The Nightline Measurement Method (NLM)

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AQUIS NLM is applied during periods with minimum consumption — typically at night time — to monitor changes in background leakage level.

NLM works in a similar manner to the IFM method (Integrated Flow Measurement), except that the NLM considers measurements in a fixed time window during periods of minimum consumption, where leakages will make up the highest proportion of the total flow.

The methodology employed is to find the minimum night flow within a fixed time window every day. This value is compared to the minimum flow found for the same weekday in average buffers calculated for the number of weeks defined by the user.

Figure 1 below shows the buffer of the latest events issued by AQUIS NLM. Double-clicking a message line will zoom on the selected message and present the complete text.

An event is either a system message or a message generated via the event management system (user defined).

AQUIS NLM event log
Figure 1. AQUIS NLM event log.