An electronic flow measurement system keeps its accumulations at more than one time scale, and the finest one it stores for custody purposes is the hour. The hourly quantity record is the object that holds a single hour's worth of measurement: how much flowed, for how long, and under what average conditions. It is the granular layer that daily totals are built from and the resolution auditors reach for when they need to see inside a day. This guide explains exactly what the hourly quantity record contains, how its flow-weighted averages and flow time are formed, and how it differs from the daily record and the configuration record it sits alongside in an API 21.1 system.
Hourly Quantity Record in one line: An hourly quantity record is the API 21.1 measurement record that stores one hour of a meter's results: the volume and energy accumulated that hour, the flow time, and the flow-weighted averages of the process conditions such as differential pressure, static pressure, and temperature. It is the finest custody-grade resolution an EFM system keeps, and the daily record is the sum of the day's hourly records. It differs from the configuration record, which holds settings rather than results, and from the daily record, which aggregates the hours.
The hourly quantity record is a snapshot of one hour's measurement result, closed on the even hour and timestamped to that boundary. Its central contents are the accumulated volume and, for gas measured on an energy basis, the energy for the hour. Alongside those totals it carries the flow time, the number of minutes or seconds within the hour that the meter was actually flowing, which is essential context because an hour's volume means something different when it accrued over sixty flowing minutes than when it accrued over ten.
The other core contents are the flow-weighted averages of the process conditions that drove the calculation: the average differential pressure across the primary element, the average static or line pressure, and the average temperature, plus whatever else the method requires. These are not simple time averages. Each sample is weighted by the flow that occurred while it applied, so that conditions during real flow dominate and idle stretches do not distort the figures. Storing flow-weighted averages rather than raw samples is what lets the hour's quantity be reproduced and audited later without keeping every sub-minute reading.
Taken together, these fields make the hourly record self-contained for verification. From the flow-weighted averages, the flow time, and the configuration that was in force, the hour's volume can be recomputed and checked against the stored total. That reproducibility is the whole reason the record stores averages and flow time rather than just a bare volume: it preserves enough of the hour's measurement to defend the number rather than merely assert it.
The clearest way to place the hourly record is against the other records an API 21.1 system keeps. The configuration record is a different kind of thing entirely: it stores the settings and constants the computer used, such as plate and pipe dimensions, composition, reference conditions, and cutoffs, not any measured result. The hourly record stores results; the configuration record stores the parameters that turn inputs into those results. You need both together to audit an hour, because the record tells you what was measured and the configuration tells you under what assumptions.
The daily record is the same species as the hourly record but at coarser resolution. It holds the day's volume, energy, flow time, and flow-weighted averages, and in a consistent system the daily figures are the aggregation of that day's hourly records: the volumes sum, the flow times sum, and the averages are re-weighted across the whole day rather than simply averaged from the hourly averages. The hourly record is therefore the building block, and the daily record the roll-up, which is why an auditor who sees a suspicious day drops down to the hourly records to find which hour carries the anomaly.
This layering is deliberate. The hourly resolution gives enough detail to localise a problem in time, to see a plugged line that only affected part of a day or a low-flow stretch that thinned an average, while the daily record gives the settlement-ready total. Neither replaces the other, and neither replaces the configuration record. An hour that will not reproduce from its own averages and the period's configuration is a finding; a day whose hourly records do not sum to the daily total is a finding of a different kind. Understanding which record answers which question is what keeps an EFM audit efficient.
In the field, hourly quantity records are the natural unit of measurement collection. A host or SCADA system typically polls the flow computer and pulls the hourly records it has closed since the last read, so that even if collection lags after a comms outage, the boundary-aligned hourly records are retrieved intact once the link returns. Because each record is closed and timestamped by the computer on the even hour, its integrity does not depend on when it was collected, which is what lets hourly data be gathered reliably from remote sites on an intermittent connection.
A cloud SCADA such as Merobix uses the hourly record as the grain for both operational and measurement views. Trending hourly volume and flow-weighted averages across many meters lets an operator see the shape of a day, spot an hour where flow time fell short of a full hour, or catch an average differential drifting in a way that hints at a plugging impulse line, all without waiting for the daily roll-up. Because the platform holds the hourly records rather than just daily summaries, the same data supports both watching the process now and auditing it later.
The value of centralising hourly records is that it collapses the gap between operations and measurement. The operator watching for a run that has gone quiet and the analyst reconciling a settlement dispute are looking at the same hourly quantity records, closed the same way by the same flow computers, surfaced in one place. That shared, boundary-aligned, reproducible hourly layer is what makes a cloud SCADA useful for custody-grade measurement and not just for real-time control, since the record that defends the number and the record that shows the trend are one and the same.
Both store measured results, but at different resolutions. The hourly record holds one hour's volume, energy, flow time, and flow-weighted averages, while the daily record holds the same fields for a whole gas day. In a consistent system the daily figures are the aggregation of the day's hourly records, so the hourly record is the building block and the daily record the roll-up an auditor drops below to localise an anomaly.
Because flow-weighted averages preserve enough of the hour's measurement to reproduce and audit the volume without keeping every sub-minute sample. Weighting each condition by the flow that occurred while it applied means conditions during real flow dominate and idle stretches do not distort the figures. From those averages, the flow time, and the configuration in force, the hour's volume can be recomputed and checked against the stored total.
The hourly quantity record stores measured results for one hour, whereas the configuration record stores the settings and constants the computer used, such as plate and pipe dimensions, composition, reference conditions, and cutoffs. Results versus parameters is the distinction. You need both together to audit an hour, because the quantity record says what was measured and the configuration record says under what assumptions it was calculated.
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