"DUCCO" couplings are general purpose couplings for use with grooved end steel pipes. Simple, quick installation procedure requiring only one spanner, makes for low installation cost. Housing key section positively engages grooves around entire pipe circumference mechanically locking pipe together. Built in deflection tolerances as par individual charts allow quicker installation and easier adjustment of pipe laying where levels vary or settlement occurs."DUCCO" couplings can accept some linear expansion and contraction thereby relieving limited pipeline stresses without costly expansion joints. A union per joint facilitates the removal of pipe sections for replacement, servicing, cleaning etc. In the grooved end pipe, the grooves are not as deep as comparable threaded pipe; less metal is removed therefore pressure rating of pipe is largely retained."DUCCO" couplings are equally economical to dismantle where reclamation of temporary pipelines is desirable.