I recently had a conversation with a chimney sweep that was very much pro 3" combustion air intake pipe. His point of view did make sense especially considering I usually run a box fan in the attic window during summer to keep the heat from the roof down...and if I don't have all the upstairs windows and maybe a few 1st floor windows open I can pull air out the baro. My only concern is that pipe could provide fresh air if a fire started (outside the stoker) in the basement for whatever reason. Two question I have: 1) is there any readily available fire damper for this application? 2) Am I over thinking this because in all likelihood the old single pane window, above the oil tank, would most likely break due to a fire anyway? I know that shutting off a 3" air intake wouldn't keep the whole house from burning down but maybe it could provide a few extra seconds to get out. Thoughts?