Quantitative Risk Assessment Revalidation of Chemical Plant Case Study

The Challenge

A leading U.S. manufacturer serving the automotive and aerospace industries required an update to its Quantitative Risk Assessment (QRA) study to meet OSHA compliance. Their facility in Louisville, Kentucky, produces synthetic rubber (polybutadiene and solution styrene-butadiene) and also a liquid polymer (polybutadiene acrylic acid acrylonitrile) known as a common fuel binder in solid rocket motors.

A prior QRA study was done in 2015, and the client wanted to update the study to incorporate their new buildings and equipment installation. The OSHA 29 CFR 1910.119 Process Safety Management (PSM) Standard requires, under the Process Hazard Analysis (PHA) element, that employers conduct a facility siting study to verify that the location and occupancy of buildings, control rooms, and trailers have been properly evaluated.

Our Approach

ioMosaic completed an updated QRA of the plant to determine the peak overpressure, positive phase duration, and impulse at the proposed new location for ammonia building maintenance based on the frequency of occurrence. The analysis and documentation were prepared using Process Safety Office^® SuperChems^®, our state-of-the-art hazard modeling software.

The purpose of the QRA study is to identify any potential hazards and risks associated with the project and to provide guidance for siting in order to minimize risks. It involves estimating the frequency of potentially hazardous events and calculating the consequences of such incidents. The results are combined with information on the expected exposure of persons to the events being studied to establish a risk of injury or death. The ioMosaic QRA process is divided into five main elements as follows:

1. Identification and development of a representative set of hazard scenarios (utilizing commonly accepted methodologies, including failure mode and effects analysis)
2. Evaluation of the likelihood of occurrence of these identified hazardous events, based on a specified number of release sizes (utilizing among other things, the fault tree analysis methodology)
3. Evaluation of the possible consequences from the identified hazardous events
4. Evaluation of risk, the combination of frequency, and consequences
5. Consideration of the significance of the resultant risk levels and, if appropriate, mitigation measures and recommendations to meet relevant risk criteria (risk tolerability criteria developed during the previous QRA will be utilized)

SuperChems^® features a database with the capability to locate buildings and other critical infrastructure on an actual site map and then defines infrastructure information, such as occupancy levels for different types of populations, construction types, and so on. The site map catalogs the overpressure time histories and the structural response of each building. The source term and explosion dynamics models are very detailed and well-validated.

The Benefits

The ioMosaic team combined the consequence and likelihood results to give an estimation of the individual risk visually via iso-risk contours displayed on plot plans. Additionally, they provided a list of predicted values in terms of peak overpressure, positive phase duration, and impulse to all buildings within the facility. The resulting project deliverables included a final report of the results and any recommendations detailing the safety risks.

Learn More

Our mission is to help you protect your people, your plant, your stakeholder value and our planet. To learn more about how we can help you manage risk, call us at 1.844.ioMosaic.