Question: My problem is small bits of hot ash exiting the vent pipe during a fire. Answer: I've seen this with Pellet Stoves and it doesn't seem to be a problem. The bits are so small and I don't think they could start a fire as long as the installation meets the factory specs. Some of the pellet caps have a screening in them, but this is fairly large and would still let some of these sparks through. Check it out with your dealer and manufacturer...but I think it's OK.