Handbook of mechanical and electrical cost data, giving shipping weights, capacities, outputs, and net prices of machines and apparatus, and detailed costs of installation, maintenance, depreciation and operation, together with many principles and data relating to engineering economics (1918)
Gillette, Halbert Powers, 1869-, Dana, Richard Turner, 1876-1928, joint author · New York, McGraw-Hill · leaf 1023
styles, collar and block. The collar form shall beused where the ducts are already installed, and the block form,where it is desired to leave an opening for the entrance of futureducts. The collar form shall be placed just over the ducts andagainst the vault form as shown on Fig. 21, and shall be… … Fig. 21. Forms for building vault tops. opening as in some cases where large cable is to be installed in thesewer tile. These forms are also used to form openings for theentrance of circular ducts. The method of mixing concrete shall be the same as describedfor conduit. The proportions of concrete…
