Inspection Detail

Inspection: 1811157 - Lockheed California Company

Inspection Information - Office: Region 09; San Francisco

Investigation Summary

THE THREE EMPLOYEES WERE PREPARING A UNIT TESTING DEVICE CONSISTING OF FUEL COMPARTMENTS WITH INTERNAL FUEL PIPING AND SWITCHING DEVICES. THE COMPARTMENTS CONTAINED RESIDUAL JP-4 JET FUEL, WITH AN LEL OF .8% BY VOLUME AND A FLASH POINT OF -4% F. WRITTEN SOP INSTRUCTIONS PRESCRIBED CLEANING AND VENTING TO REDUCE THE VAPORS TO LESS THAN 10% OF THE LEL. GAS FREEING WAS TO BE DONE AFTER ALL ELECTRICAL POWER AND ALL OTHER SOURCES OF IGNITION WERE REMOVED FROM THE UNIT AND SURROUNDING AREA. NO SYNTHETIC CLOTHING MATERIALS WAS TO BE ALLOWED IN THE WORK AREA. ALSO, CHECK LISTS WERE TO BE COMPLETED FOR ALL THE ABOVE, PLUS TESTING WAS TO BE ACCOMPLISHED WITH A COMBUSTIBLE GAS INDICATOR. WORK WAS PERMITTED TO PROCEED WITHOUT GAS FREEING AND TESTING, AND WITHOUT A POSITIVE DETERMINATION THAT ALL ELECTRICAL CIRCUITS WERE DEENERGIZED AND THAT WORKERS WERE NOT WEARING SYNTHETIC TYPE CLOTHING. THE RELATIVE HUMIDITY WAS 23% AT 80 DEGREES FARENHEIT. A SPARK, MOST LIKELY FROM AN ELECTRICAL CIRCUIT (28 VOLTS) TO A PRESSURE SWITCH, PROBABLY IGNITED THE VAPORS. CAUSE OF ACCIDENT: SOP WAS NOT FOLLOWED OR ENFORCED.

Keywords: ELECTRIC ARC, FLAMMABLE VAPORS, VENTING, CLEANING, EXPLOSION, JET FUEL, TANK