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HAZard & OPerbility

there is no ‘one-size-fits-all’ approach to identify and manage hazards

When it comes to risk management, there is no one-size-fits-all approach to identify and manage hazards. The chosen assessment method should align with the desired output based on the stage at which the assessment is undertaken. It is essential to start risk management and risk assessment processes as early as possible.

HAZOP Purpose

HAZOP (Hazard and Operability Study) is an approach employed to systematically identify and evaluate potential hazards and operational challenges. HAZOP examines the operability of the process, focusing on what could go wrong and what the outcome of failure could be. This includes analysing factors such as equipment failures, control system malfunctions, human errors, and environmental conditions. By considering various scenarios, and the outcome of those scenarios, effective control measures and safeguards can be applied to mitigate potential Incidents.

HAZOP is a logical progression from HAZID, and it is equally effective when conducted independently. It is advisable to have a well-documented and clearly defined process or procedure in place before initiating a HAZOP study. Sufficient time should be allocated post-HAZOP to ensure the complete implementation of any recommended modifications. HAZOP can also be conducted retrospectively on existing processes or procedures, providing an opportunity to enhance their safety and efficiency.


When conducting a HAZOP study, it is crucial to narrow down the focus to specific activities and ensure that adequate information and procedures are available to support. The primary objective of HAZOP is to identify the causes and consequences of any deviations from the intended design. Time should also be dedicated to identify contingency options to address potential deviations effectively. 

To facilitate the process, all identified deviations, along with their details, must be logged into a HAZOP worksheet.

It is advisable to limit the time spent on finding immediate solutions or engaging in technical redesign. Instead, the focus should primarily be on identifying and documenting the deviations and their potential impacts. Subsequent to the HAZOP workshop, the identified deviations can be thoroughly analysed and appropriate solutions can be developed and implemented. This approach ensures that the HAZOP study remains focused on comprehensive analysis and evaluation, while allowing for dedicated problem-solving activities outside the workshop setting.

HAZOP Guidewords

Guidewords serve as prompts to identify potential hazards and deviations. They are applied to assess if any missing information, errors, or deviations could lead to undesired events or consequences. Guidewords help stimulate critical thinking and facilitate thorough analysis.

HAZOP Output

The output from a HAZOP study often necessitates adjustments in engineering design, updates in procedural checks and content, or the implementation of localised control measures. Localised control measures can be incorporated into a HIRA (Hazard Identification and Risk Assessment) or TRA (Task Risk Assessment). By capturing the insights and recommendations derived from the HAZOP process, organisations can ensure that the necessary changes are properly recorded and integrated into their risk management systems. This proactive approach enhances safety protocols, facilitates ongoing risk assessments, and helps to maintain a comprehensive record of potential hazards and corresponding control measures.

HAZOP Format

For effective presentation and utilisation, HAZOP findings are best organised within a structured and tabular worksheet containing predefined headings.It is essential that this worksheet is readily accessible to all personnel involved in the activities, enabling timely updates as work progresses.

The format of the worksheet should strike a balance between simplicity and providing sufficient detail to enhance the assessment’s value. While qualitative assessment is not required during HAZOP, the main objective is to identify the causes and consequences resulting from deviations in planned activities, processes, or procedures, rather than conducting a comprehensive risk classification.

To track progress and implementation, actions within the worksheet should be marked as either ‘Open’ or ‘Closed,’ reflecting the status of identified control measures or mitigations. If a control measure is deemed suitable to mitigate the associated hazard, it can be marked as ‘Closed.’ However, if there are doubts about the effectiveness of the control measure, the action should remain ‘Open’ until suitable mitigation measures are identified and applied. In such cases, the action can be closed in the worksheet and further assessed using qualitative risk assessment methods like HIRA or Task Risk Assessment, if necessary.

Structuring HAZOP

When conducting a HAZOP, it is recommended to start by focusing on a single element of the workscope or process. This approach allows for a detailed evaluation of actions and expectations associated with the specific task. 

For example, if an operator is performing a series of actions to achieve an objective, each step should be carefully reviewed, considering the required conditions at the start and end of the operation or procedure.

