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Defects
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Probable causes for the defect
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Design for Maintainability (DfM) Guidelines
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| Clogged / soiled fixture
 Clogged drain  Clogged sink |
- Inadequate or harsh cleaning of fixture & trap. If the material in not vitreous or surface is scratched, cleaning is difficult.
- Backflow or back siphonage if the devices (stop valves, vacuum breaker, check valve etc) to prevent that are damaged with time or from mishandling. Parts should be replaced after certain interval.
- Inadequate airgap to prevent backflow.
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Design
Construction
Maintenance
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| Ponding below / around fixture |
- Inadequate grading of flooring towards the WC pan.
- Connection of fixture & discharge pipe is not watertight. Flexible type connector (collar, flange) or seals can handle fixture movement and remains watertight if installed properly.
- Connector between flush pipe of cistern & pan is damaged with time.
- Gap between fixture and walls is not sealed.
- Omission of the waste pipe / trap under the bath or overflow preventor.
- Poor maintenance of waste pipe / trap, especially if not accessible.
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Design
Construction
Maintenance
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| Ponding on floor/ slow drainage
Ponding on floor
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- Inadequate number of outlets or too far away from fixtures.
- Floor grading is inadequate or in wrong direction.
- Clogged floor trap from inadequate cleaning or entry of solid waste through misfit grating. Construction waste should not be dumped.
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| Wall-hung fixture dislodged |
- Supports and bracket are not strong enough to sustain the load or not securely fixed to the wall.
- Severe corrosion of screws bolts. Material is not corrosion resistant and initial rusting is neglected.
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Design
Construction
Maintenance
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| Auto devices no more auto |
- Wear and tear of operating parts with time and careless use (repeated / hard pressing of sensor).
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Design
Construction
Maintenance
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References
[1]
Normative References/Standards Referred to for Air Handling Unit and Fan Coil Unit