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Population Equivalents (PE)
In order to design pipe network, pump stations and sewage treatment plants, estimates need to be made of the volumetric flow rate which will be expected to be carried, pumped and treated.
Such flow rates are measured in cubic metres per second and need to be calculated for both existing land use and for expected future development.
There are many methods for calculating expected flow rates. One method is to calculate a design parameter called the "population equivalent" (PE) of a catchment and convert this to a flow rate.
The PE is an estimate of the usage made of sewage facilities. It is not a measure of population.
For residential areas the population equivalent is calculated as five per dwelling and is a direct measurement of the population in an area.
However for commercial areas it is calculated from the floor area, which is considered to be proportional to the number of people using a premises during the day. In this case it does not reflect the population living in an area.
The following table shows how the PE is calculated.
| Type of Establishment | Population Equivalent |
|---|---|
| Residential | 5 per house |
| Commercial | 3 per 100m2 area |
| Educational Institutions | |
| - Day Schools | 0.2 per student |
| - Residential Schools | 1 per student (residential) |
| Hospitals | 4 per bed |
| Hotels | 4 per room |
| Factories | 0.3 per employee |
| Market (Wet Type) | 3 per stall |
| Market (Dry Type) | 1 per stall |
| Petrol Stations | 18 per service bay |
| Bus Terminal | 4 per bus bay |
| Taxi Terminal | 4 per taxi bay |
| Mosque | 0.5 per person |
| Church or Temple | 0.2 per person |
| Stadium | 0.2 per person |
| Swimming Pool or Sports Complex | 0.5 per person |
| Public Toilet | 16 per WC (water closet) |
| Airport | 0.2 per passenger/day |
| Airport | 0.3 per employee |
| Laundry | 10 per machine |
| Prison | 1 per person |
| Golf Course | 20 per hole |
The PE may be converted to a flow rate using a simple formula such as set out in Malaysian Standards 1228 (MS1228).
