Peaking factor Kz.
The dry-weather flow variation factor by average daily flow, and the two other sets of factors that must not be mixed with it.
Basis
GB 50014-2021 Table 4.1.15 — national standard table value. Use these figures where no measured flow record exists, and interpolate between the tabulated flows. The Middle East factors are from the Saudi MEWA design guide; the 2006 values come from the superseded edition of the same standard.
Peaking factor Kz, GB 50014-2021 Table 4.1.15
Average daily flow in L/s against the variation factor Kz. The tabulated flows are the ones given in the standard.
| Average daily flow (L/s) | Peaking factor Kz |
|---|---|
| 5 | 2.7 |
| 15 | 2.4 |
| 40 | 2.1 |
| 70 | 2.0 |
| 100 | 1.9 |
| 200 | 1.8 |
| 500 | 1.6 |
| ≥1000 | 1.5 |
National standard table value. Where no measured flow data are available, use these values; interpolate for intermediate flows.
Other factors in use
| Context | Factor |
|---|---|
| Saudi MEWA — large cities | 1.6 |
| Saudi MEWA — villages and towns | 2.2 |
| GB 50014-2006, superseded edition | 2.3 / 2.0 / 1.8 / 1.7 / 1.6 / 1.5 / 1.4 / 1.3 for 5 / 15 / 40 / 70 / 100 / 200 / 500 / ≥1000 L/s |
The 2006 column is shown only so the two editions are not confused. Do not mix the editions in one calculation.
How to use and notes
- Use Kz when there is no measured flow record. Where a record exists, derive the factor from the data instead.
- Interpolate between the tabulated flows for intermediate values.
- The 2021 edition raised these factors. The 2006 edition used 2.3 / 2.0 / 1.8 / 1.7 / 1.6 / 1.5 / 1.4 / 1.3, and much material online still quotes the old values.
- The Middle East convention is different: Saudi MEWA uses 1.6 for large cities and 2.2 for villages and towns, so export documents list the two ranges separately.
- Factory confirmation pending: which edition of the factor is used in selection calculations, and whether the factor is split by export market: [to be confirmed with factory].