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by David S. Allen, Allen Consulting, LLC with photos by Brian Hagopian, Mar Cor Purification

On Tuesday, February 23rd the Boston Area Chapter presented an educational program at the Royal Sonesta Hotel in Cambridge. Our presenters were Peter Harris, Director of Operations for B & V Testing and Larry Zanko, Project Manager with Steris Corporation. Each brought a career's worth of expertise to the evening's topic. Peter and the decontamination specialists at B & V Testing have executed hundreds of gaseous space decontaminations at life science facilities ranging from small pilot plants to full aseptic production and fill/finish facilities and have been using Vaporized Hydrogen Peroxide (VHP) technology since 2005. As a Project Manager for Steris, Larry collaborates with customers in the pharmaceutical and research industries to engineer application-specific solutions. His technical expertise includes extensive knowledge of multiple-effect water stills, pure steam generators, steam sterilizers, COP washing systems, and VHP generators.

After a brief introduction by David Allen, the evening's event manager from the Educational Program Committee, Peter took us through the history of VHP sterilization, a typical VHP process, effectiveness and equipment compatibility data, and two application case studies.

Educational Program Committee Member & Meeting Manager David Allen (left) with speakers Peter Harris (center) and Larry Zanko (right).

He explained that VHP sterilization was introduced in 1991 by the American Sterilizer Company for use in isolators where it is still the most popular method of sterilization. Since that time, the use of VHP has expanded to include room decontamination for both new facilities and remediation. It is also used in aseptic process environments and for product sterilization.

Peter next walked us through a typical VHP decontamination cycle with the phases being dehumidification, conditioning, decontamination and aeration. We learned that one of the appealing attributes of VHP is that when the process is finished, all that is left is water and oxygen. There are no toxic residues. He then went on to explain the extensive testing that has proven the efficacy of VHP against bacteria, viruses, molds and yeasts. There are prescriptive doses for contaminants and various ways to confirm the dosage that has been delivered including electronic sensors and chemical test strips.

Peter concluded by explaining the steps in planning and carrying out a VHP decontamination project and told us the stories of two actual decontamination procedures. The first case was the emergency sterilization of a 240,000 square foot pharmaceutical manufacturing facility to remedy a contamination. The space included bioreactor rooms and the VHP was injected directly into 65 rooms and the air handling systems. The second case was an 84,000 cubic foot pilot production facility with 28 rooms that were sterilized as a routine preventive measure during a facility shut down.

After a short break, Larry took the stage and described the different types of equipment available for VHP applications: modular and portable. He explained that for facilities of less than 10,000 cubic feet that do not require routine sterilization, portable equipment is typically used. Portable equipment requires the use of fans to ventilate the room after decontamination. For spaces up to 80,000 cubic feet, fixed modular equipment can be installed. This is particularly valuable for rooms that require frequent, routine decontamination and for rooms that are isolated and could be compromised by bringing portable equipment into the space. Modular systems are typically integrated with the HVAC system.

Larry then went on to describe several aspects of modular installations. Since VHP passes through HEPA filters and sterilizes them, they need not be removed for decontamination. He also told us about the two cycles, single-pass and recirculating. In single-pass systems, the decontamination phase occurs while the HVAC system is shut down; in a recirculating system, the HVAC system continues to circulate air. In both cases, the HVAC is used to exhaust the air during the aeration phase. In concluding, Larry summarized the benefits of VHP compared to other sterilization techniques that can leave toxic residues.

The presentations were followed by a flurry of questions from the audience, the answers to which helped to further round out the presentations. A final thank you to Larry and Peter for their excellent technical presentations and to Claire Fritz of Steris whose behind-the-scenes efforts helped to organize the joint presentation between Steris and B&V.