CHAPTER XXV 



drainage 



Deainage of Dwelling Houses and Stock Houses 



The importance of efficient sanitary arrangements for the disposal of slop- 

 water, liquid-manure, etc., is so evident that it scarcely needs emphasizing. 

 The drains for the purpose usually consist of smooth, salt-glazed, stone- 

 ware pipes 4" or 6" internal diameter. It is not advisable to employ 

 drain pipes of a smaller diameter than 4 inches. These stoneware pipes 

 are made in lengths of about 2 feet. One end of each pipe, known as 

 the faucet or socket, is enlarged in diameter. The other (unenlarged) 

 end is called the spigot. When the pipes are laid, the spigot of one pipe 

 enters the faucet of the adjoining pipe, the joint being sealed with 1 : 1 

 cement mortar. Pipes should always be laid with their spigot end down- 

 stream, and care should be taken to lay the pipes truly in a straight line, 

 and at a uniform slope or fall, between inspection chambers (to be 

 described later). They must also be laid concentrically, or in true align- 

 ment, so that no ridge or shoulder is left at the joints. Such ridges are 

 apt to cause deposits in, and consequent blocking of, the pipes. Attention 

 must also be paid to the removal of any projecting mortar, which may 

 have been squeezed into the interior of the pipes from the joints while 

 the latter were being made. It is preferable to lay all drain pipes in 

 concrete, to diminish risk of breakages. If this be not done, the drain- 

 layer should at least rest each joint on a brick placed underneath 

 it, and should ram the earth about each joint with special care ; all 

 stones should be removed from earth which is to be rammed next to 

 the pipes. 



In order to prevent deposit in the pipes, 4-inch drains should have 

 a fall of not less than 1 in 40, 6-inch drains 1 in 60, and 9-inch drains 

 1 in 100. When these gradients cannot be obtained (on account of 

 the flatness of the ground) special facilities should be provided for the 



