A compounding cleanroom gets a wireless system to monitor temperature,
humidity, pressure, and particles — and maintain compliance.
Chesterland, Ohio I n order to stay compliant with regulations, cleanroom man- agers 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 unauthor-
Equipment for continual monitoring
ized parties to be unlikely, they were concerned about the pos-
sibility of users inadvertently modifying or deleting data, so they
knew that their prospective system’s software would need to
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.
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.
Delphin Technology’s TopMessage Data Acquisition and Control System