The building is practically 

 fireproof and takes a very low rate of insurance. 



Boyer Plant. The Boyer Plant of the Chicago Pneumatic Tool 

 Co., at Detroit, Mich., is 325 x 185 ft., with the longer dimension ex- 

 tending north and south. The roof of the building is divided into two 

 sections, having spans of about 92 ft. each, a pitch of about ^4, and is 

 covered with Patent Asbestos Roofing manufactured by H. W. Johns- 

 Manville Co., Milwaukee, Wis. laid on ij/g-in. plank sheathing. The 

 building is lighted by means of saw tooth skylights facing north and 

 extending from the ridge of the roof to within about 6 ft. of the eaves 

 on the outside and the valley gutter on the inside. The trusses are 

 spaced 16 ft. apart, and there are three saw tooth skylights between each 

 pair of trusses, making 240 skylights in the roof. The north leg of 

 the saw tooth is vertical and is glazed with double corrugated glass, 

 the south leg is covered with asbestos roofing. The building is venti- 

 lated by means of circular ventilators placed in the ridge of the roof 

 and spaced 16 ft. apart. The lighting in this building is almost perfect. 

 The roofing has given satisfaction with the exception of the large val- 

 ley gutters, which will be covered with copper or lead in the near 

 future. There has been a little trouble with condensation, but not 

 enough to make it necessary to go to the expense of putting in con- 

 densation gutters. 



This building is described in the Railway and Engineering Review, 

 March 9, 1901. 



For additional details of saw tooth roofs see Fig. 97. 



The cross-section of a locomotive shop for the Eastern Railway 

 of France is shown in Fig. 85. The entire building is made of fireproof 

 materials, the framework is of iron and the roof of sheet metal and 

 glass. The building extends from east to west and has a saw tooth roof, 

 with the shorter leg facing north, and glazed with crinkled glass. The 

 floor is made of treated oak cubes measuring 3.94 in. on the edge, set 

 with the grain vertical, on a bed of river sand about 8 in. thick. The 

 saw tooth roof is well suited to structures of this class. 



