This paper compares the practice of dilution ventilation (DILVENT), which ideally requires perfect mixing, with displacement ventilation (DISPVENT), which involves fresh air displacing contaminated air without mixing. Keeping DILVENT as a reference the approach of intervention was used to estimate the potential of DISPVENT for improving environmental conditions in a garment sewing plant. Air exchange efficiency of DILVENT came to 49%. DISPVENT improved the efficiency lo a level of 57%. At workstation level DISPVENT improved air renewal by a factor of 1 .3.
This report presents the results of a study on the efficiency of residential duct cleaning. The study was performed In 33 houses and describes the results of measuring duct flows, fan amperage, dust, and micro-organisms before and after duct cleaning. The study concludes that there were no significant improvements in duct flows, fan amperage, duct airborne dust, house airborne dust, or supply duct dust levels. Only dust concentrations in the return ducts and the concentrations in airborne micro-organisms have significantly improved after the duct cleaning.
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