Summarises the work performed in ASHRAE RP-531 and presents a number of issues that are not resolved concerning the use of industrial dust collectors in recirculation systems. Outlines parametric studies of dust collectors and work on other system components, such as hoods and sensors. States that these additional studies would help manufacturers and system designers construct and operate industrial air cleaning systems that meet applicable OSHA and NIOSH guidelines with a minimum amount of energy use and operating cost.

KEYWORDS: Industrial, factories, dust separators, air, recirculating, air cleaning, air filters, dust.