Facilities grappling with USP 797 and USP 800 verify their compliance through cleanroom certification. Airflow measurements, leakage testing, and environment measurements (differential pressure, temperature, and relative humidity) are documented and certified. Non-cGMP certified facilities do not generally have ongoing monitoring of their cleanroom space and have difficulties identifying when intervention is required. The challenge for facility managers is how to monitor their day-to-day operations without disrupting the facility or adding significant cost.

Existing cleanrooms have numerous non-invasive options to supplement their facility with monitoring products. New construction will find “combined” control systems for FFU operation/optimization containing environment monitoring to be cost-effective and convenient solutions to monitoring their facility and optimizing air-management.

Existing facility considerations

Typical 3-room USP 800 or USP 797 compliant floor plan. Image: Courtesy of Terra Universal Inc.Existing cleanrooms complying with USP 797 or USP 800 were generally not designed with centralized cleanroom monitoring. Small cleanrooms also didn’t invest in smart FFU centralized air flow controls. Air-exchanges (ISO 7 or ISO 8 levels) or exhaust (for negative pressure as specified for USP 800 hazardous material compounding) are manually adjusted by the installer/certifier to meet compliance.

Without airflow monitoring the easiest way to monitor cleanroom airflow changes/stability is by monitoring the differential pressure maintained between the controlled environments and their surrounding space (a failed or compromised FFU will materially impact the differential pressure in a small cleanroom). Significant changes in differential pressure can point to filter blockages and/or FFU failures.

Most cleanrooms follow a simple floor-plan layout with compounding or mixing rooms connected to an ante-room. For cleanrooms where monitoring systems were not designed-in, solutions are available to assist in the process: monitor the key parameters — differential pressure, temperature, RH; notify and alarm if these parameters change significantly; capture the data for reporting purposes (data log).

Simplest solutions are stand-alone sensors that can be mounted inside the cleanrooms that display their value so the cleanroom staff can manually check the values, determine if the values have changes significantly (manual notification), and jot them in a log for future reference (data log). 

Moving to more automated processes, sensor manufacturers provide solutions that have connectivity (i.e., BACNET or wireless) that allow the sensor data to be transmitted to a central PC for processing and documentation. Notification of parameter swings (alarm/notification) can be accommodated by some sensors and/or left to the PC consolidation to address. Centralized kits provide sensors and also fulfill the functions of monitoring, alarming, and notification.

Facility managers can easily find non-invasive solutions that allow real-time monitoring solutions to supplement compliance between certifier visits. From low-cost sensors that require manual daily activity to centralized monitoring systems, facility managers can find cost-effective options. Finding the right mix of sensor data, auto-alarming and/or notification, and documentation are the key determinants at different price points as all solutions can provide adequate support to supplement day-to-day monitoring.

New construction

New USP 797 and USP 800 construction have the benefit of installing cost-effective non-cGMP monitoring systems for their cleanroom space. Additionally, network-capable FFU units provide for centralized monitoring and control of air-flow and cleanroom stability. When monitoring the FFU performance and differential pressure between rooms, the FFU units can be set to optimize the air-exchange demand and the differential pressure requirements. The positive pressure requirement for non-hazardous compounding and negative differential pressure required by hazardous material processing relies on air-flow adjustments that can be efficiently addressed through FFU centralized controls. As USP guidelines consider adjustments to air-exchange requirements for compliance, systems can be easily adjusted to match the changing landscape. Facility managers may opt for ECM based FFU units that save energy and comply with California TITLE 24 specifications that specify EC motors/fans for <1HP rating (typical of FFU specifications).

New construction cleanroom monitoring and control architecture. Embedded cleanroom photo: Courtesy of Terra Universal Inc.Using smart-motor (or smart-motorized) impellers that rely on EC motor control, many cleanrooms use FFU control systems to save energy and improve cleanroom filter lifetimes. Both AC and EC based FFU control systems are preferred to allow rapid balancing of a cleanroom, identification of faulty FFU operation, and improve energy consumption.

The cost and complexity of small cleanroom management is reduced by addressing both needs on a common system. Coupling the FFU controls with sensors creates easy-to-install packages that meet most facility managers needs for cost and performance. HMI interface systems provide comprehensive facility management that optimize cleanroom performance, monitor critical performance factors, alarm and notify when the facility requires adjustment/attention and captures information.


Compliance with USP 797 and USP 800 will require ongoing certification updates — often twice annually — to existing facilities. Easing the burden of determining when the cleanroom needs rebalancing or adjustments, facility managers can install non-invasive sensors to raise their awareness when their facility is bordering on non-compliance.

Existing facility solutions range from simple individual sensors mounted in each room to centralized sensor monitoring systems that capture the measurements, notify the facility when the cleanroom is compromised, and stores data for documentation and reference.

New facility construction benefits from centralized systems that provide FFU control, exhaust adjustments, and environment monitoring that provide automatic notification (of unexpected variances) and data storage. Cost-effective monitoring/control systems allow for airflow (FFU) optimization, exhaust adjustment that eases balancing and certification and provides added benefits of reducing energy consumption and extending filter media life. These same systems address sensor measurement, alarm notification, and data storage useful in monitoring cleanroom performance stability in-between certification visits.

Howard Abramowitz is President and founder of AirCare Automation Inc. Howard is actively involved in the monitoring and control of cleanroom facilities with a focus on energy efficiency and simplifying monitoring and compliance. He has many years of experience in power management and controls systems design.; 

This article appeared in the March/April 2016 issue of
Controlled Environments.