|Operation and Maintenance of Water and Sewerage Systems (Ministry of Water - Tanzania - Rwegarulila Water Resources Institute, 1999, 90 p.)|
|A. Maintenance of Water Supply Units Principles and General Procedures|
Structures can be damaged as a result of acts of nature and/or human beings. Damages, caused by human beings can be due to ignorance, carelessness, or abuse.
The physical conditions of the units have to be checked frequently. The frequency depends on local conditions. The type and location of the unit and the available manpower are some of the major factors which govern this frequency.
This is the essential part of preventive maintenance. Inspection of each unit by at regular intervals is necessary for the detection of structural defects and other faults which may develop from time to time either from fair wear and tear or through external conditions such as ground subsidence or abnormal weather. The roadways, pathways, fences and any buildings should also be inspected regularly with the aim of noting defects for repair. Painwork, particularly of steel water tanks should be well maintained throughout the waterworks.
For some of the visual inspections it is not necessary to interrupt the operation. The aim of the inspection is to find any changes or developments in the structure and the surroundings which would adversely affect the safety or stability of the structure, the operation of the unit, and the quality of the water. Basically the inspection concerning the physical conditions is similar to the inspection which is made before the unit was put into operation for the first time. The main difference is that the inspection and the ensuing remedy for the correction of the defects are now the sole responsibility of the maintenance team. However, in cases where major repairs or reconstruction works are necessary a construction team or group can be assigned to carry out the work.
Components of units such as valves, vents, overflow pipes, etc., can be inspected without interfering with the operation of the unit in question.