Marex

Quantitative Risk Assessments (QRA)


QRA is carried out by a safety engineer. It is a means of determining the risk of fatality whilst working on an offshore installation. And the UK CA have set a standard in the UK that the IRPA, the Individual Risk Per Annum, for an offshore worker should be not more than 1 x 10-3 which equates to 1 fatality for every 1000 years worked.

Using historic data, the safety engineers are able to determine the levels of risk to persons for various types of operation, and for different worker groups, by mathematical calculation. They use data which is available in the public domain such as WOAD (The World Offshore Accident Database) and data compiled by the UK CA. For the drilling industry, for instance, it is normal for the drilling teams to be at the greatest risk and for those who work in the accommodation to be less at risk. It seems obvious, but even the risk to the drillers and their support must fall within acceptable limits.

Accidents continue to happen and therefore they are added to the data, but they are factored over time so there may still be an overall reduction in risk. Only the calculations will determine this.

A part of the QRA process is the use of specialist programmes to determine the resistance of the TR to fire and explosion, and the radiation levels at the emergency routes and the evacuation stations as a result of ignited releases. The types of programmes utilised by Marex are detailed in the Fire, Gas and Explosion Modelling page.