▁and ▁connected ▁to , ▁the ▁existing ▁pipeline . ▁The ▁effect ▁of ▁looping ▁is ▁to ▁provide ▁additional ▁capacity ▁at ▁critical ▁sections ▁of ▁the ▁main ▁tr unk line , ▁thus ▁increasing ▁the ▁total ▁possible ▁through put . ▁ ▁DB P ▁expansion ▁projects ▁▁ ▁The ▁DB NG P ▁under w ent ▁a ▁range ▁of ▁expansion ▁projects ▁under ▁previous ▁ownership ▁structures . ▁However , ▁the ▁most ▁advanced ▁have ▁been ▁undert aken ▁by ▁the ▁current ▁own ers , ▁who ▁have ▁inv ested ▁in ▁three ▁major ▁expansion ▁projects ▁since ▁acqu iring ▁the ▁asset , ▁these ▁projects ▁are ▁known ▁as ▁Stage ▁ 4 ▁( construct ed ▁by ▁N ac ap ▁Australia ▁P ty ▁Ltd ), ▁Stage ▁ 5 A ▁( construct ed ▁by ▁Sa ip em ) ▁and ▁the ▁most ▁recent , ▁Stage ▁ 5 B ▁( as ▁constructed ▁by ▁Mc Con nell ▁Dow ell ). ▁ ▁These ▁three ▁projects ▁were ▁carried ▁out ▁in ▁direct ▁response ▁to ▁increasing ▁demand ▁for ▁gas ▁in ▁the ▁south - west ▁of ▁W A . ▁The ▁own ers ▁worked ▁closely ▁with ▁major ▁gas ▁customers ▁to ▁deliver ▁the ▁capacity ▁required ▁within ▁the ▁time frames ▁needed ▁to ▁support ▁those ▁customers ' ▁projects . ▁In cre asing ▁the ▁gas ▁ha ul age ▁capacity ▁of ▁the ▁pipeline ▁was ▁cru cial ▁in ▁supporting ▁economic ▁growth ▁in ▁W A . ▁ ▁The ▁exp ans ions ▁were ▁designed ▁and ▁built ▁to ▁meet ▁DB P ' s ▁contract ual ▁oblig ations . ▁As ▁a ▁result ▁of ▁the ▁exp ans ions , ▁ 8 3 % ▁of ▁the ▁pipeline ▁has ▁now ▁been ▁dup licated