-HAZOP
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PETRONAS TECHNICAL STANDARDS HEALTH, SAFETY AND ENVIRONMENT
GUIDELINE
HAZARDS AND OPERABILITY STUDY - HAZOP
PTS 60.2209 DECEMBER 2010
© 2010 PETROLIAM NASIONAL BERHAD (PETRONAS) All rights reserved. No part of this document may be reproduced, stored in a retrieval system or transmitted in any form or by any means (electronic, mechanical, photocopying, recording or otherwise) without the permission of the copyright owner.
PTS Circular 2010 PTS No: PTS Title:
60.2209 Hazards and Operability Study - HAZOP
This revision of PTS 60.2209 – Hazards and Operability Study (HAZOP) (December 2010, Rev 2) has been updated to incorporate PETRONAS Lessons Learnt, Best Practice and new information issued by relevant industry code and standards. The previous version of this PTS 60.2209 (June 2006) will be removed from PTS binder/erepository from herein onwards.
The custodian of this PTS is: Manager - HSE MS, Standards & Regulations, GHSED. Please direct any questions regarding this PTS to the above-mentioned. Document Approval Name
Designation
Prepared
Morris Kho Kee Wee
Custodian, Safety Management Operations, Group HSE Division
Technical Approved
Morris Kho Kee Wee
Custodian, Safety Management Operations, Group HSE Division
Verified
Maureen Song Chai Kee
Approved
Mohd Tarmizi Bin Munir
Revision History Date Version Oct 2004 Original Jun 2006 Rev 1 Dec 2010 Rev 2
Date
Signature
General Manager, Group HSE Strategy and Performance, Group HSE Division Head, Group HSE Division
Description of Updates Author New PTS 60.153 HAZOP Renumbering from PTS 60.153 to PTS 60.2209 PTS Periodically Review. Restructure flow of this PTS IWG HAZOP 2 PTS 60.2209 DECEMBER 2010
PREFACE PETRONAS Technical Standards (PTS) publications reflect the views, at the time of publication, of PETRONAS Group of Companies. They are based on the experience acquired during the involvement with the design, construction, operation and maintenance of processing units and facilities. Where appropriate they are based on, or reference is made to, national and international standards and codes of practice. The objective is to set the recommended standard for good technical practice to be applied by PETRONAS' Group of Companies in oil and gas production facilities, refineries, gas processing plants, chemical plants, marketing facilities or any other such facility, and thereby to achieve maximum technical and economic benefit from standardisation. The information set forth in these publications is provided to users for their consideration and decision to implement. This is of particular importance where PTS may not cover every requirement or diversity of condition at each locality. The system of PTS is expected to be sufficiently flexible to allow individual operating units to adapt the information set forth in PTS to their own environment and requirements. When Contractors or Manufacturers/Suppliers use PTS they shall be solely responsible for the quality of work and the attainment of the required design and engineering standards. In particular, for those requirements not specifically covered, the Principal will expect them to follow those design and engineering practices which will achieve the same level of integrity as reflected in the PTS. If in doubt, the Contractor or Manufacturer/Supplier shall, without detracting from his own responsibility, consult the Principal or its technical advisor. The right to use PTS rests with three categories of users: 1) PETRONAS and its affiliates. 2) Other parties who are authorised to use PTS subject to appropriate contractual arrangements. 3) Contractors/subcontractors and Manufacturers/Suppliers under a contract with users referred to under 1) and 2) which requires that tenders for projects materials supplied or - generally - work performed on behalf of the said users comply with the relevant standards. Subject to any particular terms and conditions as may be set forth in specific agreements with users, PETRONAS disclaims any liability of whatsoever nature for any damage (including injury or death) suffered by any company or person whomsoever as a result of or in connection with the use, application or implementation of any PTS, combination of PTS or any part thereof. The benefit of this disclaimer shall inure in all respects to PETRONAS and/or any company affiliated to PETRONAS that may issue PTS or require the use of PTS. Without prejudice to any specific terms in respect of confidentiality under relevant contractual arrangements, PTS shall not, without the prior written consent of PETRONAS, be disclosed by users to any company or person whomsoever and the PTS shall be used exclusively for the purpose they have been provided to the user. They shall be returned after use, including any copies which shall only be made by users with the express prior written consent of PETRONAS. The copyright of PTS vests in PETRONAS. Users shall arrange for PTS to be held in safe custody and PETRONAS may at any time require information satisfactory to PETRONAS in order to ascertain how users implement this requirement. 3
PTS 60.2209 DECEMBER 2010
ACKNOWLEDGEMENT This document was jointly prepared with contribution from the following organizations:
No.
