Pipe Laying and Pipe Line Failures 107 



end and, therefore, much of the line was laid without first placing 

 the mortar in the bottom of the bell. Without the bottom mortar it 

 becomes difficult to fill the annular space beneath the pipe and this 

 work is likely to be done carelessly. The annular space is only ^- 

 inch, which is so narrow that no tool can work in it easily. Mr. F. 

 N. Holmquist, the engineer, states that in his opinion there is con- 

 siderable leakage through the joints at Glendale due to insufficient 

 mortar in the joint. The leakage is probably greater in those por- 

 tions of the line that were in caving ground, where trenching and 

 placing could not be carried on ahead of the jointing. 



The rate of speed in pipe laying is quite variable. Ordinarily 

 about 700 feet of 12 or 14-inch pipe, or 500 feet of 16-inch pipe per 

 day is considered good. One foreman reports 900 feet of 12-inch 

 pipe, without the laying core, on straight work with no connections 

 or short turns. At Continental one pipe laying gang with three 

 skilled men and two laborers laid as high as 1075 feet of pipe, part 

 12-inch and part 14-inch, in eight hours. At a later date, a single 

 skilled pipe layer, with six unskilled helpers, laid over 1000 feet of 

 12-inch pipe in nine hours. The highest rate reported for 16-inch 

 pipe is 800 feet. In this case two experienced men alternated at 

 jointing the pipe and banding. Experience at Continental indicates 

 the following average rates : 



TABLE VII. AVERAGE RATE OF SPEED IN PIPE LAYING 



These rates do not include the installation of risers and valves. 

 This work is usually included in the contract price, but sometimes it 

 is done on force account. 



There is great danger that a newly-laid pipe line may dry out 

 before the joint mortar has properly set and hardened. Whenever 

 laying ceases, as at noon, a plug of wood or sacks should be put in 

 the end to prevent a draught of air from blowing through the line. 

 As soon as possible after laying, a stream of water should be turned 

 into the line to keep it thoroughly wet, certain valves, of course, 

 being left open so that the line cannot be subjected to any pressure. 



