- The North American NFPA approach involves less calculations and is easierto be used
- If compared with the IEC approach, it leads to a bigger estimation of the Zone/Division extent, especially for low pressures in the containment system (gas releases)
- A bigger estimation of the Zone/Division extent often means higher expenses in the installation of the electrical equipment
- Also permits-to-work and work procedures are affected. For sure, a bigger estimation leads to a organization impact
- CFD results are much closer to the results obtained by applying the gas dispersion models provided by IEC 60079-10-1 than those suggested by NFPA 497
- NFPA 497 is a Recommended practice and “should be intended as a guideline and should be applied with sound engineering judgement. Where all factors are properly evaluated, a consistent area classification scheme can be developed”
Understanding EU Directive 2024/2853
26 February 2025