Question
While branch pipelines are connected to pipelines, now and then Y-junctions or fitting branched pipelines to key pipelines by formation of holes in pipelines are used. Which one would be better option?
Answer
Using standard precast units of Y-junction branch pipelines, it is away from doubt that joints between branched pipelines and pipelines are properly formed and quality of joints is relatively a lesser amount of dependent on workmanship. Though, it suffers from problem that with fixed precast units of Y-junctions, occasionally it might be difficult for contractors to determine precise orientation of specific angles of Y-junctions with respect to gullies.
By forming elliptical holes in pipelines and fitting side branches into them with cement mortar, quality of pipe joints is highly dependent on workmanship. It is usually found that in subsequent CCTV inspections side branches are planned inside main pipes. This is disagreeable as projected side branches decrease cross sectional area of pipes locally and influence their hydraulic presentation. Furthermore, projected side pipes could trap rubbish and dirt in vicinity. On other hand, cement mortar could not be properly applied at link joints because these areas are hidden from vision and are not easy to be inspected by engineers. Consequently, in selecting between two available processes, engineers must create their own judgments based on above considerations.