While maintaining the same level of quality and safety, is it possible to optimize the energy efficiency of a ZAC ?

Context
The cleanroom (ZAC) of our establishment, equipped with positive-pressure isolators, operates continuously regardless of activity, resulting in high energy consumption.
Under the tertiary-sector decree, a reduced-energy mode during periods of inactivity offers ecological and economic optimization potential.

Objectives
To assess the feasibility of a reduced mode approach in the ZAC and its impact on energy efficiency while maintaining the same level of quality and safety. A secondary objective was to identify energy-saving measures implemented in these zones.

Materials and methods
A microbiological profile of the ZAC was established using air sampling with an air sampler (n=3 during activity, n=3 at rest), surface sampling using contact agar (5 points after each air sampling), and sedimentation (4 hours, n=3 during activity). The most recent qualification (<1 year) was used as the reference for particulate quantification.
The reduced mode consists of reducing the airflow during periods of inactivity.
Microbiological measurements are then repeated using the same protocol, followed by requalification by an external service provider.
Finally, a questionnaire was distributed by GERPAC to address the second objective.

Results
All samples complied with microbiological requirements. The reduced mode will be automatically activated from 6:00 PM to 1:00 PM (85.1% of the week), with the possibility of manually switching back to active mode, allowing an estimated 40% reduction in energy consumption through reduced treatment of fresh air.
Of the 21 responding facilities, 14 had considered reducing their energy consumption. Among the 21 facilities, 6 had implemented measures, 12 had not initiated any measures, and 3 were considering options. Reported measures included temperature optimization (n=3), reduced air renewal (n=2), humidity adjustment (n=1), and putting isolators into standby mode (n=1).
Among the 6 facilities that implemented measures, 3 were university hospitals (CHU) and 3 were general hospitals (CH). The CHU (30,000 to 70,000 preparations/year, hoods and isolators used for anticancer drugs, non-toxic sterile preparations, parenteral nutrition, and advanced therapy medicinal products (ATMPs)) primarily optimized temperature and humidity and reduced air renewal. The CH (<30,000 preparations/year; isolators for anticancer drugs) placed isolators in standby mode, reduced air renewal, and optimized temperature.

Conclusion
Reducing ventilation airflow rates could significantly decrease energy consumption while maintaining air quality in compliance with requirements. These results remain estimates and require further work and additional studies.

Keywords: Economics, Ventilation, Pharmaceutical technology