Phast and Safeti software

Consequence estimation for HAZOP, HAZID, PHA, AND LOPA

Approach for hazard identification

Assessments such as Hazard and Operability (HAZOP), Hazard Identification (HAZID), Process Hazard Analysis (PHA), and Layer of Protection Analysis (LOPA) are essential for ensuring the safety and reliability of operation in the process industries. These exercises involve technical professionals who identify the most significant hazards present within a unit, based on hazardous (flammable and toxic) materials, their volume, storage conditions, and potential cause of loss of containment. This is a key step as identifying hazards present on a site and in its operations help prevent or reduce the potential accidental releases of hazardous materials.

Estimating the possible consequences during a process hazard analysis is usually done in a qualitative manner.

A typical hazard identification output includes:

No.	Primary Guideword	Secondary Guideword	Potential Hazard	Failure Mode / Cause	Unmitigated Consequences	Safeguards
No. 1	Primary Guideword Loss of containment	Secondary Guideword Joint / Fitting	Potential Hazard Y	Failure Mode / Cause Joint Failure	Unmitigated Consequences Loss of containment of LPG (10bar) from 50mm leak Liquid pool of flammable material on ground, with potential for fire if ignited	Safeguards Jointing Standards Competence Inspection Flange Guards

When more accurate evaluation of the potential consequences of low-consequence hazards, or when a more thorough assessment of these hazards is required, quantitative analysis of release scenarios can be performed.

The tool suitable for estimation of consequences

Phast is DNV’s consequence analysis software suitable for the process industries. It uses validated mathematical models to simulate the behaviour of hazardous substances upon release, considering factors such as type of release, the properties of the substances, and weather conditions. The tool provides comprehensive results and visual representation in the form of graphs for discharge, dispersion, thermal, overpressure, and toxic effects.

A typical workflow within Phast involves the following steps:

Phast - consequence estimation

By following the steps above, technical professionals can estimate the potential consequences of hazardous releases.

The inputs necessary for performing consequence modelling in Phast are typically obtained from:

Process and instrumentation diagrams (P&IDs)
Process flow diagrams (PFDs)
Plot plans
Heat & mass balances
Equipment ratings and data sheets
Operating procedures

A typical result obtained from Phast includes:

No.	Primary Guideword	Secondary Guideword	Potential Hazard	Failure Mode / Cause	Unmitigated Consequences	Safeguards
No. 1	Primary Guideword Loss of containment	Secondary Guideword Joint / Fitting	Potential Hazard Y	Failure Mode / Cause Joint Failure	Unmitigated Consequences Loss of containment of LPG (10bar) from 50mm leak Liquid pool of flammable material on ground, with potential for fire if ignited Quantified Results: Gas cloud disperses with 1/2 LFL cloud reaching 256m downwind, and the LFL cloud reaching 124m downwind 37.5 kW/m2 radiation level experienced up to 90.6m downwind	Safeguards Jointing Standards Competence Inspection Flange Guards

In addition to numerical calculation results, Phast provides visual representation of the consequences, which are commonly reviewed during a process hazard analysis. The visualisation of results is crucial during workshops and Phast facilitates this by allowing for consequences results from release scenarios to be overlaid on satellite imagery or plot plans. This feature provides technical professionals with confidence when evaluating hazardous scenarios.

For example, the figure illustrates the thermal radiation hazard ranges for multiple radiation levels. This demonstrates the value of Phast to provide a clear understanding of potential hazards during hazard workshops.

Phast

Control your hazards by modelling discharge, dispersion, fires, explosions and toxic effects.

Accident & incident investigation

Assess hazardous material releases, identify root causes, and develop preventive measures using the Phast software.

Emergency response

Simulate consequences from loss of containment scenarios to aid in the development of effective emergency response plans using the Phast software.

Regulatory compliance

Evaluate and manage consequence and risks associated with hazardous materials and operations for regulatory compliance using the Phast and Safeti software.

Facility citing & occupied buildings risk assessments

Support operators in conducting Occupied Buildings Risk Assessments (OBRA) for major hazard installations using the Safeti software.

Consequence estimation for HAZOP, HAZID, PHA, AND LOPA

Approach for hazard identification

No.

Primary Guideword

Secondary Guideword

Potential Hazard

Failure Mode / Cause

Unmitigated Consequences

Safeguards