BY JEFFREY A. HARWELL Large-loss fires involving fully sprinklered buildings are extremely rare these days. Consequently, when the large-loss fire described below occurred in February 2011 at a warehouse with high piled storage in the Regency I Warehouse in Grand Prairie, Texas, the nation's interest was piqued. What especially caused the fire service and related industries to ask what went wrong was the fact that this warehouse had been equipped with an Early Suppression Fast Response (ESFR) sprinkler system. At the time, this fire was thought to be the first large-loss fire involving the new ESFR technology. THE BUILDING A building permit for the Regency I Warehouse was obtained in earl...