Retrofitting Fume Hoods And Meeting USP 797 Guildelines
If your line of work has you involved in pharmaceutical laboratory construction or retrofitting, chances are very good that the topic of conversation has, at some recent point, turned to USP 797, a set of guidelines for preparing prescription drugs. While the pharmaceutical policies laid out in USP 797 act solely as a guide, these standards are rapidly being adopted by a growing number of state regulatory bodies and many of the policies spelled out in the chapter are quickly becoming law.
“While the USP 797 public standard hasn’t changed since 2008, recent events such as the 2012 meningitis outbreak that was traced back to contamination at a well-known compounding laboratory, has drawn renewed attention to the standards,” said Nils Hagen-Frederiksen, director of communications, U.S. Pharmacopeia. “As a result, many states have begun to adopt USP 797 into their regulatory code.”
Pharmacies across the country are working against the clock to adequately fulfill USP 797 guidelines. For some, this has meant the design and construction of totally new facilities.
“There are two main goals of USP 797,” said John Villani, vice president, Grumman/Butkas Associates, “first, to keep the clinical staff safe while preparing the medications, and second, to ensure the health and well being of the patients taking the medications. With our project at one major medical center, this meant ensuring that the compound rooms where the pharmaceuticals were actually prepared, met USP 797 guidelines for proper exhaust.”
Today’s pharmaceutical compound rooms are designed to ensure that contaminants never enter the rooms where the medicines are mixed and that airborne matter inside the rooms is properly exhausted. Compound rooms also typically include one or more fume hoods – stand-alone, self-enclosed workstations where the chemicals are actually mixed. These too must be properly exhausted to ensure worker safety. USP 797 includes specific guidelines regarding the proper exhaust of both the compound rooms and the individual fume hoods.
“As in many cases, the administrators at a Chicago-area medical center were looking to comply with USP 797 in as efficient and economically feasible way as possible,” said Villani. “To accomplish this, three newly constructed chemo-compound rooms located in the medical facility’s basement were connected to an existing vertical riser that spanned the five stories of the building. The riser was connected at the top to a large roof-top exhaust fan.”
Once the new rooms were connected to the existing ductwork, testing revealed unacceptable levels of duct leakage. This resulted in insufficient exhaust for USP 797 compliance. To meet the guidelines, hospital administrators were looking at having to construct a completely new exhaust system – something that would have been timely and cost prohibitive.
“At first glance, the existing duct system was inaccessible and therefore impossible to repair,” said Vilani. On the other hand, building a completely new duct system was not in the cards. Fortunately, someone on the team heard about an innovative new approach to duct sealing that worked from the inside of the ducts to locate and seal leaks.”
This inside-out approach to duct sealing offered Villani’s team of engineers one critical advantage – it made repairing the existing ductwork a fast and simple project. Applied under pressure to the interior of the ductwork, the aerosol-based technology is drawn directly to each leak, eliminating the need for workers to visually locate the individual breaches. And since the sealant is blown throughout the entire duct system, locating and treating even the most inaccessible portions of the ductwork is simple. There is no need to tear down walls or unwrap insulation to access and seal individual holes. The aerosol-sealing process takes care of all the work from the inside.
First, the roof-top fan was removed, and a long flexible tube was attached so that the sealant could be blown throughout the inside of the shaft. The vents in the compound rooms and the fume hoods were blocked so that any air entering the duct system could only escape through leaks. The duct sealing team turned on their computerized equipment and watched as microscopic particles of sealant were blown into the pressurized shaft and drawn to the leaks.
“You could tell it was working,” said Jim Manako, project manager, Ragnar Benson Construction. “We watched a graph on the computer monitor that indicated the current rate of leakage. As soon as the sealant entered the inside of the ductwork, you could see the graph begin to dip.”
It took just half a day to seal the old leaky ductwork. Testing showed that 96% of the leaks were sealed – from a loss of 400 cubic feet per minute (CFM), down to 20 CFM – well within USP 797 guidelines.
State-by-state, the acceptance of USP 797 as a regulatory requirement is on the rise, and as a result, word of aerosol duct sealing’s unique capabilities is spreading as well.
“The increased adoption of USP 797 is most likely due to stepped-up efforts by states to ensure safe practices are being followed in the various institutions where pharmaceutical compounding takes place,” said Hagen-Frederiksen. “This can include a full range of facilities from hospitals and university laboratories, to cancer treatment centers and even pediatric facilities and veterinarian hospitals.”
“This new approach to duct sealing often presents the only viable option available to these institutions,” said Vilanni, “and it was the only solution that would allow us to meet USP 797 specifications in time and within budget.”
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