Name
Designation
1.
Morris Kho
Custodian, Operations Safety
GHSED
2.
Busari Jabar
Principal, Operations Safety
GHSED
3.
Syed M Nasir
Manager, Process Safety Management
GTS
4.
Amirzudin Mizuar
Staff, Process Risk Assessment
GTS
5.
M Fazaly M Ali
Staff, Process Risk Assessment
GTS
6.
M Shaik Fareed M Naja Buddin
Staff, Process Risk Assessment
GTS
7.
M Redza Harriz Zainal
HSEMS Operations Safety Exec
GHSED
4
OPUs/HCUs
PTS 60.2209 DECEMBER 2010
TABLE OF CONTENT 1.0
2.0
INTRODUCTION OBJECTIVES ........................................................................................ 7 1.1
OBJECTIVES OF THIS DOCUMENT ................................................................... 7
1.2
OBJECTIVES OF HAZOP .................................................................................... 7
1.3
SCOPE................................................................................................................. 8
OVERVIEW ....................................................................................................................... 8 2.1
THE ROLE OF HAZOP IN A PROJECT LIFECYCLE......................................... 10
2.2
THE ROLE OF HAZOP IN EXISTING PLANT .................................................... 11
2.3
2.4 3.0
4.0
2.2.1
Plant in Operation .............................................................................. 11
2.2.2
Revamp/modification projects (brown-field developments) ............ 11
OTHER TYPE OF HAZOP TECHNIQUE ............................................................ 12 2.3.1
Batch Process HAZOP....................................................................... 12
2.3.2
Activity Base HAZOP ......................................................................... 12
2.3.3
Procedural HAZOP............................................................................. 13
2.3.4
Instrumentation and Control (I&C) HAZOP ....................................... 13
INTERFACE WITH THE HSE CASE .................................................................. 14
ROLES AND RESPONSIBILITIES OF A HAZOP TEAM ..................................................15 3.1
HAZOP LEADER ............................................................................................... 15
3.2
HAZOP SCRIBE ................................................................................................ 16
3.3
HAZOP TEAM MEMBERS ................................................................................. 16
HAZOP METHODOLOGY ................................................................................................17 4.1
4.2
PREPARATION ................................................................................................. 17 4.1.1
Team Selection .................................................................................. 17
4.1.2
Resource Planning and Scheduling.................................................. 17
CONDUCTING HAZOP ...................................................................................... 18 4.2.1
Establish Scope of HAZOP study ..................................................... 19
4.2.2
Divide System into Node ................................................................... 19
4.2.3
Define a Node and Design Intent....................................................... 19
4.2.4
Select Parameter and Deviation ........................................................ 20
4.2.5
Identify all possible Causes .............................................................. 20
4.2.6
Assess all Credible Consequences .................................................. 20
4.2.7
Identify Existing Safeguard ............................................................... 20
4.2.8
Propose Recommendations .............................................................. 21
4.3
HAZOP RECORDING AND REPORTING .......................................................... 21
4.4
IMPLEMENTATION OF ACTIONS AND FOLLOW UP ....................................... 21
5.0
ASSURANCE ...................................................................................................................22
6.0
GLOSSARY .....................................................................................................................22 5 PTS 60.2209 DECEMBER 2010
7.0
REFERENCE ...................................................................................................................22
APPENDIX 1 – DETAILS OF HAZOP TYPES IN PROJECT LIFE CYCLE...................................23 APPENDIX 2 – HAZOP TEAM MEMBER FUNCTIONS ...............................................................25 APPENDIX 3 – GUIDELINE FOR HAZOP STUDY SCHEDULING ...............................................26 APPENDIX 4 – LIST OF PARAMETERS AND GUIDEWORDS ...................................................27 APPENDIX 5 – SAMPLE GUIDEWORDS AND CAUSES ............................................................28 APPENDIX 6 – HAZOP WORKSHEET ........................................................................................31 APPENDIX 7 – HAZOP REPORT FORMAT ................................................................................32
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PTS 60.2209 DECEMBER 2010
1.0
INTRODUCTION OBJECTIVES 1.1 OBJECTIVES OF THIS DOCUMENT The objectives of this document are to:
Provide an overall understanding of the Hazard and Operability (HAZOP) process and its optimum application within a project, or plant modification or Process Hazard Analysis. A reference for HCU / OPU and project managers needing guidance in implementing a HAZOP process. Provide recommended practices for undertaking studies which HAZOP leaders, scribes and team members can use as a useful reference. Ensure consistent and effective management of HAZOP studies.
