198 



The Country House 



The following table by Professor Carpenter shows the number of changes 

 per hour required to supply one person with 30 cubic feet per minute, or 1,800 

 cubic feet per hour: 



The net area in square inches of either the hot-air or ventilating duct for 

 each 1,000 cubic feet of air, moving with any given velocity, can be determined 

 from the following table by Professor Carpenter: 



Or, the area of the duct in square feet can be determined by dividing the 

 cubic feet of air per hour by 3,600 times the velocity. 



The following approximate rules from Baldwin may be found of interest: 



Having the cubic feet of air to pass through a building in an hour (x), and 

 warmed by steam to 100 F., then: The weight of steam in pounds required to 

 warm same = x -7- 500; the weight in pounds of coal required = x 4- 5,000; the 

 square feet of grate required = x 4- 60,000; the cross-sectional area of chimney 

 flue (provided that its length be under 100 feet) = x -f- 500,000; the horsepower 

 of boiler = x ~ 15,000; the number of square feet of heating surface in boiler 

 = x -i- i ,000. 



For the sake of applying some of the foregoing rules, let us take the accom- 

 panying plans of a small six-room house which is to be heated and ventilated. 



The house is a frame structure, with the exception of the exterior walls of 

 the parlour and chamber (A), which have been assumed as brick in order to show 

 the problem under such conditions. The continuing of the brick wall so as to 

 tie the two chimneys together (see section) is not practically necessary; in fact, 

 it could just as well be omitted. 



The parlour, dining room and the three chambers are fitted with fireplaces, 

 which answer for the removal of chill and as winter ventilators. To simplify the 

 problem, the consideration of the attic has been omitted, as has also the location 

 of the return pipe to the heater. 



The heating medium is supposed to be hot water, which supplies the 

 parlour and dining room by the indirect system, and the chamber (A) and 

 bathroom by the direct-indirect system. Thus the three rooms to which it is 

 most desirable to supply fresh air are taken care of; the chamber (A), because 

 of its brick wall offering a chance to apply the direct-indirect system, is treated 



