Commercial & Industrial
Explosion Proof Lighting Calculator
Determine the correct hazardous location fixture rating (NEC Class/Division/Group) for industrial environments with flammable gases, vapors, or dusts — and calculate how many fixtures you need.
⚠ Safety Notice: This calculator is a planning tool only. Hazardous location installations must be designed and approved by a licensed electrical engineer and inspected per NEC Article 500–506. Always verify the final classification with a qualified professional.
Hazard Classification
NEC Class — type of hazardous material present
Division — probability of hazard being present
Material Group
Room & Lighting Inputs
Room Area  2000 sq ft
Ceiling Height  20 ft
Target Footcandles  30 fc
Fixture Lumens  5000 lm
Zone Diagram
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NEC Rating
Required Minimum
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Fixtures
Required
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Temp Class
Max Surface Temp
Required Fixture Specification
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Class I Group Reference
Group AAcetylene (most severe)
Group BHydrogen, butadiene
Group CEthylene, cyclopropane
Group DPropane, gasoline, butane
Class II Group Reference
Group EMetal dusts (Al, Mg)
Group FCarbon black, coal dust
Group GGrain, flour, starch, plastic
Class IIIFibers — no group required
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The calculators and tools on LightingCalc.lighting are provided for general guidance and informational purposes only. Results are estimates based on standard formulas and the values you enter — they do not constitute professional engineering, electrical, or architectural advice. Always verify calculations with a qualified professional before making decisions for any safety-critical, code-compliance, or commercial application. LightingCalc.lighting makes no representations or warranties as to the accuracy or completeness of any result, and accepts no liability for errors, omissions, or any outcomes arising from reliance on this information.