6) Pipe welding 



a) End to be welded prepared 



(1) If end damaged it may be cut off and rebeveled 



(2) End cleaned by brushes and buffers - power 

 supplies usually truck mounted 



b) Pipe lifted by side boom and aligned - clamps 

 hold in place 



c) Stringer bead is welded - power supplies truck 

 or tractor mounted 



d) Pipe set on skids after stringer bead made 



e) Side booms move down string to lift next pipe 

 for alignment 



f) Weld area recleaned between each bead 



g) Welders apply 1 to 4 more beads 



7) Welding inspection 



a) Welding inspection vehicle enters site 



b) X-ray source exposes film at weld junction 



c) Film developed on site - possible disposal of 

 developing chemicals 



d) Welders return with equipment to repair weld faults 



8) Pipe surface preparation 



a) Uncoated pipe 



(1) Pipe lifted by side boom 



(2) Cleaning and priming machine makes pass 



(3) Pipe may be set down again while enamel dries, 

 picked up before wrapping machine approaches 



(4) Wrapping machine moves along pipe - tar, 

 glass fibre, and tar paper 



(5) Supply vehicles accompany machines along 

 pipe 



(6) Faults detected and repaired by hand 



(7) Pipe reset or moved over ditch 



b) Coated pipe 



(1| Joints coated with tar 



(2) Mastic applied 



(3) Supply vehicles stop at each pipe joint and 

 mastic molds are mounted on side booms 



9) Placement in ditch 



a) Bottom of ditch prepared - loose dirt bed 



b) Ditch pumped dry if necessary 



c) Pipe lifted over ditch and placed in ditch by 

 side booms - many in a line 



d) Weights or fasteners placed on pipe if necessary 



e) For bored crossings 



(1) Pipe placed through casing 



(2) Pipe tied in by welding 



(3) Joint prepared as in IV.A.l.a,8.a.7, 

 IV.A.l.a.8.a.4, or IV.A.l.a.8.b 



10) Block values, bypass valves, and condensation traps 



a) Area excavated or enlarged as needed by dragline, 

 backhoe 



b) Assembly moved in by truck 



c) Lowered into place by side boom 



433 



