Route 9.3 a) requires the welder to undergo a full practical retest every three years. Under this route, a new test coupon must be welded and examined. Following this examination, a new certificate is issued.
Route 9.3 b) allows extension every two years based on testing of production welds. Under this route, two welds made during the last six months of the validity period must undergo volumetric or destructive testing. These tests can include radiographic, ultrasonic, bend, or fracture testing. The test welds must reproduce the original test conditions, though thickness and outside diameter may vary.