Hazard And Operability (HAZOP) Study

Q1. What is the Objective of HAZOP?

A1. The objective of HAZOP is as follows:

The purpose of HAZOP Study is to identify the hazard and operability problems and to reduce the probability and consequences of an incident in the process facilities that would have a detrimental impact to the personnel, plant, properties, environment and company reputation

Q2. What is the Scope of HAZOP?

A2. The Scope of HAZOP is as follows:

HAZOP studies shall be applied to all new, continuous process designs, including package units & utility systems. However, the applicability of HAZOP during the various life cycle phases of the system is described below as per IEC 61882 STD:-

Conceptual Design phase – In this phase, the design concept and major system components are decided, but the design and documentation to conduct the HAZOP do not exist.

Front End Engineering Design (FEED) phase – During this phase, the design is developed, methods of operation are decided and documentation is prepared.

Detail Design / Engineering Phase – HAZOP Study during this phase shall be conducted after finalizing the detailed design, before the issue of important engineering drawings and documentation including P&IDs, C&E etc.,

Installation and Commissioning Phase – In case where the proper operation sequences and instructions are critical and the commissioning and operation of the system can be hazardous

Operational Phase- HAZOP Study shall be considered during Operational Phase before implementing any changes to the existing system

Q3. What reference is commonly used for HAZOP studies?

A3. The commonly used reference for HAZOP studies is as follows:

IEC 61882: 2016 Hazard and Operability Studies (HAZOP Studies) Application Guide

Q4. What is the order of precedence for HAZOP studies?

A4. The commonly used order of precedence for HAZOP studies is as follows

IEC 61882: 2016 Hazard and Operability Studies (HAZOP Studies) Application Guide,

As per Client Guidelines and

National & International reference books.

Q5. What is the methodology for HAZOP Study?

A5. The methodology for HAZOP Study is as follows:

• Data collection
• Pre-HAZOP Workshop Preparation
• HAZOP Workshop / Site visit
• Draft Report
• Comments incorporation along with CRS (Comment Resolution Sheet)
• Final Report

Q6.What are the steps for the Pre-HAZOP Workshop Preparation?

A6. The steps for the Pre-HAZOP Workshop Preparation are as follows:

• Gather Information
• MSDS Sheet Preparation
• Node Marking on P&ID
• Client Approval for Node Marking
• Discussion with Client
• Worksheet Preparation

Q7.What are documents required for the HAZOP Study?

A7. The documents required for the HAZOP Study include the following:

• Scope of work
• Approved P&IDs
• Process design basis
• Approved PFDs
• Approved Cause & Effect Diagram
• Operating & Control Philosophy Document
• Hazardous inventories and their SDS
• Process description
• MSDS or Chemical properties of RM &FG
• Safety  Test Report
• Previous HAZOP Report
• Equipment Design and Operating Condition /MOC

Q8. What are the steps for HAZOP Study?

A8. The steps for conducting a HAZOP Study are outlined below:

• Select a Node, which contains an elementary unit of the plant.
• Define the Node design intent and process conditions.
• Apply the first parameter to the node such as Flow, Pressure, Temperature, Level, Composition, etc.
• Apply suitable Guide Word such as more, less, etc. to obtain a Deviation of the Parameter.
• Identify the potential and credible Causes associated with the Deviation by brainstorming.
• Assess the Consequences of each cause.
• Identify Safeguards included in the design to prevent and/or mitigate the hazard.
• Agree a Recommendation for action if the existing safeguards are found to be inadequate. If an immediate solution is available and acceptable to the team, the modification is recorded in the HAZOP worksheet and HAZOP master P&ID will be marked up accordingly. Where solutions are unlikely to be derived without a technical evaluation, the Chairman will refer the problem for separate assessment.
• Repeat the above procedures to the next guideword (move to step 4) until these guidewords have been completed.
• Repeat the above procedures to the next parameter (move to step 3) until these parameters have been completed.
• Move to the next node (go step 1) of the process system. All process systems will be examined

Q9. What are documents deliverables for HAZOP Study?

A9. The document deliverables for the HAZOP Study are as follows:

• Executive Summary
• Document Review
• Submission of terms of reference
• HAZOP Methodology
• Risk Ranking Matrix
• Participant Attendance sheet
• Node List
• Executive Summary
• HAZOP Worksheet
• Comments Resolving sheets
• Mark Up P&ID’s
• Reference
• List of tables
• List of appendix

Q10. What are Fundamental Assumption for HAZOP Study?

