Hot work on a steam condenser ignites a titanium tube bundle fire: A case history

Abstract

AbstractThe flammability of titanium chips, fines, and powders is widely recognized. Titanium alloy tubing is much more difficult to ignite. However, as this paper describes, titanium tubing in heat exchangers is subject to ignition as a result of hot work operations. Explosions can follow if water is applied to the burning titanium.A fire consumed the titanium tube bundle of a steam turbine condenser during demolition work in a decommissioned power plant. The titanium fire is believed to have initiated by contact with hot steel slag from torch cutting which was being conducted to remove sections of the steel condenser casing above the tube bundle. The approximately 25 ft long bundle was essentially consumed end‐to‐end, including the tube sheets.A fire watch had been stationed as part of the plant's Hot Work Permit System, but the initial phase of the fire was obscured from view. Workers reported a bright yellow flame coming from inside the south end of the tube bundle. Water application on the fire 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 incident.Loss lessons from this and two similar titanium heat exchanger fires are presented. The initiating conditions for these fires are discussed.