DESIGNING. 1/3 



A better construction is to provide for a light plate-metal 

 cover, supported upon radial rafters of light angle or channel 

 shapes, the rafters being bent to project vertically below the 

 top of the stand-pipe and form ing stiffeners for that portion of 

 the structure. 



In addition to these stiffeners spaced at regular intervals, a 

 light horizontal stiffener should be provided, set 12 or 18 inches 

 below the top; and, if a Z shape is specified, a suitable 

 support for a painter's trolley is thus secured, which will be 

 found most convenient. 



For purposes of inspection a ladder capable of safely sus- 

 taining a weight of not less than 1000 Ibs. should be designed, 

 and is sometimes used both inside and out that for the outside 

 terminating 10 ft. above the base of the structure, to prevent 

 mischievous or malicious persons from having too ready ac- 

 cess to this facility. Such ladders may be composed of two 

 side-bars, 2 ins. X f 5 g- in., with }-in. diameter rungs spaced 

 12 to 1 8 inches, which may also be a suitable spacing for 

 the side-bars. Such ladders are generally built in sections at 

 the shop, and are riveted to the sides of the stand-pipe at 

 intervals of 10 to 12 feet with light angle-clips. 



As it is sometimes necessary to empty the stand-pipe and 

 to remove deposits, it is necessary to provide some kind of 

 manhole near the base, which is usually of elliptical form, with 

 plates, arches, and bolts, and of such dimensions as to provide 

 easy ingress for a workman. 



A suitable connection for the supply-pipe must also be 

 arranged for, its dimensions being governed largely by the 

 size of the inlet-pipe; the connection is usually a short bell- 

 mouth section, flanged at both ends, the flange to be in con- 

 tact with the plate to be curved to radius while the other end 

 is planed for a standard flange-connection with the inlet-pipe, 

 the first section of which generally has both a flange and bell 

 end. 



