32 



BULLETIN 57, U. S. DEPARTMENT OF AGEICULTURE. 



7!^nww^^^^^^(^^^^ 



conditions, such as the water supply and the size of buildmg. A safe 

 rule is to allow a 35 or 40 gallon boiler to a building having one bath- 

 room and to add 30 gallons additional capacity for every extra bath- 

 room. One hundred square mches of water-back heatmg surface is 

 sufficient for a 40-gallon boiler. 



Boilers should be galvanized inside and out, particularly inside- 

 Copper boilers are preferable if properly coated uiside with block tin. 



These are classed as 

 light, heavy, and ex- 

 tra heavy, the latter 

 being tested to 150 

 pounds water pres- 

 sure. Ordinary steel 

 or iron boilers are 

 tested to 150 pounds 

 water pressure and 

 extra heavy ones to 

 250 pounds pressure. 

 The latter should be used when the gauge pressure is more than 40 

 pounds per square inch. The followmg table gives standard sizes of 

 galvanized boilers : 



Standard sizes of galvanized boilers.' 



Fig. 26. — Sewer trap at house foundation, showing ventilator. 



Capacity. 



Length. 



Diameter. 



Capacity. 



Length. 



Diameter. 



Gallons. 



Feet. 



Inches. 



Gallons. 



Feet. 



Inches. 



18 



3 



12 



48 



6 



14 



21 



3i 



12 



52 







16 



24 



4 



12 



53 



4 



18 



24 



3 



14 



63 







16 



27' 



4i 



12 



66 







18 



28 



3i 



14 



79- 



6 



18 



30 







12 



82 



5 



20 



32 



4 



14 



98 



6 



20 



35 







13 



100 







22 



36 



. G 



12 



I 120 



6 



22 



36 



4.V 



14 



120 



5 



24 



40 







14 



144 



6 



24 



42 



4 



16 



168 



7 



24 



47 



4i 



16 



182 



8 ■ 



24 



SEWER PLUMBING. 



The sewer plumbing serves as a drain for the water plumbing. 

 The dramage system should be so constructed as to carry away com- 

 ])letely everything emptied into it, and it should be constantly vented, 

 frequently and thoroughly flushed, and have each of its openings into 

 the house securely guarded. All drains, soil pipe, and waste pipe 

 should be water-tight and air-tight. Tlie soil pipe or house-drainage 

 main begins at the sewer opening and passes up through the house 

 as nearly vertical as possible and out through the roof for free venti- 

 lation. It should be at least 4 inches in diameter, of extra heavy 

 cast iron, and all joints should be tightly calked with lead and oakum. 

 All discharge from the wash basins, sinks, and toilets empties into 



