An international survey of maintenance policies and trends

General information about the utilities that responded. Quality of information is generally good but it is necessary to bear in mind that due to the nature of the information requested (e.g. replacement costs, type of equipment, age etc) much of the information was estimated. 64 responses were entered into a computerised database. Analysis of the general information obtained. Further details of the construction of the database and calculation of composite size and age factors used in the analysis are also given. The method used for detecting correlation between answers is also given.