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Tablets & Capsules May 2020 27 material was a commonly used, very fine-grained, dusty naproxen-lactose mixture that is well-suited for such tests because of its texture. The proposed system design called for the transported material to be located in an intermedi- ate bulk container (IBC) transport vessel that was docked through a double-flap system on the feed hopper. The pharmaceutical pneumatic vacuum conveyor was in a mobile frame and was connected to an empty IBC by a double-flap valve (Photo 3). The Volkmann team selected several statistically pro- cess-relevant measuring points for the test and placed the permitted air sensors with test filters for these measuring sequences within the test environment. The air sensors primarily record the fugitive dust content in the direct surroundings of the measurement points, while the per- son-related measuring point displays the cumulative, average burden of dust an operator will experience. The testing operator supervised the process during the mea- suring and changed the filled and emptied IBCs. The conveying process was performed three times for a repre- sentative result, and each individual process was mea- sured separately. The measurements themselves were completed by special compact filter systems that were perfused by a defined amount of air with the aid of a small vacuum generator. Conclusion: Particle concentration measurement occurred not only during the conveying process exclu- sively in the IBC change but also during the cleaning and subsequent disassembly of the vacuum conveyor. The evaluation of the particle measurements in the laboratory yielded that emissions were within the design limit of less than 1 µg/m 3 in all three process steps, indicating that containers and uses a manual suction lance connected to the vacuum conveyor to transfer the ingredients into the vacuum receiver in the adjacent filling compartment. From there, the transferred ingredients are emptied into the docked container via the double-flap valve. The con- tainer is situated on a weighing system to ensure that the required amount of each ingredient is filled. The emptied containers of the hazardous active ingredients are fed through the side walls via foil ports. Harmless excipients, held in containers outside the unit, are also sucked into the vacuum receiver through a second suction lance and port to complete the operation. Conclusion: The entire containment system fulfilled the OEB 4 requirement during filling and subsequent WIP cleaning and was suitable for dust-explosive pow- ders in conformance with ATEX standards. Example 2: High-containment material transfer between processing steps Objective: A classic pharmaceutical application for vacuum conveying is transferring material from a fluid- ized-bed granulator to a downstream sieve mill. In this example, another global pharmaceutical client required such a system with OEB 5 containment (less than 1 µg/ m 3 ) to eliminate any risk to the employees or environ- ment. For perspective, this dust concentration is akin to one six-hundredth portion of a small grain of sugar weighing approximately 0.6 milligram appearing in 1 cubic meter of air during an 8-hour timespan. This assignment required a sealed and closed process without an isolator as protective cover and required all material- contact surfaces to be fully cleanable within the manufac- turer's customized WIP process. This meant that the entire surface in contact with the material, including the ports to the other process facilities in the closed proce- dure, needed to be WIP. In the manufacturer's WIP process, the first step is to flood the entire facility with water, paying particular attention to the contaminated conveyor hoses and pro- cess lines. Wetting the material contact surfaces serves to prewash the vacuum receiver, the filters, and the valve. Once this initial cleaning is complete, the intensive cleaning begins, with rotating nozzles repeatedly wash- ing the stainless-steel primary filter as well as the vacuum hose exiting the primary filter and a secondary filter, which may also be contaminated. Solution: To fulfill these high demands, the manufac- turer selected a Type 316L stainless-steel pharmaceutical pneumatic vacuum conveyor sized for the application. The conveyor was further developed and augmented with a HEPA 14 secondary filter level and suitable isola- tion valves. The conveyor's one-piece, gap-free vessel design lent itself readily to WIP. Process: To verify that the vacuum conveyor met the OEB 5 requirement, the emitted particles needed to be measured. To accomplish this, the chosen conveyor was tested in a prepared clean room under conditions compa- rable to the actual production environment. The test Photo 3: OEB 5 containment was verified in prepared clean room, with the vacuum conveyor mounted in a mobile frame and connected to an empty intermediate bulk container by a double- flap valve.