To ensure accurate assessment, it is crucial to have a person who is familiar with or responsible for completing the activity explain each step in detail. This individual’s expertise will provide valuable insights during the HAZOP process.

Once the activity is understood, guidewords should be applied to evaluate potential deviations and their consequences. The selection of guidewords should be relevant to the content being assessed. A list of suggested guidewords can be found here.

Similar to HAZID, HAZOP can be an ongoing process of evaluation, often conducted in smaller groups. Worksheets can be updated as new content arises, and it is important to regularly update the worksheet to reflect the latest information. Emphasis should be placed on evaluating and updating control measures based on the assessments conducted. Additionally, participants should be encouraged to add new activities or steps and identify potential deviations during the HAZOP study.

HAZOP – Continual Evaluation

Updating HAZOP worksheets should be encouraged throughout the HAZOP phases and not limited to HAZOP workshops. Deviations and scenarios that present concern to the safe completion of the workscope can be identified outside of HAZOP workshops, work with HAZOP worksheets should be considered as an ongoing process. To facilitate this continuous and collaborative approach your organisation should adopt an accessible format for HAZOP.

By promoting continuous assessment throughout the project lifecycle, your organisation can proactively address risks and enhance safety measures. This approach fosters a comprehensive understanding of potential hazards and encourages a proactive mindset towards risk management.

HAZOP – Workshops

HAZOP workshops allow for a structured review of potential deviations that could result in an incident. 

The success of HAZOP workshops is largely dependent on how the workscope is defined and the attendees.  A HAZOP workshop can be conducted on a large workscope or several more focussed HAZOP workshops conducted on smaller elements which combine  to create the larger workscope.

To ensure a focused and productive HAZOP study, it is beneficial to schedule frequent sessions that concentrate on specific areas or elements of the process. This approach enables in-depth analysis and meaningful discussions.

HAZOP Leader

For an effective HAZOP workshop, it is crucial to designate a capable leader. The leader’s role is to maintain control over the workshop, keeping it focused on the intended purpose and scope of the HAZOP study. They should facilitate clear understanding of discussion points and ensure that all important insights are properly noted.

The leader of the HAZOP workshop should possess knowledge and expertise in the relevant HAZOP topics. This allows them to guide and encourage meaningful discussions among the participants, fostering an environment where valuable insights can be shared and explored.

Having a dedicated scribe during the workshop is highly recommended. The scribe’s role is to assist in note-taking and promptly add relevant content into the HAZOP worksheet as discussions unfold. This ensures that no valuable information or recommendations are lost during the workshop. Once the content is added, the HAZOP worksheet should be shared with participants for review and verification, ensuring the accuracy and correctness of the recorded entries.

By implementing these practices, organisations can optimise the efficiency and outcomes of HAZOP workshops, enabling comprehensive documentation of discussions and promoting a collaborative and focused approach to the study.

HAZOP Duration

The duration of a HAZOP study should be carefully planned to accommodate the scope of the analysis and ensure sufficient time for comprehensive discussions. It is important to allocate ample time to cover all the content identified within the defined scope. As a general guideline, it may be beneficial to conduct shorter, more frequent HAZOP sessions instead of infrequent, lengthy sessions. This approach allows for better management of personnel availability, which can often be challenging.

To maintain focus and productivity throughout the workshop, it is advisable to structure the sessions with regular breaks. These breaks provide participants with opportunities to refresh and recharge, enabling them to remain engaged and attentive for the duration of the workshop. By incorporating well-timed breaks, participants can maintain their concentration and actively contribute to the HAZOP discussions.

By considering these factors and implementing a well-planned schedule, organisations can ensure that HAZOP sessions are efficiently managed, allowing for thorough analysis and meaningful participation from all involved parties.


The selection of attendees for a HAZOP workshop should be based on the scope of the study and the specific topic areas to be assessed. In certain cases, a HAZOP can be conducted informally with just two or three individuals present. However, for a more structured and comprehensive workshop, it is recommended to have approximately 8 to 12 participants. These individuals should be chosen based on their subject matter expertise and their direct involvement in the activities being assessed.

