Rosedale Products' Versatile Basket Filters ... - Filtration News

Air | FiltrationThe Evolution of Air Filtration TestMethods Employed in QA/QC ProgramsBy Christina Clark, Jeff Smith, Terry Williamson and John McKenna, ETS, Inc.ETS team reviewing bag specifications and QA/QC Plan.The first time ETS was commissionedto conduct a comprehensive,in depth, QualityAssurance/Quality Control (QA/QC)program on air filtration media andbags was in the 1970s. A very largeelectric utility facility elected to employa reverse air baghouse using wovenfiberglass bags. The test program includedmeasuring permeability andstrength. Ironically, filtration performancewas not included. While there existedASTM International (formerlyknown as the American Society forTesting and Materials) test methods for30 • June 2013 • www.filtnews.compermeability and strength, no generallyaccepted method had been publishedfor filtration performance testing at thattime and it would be decades beforeone evolved. The utility baghouse wasthe largest baghouse system built up tothat time and therefore there was agreat deal at stake for both the utilityand the baghouse vendor. Given thelarge number of bags involved and theamount of fabric required, the fabricwas produced and coated in separatebatches. The QA/QC program identifieda bad coating batch in the middleof production. This batch was then rejectedand replaced. The cost of theQA/QC program was a only a few percentof the bag set cost, thus the baghousevendor and the utility found thisprogram well worth including.The tightening of the air emissioncodes and the focus on fine particleshave driven the need for inclusion offiltration performance testing as an essentialpart of any fabric filter QA/QCprogram. In the 1990s the USA EPA developeda filtration test method basedon a test method developed in Germany.1 Subsequently, ASTM and theInternational Organization for Stan-