414 



ENGINEERING ON THE FARM 



pipe. All pipes should be reamed out, as the diameter is 

 materially reduced when the pipe is cut with a wheel cutter 

 (Fig. 318). This reduction is sometimes as much as 18 per 



cent and will naturally 

 affect the flow of water. 

 Radiators. The size of 

 radiators, their location, 

 and their covering are all 

 important. If possible 

 radiators should be set 

 against an outside wall; 

 i. e., on the coldest side 

 of the room. 



All coverings check 

 radiation, but paint 

 checks it far less than 

 aluminum bronze. 



To determine the num- 

 ber of square feet of 

 radiation for each room, 

 there are several formu- 

 las, only one of which gives results large enough to cope with 

 winters in the latitude of Minnesota, where a temperature of 

 1 5° below zero is frequent and one of 2 5 below not uncom- 

 mon. The size of the room, window surface, and outside 

 wall enter into the problem. 



The following formula will give the radiation for a given 

 room: 



Find the cubic contents, in feet, of the room, and 

 divide the number by 200. Find the number of square feet 

 of glass in the windows and divide it by 2. Add to the quo- 

 tients thus obtained the number of lineal feet of exposed 

 wall and multiply by 2. The product will be the amount 

 of radiating surface required for the room. 



Suppose the room is 12X16 feet, with 8-foot ceiling, three 

 windows 24X60 inches, and two sides of the room exposed. 



After University of Minnesota 



Fig. 318. A reaming tool 



