196 



The Country House 



The low-pressure steam radiator is usually assumed to have a temperature 

 of 210 F., while in low-pressure hot water it is 140 F. One hundred running 



feet of 3-inch pipe in a coil for indirect 

 radiators contains about loo square feet 

 of radiating surface. To heat a room by 

 indirect radiation, which necessitates 

 ventilation, requires nearly twice the 

 amount of radiating surface that is 

 necessary for indirect radiation, which 

 has no other change of air but that of 

 leakage. 



The size of a steam-heating boiler 

 is fixed by the amount of radiating 

 surface to be supplied. At 20 F. a 

 square foot of heating surface in the 

 boiler will be required for each 5 square 

 feet of radiating surface; at zero F. 

 6 square feet are necessary. One 



The screens of this unique bracket lamp are constructed 

 so as either to shade the light, as in the illustration, or to 

 swing around and leave the light exposed. It is suitable for 

 either gis or electricity 



horsepower is equal to the supplv <>t 



heat for 90 square feet or radiating surface; thus an 1 1 

 horsepower boiler is required for 1,000 square feet of 

 radiating surface. 



Where warm air is delivered or ejected through flues, the 

 velocity increases with the length of the flue under normal 

 conditions. We assume as a basis of calculation that, with 

 the temperature below 50 F., hot air thus delivered to the 

 first floor has a velocity per second of 4 feet, to the second 

 floor 5 feet, and to the attic 6 to 7 feet. In natural-draught 

 ventilation the velocity per second of the ejected air is 6 i\ it 

 from the basement, 5 feet from the first floor, 4 feet from the 

 second floor, and 3 feet from the attic. 



In making the rough estimate, the first and second story 

 halls are usually considered as one room. 



The amount of radiating surface necessary for the 

 heating of a room is that required to supply the heat carried 

 out of the room by the escape of warm air (in other words, 

 to heat the incoming cold air), plus that required to make- 

 good the loss of heat sustained by the incoming air by 

 radiation from windows, doors and walls. For steam and 

 hot water the following rules given by Baldwin are as good and as simple as any: 

 To determine the amount of radiating surface necessary to supply the heat 

 carried out of the room by the escape of warm air, multiply the number of cubic 

 feet of air per hour by the number of degrees F. at which it is to be heated, and 

 divide the product by 12,500; the quotient is the radiating surface required in 

 .square feet. 



To determine the amount of radiating surface necessary to compensate 



Exterior bracket lantern 



