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What is the difference between HAZID and HAZOP?

By Steve Theunissen | Last updated: February 27, 2022

Both HAZID and HAZOP are risk analysis tools used in workplace settings. They are, however, separated procedures with distinct purposes:

  • HAZOP (Hazard and Operabiltiy Study) is used to identify abnormalities in the work environment and pinpoint their root causes
  • HAZID (Hazard Identification) is a general risk analysis tool designed to alert management of any threats and hazards on the jobsite

A HAZOP study is a well-documented process that is part of a Quantitative Risk Assessment (QRA).

HAZID, on the other hand, can be carried out at a unit level and does not necessarily require much documentation.


Let's take a closer look at each procedure to better tease them apart.

Hazard and Operability (HAZOP) Study

HAZOP deals with comprehensive and complex workplace operations, which in case of malfunctions could lead to significant injury or loss of life. HAZOP studies are mainly used in the oil and gas, chemical, pharmaceutical, and nuclear industries.

The purpose of a HAZOP study is to review and study designs to identify and rectify engineering issues that could have been overlooked. It is performed by breaking complex process designs into smaller and less complex sections called "nodes" and reviewing those nodes individually.

HAZOP helps organizations deal with the following:

  • Addressing probable hazards in business operations
  • Studying past incidents that had the possibility for catastrophic consequences
  • Increasing sampling and testing frequency
  • Addressing human-controlled factors
  • Addressing consequences of failed control measures, including possible health and safety risks

HAZOP studies are performed by teams consisting of experts in areas such as operations, maintenance, engineering, instrumentation, and process design. The size of the team will depend on the process or procedure to be evaluated.

Hazard Identification (HAZID)

HAZID is a general risk analysis tool designed to alert management to threats and hazards as soon as possible. The identified hazards are classified on their probability of occurrence and the severity of the consequences.

HAZID procedures generally examine all practically potential sources of hazard during project design, construction, installation, and decommissioning activities. Once the procedure is complete, the HAZID report serves as a permanent record that can be referred to as needed.

The procedure should be performed by a qualified team who are experts on the process, materials, and work activities. They consist of subject matter experts from engineering, operations, maintenance, and other departments.

Once the study is complete, management decides whether to implement the suggested risk reduction measures to achieve its risk goals.

The objectives of HAZID are to:

  • Identify potential hazards
  • Assess the possible consequences of the hazards
  • Identify existing safeguards
  • Recommend prevention, control, or mitigation methods
  • Provide risk inputs and safety advice to design and safety management
  • Draft clear guidelines for accident event screening

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Written by Steve Theunissen

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I am a passionate writer who strives to engage the reader with the power and beauty of language. A life-long learner with the ability to adapt and enhance ideas, I have the drive, dedication and self-discipline to excel in any environment. As a teacher, I am at the coal-face of the young adult reading market on a daily basis. I will bring experience, energy, commitment and passion to your writing project.

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