Challenge

The design and location of legacy occupied buildings on a customer’s multiple sites did not meet current good practice with respect to the hazards they were exposed to. An occupied buildings assessment was required to determine whether the risks to the building occupants were as low as reasonably practicable (ALARP), or whether additional risk reduction measures were required.

DNV solution

DNV conducted a survey of the site and occupied buildings, including details of the building construction, ensuring that the structures were assessed in accordance with guidance published by the Chemical Industries Association. Part of the scope was to conduct a workshop with customer personnel to identify possible risk reduction measures, and further to perform a cost benefit analysis of the selected measures and recommend a set of measures that would make risks as low as reasonably practicable (ALARP).

Outcome and benefits

Cost benefit analysis was used to rule out the need for extensive modifications in most cases, and to assess a variety of risk reduction measures so that the most cost effective could be chosen to ensure that risks are ALARP. Also, key to the assessment was the recommendation of lower cost measures required to meet good practice including improving detection and isolation of releases, removal/modification of windows facing the plant and improving accessibility of escape routes.