Each OPU / JV shall develop their site specific HAZOP procedures based on this PTS. 1.2 OBJECTIVES OF HAZOP The objective of a HAZOP is to carry out a rigorous and systematic evaluation of process systems with respect to operational safety and potential hazards with foreseeable upsetting conditions. This can be summarized as follows:
To identify/analyze potential hazards and operability issues due to deviations from normal process or operating conditions or intended design in a systematic manner. To evaluate the adequacy of the existing safeguards with respect to safety and operations to address the causes and / or the consequences. To identify additional safeguards required for the system under study to address the causes and minimise the consequences of deviation. To recommend ways to mitigate the Consequences of deviations and return to normal and safe operations.
It is beneficial to undertake HAZOP early in the lifecycle of the facility as it is easier to change the design of the facility rather than modify it later as shown in Figure 1.1 Time/Benefit/Cost Graph below. This does not mean that it is not beneficial to undertake HAZOP on operational facilities. However, it is to note that implementing the recommendations is easier during the design stage of the facility lifecycle.
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PTS 60.2209 DECEMBER 2010
Figure 1.1: Time / Benefit / Cost Graph 1.3 SCOPE The document shall be applied to the development, planning, implementation, follow up, auditing and reviewing of all HAZOP study within PETRONAS Group of Companies activities. This scope encompasses all PETRONAS HCU / OPU / JV existing facilities and any future developments
2.0
OVERVIEW
HSE management is a key consideration for all plant, driven both by company philosophy and external requirements. New technologies and the trend towards complex integrated designs have resulted in the need for more thorough and systematic methods to identify and assess hazards. HAZOP is a structured hazard identification tool using deviation analysis by a multi-disciplined team. It has become accepted as the main technique for the identification of process hazards in the design and operation of a facility. Other hazards identification techniques by discipline review or compliance with checklists are limited by their reliance on previous experience and constrained by their approach. HAZOP is based on brainstorming and has advantages over other techniques for non-standard designs. The strength of HAZOP technique is it allows personnel from all disciplines to interact and question aspects of the facilities beyond their usual sphere of activity. One formal definition would be 'The application of a formal systematic examination to the process and engineering intentions of new or existing facilities to assess the potential of mal-operation or malfunction of individual items of equipment and their consequential effects on the facility as a whole. The method is applicable to:
Periodically assessing hazard (PHA) in existing plant (Refer to PTS 60.2204). 8 PTS 60.2209 DECEMBER 2010
Plant modifications as identified by MOC (refer to PTS 60.2201). Greenfield developments. Brownfield projects. Operating procedures Instrumentation and Control. Preparation for CIMAH Report, DOSO Report, HSE Case and other relevant statutory requirements.
The HAZOP methodology can be summarized by schematic in Figure 2.1.
