About Defining Components for a HAZOP Analysis

To define components for a HAZOP Analysis, the HAZOP Analysis team will:

Review the hazardous processes that take place in a facility.
Identify the steps in those processes that cause abnormal or unsafe results.
Create records to represent the various scenarios for each process. These scenarios are the components of the analysis.

As part of defining the components, the HAZOP analysis team will:

Assess the risk associated with the components.
Determine actions that should be taken to mitigate the risk associated with the component and create records to represent those actions.

For example, assume the HAZOP Analysis team has discussed a process that is controlled by System 1A. During the discussion, the team describes the following scenario for System 1A:

When the pressure monitor stops working, the pressure switch is not triggered to open or close appropriately, causing hazardous chemicals to leak out of the connector, which may result in human injury. To prevent this condition, a toxicity detector is in place, which sounds an alarm when the toxicity levels in the facility reach a high-risk level.

To define this scenario within a hazards analysis, the team creates one record in each family described in the following table. The column In the example, this record represents contains an item from the previous example and serves as a reference for the type of information that record represents in the HAZOP Analysis.

A record in this family...	Stores...	In this example, this record represents...
Hazards Analysis System/Node	Details on the asset, asset group, or functional location that is used to perform the process.	System 1A
HAZOP Deviation	Details about the condition that deviates from the normal behavior of that process and directly leads to a risk. This condition is referred to as a deviation or guideword. A Deviation is linked to a Cause.	Pressure switch is not triggered to open or close appropriately.
Hazards Analysis Cause	Details on what has caused the deviation, including how frequently it may occur, and the asset that is associated with it. Causes can include human error, equipment failure, or other factors.	Chemicals leak
Hazards Analysis Consequence	Details on the negative outcome that results from the event that is defined in the Cause.	Multiple fatalities
Hazards Analysis Safeguard	Details on the safety precautions that are currently in place to prevent or lessen the impact of the negative outcome that is defined in the Consequence.Additional details about a safeguard defined in a Safeguard that is considered to be an independent layer of protection. Not all safeguards are independent layers of protection.	Toxicity detector

Note: If the safeguard is an instrumented function that exists within a safety system and is represented by an Instrumented Function in the GE Digital APM database, you can link that Instrumented Function to the Safeguard. For more details on instrumented functions and safety systems, see the SIS Management section of this Help system.

In addition to the records described in the table, the HAZOP Analysis team creates two Risk Assessments, where:

One is linked to the Consequence to store the unmitigated risk value associated with the scenario without a safeguard in place. In other words, the team will define the risk value that is associated with that scenario without the toxicity detector.
One is linked to the Safeguard to store the mitigated risk rank value of the scenario with that safeguard in place. In other words, the team will define the risk value associated with a scenario when the toxicity detector is in place.

Once all the safeguards that are available have been applied, the team determines if additional risk mitigation is required to meet tolerable level of risk. If the risk is to be mitigated further, then the team proposes one or more recommendations to reduce the risk to tolerable limits. A Recommendation created in a Hazards Analysis is called a strategic recommendation. It can be leveraged within a strategy to define Actions that will mitigate the risk further.