A10. The Fundamental Assumption for the HAZOP Study are as follows:

• The potential for hazard and operability problems does not exist when the process is operating within its design envelope.
• Cause shall be in the same node; consequences can be anywhere in the process.
• Everything is running well and then “SOMETHING” happens

Q11. What software is to be used for HAZOP study?

A11. The software to be used for the HAZOP study is as follows:

PHA Pro version 8.19 software.

Q12. What are Exclusion for HAZOP Study?

A12. The Exclusion for the HAZOP study is as follows:

• Simultaneous occurrence of two unrelated incidents
• Operator’s negligence(Except common human error)
• Simultaneous failure of more than one independent protective device
• Natural calamity( Flood, Earthquake) except where it is design case
• External fire/escalation

Q13. What are Consideration Of Safeguards for HAZOP Study?

The Consideration Of Safeguards for the HAZOP study is as follows:

Following is deemed as protection/safeguard

• Interlock/ Shutdown system/ Trip
• Alarm system for operator action
• Sample monitoring system
• Mechanical monitoring device
• Operating instructions and operating manual
• Indicator and status signal gauges when the associated system in operator

Q14. What is Study Nodes?

A14. The definition of study node is as follows:

The Node is the portion of the plant subject to the study, where single or limited process functions are assigned.

Q15. What is Parameters ?

A15. The definition of parameters in HAZOP Study is as follows:

The usual parameters applied to all nodes are Pressure, Temperature and  Composition. Additional parameters are Flow, Level, etc. These additional parameters may be required by the nature of each node.

Q16. What is Guidewords?

A16. The definition of guidewords in HAZOP Study is as follows:

The Guidewords, such as More, Less, Reverse and Other Than, are  combined with parameters, Flow, Temperature and Pressure to derive  meaningful deviations.

Q17. What is Deviation?

A17. The meaning of deviation in HAZOP Study is as follows:

Deviations consist of a GUIDEWORD + PARAMETER

Q18. What information does the executive summary of a HAZOP Report typically include?

A18. The information which are typically included in Executive summary is as follows:

The executive summary of a HAZOP (Hazard and Operability Study) Report provides a overview of the study’s objectives, methodology, key findings, and recommendations.

It typically includes:

• Introduction: Briefly outlines the purpose of the HAZOP study and the systems/processes analyzed.
• Methodology: Describes the approach used in the study, including the team composition, brainstorming sessions, and node identification.
• Key Findings: Summarizes the significant deviations or hazards identified during the study, along with their potential consequences.
• Recommendations: Provides high-level recommendations for mitigating the identified hazards and improving the safety and operability of the system.
• Conclusion: Concludes with a summary of the overall importance of the study and any next steps.

Q19. How are recommendations typically classified?

A19. Recommendations are classified as follows:

Recommendations in HAZOP (Hazard and Operability Study) are typically classified based on their urgency, impact, and status. Here are the common classifications:

• Category A: Urgent Actions- Recommendations that require immediate attention and should be implemented before the system is commissioned or operated. These actions are critical for preventing severe consequences or hazards.
• Category B: Important Actions- Recommendations that are important for safety or operability but can be implemented after the system is commissioned. These actions should be completed within a specified timeframe to mitigate risks effectively.
• Category C: General Improvements- Recommendations that focus on enhancing overall plant performance, efficiency, or reliability. These actions typically have no immediate safety implications but contribute to long-term improvements.
• Category D: Pending Actions- Recommendations for which a final decision or conclusion is pending. These actions may require further evaluation or discussion before being classified as Category A or B recommendations.

Q20. What is the format of Recommendation Table and legends for place used?

A20. The format used for Recommendation Table and legends is as follows:

Q21. What is the HAZOP Worksheet format?

A21. The format used for HAZOP Worksheet is as follows:

Q22. What is the Comment Resolution Sheet?

A22.The meaning of Comment Resolution Sheet (CRS) is as follows:

A comment resolution sheet is a document used to track and address comments, feedback, or issues raised during a review process, audit, or evaluation.

DISCLAIMER

This Blog is provided solely for informational and educational purposes. It is advisable to verify all information presented and consult with appropriate experts or professionals before making any decisions or implementing any strategies based on the content of this Blog. HSE Risk Management Services Pvt. Ltd. accept no liability for any actions taken or not taken based on the information provided herein.