While we're on the topic of filters,

Does anyone have any rough numbers for pressure loss/particle size
across the various types of filters:
fibreglass mat, paper, foam, foam and oil, other?

Another question would be what size particulate are we concerned with?
big and solid is obviously bad, duststorms also bad, do we need to go to
electrostatic HEPA dust filters?

Has anyone used large flat panel furnace filters?


Thanks
Cary

Easy way to compare them on a given area basis is hold them up to the
intake pipe on a vacuum cleaner and measure the pressure drop in the vacuum cleaners
with a water manometer.