Bridging Pit Gauges

The Bridging Pit Gauge System is built for areas of weight-loss corrosion too wide for a single blade to span. Its blades and tees are segmented, so the bridge can be assembled in a spanning configuration, with the indicator in the middle, or cantilevering, with the indicator at one end to work beside circumferential, long-seam or spiral welds, reinforcing pads and risers. Extra tees and connector blades extend its length, and the bridge can follow a slightly irregular surface or be assembled rigidly. Originally developed for pressure vessels, it was adopted for pipeline corrosion assessment under US DOT PHMSA 49 CFR Part 192 once Western introduced its magnetic hold-downs.

The Jr. Bridging Pit Gauge, Jr. Bridging Pit Gauge Plus and Jr. Bridging Pit Gauge Super are just over 394 mm (15½ in) long as a standard kit, and pipeline inspectors have extended them to 915 mm (4 ft) to evaluate field over-bends and buckling. The Bridging Pit Gauge (N88-9) and Bridging Pit Gauge Plus (N88-9P) are the full-size systems; the Plus allows longitudinal scans of up to 610 mm (24 in) without resetting the magnetic bridge, supporting remaining-strength (RSTRENG) evaluations of corroded pipe.