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Basics of Occupied Buildings Risk Assessment (OBRA)

process safety training


Dates 03/10/2017
Location Manchester
Included Lunch, Refreshments & Course Notes
Venue Training will be hosted by the Renaissance Manchester Hotel, where accomodation can be booked directly.


Many recent and historic industrial accidents have highlighted the vulnerability of people in buildings on chemical plants. Examples include Flixborough and more recently the BP Texas City explosion in which a number of people were killed in portacabins located close to the explosion epicentre. Although some buildings can provide shelter in place protection from toxic releases, if an explosion occurs, the potential for the building to collapse at low overpressure actually can place occupants at increased risk. Most people on chemical plants do not need to be sited close to the processing units. In the UK, Chemical Industries Association (CIA) guidance on how to assess risks to people in buildings has existed for a number of years. Regulatory focus on this issue has generally been limited to COMAH regulated sites although DEKRA Insight’s experience indicates that even companies who are not regulated under COMAH might still be placing people at an unacceptable level of risk from major hazards such as fire and explosion.

This one day course aims to provide an introduction to the topic to enable delegates to determine if they have a potential OBRA issue and to practice the methodology for carrying out assessments on their site. The course calls upon the many years’ experience of the presenter in helping companies assess risk to building occupants and find pragmatic solutions to sometimes quite complex siting issues.


An introductory module describing the stages of OBRA, beginning with a background – what can go wrong and consequences to people in buildings. We will move on to the identification of hazardous events and their inclusion in the assessment, modelling the hazardous effects of major process incidents such as fire, explosion, pressure vessel burst and toxic gas releases and how to select which buildings need to be considered alongside assessing hazardous effects on different building types. Finally, we look at the quantification of the risks to occupants of buildings and the use of risk tolerability criteria to help with decision making. Consideration will be given to options for reducing risk and demonstrating ALARP including when toxic refuges are required, their basic design requirements and the subsequent development of management systems for occupied buildings. Workshops will be employed throughout the training to help understanding and to practice the methods described. Use will be made of the CIA Guidance for occupied building risk assessment.


  • Health & Safety Personnel
  • Engineering Staff
  • Plant Engineers
  • Regulatory Staff
  • Staff in Hazardous Areas

A key aspect to our courses is for our delegates to gain the knowledge and solutions applicable to their own situations, so numbers are capped to ensure we have sufficient time for your feedback and early booking is therefore recommended.

Phone: +44 (0)23 8076 0722 - Fax: +44 (0)23 8076 7866

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