Quantitative Risk Analysis (QRA)
QRAs provide numerical estimates to allow clients to understand risk exposure to people, business, the environment, markets, or other areas of interest. Determining potential consequences posed by facility operations is a necessary step in the process of developing a comprehensive safety plan. If consequences are significant, a QRA can be performed to determine risk levels for comparison to risk tolerance criteria and to provide input on decisions regarding mitigation strategies. QRA results can be used to identify cost-effective mitigation strategies, provide a defensible basis for dismissing mitigation strategies that cost significantly more to implement than the safety benefit they afford, and prioritize mitigation strategies selected for implementation as part of a master planning process.
BakerRisk engineers have performed QRAs at a wide range of facilities around the world, including refineries, terminals, gas plants, LNG and LPG operations, pipeline systems, offshore platforms, floating production storage and offloading (FPSO) facilities, oil and gas wells, and chemical, petrochemical, and pharmaceutical plants. A QRA typically evaluates consequences to people and likelihood of fire, explosion, and toxic impacts (as applicable) for a facility.
For an international client base, BakerRisk has identified onsite and offsite population risks in several ways including FN curves, societal risk results, individual risk results, etc. FN curves allow calculated risk values to be compared to risk tolerance criteria. Societal risk results summarized by risk dominant sources focus attention on hazards that may be candidates for risk reduction efforts through prevention or consequence mitigation such as improved testing and maintenance, leak detection and isolation, water curtains, and improved startup, shutdown, and lockout/tagout procedures. Societal risk results summarized by risk dominant buildings and process areas along with the type of hazards impacting them to focus attention on buildings and plant areas that may be candidates for risk reduction efforts. Such efforts can include consequence mitigation such as relocating personnel, detection and alarms, protective gear, building upgrades for blast resistance, and flammable or toxic ingress prevention.
Individual risk results can be summarized by work group, building/process area, or by geographic area. Work group individual risk results focus attention on workers to ensure that no worker incurs excessive risk. Building/process area risk focuses attention on minimizing risk to buildings and process areas by locating personnel in the lowest risk buildings and process areas to the extent practical. Geographic risk contours show the amount of risk incurred by a person outside at a given location (24 hours a day, 7 days a week) and is independent of the actual population surrounding a given hazard. Geographic risk contours focus attention on high risk areas within a site and are also useful to determine risk to surrounding offsite areas.
A QRA can be conducted at the conceptual design phase of a project to assist with decisions such as layout of process equipment, buildings, and location of personnel. It can be performed at the detailed design phase to identify potential issues with plant layout, building locations and structural blast resistance, and mitigation system design. A QRA can be performed for an operating facility to evaluate risk and identify potential mitigation strategies and evaluate their cost effectiveness. BakerRisk has been able to drive down risks and save clients considerable sums of money by using current base case risk results and comparing them to proposed changes (plant expansions, new buildings or population developments, etc).