Understanding HAZOP: The Comprehensive Guide to Methodology

Posted on Jun 09, 2023 at 10:06 PM

Hazard and Operability Study (HAZOP) is one of the most well-known techniques for managing, studying, and analysing potential industry risks. This study can be applied to any industry but is most widely used in the oil, chemical, nuclear, power, and processing industries.

In today's article, we will explain in detail to you this approach and when to apply it. We will also discuss the benefits of (HAZOP), explaining the stages of its application. 

Read on.

What Is a HAZOP Study?

HAZOP Hazard and Operability Study or Operational risk management is an internationally recognised system or technology. It is a technique that analyses, identifies, and evaluates the risks of planned or existing industrial operations and knows the degree of their vulnerability to avoid any accidents or threats within the work that may directly affect the safety of personnel or equipment or hinder work.

HAZOP studies are conducted through structured and systematic examinations based on simple guiding words for operation. For example, more, less, none, and other terms. These words are applied to different processing parameters such as (temperature, flow, pressure, etc.).

The HAZOP approach dates back to 1963, with Imperial Chemical Industries (ICI) designing a plant to produce acetone and phenol from cumene. The production manager spent a year developing and examining the possibility of applying necessary checks to the plant design to highlight deficiencies.

This is what is known today as the HAZOP study. Subsequently, HAZOP studies were developed to analyse various engineering industry systems, including chemical, oil, gas, and nuclear.

When Should a HAZOP Study Be Performed?

There are several stages in which the HAZOP approach is applied as a critical tool to determine the size of the risk and the required response speed. Here's what:

• Early in the design stage, when things are in the sketch and layout stage, the HAZOP study can thus enhance the design.
• During the construction and installation stages, This ensures that recommendations and risk mitigation measures are implemented.
• During commissioning, identify modifications that need to be implemented to reduce risks and identify operational issues.
• During operation, ensure that operating and emergency procedures are reviewed and updated regularly as required by regulations and standards.

What are the Benefits of Conducting a HAZOP Study?

Conducting HAZOP studies can be very beneficial to companies. Some of these benefits include:

• Improvements to the systems and operations.
• Reduce risk to personnel and equipment.
• More efficient operations
• Increased productivity
• Improvements to procedures; allow for policies to be done in a logical order
• Increases awareness among all parties concerned
• Facilitates team building.

How is the HAZOP Study Process?

HAZOP systematically investigates each element of the process. The goal is to find potential situations that would cause that element to pose a hazard or limit the operability of the process as a whole. There are 4 basic steps to preparing a compelling study:

• Team Setting

Like any strategy, the team is the secret of success. The team should be multidisciplinary and made up of experts with good knowledge and understanding of the parts of the system. The company must build a successful and integrated team that includes the following:

• Team Leader: A HAZOP Team Leader is responsible for defining the purpose of the study, selecting team members, planning and preparing the survey, and chairing meetings.
• Secretary: Responsible for preparing study worksheets, recording discussions during meetings, and training necessary reports.
• Team Members: The specialisation of the team members differs from one study to another about the nature of the industry in which the study is conducted and their field of expertise. For example, a processing industries team should include a project engineer, a process engineer, an electrical engineer, a safety engineer, a maintenance engineer, and an operating team leader.

Furthermore, each member of the HAZOP team is required to contribute significantly, sharing their ideas and knowledge to achieve the best results. Each member must be critical, positively and constructive.

• Identify Each Element and its Parameters

The HAZOP team will then create a plan for the complete work process, identifying the individual elements. In its work, the team reviews all available process safety information, identifies any missing parts needed to prepare an effective risk management plan, and examines each section and component of the process.

This typically includes piping and instrumentation (P&ID) diagrams, operating procedures, equipment design specifications, hazardous and flammable material properties, etc. The team then determines the operational parameters that need to be applied in each department to prevent a threat from occurring. These parameters include flow, pressure, temperature, vibration, and more.

• Consider the Effects of Variation

With each element selected, you should explore what happens when you change it from its normal state. For example, what will happen to valve X if the pressure rises or falls by large amounts unexpectedly? Will that differential pressure cause any problems?

In addition, how each component interacts with the others over time must be considered; For example, “What will happen if valve X opens too early or too late?”

• Identify Hazards and Failure Points

Where the result of a variation would be a danger to workers or the workflow, we've found a potential problem. We have to document these risks and estimate the impact of a failure at that point. This is within the framework of writing all the data obtained.

Then we must determine the probability of this failure; Is there a real cause for that? Existing protection and safety systems should be evaluated, and their ability to handle the problems that have arisen should be assessed.

• Processing Procedures

This last step is to prepare reports including all threats and apparent risks, consequences, causes, and protection requirements.

In addition, decisions and recommendations must be made to analyse potential risks and modify the process or system to evaluate results and prevent or mitigate problems. Therefore, Safety Training Courses in London are helpful for a greater understanding of preparing and implementing safety reports and managing public health and safety in the workplace.

Some typical HAZOP procedures that should be applied:

• A review of existing protection system designs by a specialised expert and compliance with the international system and standards.
• Amending alerts that warn of risks or adding them if they do not exist.
• Adding or modifying alarms that warn of deviations
• Adding or modifying relief systems if they do not exist.
• Adding or modifying ventilation systems if they do not exist.
• Increasing sampling and testing frequency.

Once the above steps are completed, the information collected can help improve the system. For example, adding warning signs or traffic lights and determining the best mechanism for applying the HAZOP study results to the studied system's nature.

In Conclusion,

The duration required to complete HAZOP studies is unpredictable. This is because such studies depend on the nature of the studied system, the team's sound knowledge of the methodology, the complexity of operations, the nature of risk, and other related factors.

However, the study should only be carried out with a discretionary agenda that can be modified and flexible according to the continuous change in the progress of the action plan.