Sorry I thought you had said you saw sparks but I went back and read it I was wrong. But still there is enough in that pipe to burn. And if you saw a glow I don't see any way it could be anything but a small fire. Again I doubt it was enough to damage anything just because there was so little fuel. But pretty sure it was a fireI did not see any sparks. Or flames shooting out the top. Just a glow that lasted for maybe 30 seconds to a minute.