Case 2
- Introduction
- Causes of Defects
- Good Practices
- Standards
- Maintenance and Diagnostics
- Remedial
- Similar Cases
- References
Maintenance and Diagnostics
PUB maintains the water pipes up to the meter for landed properties and the master meter for residential
and commercial blocks. The maintenance of the water supply system between these meters and the sub-meters is managed by town councils for HDB homes and the building management for condos and commercial buildings. Home owners are responsible for pipes in their own premises and should get them checked yearly. Carry out quarterly chemical and bacteriological analyses of the water used. Perform monthly checks of the water supply for visual signs of leakage, scaling and corrosion of pipes, joints, valves and taps, and mixers. Increase the frequency of inspection for damp or polluted areas in accordance with BS 8554 or equivalent. Carry out monthly inspections and clean off / remove any rust
or scale. Re-paint parts in a timely manner, if needed, in accordance with BS EN 806-5 or equivalent.
Replace corroded water fittings promptly. Replace unlined galvanised iron pipes with cement-lined
ductile iron or copper pipes to prevent corrosion.
Discharge pipe system should be kept in clean regularly in order to maintain the maximum efficiency. Care should be taken in the use of chemical descaling agents, which are often a corrosive nature.
Therefore, it is important to clearly identify the materials used in the system before using the chemicals. Table 1 gives various solutions to be used for different scales of deposits.
The following alternatives may be considered for different scales:
| Type of scale | Cleaning method | Possible locations |
| Deposits due to misuse of the discharge system | blockage due to large object or compacted masses such as toilet paper and sanitary towels can be loosened by rodding. | discharge pipe |
| Lime scale | periodic de-scaling using a suitable inhibited acid based cleaners (see Table NG.2 in BS EN:12056-2:2200) | discharge stack and pipes from urinals |
| Accumulation of greases and soap residuals | This can partially be removed by use of a plunger, but most effective way is by flushing the system with a strong solution of soda crystals dissolve in hot water (see Table NG.2 in BS EN:12056-2:2200). | discharge pipes from sinks or wash basins |
- Periodic inspection and tests can be advisable to ascertain any other defects such as water leakages, wear and tear or negligence.
- The following instruments and techniques can be used to diagnose water leakages in sanitary fittings and pipes.
Diagnostics of Defect (see also NDT)
Fibrescope / Borescope
A fibrescope or a flexible borescope is a flexible optical inspection device that consists of fibre optic bundles with an eyepiece at one end and a lens at the other. A fibrescope usually comes in two bundles: (i) a fibre optic light bundle that is for illuminating the object to be investigated, and (ii) a fibre optic image bundle to relay the image to the eyepiece. It allows a direct visual inspection for an otherwise inaccessible part, as observations of remote, difficult-to-reach areas can be made through a video monitor with high-resolution images. The flexible fibres allow it to be manoevred in hard-to-reach or inaccessible areas.