Calculation set

In RISKCURVES, a calculation set represents a crucial component of the project tree, acting as a second-level node with its individual subtree. It encapsulates all input data and settings necessary for performing a comprehensive Quantitative Risk Assessment (QRA).

Key functions

• Easy modification: Each calculation set contains all the input parameters that influence the outcome of the risk assessment. This includes system settings, meteorological data, population data, and accident (Loss of Containment) scenarios. It serves as a placeholder for a complete QRA calculation under one node.

• Risk results combining multiple scenarios: Calculation sets are used to compute Individual Risk Contours, Societal Risk Graphs, and Societal Risk Maps. These results combine the effects of multiple scenarios, providing a comprehensive risk profile.

• Compare risks: Multiple calculation sets within a single project file allow users to compare the changes in risk due to modifications. For example, comparing the risk profile with a base population against a modified population due to urban development plans.

Structure

A calculation set in RISKCURVES includes the following the sub-nodes:

• Calculation settings: Defines the general parameters and settings for the risk calculation.

• Meteo data: Contains meteorological information crucial for dispersion and fire modelling and risk assessment.

• Total Population: Input required if societal risk calculations are performed, detailing population distribution either as grids or polygons.

• Stationary equipment: Details of equipment that remains fixed in location (such as storage vessels, heat exchangers, etc), important for scenario modelling.

• Transport equipment: Information on the movement of hazardous materials, essential for transport-related risk scenarios (such as pipe transport, railroad transport, ship transport, etc).

• Consequence risks: Calculates the risk of exceeding one or multiple threshold levels for heat radiation, overpressure, toxic concentration, etc.

• IRPA: Defines the inputs required to calculate Individual Risk Per Annum.

• Analysis Points: Specific locations within the facility or surrounding area where a risk contribution calculation is performed.

Societal Risk calculations

A calculation set provides options for enabling the calculation of Societal Risk and Societal Risk Maps.

• Perform Societal Risk calculation: This option generates Societal Risk graphs (fN curves). When enabled, a population definition is necessary, either as a grid or as polygons. An Individual Risk calculation, resulting in Iso Risk Contours on a map, is always performed.

• Create Societal Risk Maps: When activated, these calculations will also display Societal Risk Maps in the map view.

• Cumulate transport routes in fN graphs: If selected, this option will include the results for the entire transport route in the total fN curve. If cumulation is skipped, transport scenarios will provide fN graphs for specific sections of the route (default is 1 km).

By understanding and effectively utilising calculation sets, users can perform detailed and comparative risk assessments, ensuring thorough evaluation and management of risks associated with hazardous substances in industrial settings.