THE FLOW OF WATER IN WOOD-STAVE PIPE. 67 



velocity and entry head is found to be 0.303 feet. Therefore, the final 

 figures are 28 =0-536 = H. 



Again, referring to Plate X, at the intersection of Q = 63 and 

 H = 0.536 the diameter of the required pipe is found to be 60 inches 

 and the peak-load velocity to be 3.3 feet per second. The difference 

 between the preliminary figure for combined velocity and entry heads 

 and the final figure is not snSicient to warrant more trials. 



2. A power trunk fine from a reservoir to a surge tank to convey 

 a peak load of 700 second-feet is required. The length of pipe will 

 be 11.3 miles, the total loss of head under peak load shall not exceed 

 20 feet, and the value of head shall be sufficient to warrant a factor 

 of safety of 15 per cent in designing. Required for comparison, the 

 size of pipe for both a single and a double pipe line with the same loss 

 of head. 



The length of pipe is so great that velocity and entry head may be 

 ignored. 



One hundred and fifteen per cent of 700 = 805 second-feet. 



Eleven and three-tenths miles = 11.3x5,280 = 59.664 X 1,000 feet. 



1^ = 0.335 feet per 1,000 feet = H. 

 59.7 



Enter Plate X at Q = 805. Intersection of Q = 805 with H = 0.335 

 is at D = 14.5 feet and at V = 5 feet per second. Thus a single pipe 

 line 14.5 feet in diameter will convey the peak load at a velocity of 

 about 5 feet per second. 



To study the possibihties of a double pipe line, turn to figuje 6. 

 Enter at intersection of diameter 14.5 feet and relative capacity 1. 

 From this point the left slanting line intersects relative capacity 

 line ^ on diameter line 135 inches or diameter line 11.25 feet. Thus 

 twin lines each Hi feet in diameter will convey the given quantity 

 of water with the same loss of head as will a single fine 144 feet in 

 diameter. 



Pipe problems involving velocities less than 0.7 foot per second or 

 more than 9 feet per second may be solved by the use of Plate VIII. 

 With a straightedge join the two discharge scales at the given dis- 

 charge. All points on the straightedge wlU now give simultaneous 

 values of diameter, loss of head, and velocity. For instance, the 

 dash-dot line representing 100 second-feet intersects the 84-inch pipe 

 line on the H-line of 0.237 foot per 1,000 feet and on the V-fine of 

 2.58 feet per second. Thus an 84-inch pipe will convey 100 second- 

 feet of water at a velocity of 2.58 feet per second with a loss of head 

 of 0.237 foot per thousand feet of pipe. 



