No modern masonry chimney, reinforced and strapped to the house
as required by code, has failed that we know of in recent
American Earthquakes. Tall and unreinforced In the Northridge
and Loma Prieta quakes in California and the Nisqually quake in
Washington many old chimneys - even tall chimneys - did not
fail. Even near the epicenter, many old and un-reinforced
chimneys were not damaged. The chimneys that did fail were, by
in large, already in poor condition and in need of ordinary
maintenance. Chimneys that served fireplaces and not furnaces
generally faired better. Many of the chimneys that failed were
lined with small metal flues indicating that a gas furnace had
been vented into the chimney, and that probably the chimney had
been damaged by acid flue gas condensation before the lining was
installed. Chimneys that were poorly built to begin with or that
were not maintained were the ones that failed. Again, we found
no modern masonry chimney built to code that failed in any of
the three earthquakes. Excer