This is a ready-to-use form for the sensor placement record that anchors a temperature mapping study. It attaches to the mapping protocol as the placement diagram and location rationale. Replace every <<FILL: ...>> placeholder with your specifics. A worked filled specimen follows. The count follows the risk, not a template; justify every position.
Document control header
| Field | Entry |
|---|---|
| Form title | Sensor Placement Diagram and Location Rationale |
| Record number | <<FILL: FORM-ID, e.g. FRM-QUAL-030-01>> |
| Parent protocol | <<FILL: protocol number>> |
| Unit / asset ID | <<FILL: UNIT NAME / ASSET ID>> |
| Rated condition | <<FILL: temperature +/- tolerance, RH if applicable>> |
| Study type | <<FILL: empty / loaded / door-open>> |
| Date | <<FILL: date>> |
1. Purpose
This form records where each data logger was placed for the mapping of <<FILL: UNIT NAME / ASSET ID>>, and why, so the study is reproducible and a reviewer can see that the count and positions bound the usable volume and target the suspected worst cases. Mismatched or unjustified sensor placement is one of the most common mapping findings; this record prevents it.
2. Usable volume and count basis
| Field | Entry |
|---|---|
| Usable volume defined | <<FILL: dimensions / shelf range; dead zones excluded>> |
| Load lines marked in unit | Yes / No |
| Baseline count for this unit class | <<FILL: e.g. 9 for a reach-in, 15+ for a walk-in>> |
| Actual count used | <<FILL>> |
| Basis for exceeding baseline | <<FILL: which extra positions and why>> |
3. Sensor-to-location table
Include a labeled diagram (attachment) and this table. Every logger ID here must match the diagram and the data file.
| Logger ID | Physical location | Category | Rationale | Calibration cert # |
|---|---|---|---|---|
<<FILL: T1>> | <<FILL>> | Corner / center / control-adjacent / door / supply / return / heat source | <<FILL>> | <<FILL>> |
<<FILL: T2>> | <<FILL>> | <<FILL>> | <<FILL>> | <<FILL>> |
<<FILL: ...>> | <<FILL>> | <<FILL>> | <<FILL>> | <<FILL>> |
4. Mandatory-position checklist
| Position | Included? | Logger ID(s) |
|---|---|---|
| 8 geometric corners of usable volume | Yes / No | <<FILL>> |
| Geometric center | Yes / No | <<FILL>> |
| Adjacent to control sensor | Yes / No | <<FILL>> |
| Door / door seal | Yes / No | <<FILL>> |
| Supply air | Yes / No | <<FILL>> |
| Return air | Yes / No | <<FILL>> |
| Internal heat/cold source (coil, defrost, lights) | Yes / No | <<FILL>> |
| Adjacent to routine monitoring / BMS probe | Yes / No | <<FILL>> |
5. Acceptance criteria
- The count is justified against the unit-class baseline, not copied.
- All eight corners, the center, and the control-adjacent position are included.
- The door and each suspected worst case (supply, coil, defrost, stratification top) are instrumented.
- Every logger ID matches the diagram and the data file, and links to a calibration certificate.
- No sensor sits in an unqualified dead zone.
6. Signatures
| Role | Name | Signature | Date |
|---|---|---|---|
| Executor | <<FILL>> | ||
| Reviewer | <<FILL>> | ||
| QA | <<FILL>> |
7. References
WHO Technical Report Series guidance on temperature mapping of storage areas. EU GDP Guidelines 2013/C 343/01, section 3.2.1 (initial mapping). 21 CFR 211.68 (equipment controls).
Confirm the current version of each reference before issue.
Filled specimen
The following shows the form completed for an example upright freezer rated -20 degrees C +/- 5, loaded study. The specifics are illustrative.
Count basis: baseline 9 for a reach-in; 12 used. The three extras target the two suspected extremes (door, coil) and the control-adjacent comparison.
| Logger ID | Physical location | Category | Rationale | Calibration cert # |
|---|---|---|---|---|
| T1-T4 | top four corners | Corner | top of unit, near supply air (warmest expected zone) | CAL-2026-118 to -121 |
| T5-T8 | bottom four corners | Corner | bottom, near floor / cold sink | CAL-2026-122 to -125 |
| T9 | geometric center | Center | reference center | CAL-2026-126 |
| T10 | adjacent to control probe | Control-adjacent | compare mapping to what the controller reads | CAL-2026-127 |
| T11 | just inside door, mid-height | Door | door ingress, warmest expected point | CAL-2026-128 |
| T12 | near evaporator/coil | Heat/cold source | coldest expected point | CAL-2026-129 |
Mandatory-position checklist: all eight corners, center, and control-adjacent included; door and coil instrumented; the co-located monitoring probe covered by T10. No sensors in the fan-baffle dead zone.
In this example the two extra loggers at the door and coil are what let the study report a defensible hot spot and cold spot, and the control-adjacent logger is what lets the report say whether the controller reads true. Without those three, the “9-point map” would have bounded the volume but missed the positions that actually decide where routine monitoring goes.
Common findings this form prevents
- A sensor count with no justification, or clustered where it was convenient.
- Logger IDs in the data file that do not match the diagram, making the study hard to reconstruct.
- The door or coil never instrumented, so the real worst case is unknown.
- Sensors placed in dead zones product cannot occupy, penalizing the unit unfairly.
How to adapt this form
- Set the record number and parent protocol; carry the rated condition from the protocol.
- Expand the sensor-to-location table for walk-ins and warehouses (a full 3D grid plus dock, wall, and rack-top positions).
- Attach the labeled placement diagram and the calibration certificates.
- Keep the logger IDs identical across the diagram, this table, and the data file.