Select NODE, State INTENT, Select PARAAMETER + GUIDEWORD IDENTIFY
BRAINSTORM CAUSE DEVIATION
ASSESS NO
CAUSE Is it possibly? Is it likely? YES
NO
CONSEQUENCES Can safeguards fail? Does it matters? YES RECOMMENDATION Figure 2.1 HAZOP methodology
HAZOP represent one of the methods available to be applied in the Hazard Identification phase of HEMP, which is the methodology employed to achieve demonstrably the HSE objectives which are defined in, and to be managed by, the HSE MS. The relationship between this document and its component parts and HSE MS is shown schematically in Figure 2.2
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PTS 60.2209 DECEMBER 2010
Figure 2.2: HSEMS Relations with HAZOP 2.1 THE ROLE OF HAZOP IN A PROJECT LIFECYCLE In a project lifecycle normally different type of HAZOP is applied at different stage of project as demonstrated in Figure 3.1. The sequence of HAZOP studies should be planned, varying in scope from conceptual to detail. Planned HAZOP studies should be included in the Project Schedule on the critical path, with the timing determined by the availability of the PSI (Refer to PTS 60.2203). It is the responsibility of the project manager to determine whether HAZOPs are needed, when they are required, and which type of study is appropriate (Refer to 60.2206, DI). Details of each type of HAZOP in a project lifecycle are described in Appendix 1.
Procedures Coarse HAZOP
HSE HAZID
Final HAZOP
Main HAZOP
Minor Change Mini HAZOP Identification Phase
Definition Phase
Execution Phase
FRONT END LOADING FRAMING
EXECUTE FEL 1
FEL 2
FEL 3
START UP OPERATION
Figure 3.1: Sequence of HAZOP Studies throughout a Project Lifecycle 10
PTS 60.2209 DECEMBER 2010
2.2 THE ROLE OF HAZOP IN EXISTING PLANT 2.2.1
Plant in Operation Existing plants have an inherent hazard potential. Plants can continue in operation for several years and may undergo minor modifications and debottlenecking several times. Older plants may also never have been subject to a HAZOP study. There is an increasing need to demonstrate adequate management of hazards for existing facilities, especially those that require a HSE Case. HAZOP is a valuable tool for this purpose for existing plant.
2.2.2
Revamp/modification projects (brown-field developments) The objective of a HAZOP of a brown-field development is to ensure that the proposed modification is safe and operable. Interfaces between the modification and the existing facilities must not jeopardise the original design basis of the facilities. Essentially a brown-field HAZOP is conducted identically with a green-field project. Difficulties may arise however when establishing the scope and information required for the study. In summary the main concerns when preparing for a HAZOP on a brown-field project are:
The selection of the nodes for a modification HAZOP should reflect the interfaces with, and allow analysis of, the effects on the surrounding systems.
The interfaces between the new and existing plant (tie-in points, etc) must be sufficiently understood and documented so that the team can establish if any hazards can cross the boundary.
The physical interfaces of the new with the existing installation shall be clearly shown on the HAZOP drawings. Prior to the study the process engineer shall analyse the extent to which the process parameters change within the existing facilities due to the modification (including those that have to be made to other systems to accommodate the new facilities, e.g. changes in relief valve sizes). He shall mark up the HAZOP drawings accordingly. Nodes should include all parts of the existing facilities where a change in process conditions is caused as a result of the modification. Likewise the operator shall analyse the applicability of existing procedures to the modification and the applicability of any modified procedures to the modifications as well as to the existing plant.
Sufficient design and operating information must be available for all common systems (vents, drains, etc) as well as the existing plant local to the tie-in points liable to be affected by the new development.
If the design codes and practices differ for the existing and new plant the consequences must be fully understood and screened. A particular problem with major modification projects is the potential compatibility problems between old and new design codes and project standards. The scope of the application of new codes and standards should be established as part of the project philosophy. The HAZOP should focus on ensuring that the philosophy is consistently applied across the modifications.
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PTS 60.2209 DECEMBER 2010
The design must clearly identify and address intermediate operating modes whilst the new plant is being constructed and commissioned. Sufficient information must be available to the HAZOP team to assess the intermediate operating mode risks.
On brown-field projects there is often a concern to minimise disruption and lost production, with commissioning of new equipment in parallel with the existing equipment. This may result in a series of short-term hook-up arrangements, which are potential sources of hazards. Consideration should also be given to the increased numbers of personnel likely to be required during modification projects. The intermediate phase of the change-over from old to new systems should be treated as a separate operating phase. This may mean that the modifications require a number of individual HAZOPs to ensure the inter-stage steps of the revamp work are adequately considered.
