WARMING AND VENTILATION. 



301 



FIG. 29 



In such a Ccase, each ward would ha^e a maia ventilating-chimney 

 carrying off the foul air from each story in flues separated from each 



other as ftir as to the top of the upper 

 story. At the bottom of each of the col- 

 lecting-flues maybe kept a little auxil- 

 iary heater, to be used only when neces- 

 sary in order to obtain a sufficiently 

 powerful draught. 



It should also be understood that iti 

 every case the interior surface of the 

 flues should be covered with as smooth 

 a coating as possible, to diminish the 

 resistance to the motion of the air, and 

 that the openings should be arranged so 

 as to permit of cleaning the flues at least 

 twice a year, in order to remove the cob- 

 webs and other obstacles which would 

 interfere with the circulation of air. 



In general, it would be well to place on 

 top of the ventilating-chimney a cowl, 

 which the wind would keep with its 

 mouth away from the wind, so that 

 strong Avinds would assist the draught, 

 instead of checking it, as they would do 

 without this precaution: 



The proportions and the general ar- 

 rangements which have been indicated 

 should also be observed when it becomes 

 necessary to draw off the foul air either 

 at the level of the floors, as just men- 

 tioned, or at the top of the buildings, as 

 will often occur, especially in the case 



of existing buildings. 



Whenever local conditions permit, the smoke-flues of the heating-ap- 

 paratus should be carried up in the main ventilating-chimney, in order 

 to use the heat they give out. They should be made of cast iron and 

 kept separate. 



89. Utilization of the waste heat of laundries and Icitchens.— The furnaces 

 of the laundry-boilers should, if possible, be placed at the base of the 

 ventilating-chimney, in order to assist the ventilation by means of the 

 heat given out in the furnaces by the gaseous products of combustion. 



90. Application of the preceding rules.— Let us take the case of a hospital 

 of 100 beds, containing two wards, with but one ventilating-chimney, hav. 

 ing two stories, containing together 50 beds in each ward there being 

 four halls with 12 beds, and two rooms with one bed each. 



Under these conditions, each hall will contain six beds on each side, 



