clipped
One other thing, the glass door is actually 4 separate pieces of glass
with 1/4" or so of space between each piece. Maybe when the fire gets
real hot, the differential heating caused by the sucking in of room air
through that crack causes local low temperatures near the spaces and
thermally stresses the glass too much?

cj
I would have to re-take physics to answer that one, and I didn't do that
well the first time )