While larger numbers of attendees can be accommodated, it is important to consider the challenges associated with managing individual contributions and maintaining focus on the defined scope. It is crucial to assess the benefits of having more participants and weigh them against the potential drawbacks. The key is to strike a balance between having a sufficient number of knowledgeable participants and avoiding an overly large group that could hinder effective discussions and decision-making.

By carefully selecting the appropriate number of attendees, organisations can ensure productive and focused HAZOP workshops, maximising the expertise and contributions of participants while avoiding potential logistical challenges.

Defining your HAZOP Purpose

The purpose of a HAZOP study should be clearly defined and effectively communicated to all those involved. It is essential to ensure that there is no confusion or ambiguity regarding the intent of the HAZOP and the desired outcome. This clarity of purpose enhances the effectiveness of the study and promotes a common understanding among participants.

To achieve this, it is important to clearly articulate the objectives of the HAZOP and communicate them to the relevant stakeholders. This includes explaining why the HAZOP is being conducted, what specific aspects will be assessed, and the expected outcomes or deliverables. It is crucial to address any questions or concerns that participants may have and provide them with the necessary information and context to understand the purpose and value of the HAZOP study.

By establishing a shared understanding of the HAZOP purpose and desired outcome, organisations can ensure that all participants are aligned and actively contribute towards achieving the study’s objectives. This clarity promotes effective collaboration, enhances decision-making, and maximises the overall success of the HAZOP process.

Defining your HAZOP Scope

Determining the extent of the area or subject matter to be covered in a HAZOP study is crucial. Similar to defining the purpose, it is important to clearly outline the scope and limitations of the HAZOP. Consider the following aspects when outlining the scope:

Subject Matter Content: Identify the specific content areas that will be included in the HAZOP study. This could be related to processes, procedures, equipment, or any other relevant aspects that require analysis.

Starting/Baseline Conditions: Clarify the starting or baseline conditions that will be assumed and implemented for the HAZOP. Make it clear that these conditions will not be open for discussion during the study.

Applicable Guidewords: Specify the guidewords that will be used during the HAZOP analysis. These guidewords help guide the identification of deviations and their potential consequences.

HAZOP Workshop Process: Provide an overview of the HAZOP workshop process, including how it will be conducted, the roles and responsibilities of participants, and any specific methodologies or techniques that will be employed.

‘Housekeeping’ Rules, Agenda & Schedule: Outline any administrative rules or guidelines that will be followed during the HAZOP sessions. This includes the agenda and schedule for the workshops, ensuring that participants are aware of the expected timeline and structure.

Method of Hazard Identification, Mitigation, and Reporting: Describe the approach that will be used for identifying hazards, assessing their potential impacts, and developing appropriate mitigation measures. This includes specifying the format for documenting the HAZOP findings and action logging.

By clearly outlining the scope and limitations of the HAZOP study in relation to these factors, organisations can ensure that all participants have a comprehensive understanding of what will be included, how the study will be conducted, and the expected outputs. This clarity helps to streamline the HAZOP process, promote effective communication, and facilitate accurate reporting of hazards and recommended actions.

HAZOP Report & Tracking

If necessary, a comprehensive HAZOP report should be generated to document the findings and outcomes of the study. The report should include the following suggested content:

Attendees: Provide a list of participants who attended the HAZOP workshop, including their roles and affiliations.

Agenda: Outline the agenda or schedule followed during the HAZOP workshop, indicating the topics covered and the timeline.

Guidewords Applied: Specify the guidewords that were applied during the HAZOP analysis, highlighting their relevance to the subject matter.

HAZOP Worksheet: Include the HAZOP worksheet as an appendix or attachment to the report. This serves as a detailed record of the identified deviations, associated consequences, and recommended actions.

Presentation Material Used: If any presentation materials were utilised during the HAZOP workshop, such as slides or visuals, include references or attachments to them in the report.

References to Procedures Utilised: Mention any specific procedures or guidelines that were referenced during the HAZOP study. This provides context and ensures traceability of the analysis.

Follow-Up Actions and Closeout: Document the follow-up actions and closure process, including any additional planned HAZID workshops or related activities. This demonstrates the commitment to addressing identified hazards and implementing necessary mitigations.