2.3 OTHER TYPE OF HAZOP TECHNIQUE A part from the normal HAZOP Technique or also known as the Continuous HAZOP, there are other variation of HAZOP Technique for special cases or situations e.g. Batch Process, Activity Base, Procedural and Instrumentation and Control. 2.3.1
Batch Process HAZOP The HAZOP method for batch processes deals with each part of the plant in exactly the same manner as the more familiar method for continuous processes. Differences occur when the team examines the changes in plant configuration as the steps in the batch process are progressed. The status of the system changes frequently and in order to perform an adequate study, the valve positions and process conditions must be adequately described for each separate stage. As these are normally cyclical operations, it may be necessary to prepare diagrams showing the status of each line and vessel throughout the process. Operating instructions, including logic diagrams or instrument sequence diagrams, are essential in understanding the steps. Time-dependent concepts (sooner/later) are added to the guide words. The method is the same as normal but examines the changes in plant configuration as the steps in the batch process are progressed
2.3.2
Activity Base HAZOP The activity HAZOP technique consists of the systematic critical search for deviations and hazards applied to activities and the facilities involved in operations. The technique examines sequences of mechanical and manual handling operations. The study can be held at any time during the project phase, the level of detail and study technique being dependent on the timing chosen. Activity-based studies may however be required for the small number of potentially difficult activities that are not continuous, and do not form a part of the daily operations workload. Such activities may be:
Drilling Unloading at a jetty Well workover Shutdown. 12
PTS 60.2209 DECEMBER 2010
The basic technique is the same as other HAZOPs. Specific activity guide words, etc., are used. These include incorrect activity and the time/movement elements of movement and early/late operation. Additional parameters included are: time, decision and position The recommendations from an activity HAZOP are not necessarily limited to the operating procedures. Changes both to the design of the equipment and the operating procedures may be suggested. 2.3.3
Procedural HAZOP Safety-critical procedures should be explicitly studied as a primary document, with guide words applied directly to the steps in the procedure. Procedures are unlikely to be available in sufficient detail until the Main or even Final HAZOP. Procedural HAZOPs may be particularly beneficial for an existing (older) plant. Procedural HAZOP meetings may include any operating procedure written for a plant and may be conducted in addition to the normal HAZOP for that equipment item or dealt with separately. They are usually conducted however on the activities such as:
commissioning pigging inspections start-up maintenance plant testing safety critical operating procedures.
The standard guide words of No, More, Less, As Well As, Part of, Reverse and Other Than take slightly different meanings. The results will specifically affect the operating procedures and in some cases may have an impact on the design of the equipment 2.3.4
Instrumentation and Control (I&C) HAZOP Normal HAZOP does not identify all the potential I & C system related hazards because the P&IDs give only the brief I & C system information. A more detailed HAZOP on the I & C system will identify causes and consequences of I & C system failure. I & C HAZOP should be done after the normal HAZOP where more detailed study of critical I & C loops identified during the P&ID HAZOP and Process design is frozen following the Normal HAZOP therefore providing fixed functional specification for I & C system. Technique for the I & C HAZOP is similar to that for the conventional HAZOP and also similar guidewords are used but on the control diagrams/specifications and information are reviewed section by section. The result will affect design of the control system and modifications are made if necessary.
