Score Perth was recently tasked with the challenging overhaul of two 24” x 1500# Ball Valves, a 36” x 1500# Ball Valve and a 26” x 1500# Y-Globe Valve, the heaviest weighing in at 33 Tonnes. The valves were identified by the client as highly critical for installation to the Ichthys LNG project, located near Darwin in the Northern Territory, Australia.
The work scope involved considerable localised weld repairs to the end connections on 3 valves where porosity had been identified. It was necessary to establish the required personnel and equipment at short notice to meet the imposed delivery schedule. The relevant porosity indications were excavated, examined and welded in accordance with the client’s specification and with cooperation from the valve OEM. The operation was conducted with 24/7 coverage throughout the Christmas period with the client and valve OEM in attendance to monitor all welding, machining and NDE activities. Hydrostatic pressure testing was successfully completed and witnessed on all valves after the end connection repair.
It was however discovered that the 24” ball valves were not able to meet the required seat leakage criteria during FAT. The decision was taken by the client to strip the valves and complete full overhaul on the internals, including upgrade of the seat pockets to Inconel 625 overlay. Score Perth was assigned the task of completing the full scope, including weld overlay, prior to arrival of the new trim components. The valves were overhauled, built and tested ahead of schedule and with successful results.
Score Perth have established the capability of completing in-house welding with the construction of 2 large welding bays and the investment in equipment to cover a wide range of welding processes. The purchase of a Webster and Bennett vertical borer with a 48” diameter table has also increased machining capability to handle larger valves and equipment.