Sanitary plumbing system
above ground
sanitary drainage system
underground
who has jurisdiction over sanitary plumbing in sg?
Ministry of the Environment & Water Resources (MEWR)
Parts of a sanitary plumbing system
- discharge pipe
- discharge stack
- ventilating pipe
- ventilating stack
Discharge pipe
pipe which conveys the discharges from a sanitary appliance or a floor trap
discharge stack
a main vertical discharge pipe
ventilating pipe
A pipe provided to limit the pressure fluctuations within any sanitary plumbing system
ventilating stack
A main vertical ventilating pipe
GO NOTES SEE FIG ONE
- Water closet
- long bath
- ventilating pipe
- ventilating stack
- discharge pipe
- discharge stack
- floor trap
- wash basin (have u-trap)
Trap Types
- integral trap
- P-trap
- S-trap
- Bottle trap (wash basin)
what are integral traps used for?
- water closets
- urinals
P & S traps used for
- floor traps, bath tubs
bottle traps used for
- wash basins
- sinks
Types of Sanitary Plumbing System
- single stack system
- ventilated stack system
- fully ventilated system
single stack system application
Where sanitary appliances are closely grouped around a discharge stack for buildings up to six storeys.
Ventilated Stack System
Where sanitary appliances are closely grouped around a discharge stack for buildings up to thirty storeys
Fully Ventilated System
Where there are large numbers of sanitary appliances in range or where they have to be widely dispersed
info about single stack system
- No ventilating stack is required as the discharge stack is large enough to limit pressure fluctuations.
- discharge stack has a uniform diameter of not less than 150 mm (except for conventional housing where 100 mm can be used) without offset throughout its entire length.
- The maximum length of the discharge pipe is 2.5 m.
- The maximum number of connections to the discharge pipe is two.
Ventilated Stack System
- Discharge pipes can be provided without the need for ventilating pipes.
- Maximum length of the discharge pipe is 2.5 m.
- Maximum number of connections to the discharge pipe is two.
- Main discharge stack has a uniform diameter of not less than 150 mm throughout its entire length.
- A separate discharge stack of minimum diameter 100 mm shall be provided to serve the 2nd and 3rd storeys.
- Secondary discharge stack extended to serve as ventilating stack.
- Ventilating stack should terminate as high as discharge stack or connected to discharge stack above the highest sanitary appliance.
- Cross venting between secondary discharge stack and discharge stack is
provided at the 1st storey. - Cross venting between the ventilating stack and discharge stack is
provided on the multiple of 3 storeys.
Fully Ventilated System
- Separate discharge & ventilating stacks have to be provided and be extended to the atmosphere.
- Individual traps/soil sanitary appliances connected directly to the discharge pipe or stack need to be provided with branch ventilating pipe which is connected to ventilating stack.
- Discharge stack has a uniform diameter of not less than 100 mm throughout its entire length.
- Traps connecting directly to discharge pipe shall be provided with a branch ventilating pipe of not less than 50 mm in diameter.
- Ventilating pipe shall be constructed upwards individually and be connected to a main ventilating stack. Such connection shall be above the spill over level of the soil sanitary appliance or floor trap served by such ventilating pipe.
- Top end of every ventilating stack shall either terminate as high as the discharge stack or connect into the discharge stack at a point not less than 150 mm above the spill over level of the topmost soil sanitary appliance or floor trap.
What is inspection chambers
- provide access to drains for inspection, testing, and clearing of blockages
invert and soffit
- Invert : Lowest point of internal surface of a pipe.
- Soffit : Highest point of internal surface of a pipe.
Design requirements of a sanitary drainage system
- water tight
- self-cleansing
Water-tight why
- if the system is not water-tight, the ground surrounding the drain would become polluted giving rise to unpleasant & unhealthy conditions
- Rain water may also enter the system leading to overloading of the sewage treatment plant
