Accidental release modelling
Execution of accidental release modelling and consequence calculation for hazard analysis.
i.e. Dispersion modelling, cloud contours, explosion pressure modelling.
A RAM study (Reliability, Availability and Maintainability) assesses a production system. RAM study fits in the asset management program.
The factory is modelled to determine the installed production capacity based on the reliability data of the individual components, sometimes taking into consideration the maintenance crew restrictions. Typically, the total production over the lifetime of the plant is calculated. Sensitivity analysis covers the lack of information. Collected statistical data from a plant in operation is used.
Inputs are equipment reliability data, repair time data, maintenance crew requirements and restrictions. The modelling is performed using a Monte Carlo technique.
A RAM study is resulting in an asset optimization program that can lower project costs.
The typical RAM team is composed from a maintenance and reliability engineer, process engineer, process safety and risk engineer, a production engineer, and the RAM- modelling team.
A QRA (Quantitative Risk Assessment) is a formal and systematic engineers’ approach to estimating the likelihood and consequences of hazardous events. The result is quantitatively for the risk to people and the environment (typically risk outside the production site).
The QRA allows an owner of an installation to demonstrate the risk from its installation on the environment is tolerable from industrial risk point of view.
Because QRA is a formal study, trying to determine the potential impact from the installation on the environment a set of rules is available. The rules are generally stipulated by the local government. A good reference is the “Reference Manual Bevi Risk Assessment from National Institute of Public Health and the Environment (RIVM)”.
The typical QRA team is composed from a process engineer, process safety and risk engineer, a production engineer, and the QRA-modelling team.
The increased use of computer-based safety systems has resulted in functional safety standards like IEC 61508, and IEC 61511. IEC 61508 provides a basis for specification, design, and operation of SISs with emphasis on safety activities in each lifecycle phase of the system.
Reliability calculations are needed for SIL classified loops to demonstrate the reliability as specified in the allocation report.
The calculation method we use is in line with the IEC 61511 Rev 2016 and has the advantage of an open scientific approach where the effects of the applied parameter are well-understood.
The study develops in 5 steps:
- Determination of the SIL requirement (if not already performed)
- Data collection concerning the equipment and the architecture which is used (or foreseen)
- Agreement of the variables and parameters
- Modeling and calculation
- Feedback and adjustment
The team typically consists out of a process engineer, process safety and risk engineer, an instrumentation engineer, and a functional safety engineer.