On the 1st of October 2024, the Energy Institute published the 5th edition of their ‘Model Code of Safe Practice Part 15: Area Classification for Installations Handling Flammable Liquids’ (EI15). The introduction of this publication is a perfect opportunity to review your current hazardous area classification.
Under Regulation 7 of DSEAR; ‘every employer shall classify places at the workplace where an explosive atmosphere may occur into hazardous or non-hazardous places […] and shall classify those places so classified as hazardous into zones.’
Hazardous area classification is a tool to help you manage your potential ignition sources to ensure that the risk from fires and explosions is suitably understood and appropriately managed.
EI15 was last updated in 2015, and the new 2024 edition includes adjustments and refinements, that could result in changes to your hazardous areas.
EI 15 states:
Hazardous area classification should be reviewed, and if necessary, amended as part of any project or modification to either the equipment or process or,
- Where there are any significant changes to plant layout, hazardous substances or operating conditions;
- Where specific dispersion modelling is carried out for release source(s), and
- Following updates to industry guidance and standards.
Hazardous area classification should be reviewed every 5 years.
Key changes in EI15 5th edition
The Energy Institute highlighted the most pressing changes made to the guidance and an overview of some of the details of these changes are listed below:
- Updated advice on mists to include information from HSE/industry research projects e.g. tests found that diesel could only be ignited in the test rig at pressures above 5 barg, with biodiesel requiring a 20barg release.
- Extensive remodelling of all release cases in Phast v8.4 (affecting direct examples, equipment leaks and releases from vents), with all modelling reviewed by the HSE.
- Inclusion of releases of pure hydrogen in both gaseous and cryogenic liquid forms.
- Update of hazard range look up tables for higher pressure releases of substances A, B, G(i), G(ii), and LNG.
- Update of direct examples to tabular format that gives sources for hazard radii presented in direct examples. The direct examples are now easier to apply and interpret.
There is no universal trend that can be seen throughout the new data, with hazard radii for certain release cases increasing, yet decreasing for others. This variation emphasises the importance of reviewing your hazardous areas. For those substances with a greater hazard radius than previously determined, does your site’s Hazardous Area Classification need to be amended? What is the impact of any changes to your zones? Have you now got equipment outside of zones, or in a less onerous zone? This could mean you need to change equipment, improve safeguards, or it could mean that you may potentially reduce your inspection and maintenance activities.
Although EI15 is a widely recognised and accepted code of practice for undertaking HAC, there exists a wide range standards and industry specific guidance for hazardous area classification, all with the same objective of ensuring that fires and explosions are appropriately understood and protected against such that the risk is as low as practicable. Different guidance may be more applicable to different organisations and situations; therefore, we encourage you to take this opportunity to check when your hazardous area classification was last reviewed and ensure that it is up to date with the latest relevant guidance.
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