WARMING AND VENTILATING OCCUPIED BUILDINGS. 



299 



Figs. 6, 7, 8, 9, 10, show that these fire-places consist of an ordi- 

 nary grate for wood or coal, completely separated from the wall behind. 

 The flue, as far as to the top of the room to be 

 warmed, consists of a cast-iron pipe placed in the 

 center of a shaft extending to the ceiling, and 

 into the latter passes the external air admitted 

 from below, on the side or at the back, according 

 to local conditions. 



Near the ceiling the shaft through which the 

 J external air has passed and been warmed con- 

 tains an opening fitted with inclined slats, wliich 

 direct the air toward the top of the room. This 

 opening should contain a register, which may be 

 easily opened or closed according as the fire is 

 bright or dull. 



Observation shows that with 

 the dimensions given below 

 the amount of air thus intro- 

 duced at 80° differs but little 

 from that passing off up the 

 chimney, so that the admission 

 of cold air through the doors 

 is almost prevented. This in- 

 troduction of warm air, in ad- 

 dition to the warmth produced 

 by the ordinary radiation from 

 the fire, increases its heating- 

 effect, which becomes as much as 35 per cent, of the heat produced by 

 the fuel, while the common forms of fire-place give but 12 or 14 per cent., 

 and those supplied with Fondet's apparatus but about 20 per cent. 



14. In every building where this form of fire-place can be used it is 

 evident that it should be preferred to all others, and in its construction 

 the proportions given below should be followed. 



It is well to add that most forms of iron grates suitable for burning 

 coal or coke are easily adapted to this form, provided that it be possible 

 to provide for the admission of the external air. 



Size of room to be 



Amount of air to be 



Sectional area of 



Sectional area of 



Sectional area of 



"warmed. 



cbangerl every hour. 



smoke-pipe. 



shaft. 



fresh-air Hue. 



Cubic feet. 



Cubic feet. 



Square inches. 



Square inches. 



Square inches. 



3, 533 



17, 658 



78 



39 



217 



4,238 



21, 190 



93 



47 



260 



4,297 



26, 487 



116 



58 



326 



6, 357 



31,784 



140 



70 



331 



7,770 



38, 848 



171 



85 



477 



9,182 



45,911 



202 



101 



564 



10, 595 



52, 974 



233 



116 



651 



