Temperature mapping report: a worked example
A complete mapping report for a 2–8 °C cold room, with the actual numbers: per-sensor statistics, hot and cold spots, an excursion, data-quality findings and the acceptance decision. Demo data throughout.
Demo data. Every value below is fabricated to illustrate the structure of a mapping report. It is not a real study, describes no real facility, and must not be presented as evidence for any space.
Most guidance tells you what sections a mapping report should have. This one shows the sections filled in, because the difficulty is never the table of contents — it is knowing how much detail each number needs, and what to do when a position fails. The study below is a 2–8 °C cold room, mapped loaded, over three days.
1. Study information
| Field | Entry |
|---|---|
| Report number | MAP-REP-0042, version 1.0 |
| Protocol reference | MAP-PROT-0042 v2, approved 2 March |
| Area | Cold room CR-2, 46 m³, set point 5.0 °C |
| Storage condition | 2.0 °C to 8.0 °C (inclusive) |
| Loading condition | Loaded — 71 % of pallet positions occupied, representative of routine stock |
| Study period | 11 March 08:15 to 14 March 08:15 (72 h) |
| Season / ambient | Late winter; external 4–11 °C, plant room 19–23 °C |
2. Dataset and calibration
| Item | Value |
|---|---|
| Loggers | 12 × single-channel, 0.01 °C resolution |
| Calibration | Accredited laboratory, certificate CAL-24-7781, points 0.0 / 5.0 / 10.0 °C |
| Reported uncertainty | U = 0.30 °C (k = 2) at 5.0 °C |
| Post-study verification | All 12 within 0.05 °C of the pre-study ice-point check |
| Sampling interval | 5 minutes, identical on every logger |
| Records | 864 per logger, 10 368 total |
| Unit | °C, confirmed in the logger configuration and the export header |
| Time zone | UTC+00:00, no daylight-saving transition in the period |
3. Data quality
Checks are run before any statistic is computed, and every finding gets a decision rather than a shrug.
| Finding | Detail | Decision |
|---|---|---|
| Gap | S09, 25 minutes (5 readings) during the 12 March download | Accepted with limitation — outside the excursion window; noted in section 8 |
| Duplicate timestamps | None | — |
| Flatlines | None beyond 3 consecutive identical readings, within resolution | Accepted |
| Abnormal jumps | S04, one 1.8 °C step at 11 March 14:02 | Retained — coincides with the logged door opening, physically plausible |
| Out-of-range readings | None outside the calibrated 0–10 °C span | Accepted |
| Scope | S12 is the external ambient reference | Excluded from acceptance by design, per protocol §5 |
4. Configuration used for the analysis
- Limits: 2.0 °C to 8.0 °C inclusive, applied to all in-scope sensors for the whole study.
- Excursion: any reading outside the limits, with duration reported; no permitted grace period was claimed.
- Hot spot: highest per-sensor maximum, confirmed against the highest mean. Cold spot: the mirror of that.
- Decision rule: a position is accepted only if its extreme plus the expanded uncertainty stays inside the limits (guard band w = U = 0.30 °C), per ILAC-G8.
- In scope: S01–S11. Out of scope: S12 (ambient reference).
5. Results
| Sensor | Location | Min | Max | Mean | SD | Finding |
|---|---|---|---|---|---|---|
| S01 | Rack A, top, front | 4.2 | 7.1 | 5.6 | 0.52 | Within limits |
| S02 | Rack A, bottom, beside door | 3.1 | 6.2 | 4.6 | 0.61 | Cold spot |
| S03 | Rack A, mid, rear | 4.5 | 6.4 | 5.3 | 0.38 | Within limits |
| S04 | Rack B, top, front | 4.7 | 7.4 | 5.9 | 0.57 | Within limits |
| S05 | Rack B, mid | 4.4 | 6.9 | 5.5 | 0.41 | Within limits |
| S06 | Rack B, bottom, rear | 3.6 | 6.0 | 4.9 | 0.44 | Within limits |
| S07 | Rack C, top, below light fitting | 5.0 | 8.4 | 6.3 | 0.68 | Hot spot · excursion |
| S08 | Rack C, mid | 4.6 | 7.2 | 5.7 | 0.49 | Within limits |
| S09 | Rack C, bottom | 4.1 | 6.5 | 5.2 | 0.45 | Within limits · 25 min gap |
| S10 | In front of the evaporator outlet | 2.9 | 5.8 | 4.3 | 0.66 | Coldest air, no product stored |
| S11 | Geometric centre | 4.6 | 6.7 | 5.4 | 0.40 | Within limits |
| S12 | External ambient (reference) | 4.0 | 11.2 | 7.8 | 1.90 | Out of scope |
Study-wide, across the eleven in-scope sensors: minimum 2.9 °C, maximum 8.4 °C, mean 5.3 °C. Quoting only that summary would hide both of the findings that matter, which is why the per-sensor table comes first.
6. Hot and cold spots
| Sensor | Location | Value | Confirmed by mean? | |
|---|---|---|---|---|
| Hot spot | S07 | Rack C, top, below light fitting | 8.4 | Yes — also the highest mean at 6.3 °C |
| Cold spot | S10 | Evaporator outlet | 2.9 | Yes — also the lowest mean at 4.3 °C |
| Coldest product position | S02 | Rack A, bottom, beside door | 3.1 | Yes — lowest mean of the product positions |
S10 sits in the evaporator air stream where no product is stored, so it is reported as the coldest air but S02 is the position that governs the cold end for product. Both are stated; collapsing them into one number is how a report becomes misleading.
