2016 01 Paper: New Standards for Old Penstocks

Mercury has nine power stations on the Waikato River with a total of thirty nine penstocks. The penstocks have been designed and constructed by people who have left the industry. The knowledge and understanding of these penstocks have typically left the industry with the people. As the assets age and wear questions are being raised about the design of the penstocks and the limitations on metal loss.
Mercury in developing its latest Penstock Asset Management Strategy has adopted the API 579 Fitness for Service standard for run or repair decision making. This approach uses new tools developed for the assessment of common defects in piping and pressure vessels. These new tools utilise more accurate data and calculations to arrive at less conservative results. Their use can result in significant reductions in repair scope and costs without increasing risk or reducing safety. There is also a readily available pool of engineers who have the knowledge and experience to use them. This paper uses some recent examples to demonstrate the application of API 579 to the older penstocks on the Waikato River

• Author: Colin Steed
• Exchange: 2016 - Queenstown Meridian
• Company: Mercury
• Topic: Refurbishment
• Key Words: Asset, Penstock, Rehabilitation