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close this bookOperation and Maintenance of Water and Sewerage Systems (Ministry of Water - Tanzania - Rwegarulila Water Resources Institute, 1999, 90 p.)
close this folderA. Maintenance of Water Supply Units Principles and General Procedures
View the document1. Introduction
View the document2. Operation and maintenance
View the document3. Inspections
View the document4. Inspections made before putting the unit into operation for first time
View the document5. Periodic inspections made normally without interrupting the operation
View the document6. Periodic inspections made by interrupting the operations
View the document7. Remedial measures
View the document8. Records
View the document9. Maintenance programmes

3. Inspections

Inspection consists of checking the physical conditions of a structure and its surroundings.

Inspections are made in order to find out what is missing, gone wrong, or about to go wrong and to decide on the remedial actions that have to be taken.

3.1 Scope of Inspections

The inspections shall be made in order to assess the conditions of the units and determine the steps to be taken to remedy the deficiencies. Thereby, equal emphasis should be placed on the

- structural;
- operational, and
- hygienic


The conditions will show whether and to what extent the deficiencies adversely affect

- the safety and stability of the structure;
- the proper operation of the unit; and
- the quality of the water.

3.2 Extent of Inspections.

A record should be made of the observed deficiencies.

Water samples should be taken. Notes should be made on the accumulation of sediments, the presence of small animals and the origins of small animals.

The inspection must look out for

- rock pockets (porous, mortar deficient portions of hardened concrete consisting primarily of coarse aggregate and open voids; caused by leakage from formwork, or separation during placement of concrete or insufficient consolidation, or both);

- cracks;

- insufficient bond of screeds and plaster;

- cavities under screeds and plaster;

- roots (these are an indication for cracks and harmful connection with the exterior);

- roofs and covers which are not watertight; porous parts; holes; insufficient cover of the reinforcement steel;

- defective inlet, outlet, overflow, and wash-out pipes;

- defective measuring facilities; and

- blocked vents.

3.3 Types of Inspections

Inspections can be classified according to the times when they are made. It is necessary to distinguish between three types of inspections.

1. Inspections made before putting the unit into operation for the first time;
2. Periodic inspections made normally without interrupting the operation; and
3. Periodic inspection made by interrupting the operations as necessary.