Skip to main content.

Technical risk analysis and hazard studies


Before risk can be managed, organisations and projects must understand what could happen and what it could lead to in terms of their goals and objectives.

Risk identification and analysis should always involve the application of a system that helps us discover and understand risks. Sometimes we may need to use additional technical tools to gain further insight into the risk of a project, operation or activity.

Technical risk analysis and hazard studies cover a broad range of techniques, many of which Broadleaf offer. In particular, due to the capability and experience of several of our personnel, we focus on technical risk analysis and hazard studies that are complex, high profile, urgent, critical or where there are potential issues to manage between the stakeholders involved.

The methods we use include:

  • Structured what-if technique (SWIFT)
  • Hazard and operability study (HAZOP)
  • Failure modes and effects analysis (FMEA) and failure modes, effects and criticality analysis (FMECA)
  • Fault tree analysis (FTA)
  • Event tree analysis (ETA)
  • Safety integrity level (SIL) determination
  • Root cause analysis.

The form and timing of technical risk and hazard assessments depends on the information available at the time and the requirements of the design, construction, operations and approval authorities.

Examples of risk identification studies

A SWIFT analysis is usually performed early in the design process when there is less detailed information. The facilitator prepares a list of questions, usually starting with ‘What if…’, or ‘Could someone…’, that lead the workshop participants systematically through the design, identifying possible hazardous scenarios.

A HAZOP study is a detailed and systematic examination of a process or design, structured around a set of guidewords, to identify and assess the risks and operability problems and the existing controls. It systematically considers the potential deviations from the design intent. The standard HAZOP study approach is often not straightforward, particularly when it isn’t being applied to standard fluid systems. Our wide experience in planning and leading HAZOP studies across many different kinds of systems allows us to tailor the guidewords effectively and conduct HAZOP studies to provide high quality outcomes.

The HAZOP study technique is also readily and successfully applied to other systems such as control systems (CHAZOP studies) and electrical systems. It can also be applied to other systems and processes that can be tested through consideration of deviations from the design intent, such as procedures, organisational changes and contracts. Three members of the Broadleaf team are involved in updating the international standard, IEC 61882 Ed 2 Hazard and operability studies (HAZOP studies) – Application guide and two were major contributors to ISO 31010:2009 Risk Assessment Methods.

Figure 1 shows a section of a drawing that was subjected to a HAZOP study led by Broadleaf.

Figure 1: Section of HAZOP study drawing

Photo credit: Geoff Raymond

It is critical that the design of a system has been reviewed prior to any HAZOP study conducted on it. Broadleaf often facilitates such design reviews.

FMEA involves reviewing the components, assemblies, and subsystems of a design to identify failure modes, and their causes and effects. FMECA is a similar study, but takes into account the criticality of each failure and assesses the risk associated with the failure mode; this is usually a qualitative process, but sometimes quantitative methods are used as well.

Examples of risk analysis studies

Fault tree analysis and event tree analysis are tools that allow the causes of a failure (FTA) or the development of the consequences of a failure (ETA) to be represented. Failure rate data and probabilities allow FTA and ETA to be used to calculate the frequency of a failure or the likelihood of a particular consequence for comparison with acceptance criteria.

Figure 2 shows a simplified example of a fault tree for the failure of a pump at a coal terminal. Figure 3 is the linked event tree.

Figure 2: Example fault tree

Figure 3: Example event tree

We conduct safety integrity level or SIL studies, but our activities are usually limited to the calculation of the required SIL and not the complete verification process. A SIL study can be very effectively linked to a HAZOP study or FMECA.

Associated studies

We conduct fire safety studies (FSS), often required as part of the approval process for new developments. An FSS can identify the sources of fire and explosion, evaluate the consequences and outline the prevention, detection and protection systems required.

We also undertake detailed root cause analyses, for both failures (accidents and incidents) and successes. The aim of root cause analysis is to understand how existing controls worked (or failed to work) and to develop actions to ensure similar successes are repeated and similar failures are avoided. As well as generating lessons from the success or failure, our approach to root cause analysis concentrates on how the organisation can learn from its past experiences.

Related international standards

Many of the techniques noted above are described in more detail in international standards.

IEC 60812 Failure mode and effects analysis (FMEA)

IEC 61025 Fault tree analysis (FTA)

IEC 61882 Hazard and operability studies (HAZOP studies) - Application guide

IEC 62502 Analysis techniques for dependability – Event tree analysis (ETA)

IEC 62740 Root cause analysis (RCA)

IEC/ISO 31010 Risk management – Risk assessment techniques