Tracking Environmental Data

Stewart Thompson

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In order to stay compliant with regulations, cleanroom managers need to have accurate data on the status of the facility. This means continual assurances that everything is running as it should and being notified when it’s not. An unintended or unexpected event can cause damage, downtime, or worse if not handled in a timely manner. But how can a manager respond unless they have the appropriate tools to monitor the space and alert them if something is not within spec?

Recently, a company in Nashville, Tenn. that stores pharmaceuticals for several manufacturers addressed this issue. Their facility contains two cleanrooms where technicians work to compound different types of chemotherapy drugs which need to be mixed especially for specific patients based on their individual diagnoses and history.

The chemotherapy cleanrooms each measure about 950 ft² and are housed within a larger warehouse which also includes product storage rooms and research areas. Staff members use full cleanroom suits to enter and exit through the airlocked antechambers, while the cleanrooms are equipped with HEPA filters and blower systems in accordance with USP-797 regulations. Additionally, three laser particle counters are installed in each cleanroom to scan the HEPA filters.

To ensure their cleanrooms’ integrity and document best practices, staff continually log extensive environmental data. Each cleanroom’s temperature needs to be maintained at 70°F with a variance of +/- 2°F and a relative humidity of about 50% depending on the drug or product monitored. Within the cleanrooms, staff also have to ensure the minimum .03 in. water column positive air pressure per facility policy in respect to the anteroom environment to ensure that particulate matter is blown outside. This value is continually measured at a pair of differential pressure points located inside and directly outside each cleanroom.

During the selection process for their monitoring system, the staff wanted to go with a wireless setup to monitor differential pressure, temperature, and relative humidity. Technicians also wanted to avoid complications arising from the extensive wiring necessitated by Ethernet systems. Automated alarm functionality was another major priority for the facility — for example, if pouches of these drugs were torn or spilled. Continuous alarm sampling was also requested to alert staff if the blower system failed or the HEPA filters became blocked from long use, either of which would quickly compromise the cleanrooms and product safety.

While the staff considered system intrusion from unauthorized parties to be unlikely, they were concerned about the possibility of users inadvertently modifying or deleting data, so they knew that their prospective system’s software would need to prevent this.

Equipment for continual monitoring

After a review of product and equipment options, the staff selected a system that addressed their needs. The equipment included four wireless temperature and humidity data loggers, two in each cleanroom, mounted on wall brackets. The data loggers have an external sensor that measures and records both temperature and humidity at a temperature range of 32°F to 131°F, and relative humidity from 10% to 95% RH.

To monitor differential pressure, four wireless voltage data loggers were connected to four commercial pressure transducers at two points just inside and outside the cleanrooms. The 0 to 5V outputs of these sensors were connected to the loggers along with current cables. Meanwhile, installers ran tubes to the inside and outside of each cleanroom to begin wirelessly recording the differential pressure. In the event of an accident, data loggers are housed in water-resistant cases and protected by a rugged design.


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Two wireless USB stations, one in each cleanroom, were also installed to automatically collect the pressure, temperature, and humidity data from the loggers. The base stations’ integrated repeater mode allows users to configure the devices to function as a daisy-chainable repeater. This extends communication range and eliminates wireless range problems. If necessary, the USB-connected base stations can also connect directly to a PC through their integrated USB ports. Wireless range for the data loggers extends to a distance of up to 100 meters in the unobstructed chambers.

After quick configuration and setup, each logger now automatically records and transmits readings to the wireless base stations over the Internet, and each can also store readings to its 16,000 point memory.

The base stations also include software which is connected to the facility’s network and supports data collection functions including real-time monitoring and scheduled downloads. The software also allows users to print data and create text files, tables, and graphs of the data collected by the remote units.

Users can flexibly set sample rates on the data loggers to measure at frequencies from every second up to every hour for up to 64 units in one group. The data loggers are set to take a reading and perform an alarm check every ten minutes.

Alarms, alerts, and information retrieval

The wireless base stations also send out automated alarm emails. Users have configured warning settings so that whenever any of the environmental data goes outside the limits, email alarms are sent out to all specified addresses. Staff receive immediate alerts on their mobile devices and pagers which greatly decreases response times. Up to 50 addresses can receive these automated alerts.

The wireless base stations transmit all logger data to the manufacturer’s dedicated Internet server for cloud-based retrieval. This service lets users remotely access all current readings and share recorded data from their browsers.

The online service is regularly accessed via smartphone by an onsite worker who periodically checks it for irregularities. Additionally, offsite IT support can also access the data in the event of emergencies or to zero in on problems. The service also prevents accidental alteration or deletion of the data by assigning user IDs.

Data and compliance

The facility’s cleanroom integrity benefits in several key ways following installation of the wireless system. The system’s communication capability spares technicians the trouble of installing wiring or having to travel to gather the readings manually. The wireless data loggers help staff maintain the cleanrooms’ differential pressure, temperature, and relative humidity via continual monitoring and alarming. The data loggers automatically record all these values and then transmit their measurements to the wireless base stations in each cleanroom.

Using the base station to aggregate the data, staff can view and download the real-time numbers anytime from anywhere, and receive an alert when vital parameters suddenly go out of specification, eliminating delays. Meanwhile, the off-site service keeps all the online data secure from alteration by unauthorized users.

Due to faster response times and complete data overview, the facility’s cleanrooms are now fully compliant with USP-797 regulations and the facility has online documentation of its best practices. The warehouse has since expanded from the initial eight data loggers to monitor products in adjacent storage rooms.