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2.4 INTERFACE WITH THE HSE CASE There is a relationship between a HAZOP study (or any other HEMP study) and an HSE Case. This is best considered separately for existing facilities and new developments. New developments An HSE Case is likely to be planned for any significant new development. As a means of commencing the process of compiling the HSE Case, but particularly part 5 - the Hazard Register - an HAZID study may have been performed. Alternatively during the initial design phase a separate study or process may have been put in place specifically to collect information for the Hazard Register. This information may thus be available to the HAZOP team as part of the information pack, i.e. as an inventory of the HSE hazards pertinent to the development. It should be noted however that the Hazard Register may not at this stage have identified all the hazards inherent in the design, nor assessed the hazards in any significant depth. There are no specific guidelines on the process of documenting the HSE Case as a project design matures, however it is most likely that the HSE Case will evolve either progressively or step-wise throughout the engineering phase, and be published around the time of plant startup. The HSE Case (Hazard Register) may then contain reference to HAZOP study findings, and/or transcribe/summarise from the HAZOP report information on the safety critical equipment, systems and procedures, in order to comprehensively demonstrate management of hazards. It may include such items as the sequential analysis and protection measures discussed in the HAZOP report for a particular deviation from design intent, i.e. where the consequence of that deviation presents significant risk. The HAZOP study therefore is of one of the important information sources for completion of HSE Case. Existing Facilities For existing facilities the compilation of a HSE Case may indeed be the cause of the HAZOP study, i.e. as a means to demonstrate adequate assessment of the hazards inherent to the process. In such situations the HSE Case will also refer to or transcribe information from the HAZOP report. Even if this is not the case, the relationship between HSE Case and HAZOP report is similar. Modification Projects Where a plant is undergoing modification or revamp, the HAZOP study should draw on the HSE Case as part of the information pack, and similarly on completion of the study the results of the HAZOP should be incorporated into the HSE Case.
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3.0
ROLES AND RESPONSIBILITIES OF A HAZOP TEAM
The HAZOP team shall consist of multi-disciplined personnel and the brainstorming procedure relies on the broad experience of the team to identify potential hazards and operability problems. A balanced team is required to provide an appropriate level of project/process knowledge coupled with independent members providing relevant expertise. A HAZOP team usually consists of five to eight people although a smaller team may be sufficient for a small facility or a minor modification, and in these cases three to four is adequate. More may be required in a hand-over meeting where two project teams are represented. This is often the case for studies where there is some duplication in client and contractor representation. Generally, a HAZOP team comprises of: HAZOP Leader Scribe HAZOP team members - Process Engineer - Project Engineer - Operation Personnel - Instrument (Control System) Engineer - Maintenance Personnel - Vendor / Contractor representatives - Specialist Engineers If the team is too large, the group approach fails because so many people are trying to communicate with one another and are inhibited from working closely. It is also highly probable that a large team will result in high number of spectators in the team. On the other hand, if the group is too small, it may lack the breadth of knowledge needed to help assure completeness and creativity generated by interactions of multiple-disciplined members. 3.1 HAZOP LEADER Roles & Responsibilities HAZOP leader shall be independent of the facility / project under study to ensure impartial assessment. The main role of the HAZOP Leader can be broken down into the following sections: Preparation Facilitate the HAZOP study Produce HAZOP report Action response follow up Competency HAZOP leader shall have minimum competency requirement as follow but not limited to: Experience - Sufficient experience in the oil and gas industry or an equivalent process industry, both in theoretical and practical application of the design and operation of oil and gas production/processing facilities. - Adequate knowledge of equipment, procedural and human failures that can lead to major incidents, with a sound appreciation of process design and safeguarding. - Aware of technical standards and regulations 15
PTS 60.2209 DECEMBER 2010
Training - Attended both the HAZOP and management techniques including a recognized HAZOP leadership course, which meets requirements this PTS. - Undergone mentoring with competent HAZOP leader. - Appreciation of other risk assessment techniques. Facilitation skills - Hazard identification skill. - Suitable application of the HAZOP methodology to identify significant hazards and issues. Time management skills - Ability to plan the study in depth and estimate the time required for the HAZOP. This includes maintaining the pace and momentum of study and suitable allocation of time for deliberation of issues. Communications/motivation skills - Able to keep the team’s focus and working together and motivate all members of the team. - Form a good working relationship with the Scribe and supervise the Scribe's work to ensure that adequate minutes are recorded. 3.2 HAZOP SCRIBE Roles & Responsibilities The role of HAZOP scribe is to record discussions during HAZOP study. The record shall be complete, clear, and accurate. This includes a complete record of points discussed and not just a record of recommendation Competency HAZOP scribes should have training and experience similar to that required by the Leader. The Scribe should also be able to take minutes in a concise and accurate manner using plain language. 3.3 HAZOP TEAM MEMBERS Roles & Responsibilities HAZOP team members are responsible for providing essential information and input through active involvement in workshop and contribute their skills, knowledge and experience to the process. Competency HAZOP team member should have minimum competency requirement as follow but not limited to
Sufficient experience and knowledge of respective area and discipline both in theoretical and practical application of the design and operation of the facility / unit under study. At least one team member should have sound knowledge in codes, standards. Adequate knowledge to anticipate potential equipment, procedural and human failures operational with a sound appreciation of process design and safeguarding.
