CHAPTER VIII. 

 DESIGNING. 



HAVING formed a clear conception of the principles ex- 

 plained in the preceding chapters, it is possible to consider 

 intelligently the subject of designing metallic reservoirs and 

 their supporting substructures. 



By the use of the various tables, applicable to included 

 sizes, the study of suitable design is greatly facilitated and 

 simplified. In the general scheme of a water-supply system, 

 where storage and gravity supply is included, in the absence 

 of a sufficiently elevated natural location, the necessity for 

 some form of metallic reservoir to supply or supplement the 

 deficiency is apparent. 



From the general requirements as to pressure and storage, 

 the dimensions of the structure will be determined. 



From the analysis of " Stand-pipe Statistics," page 8, it 

 has been found that the average domestic pressure, as required 

 in the United States, is 61.2 Ibs. per sq. inch. If this pres- 

 sure is satisfactory to the designing engineer, as shown on 

 page 65, the corresponding height or head is approximately 

 142 ft., which would be the required height of the stand-pipe. 

 Under ordinary conditions, however, the local topographical 

 condition is likely to afford certain convenient natural eleva- 

 tions, advantage of which may be taken to reduce the height 

 of the metallic reservoir, which height, supplemented by the 

 natural elevation, will give the required pressure. 



In the case of a particular design, where there occurs an 



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