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' November 29, 2018 <br /> (1) In which ignitible concentrations of flammable gases,flammable liquid— <br /> produced vapors,or combustible liquid—produced vapors can exist under <br /> normal operating conditions, or <br /> (2) In which ignitible concentrations of such flammable gases,flammable liquid— <br /> produced vapors,or combustible liquids above their flash points may exist <br /> frequently because of repair or maintenance operations or because of leakage, <br /> or <br /> (3) In which breakdown or faulty operation of equipment or processes might <br /> release ignitible concentrations of flammable gases,flammable liquid—produced <br /> vapors,or combustible liquid—produced vapors and might also cause <br /> simultaneous failure of electrical equipment in such a way as to directly cause <br /> the electrical equipment to become a source of ignition <br /> 2017 NEC section 500.5.6.2 defines Class I Division 2 areas as: <br /> (2)Class I,Division 2.A Class I, Division 2 location is a location: <br /> (1) In which volatile flammable gases,flammable liquid—produced vapors,or <br /> combustible liquid—produced vapors are handled, processed,or used, but in <br /> which the liquids,vapors,or gases will normally be confined within closed <br /> containers or closed systems from which they can escape only in case of <br /> accidental rupture or breakdown of such containers or systems or in case of <br /> abnormal operation of equipment, or <br /> (2) In which ignitible concentrations of flammable gases,flammable liquid— <br /> produced vapors, or combustible liquid—produced vapors are normally <br /> prevented by positive mechanical ventilation and which might become <br /> hazardous through failure or abnormal operation of the ventilating equipment, <br /> or <br /> (3)That is adjacent to a Class I, Division 1 location, and to which ignitible <br /> concentrations of flammable gases,flammable liquid—produced vapors, or <br /> combustible liquid—produced vapors above their flash points might occasionally <br /> be communicated unless such communication is prevented by adequate <br /> positive-pressure ventilation from a source of clean air and effective safeguards <br /> against ventilation failure are provided. <br /> Using the hazardous area definitions in lieu of the prescriptive definitions to <br /> manage risk requires accounting for the accuracy of the CFD model, the range of <br /> building conditions, and the range of process conditions that can exist during the <br /> paint process. <br /> Accuracy of the CFD model <br /> Geminus has estimated the accuracy of the CFD model at a factor of 5. <br /> This is discussed in more detail in the CFD analysis report, but in essence <br /> this is the result of potential velocity error (estimated at a worst case factor <br /> of 3) and potential momentary %LEL peaks due to turbulence (estimated <br /> Page 6 of 10 <br />