Client Requirements
A regional power generation facility needed replacement exhaust ductwork with large-diameter sections that had to mate perfectly to existing in-plant flanges during a scheduled outage. Field alignment was the expensive risk: large-diameter sections had to mate to fixed existing flanges within a fixed outage window, so every section had to fit on the first attempt.
Northern’s Approach
Sheet stock was CNC laser cut to programmed flat patterns, rolled to diameter on our Roundo PS 310 plate roll, then seam-welded with manual GTAW on the long longitudinal passes, tie-ins, and branch fittings, under procedures qualified to ASME BPVC Section IX. Before release, every assembly was fit up dry on the shop floor against its mating section to verify alignment to our inspection drawings. No “we’ll adjust in the field” allowances.
Outcome
Field crews installed the duct run without rework, with sections dropping into position on the first attempt. The facility’s project manager credited the factory dry-fit: every section dropped onto its mating flange without forced alignment or field rework.
