13.1 INTRODUCTION

Underground piping is one of the largest investments a utility can have and the cost to maintain and or replace old piping is often prohibitive, due not only to the physical costs of the pipework itself but also to the excavation and reinstatement in often dense urban situations. Unfortunately, maintenance is often overlooked, as the problem is out of sight and therefore can be out of mind until an emergency situation occurs. However, any good proactive loss management program should address ongoing maintenance as one of the key issues. The diagram at the right shows where maintenance, rehabilitation, and replacement figures in our four-arrows concept of real losses control.

Pipe maintenance can come in many forms and can be undertaken at varying time frequencies, depending on the nature of the problem, the attitude of the operator, and the seriousness of the situation. However, some of the more frequent maintenance programs encountered to counteract losses are corrosion control, and pipe lining and replacement. In the case of pipe replacement, new technologies are being used to undertake trenchless replacement.

This chapter touches on some of the problems and methodologies encountered in the market today, although both subjects are sciences in their own right and have been widely discussed and published...