Detail description of function for individual discipline for HAZOP team member is summarized in Appendix 2.
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PTS 60.2209 DECEMBER 2010
4.0 HAZOP METHODOLOGY 4.1 PREPARATION Activities that shall be carried out prior to HAZOP study sessions to ensure effectiveness of the HAZOP study is described below: 4.1.1
Team Selection HAZOP Leader shall select and determine the HAZOP team members. This is normally based on the scope of HAZOP study. Appendix 2 provides a guideline on selecting HAZOP team members.
4.1.2
Resource Planning and Scheduling HAZOP leader shall ensure that administrative requirements (e.g. room, refreshments, meeting notification), tools (e.g. briefing package, software) and updated information package (e.g. PEFS, CSDS / MSDS, plot plan) are sufficient to ensure effective HAZOP. Information package required depends on type of HAZOP study i.e. Coarse HAZOP, main HAZOP, Final HAZOP, and Mini-HAZOP. HAZOP Leader should plan and schedule the study to optimize time and resources. Required time to complete HAZOP of one PEFS depends on the complexity of the facility. Correct estimation of HAZOP duration is important to ensure availability and commitment of team members. If the study includes several operating modes this will add significantly to the time required. The best assessment method is to estimate the number of additional case nodes that will be studied and allow about half the time of the original node for each one. For identical process units / trains, the time estimation for the second and following unit maybe reduced but specific issues shall be reviewed and addressed adequately e.g. maintainability, interconnection between trains, equipment siting, preferential flow. Typically, time frame for HAZOP can be estimated using table in Appendix 3.
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PTS 60.2209 DECEMBER 2010
4.2 CONDUCTING HAZOP The Typical HAZOP work flow is summarized in figure 4.1 below. The work flow is also applicable for other HAZOP techniques e.g Batch Process, Activity Base, Procedural and Instrumentation and Control.
Divide System into Node
Define Node and Design Intent
Select Parameter and Deviation
Identify all Possible Causes
Assess all Credible Consequences
Identify Existing Safeguards
Propose Recommendations (if necessary) No
Last Deviation? Yes No Last Node? Yes END Figure 4.1 Typical HAZOP work flow
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PTS 60.2209 DECEMBER 2010
4.2.1
Establish Scope of HAZOP study HAZOP leader shall establish the scope of the study, appropriate HAZOP technique and the assumptions with agreement with team members to be applied throughout the studies. Typical assumptions for HAZOP study is as follow but not limited to;
In principle, only single failure results in hazard – no double jeopardy All equipment were well designed, manufactured and properly installed and inspected Facilities are well maintained and operated with acceptable standard and in accordance with applicable Operating Procedure. The system will perform as the design intents Generally, failure of instruments gauges were not considered All safety interlocks and PLC for valve sequence considered functioning as intended.
Careful consideration should be taken when applying these assumptions so that significant hazard will not be overlooked. 4.2.2
Divide System into Node HAZOP Leader and with agreement with team members shall determine the selection of the node sizes and the route through the system s before starting the study. The HAZOP Leader shall select the nodes based on the stage of the project life cycle and the amount of information available. A HAZOP study progresses through the system node by node. A node is a manageable segment of system which has distinct design intent. The node, typically comprise one major equipment (vessels, etc.), associated minor equipment (pumps, valves, etc.), instrumentation, and other ancillary equipment. Normally, the selection of node should follow the process flow. Start at an isolation point (valve or equipment item) of where the line enters or leaves the P&ID. HAZOP Leader should mark up the nodes in the document for differentiation and assist the study.
