Choosing sampling interval and study duration
Short enough to see events, long enough to include the cycles that matter — and consistent across all sensors.
Two parameters shape the dataset. The sampling interval sets what events can be resolved; the duration sets which cycles are included.
Interval
One to five minutes resolves door openings, defrost cycles and compressor cycling. Fifteen minutes can miss them entirely. Longer intervals reduce data volume but not usefully — modern loggers store weeks at one-minute resolution.
Duration
- Refrigerators and small chambers: at least 24 hours, commonly 48–72 hours.
- Cold rooms and warehouses: long enough to include weekdays and a weekend, deliveries and defrost cycles — several days to a week or more.
- Loaded studies: at least as long as empty ones.
Whatever the choice, use the same interval on every logger and align clocks before the study. Misaligned or drifting clocks produce apparent gradients that do not exist.
Frequently asked questions
- What sampling interval should be used for temperature mapping?
- One to five minutes is typical. It resolves short events while modern loggers store weeks of data at that rate.
- How long should a temperature mapping study last?
- At least 24 hours for small units, 48–72 hours commonly, and long enough for cold rooms and warehouses to include a weekend, delivery days and defrost cycles — typically a week.
References
- [1]WHO Technical Supplement 8 to TRS 961 Annex 9: Temperature mapping of storage areas (2015)
General technical guidance written against the cited sources. It is not regulatory or legal advice and does not replace the applicable standard, guideline or a qualified reviewer's judgement.
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