Can The GMP Cleanroom’s HVAC System Be Turned Off At Night?
Today we'll discuss whether the cleanroom’s HVAC system can be turned off at night or not in use to save energy.
We generally do not recommend completely shutting down the ventilation system. Facilities, pressure differentials, microorganisms—everything could potentially spiral out of control during this period, making the subsequent restoration of GMP compliance extremely complex. However, the frequency of ventilation can be reduced.For this purpose the following points must be observed:
Reducing the ventilation system frequency can only be done to a specified extent to ensure that specific limits are maintained within the cleanroom in a particular case. In each case, these limits, both in the operating state and in the reduced frequency state, must be defined, including permissible minimum and maximum values, such as cleanroom class level (particle number and associated particle size), product-specific values (temperature, relative humidity), and differential pressure conditions (pressure difference between rooms). Note that the values chosen in the reduced frequency mode must ensure that the facility achieves GMP compliance within a specified timeframe before production begins.
Furthermore, it is recommended to install a separate cleanroom monitoring system to continuously monitor and record the aforementioned cleanroom specific parameters. This allows conditions in the area of concern to be monitored and recorded at any time. If deviations occur (limits are reached), appropriate adjustments can be made, depending on the availability of measurement and ventilation system control technologies in the case.
When reducing fan frequency, care must be taken to ensure there are no unintended external disturbances, such as personnel entry. Appropriate personnel access control is recommended in such cases. If an electronic lock system is used, access permissions can be linked to the aforementioned time schedule and to an independent cleanroom monitoring system. Therefore, access authorization must meet predetermined requirements.
In principle, both states must be confirmed first, and then periodically reconfirmed. Typically, measurements under normal operating conditions, such as recovery time measurements in the event of complete equipment failure, are mandatory. If a cleanroom monitoring system exists and the procedure is validated, further measurements are generally not required—as mentioned above—after restarting operation with reduced ventilation frequency. Special attention should be paid to the restart procedure because, for example, a brief reversal of airflow direction may occur.
Suzhou Pharma Machinery Co.,Ltd.
2026/01/26
Icey
