What is HAZOP and its Purpose

Learn about HAZOP, its purpose, and the reason why it is important to chemical, pharmaceutical, oil and gas, and nuclear industries

Published March 18th, 2021

What is HAZOP?

Hazard and Operability (HAZOP) is a systematic approach to determining potential problems that may be uncovered by reviewing the safety of designs and revisiting existing processes and operations in chemical, pharmaceutical, oil and gas, and nuclear industries.

What is the purpose of HAZOP?

Also known as HAZOP study or HAZOP analysis, HAZOP is a Process Hazard Analysis (PHA) method recognized in OSHA’s Process Safety Management (PSM) standard as a way to identify, evaluate, and control hazards and risks in complex processes that involve highly hazardous chemicals that can cause significant harm to workers and extensive damage to property and company reputation if not properly processed and handled.

Importance of HAZOP for multiple industries

HAZOP can help proactively catch hazards and help formulate risk mitigation early on during the planning or design stage of projects. HAZOP also helps realize risks during modification of current processes and see how deviations may occur from the design intent. As a recognized PHA method, HAZOP can also be followed during periodic reviews of operations and processes as required by regulations and industry standards.

The difference between Risk Assessment, HAZID, and HAZOP

While risk assessments, HAZID, and HAZOP all aim to uncover safety risks in the workplace, there are differences.

Risk Assessment

Risk assessment is the term used for the process of identifying risks, determining the severity of their impact, and coming up with controls to eliminate or mitigate the identified risks.

Risk Assessment Template

For identifying hazards and determining their risk rating, use this risk assessment template to record findings and provide some details on the most applicable control measures that can be used to mitigate or eliminate the risks discovered during risk assessments.


Stands for Hazard Identification, HAZID is the process of proactively identifying hazards that can affect people, property, and the environment at the early stages of a project.
HAZOP HAZOP is potentially more time-consuming because it involves the rigorous review of newly designed or already established complex processes in order to uncover potential risks and deviations from the original design intent.

HAZOP Template

You can use this HAZOP template when in the process of identifying risks in design, procedure, or operation. Using this HAZOP template to conduct a HAZOP analysis of your processes, you can:

  • Identify multiple scenarios or deviations to study;
  • determine the critical safety and improvement points for your plans, systems, or processes; and
  • immediately assign actions for urgent risks and notify the right person in real-time.

What is the HAZOP procedure and how is it done?

As HAZOP undertakes the careful review of complex processes involved in the handling and processing of chemicals and materials that can potentially harm workers and stakeholders if not properly contained and handled, it is important to follow the following steps:

1. Build a HAZOP team

Create a multidisciplinary HAZOP team composed of a team leader and members who can collaborate and provide different perspectives based on their fields of expertise at realizing sources of risks and possible deviations from design. An example of HAZOP team members would be design engineers, those who are very familiar with operations, and safety professionals.

2. Identify processes, P&ID, and HAZOP nodes

When beginning a HAZOP study, it is important to identify the processes in operations, be familiar with the process/piping and instrumentation diagram (P&ID), and be aware of all the nodes.

P&ID are drawings or diagrams that provide the visual representation of interconnected processes, equipment, and controls in the physical plant. HAZOP nodes are sections in the entire process where changes happen and they need to be reviewed along with Material Safety Data Sheets (MSDS) so that parameters can be defined and deviations are identified.

Safety Data Sheet Template

Use this SDS template when identifying chemicals and other materials’ properties that can pose hazards to workers. Completed SDS in iAuditor can be easily retrieved during HAZOP reviews.

3. Define the parameters, determine deviations, and select guide words

Define parameters or safe operating limits during the review of nodes so that deviations can be determined and guide words are selected.

Examples of common HAZOP guide words:
No or not

With the use of guide words, hazards can be clearly identified as they are the deviations that go beyond acceptable parameters or safe operating limits.

4. Identify controls and establish safety monitoring

With hazards identified, the corresponding hazard mitigation or elimination strategies should be applied to maintain the safety of the workplace. With ongoing processes and production, monitoring should also be established to ensure that safeguards are still effective and safety procedures are being followed.

Monitoring is only effective when it is actually conducted regularly. With iAuditor of SafetyCulture as mobile safety monitoring software, you can ensure that safety checks and audits are conducted regularly through scheduled inspections and automated notifications. Administrators can schedule and assign inspections and be made aware if inspections are indeed being done on time and on a regular basis. Register here for free.

Another safeguard is to automate safety monitoring through sensors. Sensors can trigger automated notifications for intended personnel whenever safety parameters are exceeded in real-time.

hazop example

HAZOP Example

This HAZOP example is a result of using this HAZOP template that you can download for free through the iAuditor app or as PDF.

5. Communicate HAZOP results and improve processes

The result of the HAZOP analysis can be used to help elevate safety within the plant and improvements in safety practices and processes should be communicated to as appropriate to employees.

An effective approach to training will also help hasten the implementation of changes and reinforce safety across the board.

HAZOP is rigorous and can take a lot of time and resources to complete, but by following HAZOP steps and using tools that can help hasten the process without compromising the quality of the process and its result, HAZOP can be effectively conducted and completed sooner and the workplace can be made safer and more efficient.


Erick Brent Francisco

SafetyCulture staff writer

As a staff writer for SafetyCulture, Erick is interested in learning and sharing how technology can improve work processes and workplace safety. Prior to SafetyCulture, Erick worked in logistics, banking and financial services, and retail.