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CAPACITY OF TEANSMISSIOR SYSTEM "A" <br />Transmission System "A" is comprised of a 20 -inch wood pipe and a 20- <br />inch cast iron pipe. The theoretic capacity of this system was calculated <br />using *Hazen and Williams friction factors of 110 for the wood line and 90 <br />for the cast iron. These theoretic capacities are shown graphically, for <br />various levels in the storage tanks, on Exhibit No. 6. All values shown here <br />are based on the assumption that the clear -well is full. <br />Actual flow tests were conducted in conjunction with Water Department <br />personnel on April 13, 1961. During this test the wood -stave line was <br />isolated and its capacity verified both under gravity flow conditions and with <br />the aid of the booster pump at the water treatment plant. This was followed <br />by like tests when both lines of the system were conveying water. For each <br />condition studied, complete data was recorded concerning clear -well water <br />levels, pump discharge pressures and tank water levels. <br />From the results of this test we have plotted the actual capacity of the <br />Transmission System "A" on Exhibit No. 6 for easier comparison of the actual <br />and theoretic capacities. <br />The results of the flow tests also allow us to determine the actual <br />friction factors presently effecting the flow. The factors chosen in the <br />calculation of the theoretic capacities are those one might normally antici- <br />pate in pipelines of these materials and age. The tests indicate that the <br />friction factor effecting the cast iron pipe is actually 89 as compared to <br />the value of 90 which we could expect. However, the friction factor in the <br />wood -stave line is actually only 80 when we should expect a value of 110. <br />The reason for this appreciable loss in capacity is somewhat difficult <br />to pin - point. Flow tests tell us only that some physical condition within <br />*This friction factor is a measure of the resistance to flow, due to friction, <br />in a pipeline. As the unit friction increases, the factor decreases. <br />- 23 - <br />