• Published: October 2024
• REF/ISBN: 978 1 78725 441 1
• Edition: 5th
• Status: Current

Model code of safe practice – Part 15: Area classification code for installations handling flammable fluids (a.k.a. EI 15) provides guidance on the classification of areas around equipment handling or storing flammable fluids and provides a basis for both the selection of fixed electrical and mechanical equipment and the location of other sources of ignition in those areas. It is aimed at HSE managers, design, process and maintenance engineers, and all those involved in the hazardous area classification of installations handling flammable fluids.

This 5^th edition of EI 15 provides clarification on issues that have been raised by users of the fourth edition since its publication and incorporates key findings from several research studies commissioned by the EI. Whilst amendments have been made throughout the document, major technical changes include:

• Update of A.1.2 to give guidance on mist based on research published since previous (4^th) edition.
• Incorporation of conclusions in the 3^rd edition of EI Research report: Dispersion modelling and calculations in support of EI Model code of safe practice – Part 15: Area classification code for installations handling flammable fluids, including a sensitivity analysis to various parameters. The modelling work reported in this research report was carried out using the latest version of PHAST.
• Update of Table C.3 to include hazard radii for releases of pure hydrogen in both gaseous and cryogenic liquid forms.
• Update of Table C.3 to include hazard ranges for higher pressure releases of substances A, B, G(i), G(ii), and LNG.
• Update of Annex D to tabular format that gives sources for hazard radii presented in direct examples.

Whilst EI 15 provides guidance on applying a risk based approach for specifying hazardous areas, the full methodology is outlined in a separate EI publication titled A risk-based approach to hazardous area classification.