Pipe Materials in Calgary Presentation Slide #03

In consequence, our break-rate has now been stable for some years at only 500 breaks/year, 400 of them main breaks. Roughly 60-70% of them are related to external corrosion. We have reduced our replacement program repeatedly in recent years, and now feel that we have come through the other side of a 25-year problem that started in the early 70's when our main break rate started to climb alarmingly. After a few years of it, we started to increase our replacement program, and continued those increases until just a few years ago, with total added costs in this period in the high tens of millions - a lot of money even in Canadian dollars. We had a serious concern that the break rate would spiral out of control as we had a great deal of pipe all installed during short "boom" periods that could conceivably have reached the end of its life all at once.