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 HSE (The Health and Safety Executive) 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 that is each individual should be able to work for 1000 years before being at risk of death
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 HSE. 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 mentioned here are part of the Marex suite of QRA tools used by its safety engineers.