Articles
Hazard Identification Study (HAZID Study)
Effective management of vented and accidental gas releases remains a cornerstone of safe operations in the oil and gas (O&G) industry. A well-executed Gas Dispersion Study is not merely a regulatory obligation it is a critical engineering tool that supports informed design, risk assessment, and operational decision-making.
At PRISM, our experience supporting major operators in the Middle East and Asia has demonstrated that understanding dispersion behavior is vital to protecting people, assets, and the environment. Gas dispersion modelling provides visibility into how flammable and toxic gases, such as hydrogen sulfide (H₂S) or hydrocarbons, behave once released into the atmosphere. Through this analysis, engineers can identify potential exposure zones, define safe separation distances, and optimize vent stack configurations to minimize risk.
A comprehensive Gas Dispersion Study involves integrating process data, release scenarios, and meteorological conditions to predict how gases disperse under various operating states. Using advanced tools such as DNV PHAST, the study evaluates parameters including gas composition, release rate, temperature, and pressure to simulate the behavior of vapour plumes.
Results from the study inform design and safety decisions such as:
These insights allow engineering teams to ensure that vented gases are dispersed to safe concentrations before reaching manned areas or air intakes, reinforcing both process safety and environmental compliance.
A key advantage of dispersion analysis lies in its ability to translate data into actionable design improvements. For instance, where modelling identifies high gas concentrations near occupied zones, corrective measures can include revising vent elevations, reorienting discharge points, or installing flame arrestors. The outcomes of such studies are also integral to Quantitative Risk Assessments (QRA) and Emergency Systems Survivability Analysis (ESSA) ensuring a consistent, data-driven approach across safety domains.
Furthermore, by incorporating site-specific meteorological data and terrain characteristics, PRISM’s dispersion studies achieve high accuracy and relevance to real operating conditions. This precision helps operators meet both regulatory requirements and corporate safety commitments.
PRISM’s multidisciplinary team of Process Safety Engineers applies deep technical expertise to help clients in regions such as Qatar, Malaysia, and the UAE meet international safety benchmarks. Our gas dispersion assessments are tailored to the client’s operational profile ensuring each study is defensible, auditable, and aligned with industry best practices.
A robust Gas Dispersion Study is not just an analytical exercise it is a vital safeguard in preventing incidents, protecting personnel, and ensuring environmental stewardship. As O&G operations continue to evolve toward higher safety and sustainability standards, PRISM remains committed to delivering engineering solutions that uphold integrity, reliability, and compliance across all stages of asset development.
American Petroleum Institute. (2014). API Standard 521: Pressure-relieving and depressuring systems (6th ed.).
DNV GL. (2021). PHAST user guide: Process hazard analysis software tool (Version 8.4). Høvik, Norway: DNV GL Software.
International Electrotechnical Commission (IEC). (2015). IEC 60079: Explosive atmospheres – Part 10: Classification of areas. Geneva, Switzerland: IEC.
Occupational Safety and Health Administration (OSHA). (2022). 29 CFR Part 1910 – Occupational safety and health standards. Washington, DC: U.S. Department of Labor.
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