DRAINAGE 273 



size, for the disposal of kitchen slop-water, is 20 feet long, by 2 feet wide, 

 by 3 feet deep (depth of stones). 



So as to guard against dampness in the foundations of the house, it 

 is desirable not to have the nearest part of the French drain closer than 

 20 feet from the house, though in some cases the distance from the house 

 is less than this. 



If the drain pipe (leading, say, to some water-course) be a long one, 

 or if it has a change (or changes) of direction in it, then the usual 

 inspection chambers, or cleaning eyes, should be provided. These will 

 be described shortly. 



Simpler Arrangements for the Disposal of Kitchen Slop-water. — A 

 simpler type of grease and intercepting trap is illustrated by Fig. 209. 

 It consists of a concrete well, divided by the slab S into two chambers 

 A and B. The mouth of chamber A is surrounded by a concrete curb 

 on which the filter bucket sits, and is covered by an iron grating; or 

 even a piece of galvanised iron perforated by a number of holes would 

 do in place of the grating. 



Chamber B must be airtight, and from near the top of it the 

 drain pipe takes off. 



Solid matter, which accumulates on the bottom of the two chambers, 

 must be removed by baling from the chamber A. 



The inside surfaces of the trap should be plastered as smooth as 

 possible, but since the smoothness of the surface thus obtained cannot 

 nearly equal that of the glazed stoneware trap last described, the latter 

 will be much the more sanitary. 



Inspection Chambers. — A typical inspection chamber, at a right-angle 

 change of direction, is shown in Fig. 210. The bottom is of concrete, and 

 the walls are of 9-inch brickwork topped with concrete, into which is 

 built the iron frame to receive the cast-iron air-tight inspection cover. 

 The inside of the chamber is finished, as smooth as possible, in cement 

 plaster. 



The inspection cover has a projecting flange or rib formed on its 

 lower face, near the edge. This flange projects into a channel or chase 

 formed in the frame, being pressed into the stiff grease with which the 

 chase is filled, to make the joint air-tight. 



The course of the drain is continued across the bottom of the 

 inspection chamber by means of a half- section, white-glazed channel 

 of the same diameter as the drain pipe. That part of the bottom of the 



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