Night Flow Analysis — Water Loss Research & Analysis
N1 Triage · N1 Calc

Getting your pressure:leak flow rate calculations right

Using the same N1 value for each zone or DMA can significantly under- or over-estimate how leak flow rate varies with pressure, especially at low AZPs.

Step 1

N1 Triage

→

Step 2

N1 Calc

Which zones need testing?

1

Screens all zones at once

Analyses pressure and flow data across one zone to thousands, simultaneously — flagging where an assumed N1 value looks unsafe to rely on.

2

Prioritises where to test

Produces a ranked list of zones/DMAs that would benefit most from an N1 test — and confirms which ones don’t need one.

Calculate the variable N1:AZP relationship

1

Calculates your actual N1

Uses your N1 test data plus zone characteristics to derive N1 at your Average Zone Pressure, and how it changes across a range of AZPs.

2

Splits Fixed vs Variable leakage

Shows the split at your current pressure, and how it shifts across a range of possible AZPs — the input your PM savings forecast depends on.

3

Re-calculates your Hour Day Factor

Updates your Hour Day Factor using the corrected N1 and leakage split, so night-to-day conversions reflect your zone’s actual pressure response.

See our conference talks and presentations on Pressure:Leak Flow →

Build your team’s expertise — Component Analysis and Pressure:Leak Flow Rate training courses

Want to see this run on your own zones?

Tell us about your network and we’ll suggest where to start.

Talk to us