Regardless of whether a formal report is required, it is crucial to emphasise that the HAZOP worksheet should be continuously updated and used as an input for developing the identified activities. The HAZOP worksheet should be treated as a dynamic document, with content regularly reviewed, updated, and added until the HAZOP process is formally closed for the specific work scope.

By documenting the necessary information in a HAZOP report and ensuring the ongoing utilisation of the HAZOP worksheet, organisations can maintain a comprehensive record of the study, facilitate knowledge sharing, and support effective implementation of the identified actions and improvements.

The Next Steps

In specific industries or projects, HAZOP can be an ongoing and continuous process. When there are changes to procedures or the introduction of new equipment, it is necessary to repeat the HAZOP to identify any new deviations that may arise as a result of these changes.

During the HAZOP process, content may be identified on the HAZOP worksheet that cannot be effectively mitigated through engineering or procedural changes. In such cases, it becomes crucial to address these issues at a local management level. The identified activities should be added and assessed as part of a HIRA (Hazard Identification and Risk Assessment) or TRA (Task Risk Assessment).

By recognising the need for iterative HAZOP studies and the involvement of local management in addressing certain identified hazards, organisations can ensure the continuous improvement of safety measures and effectively manage risks associated with procedural or equipment changes. This proactive approach enhances safety protocols and reduces the likelihood of potential incidents or accidents.

At a suitable period following a HAZID: HAZOP is carried out after the Hazard Identification (HAZID) study to delve deeper into the identified hazards and assess their potential consequences.

When concept/methodology design is underway; first draft documentation/procedures issued: HAZOP is conducted during the design phase when concepts and methodologies are being developed. The focus is on evaluating the initial draft documentation and procedures to identify potential deviations.

As part of an ongoing design/system review: HAZOP can be an integral part of ongoing design and system reviews to ensure continuous assessment and improvement of the project. It helps identify any new hazards or deviations that may arise during the design process.

Continual assessment on the suitability of existing processes/methods: HAZOP can be used as a tool for continuously assessing the suitability of existing processes and methods. It aids in identifying any shortcomings or areas where improvements can be made to enhance safety and efficiency.

Review of existing processes/methods or following an incident: HAZOP can be conducted as a targeted review of existing processes and methods, especially after incidents or near-misses. It helps identify potential areas of improvement and ensures that appropriate measures are implemented to prevent future occurrences.

Input encompasses various aspects, including early stage or existing procedures, intended and/or existing operational practices. To guide the assessment process, a predetermined list of applicable guidewords is utilised. These guidewords serve as a framework for identifying potential hazards, errors, or deviations that could lead to undesirable events. By engaging personnel, considering procedures and practices, and employing guidewords, a comprehensive and effective HAZOP analysis can be conducted to enhance safety and mitigate risks.

Deviations are logged, and corresponding actions are assigned to address them effectively. A traceable log is maintained, documenting the entire process of hazard identification, mitigation, and management, including the decisions made and their justifications. To ensure safe and efficient operations, clear and concise procedures and/or actions are developed to complete activities in a prescribed manner, taking into account the identified deviations. Hazards are mitigated and managed throughout the engineering and procedural stages, and localised control measures may be introduced for further assessment during Hazard Identification and Risk Assessment (HIRA or TRA) processes. By following these comprehensive measures, organisations can enhance safety, minimise risks, and maintain control over potential hazards in their operations.

RISKUL offers a comprehensive suite of risk assessment and risk management tools, comprising five distinct methodologies organised in a hierarchy. The RISKUL HAZOP tool incorporates over 40 specific design and functionality features that are exclusive to RISKUL.

In addition to HAZOP, RISKUL encompasses other essential risk assessment methods, including HAZID, HIRA, TRA, and Risk Register. Each methodology provides unique insights and approaches to effectively identify, analyse, and mitigate risks.

We invite you to experience the benefits of RISKUL by taking advantage of our 30-day free trial. Alternatively, feel free to reach out to us for a consultation to explore how RISKUL can revolutionise your organisations risk management practices. Discover the power of RISKUL and elevate your approach to risk management.
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