HOT WORK ON A STEAM CONDENSER IGNITES A TITANIUM TUBE BUNDLE FIRE - ACASE-HISTORY

The flammability of titanium chips, fines, and powders is widely recog nized. Titanium alloy tubing is much more difficult to ignite. However , as this paper describes, titanium tubing in heat exchangers is subje ct to ignition as a result of hot work operations. Explosions can foll ow if water is applied to the burning titanium. A fire consumed the ti tanium tube bundle of a steam turbine condenser during demolition work in a decommissioned power plant. The titanium fire is believed to hav e initiated by contact with hot steel slag from torch cutting which wa s being conducted to remove sections of the steel condenser casing abo ve the tube bundle. The approximately 25 ft long bundle was essentiall y consumed end-to-end, including the tube sheets. A fire watch had bee n stationed as part of the plant's Hot Work Permit System, but the ini tial phase of the five was obscured from view. Workers reported a brig ht yellow flame coming from inside the south end of the tube bundle. W ater application on the five by workers and the local fire department was followed by explosions within the tube bundle and discharge pipes. Fortunately, no injuries or property damages occurred from this incid ent. Loss lessons from this and two similar titanium heat exchanger fi res are presented. The initiating conditions for these fires are discu ssed.