DISPOSAL OF EXCEETA 367 



The joint between the pipes must be made water-tight by 

 the use of neat Portland cement ; but none of this must find 

 its way into the interior, or a projecting rim will be formed 

 which will produce an obstruction. 



Pipes near the surface, as in a stable, are liable to be 

 displaced, and must be laid on brickwork or concrete. The 

 same method must be adopted where the drains pass 

 through recently made ground, or ground likely to be 

 affected by settlement which would lead to fracture of the 

 pipe. Where the ground is solid and good, the drain pipes 

 outside a building may rest on it with a slight excavation 

 for the collar, or better still laid on a brick supporting 

 each pipe in front of the collar. 



Drains should run as nearly straight as possible, every 

 angle or elbow forms a possible source of obstruction, and 

 reduces the rate of flow of the contents. Where a branch 

 drain joins a main drain care should be taken that the pipe 

 enters by a V-shaped junction (Fig. 155), so as to ensure its 

 contents being delivered in the line of flow of the main 

 current. A right - angled junction would only lead to 

 obstruction. 



Where, as in farms or large blocks of stabling, several 

 drains may have to be coupled • together, a man-hole or 

 inspection chamber should be established, so that in the 

 event of stoppage the parts are readily got at. A man-hole 

 inspection chamber should also exist wherever the drain 

 has to undergo a change of direction, this ensures that 

 the pipes shall run in a straight line between each 

 man-hole. 



Where the drains pass through the man-hole, only half 

 pipes are used, so that the contents may be seen and ready 

 access afforded. 



Sometimes half pipes with a cover (Fig. 154) are em- 

 ployed at intervals so as to afford access in case of a block. 

 These are useful on a long length of drain. 



For small stables a pipe of 4 inches in diameter is quite 

 large enough, for a larger stable a 6-inch pipe; it is 

 seldom anything bigger than this is required. It is a great 



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