7. Excursions
| # | Sensor | Start | Duration | Peak | Event |
|---|---|---|---|---|---|
| 1 | S07 | 12 March 10:40 | 14 min | 8.4 | Goods-in delivery; door held open 9 min (event log ref EL-118) |
One excursion, at the hot spot, during a logged delivery. No excursion occurred at the cold end: S10's 2.9 °C minimum is inside the limit, and with the guard band applied it remains inside.
8. Acceptance decision
The acceptance criterion is applied with the decision rule from section 4, not to the bare statistics. With U = 0.30 °C and a guard band of w = U, the internal acceptance band is 2.30 °C to 7.70 °C.
| Position | Extreme | With uncertainty | Against 2.0–8.0 °C |
|---|---|---|---|
| S07 (hot) | 8.40 | 8.70 | Outside the limit even before the guard band — fail |
| S02 (cold, product) | 3.10 | 2.80 | Inside the acceptance band — pass |
| S10 (cold, air) | 2.90 | 2.60 | Inside the acceptance band — pass |
| All other in-scope | ≤ 7.40 / ≥ 3.60 | ≤ 7.70 / ≥ 3.30 | Inside the acceptance band — pass |
Outcome: the study does not meet its acceptance criteria. Ten of eleven in-scope positions pass; S07 fails. A report that buried this in a summary paragraph would be the problem, not the excursion.
9. Limitations
- Late-winter ambient only. The behaviour of S07 under summer ambient is not demonstrated, and the light fitting's contribution would be expected to compound with a warmer plant room.
- One loading configuration, at 71 % occupancy. Full occupancy was not tested.
- S09 has a 25-minute gap; its statistics rest on 859 of 864 readings.
- No power-failure challenge was run; recovery behaviour after a supply interruption is unknown.
- Three days captures two deliveries and six defrost cycles — enough for routine behaviour, not for rare events.
10. Findings and recommendations
- Exclude the top level of Rack C from product storage until remediated, and mark it physically.
- Relocate or shield the light fitting above S07, then re-map that position; a targeted re-map is proportionate because the cause is identified and local.
- Place routine monitoring at S07 (hot) and S02 (coldest product position), not at the control probe.
- Set the monitoring alert at 7.5 °C and the alarm at 8.0 °C, so the alert gives time to act before the product limit is reached.
- Review door discipline at goods-in: a 9-minute opening caused the only excursion in the study.
- Re-map on change of racking, HVAC or use, and at the next periodic review in 24 months.
11. Review and approval
| Role | Decision |
|---|---|
| Author | Issued for technical review |
| Technical reviewer | Reviewed — agrees the S07 failure and the targeted re-map |
| Quality approval | Approved with the exclusion of Rack C top level pending re-map |
Until all three are signed, the report stays marked draft and not technically approved. That status is part of the record, not a formality.
How to use this
Take the structure, not the numbers. The blank version of this report is available as a template, and the checklist covers what to settle before the loggers go in. If you have your own logger export, the MKT and excursion calculator will compute the statistics section for you in the browser.
Frequently asked questions
- What does a temperature mapping report look like?
- It is a standalone technical record: study identification, dataset and calibration evidence, data-quality findings, the analysis configuration, per-sensor statistics, hot and cold spots, excursions with durations, the acceptance decision, limitations, recommendations and signed approvals. The worked example above shows each section filled in.
- Should a mapping report show the raw per-sensor data?
- It should show per-sensor statistics and reference the raw export, which is retained unchanged as the original record. Printing 10 000 readings helps nobody; hiding which sensor produced which extreme helps nobody either.
- What happens if one position fails the acceptance criteria?
- The report says so plainly. The usual outcomes are excluding that position from storage, remediating the cause and re-mapping it, or assessing the affected product specifically — each recorded with its rationale and approved. A failure handled openly is a working quality system; a failure smoothed over is a finding waiting to happen.
- Does measurement uncertainty have to be in the acceptance decision?
- The product limits do not move, but the decision rule states how uncertainty is treated when a reading sits near a limit. The example applies a guard band equal to the expanded uncertainty, so a position is accepted only if its extreme plus U stays inside the limits.
- How long should a mapping report be?
- Long enough that someone who was not present can follow it, and no longer. The example above is a complete report for a single room; the per-sensor table and the excursion list do most of the work.
References
- [1]WHO Technical Supplement 8 to TRS 961 Annex 9: Temperature mapping of storage areas (2015)
- [2]EU Guidelines on Good Distribution Practice of medicinal products for human use (2013/C 343/01)
- [3]ILAC-G8:09/2019 — Guidelines on Decision Rules and Statements of Conformity
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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What a temperature mapping report should contain
A report is a technical record that lets a reader who was not present understand what was done, what was found and what was decided.
What a temperature mapping protocol should contain
The protocol is the contract for the study: fix the purpose, limits, sensor plan and analysis rules before a single logger is placed.
Setting acceptance criteria for a mapping study
Acceptance criteria come from the product's storage condition, expressed as limits, a permitted excursion definition, and a rule for what happens at the boundary.