1. Mapping before use

GDP requires temperature mapping of warehouses before they are placed into use. Mapping must identify hot and cold spots, validate environmental controls, and justify permanent monitoring placement. WHO TRS 961 and EU GDP both state that mapping is mandatory before first use and must reflect representative operating conditions.

Inspector insight: Authorities expect mapping under representative conditions with RP sign-off. Seasonal mapping is required if ambient variation impacts the warehouse.

Also read: GDP temperature mapping guidelines

2. Risk-based requalification

Warehouses must be re-mapped on a risk basis. Triggers include layout changes, HVAC modifications, operational shifts, or monitoring trends showing instability. There is no fixed interval, but inspectors expect a documented policy consistent with ISPE GPG and MHRA guidance.

Real-world example: After replacing an air handling unit, a facility re-mapped only zones historically prone to variability. The RP approved the limited scope based on continuous monitoring data.

Also see: The key components of GxP compliance

3. Continuous monitoring

Permanent monitoring devices must be installed at the hot and cold spots identified during mapping. Devices must be calibrated, qualified, and records must be retained throughout the product shelf life. EMA and WHO guidance both emphasize that monitoring placement must be justified by mapping data.

Inspector insight: Inspectors often ask to see the monitoring plan linked directly to mapping results.

Also read: Guide: GDP monitoring requirements

4. Alarm configuration and response

Alarm thresholds must be set according to labelled storage ranges and mapping results. SOPs must define escalation, ownership, and CAPA workflows. Both EU GDP and 21 CFR Part 11 require that alarm data be secure, reviewed, and linked to deviation handling.

Real-world example: A warehouse near a loading dock applied a 10-minute delay on alarms to prevent nuisance notifications. The change was documented, justified, and approved by the RP.

Inspector insight: Alarm justification and RP approval are frequent inspection focus points.

5. Calibration and traceability

Monitoring devices must be calibrated at defined intervals, with ISO 17025 traceability. Calibration certificates must be linked to each device in use and available during inspections. Regulators often cite missing or expired calibration certificates as a deficiency.

Inspector insight: Missing calibration certificates are one of the most common GDP findings.

Also read: On-the-wall calibration: How does it work?

6. SOPs and documentation

GDP requires written SOPs for all critical processes, including mapping, monitoring, alarm handling, calibration, and deviation management. Records must be accurate, complete, and readily retrievable for audits. EMA and MHRA emphasize that SOPs must assign ownership and review responsibilities.

Inspector insight: Inspectors frequently request deviation logs and CAPA records to verify effective quality systems.

7. Audit readiness

Warehouses must maintain documentation and reporting systems that demonstrate compliance at any time. This includes deviation handling, monitoring records, calibration certificates, and SOPs. Best practice is to maintain a monitoring placement matrix and calibration index that can be presented quickly to inspectors.

Real-world example: A logistics operator avoided a major observation when it presented a complete monitoring placement matrix, calibration log, and deviation records within minutes of an inspector’s request.

Inspector insight: Audit readiness is judged by how quickly and completely records can be retrieved.

Also read: Good distribution practice (GDP): Guidelines for pharma logistics

References and further reading

• EU GDP guideline (2013/C 343/01): Monitoring and records requirements.
• Annex 11 (EU): Electronic records and audit trails.
• 21 CFR Part 11 (US): Electronic signatures and data integrity. See also 21 CFR Part 11 explained.
• WHO TRS 961: Guidance on monitoring in storage and transport.