4.2.3
Define a Node and Design Intent HAZOP Leader with assistant with team member shall define and record the node and its design intent. The design intent should provide specific information on how the node will be operated under all system operating conditions (described parameters such as pressure, temperature, flow rate, level, etc.). HAZOP team member should give a brief description of the design intent and also specific hazard at the beginning of each node. Similarly they should give a brief stepby-step description of start-up and shutdown actions before these topics are addressed.
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PTS 60.2209 DECEMBER 2010
4.2.4
Select Parameter and Deviation HAZOP Leader shall select and record the parameter and deviation relevant to the nodes, mode of operation and HAZOP technique applied. Parameters and Deviations are the key to the HAZOP process. They are difference from the design intent of the process and are identified by the systematic application of the appropriate parameter/guide word combinations Not all parameters are applicable to each node. A parameter may only be left out if the Leader thinks fit. He should tell the team why it is not relevant, e.g. level on a flow line. Appendix 4 shows the list of parameters and guidewords normally used in various types of HAZOP technique.
4.2.5
Identify all possible Causes HAZOP Team shall identify and record all possible causes of a node guided by the parameter and deviation selected. The possible causes shall be within the node (Except for nodes at interfaces, battery limit or beginning of a system), credible and specific in the description. Avoid double jeopardy scenarios but not to be mistaken with latent failure. Brainstorm and list all the possible cause before proceeding with the consequence
4.2.6
Assess all Credible Consequences HAZOP Team shall assess and record the credible consequences of each cause by assuming assume there is no safeguard in place. The consequence statement shall consist of the initial system response to the worst credible consequence. Consequence also can be upstream or downstream of the node under study but not as detail as within node. Consequences should consider the effect to People, Environment, Asset and/or Reputation.
4.2.7
Identify Existing Safeguard HAZOP Team shall identify and record the existing safeguards. The safeguards can be within or outside the node (upstream or downstream) Safeguard shall be able to address causes and consequences. E.g. alarms shall be together with operator actions and must be adequate for the system. Safeguards can be categorized into these three types:
Prevention - prevents deviation from happening (e.g., check valves, relief, trip system) Detection - detects causes or consequences (e.g., alarms) Mitigation - control or reduce the consequences (e.g., ERP, Tank bund ) 20
PTS 60.2209 DECEMBER 2010
4.2.8
Propose Recommendations HAZOP Team shall propose and record recommendations when they feel that existing safeguarding system is not adequate to protect the system under study. The recommendation shall address the cause and the consequences. The HAZOP Team should generate specific recommendations that address the risk exposure, and be clear on what they consider to be the most appropriate option. Recommendations can generally come in two forms:
Definitive – Recommendations that are implementable as they stand. Initiating – Recommendations that initiate further work to clarify the required actions
Preferably, HAZOP team should propose definitive recommendations. However, if the team could not agree or significant time is required to deliberate in certain issue, the team may propose initiative recommendation. Recommendations should be presented in the form:
What is required to be done Where the recommendation applies Why the recommendation should be completed
HAZOP Leader should identify the responsible person and due date for any recommendation(s) issued. 4.3 HAZOP RECORDING AND REPORTING HAZOP discussion shall be recorded in HAZOP worksheet (See Appendix 5 for typical HAZOP worksheet). The record shall complete & accurate. This includes recording all deviation discussed even though the deviation does not cause significant consequences and no recommendation generated. HAZOP Leader shall prepare the HAZOP Report after completion of a study. The HAZOP report is an important document describing the objectives and success of the whole study and is used to compile and preserve the results of the study for future reference. HAZOP final report format should follow reporting format as shown in Appendix 6. The draft final report should be reviewed by team members prior to the formal and, timely issue. HAZOP Final report shall be distributed to relevant parties affected by the HAZOP studies. 4.4 IMPLEMENTATION OF ACTIONS AND FOLLOW UP The relevant Facility/Project Owner for each HAZOP is accountable for the implementation of the recommendations. The recommendations arising from the HAZOP study shall be presented to the Facility/Project Owner by the HAZOP Leader or representative. This provides an opportunity to challenge the recommendations and to agree on actions, assign responsibilities and define priorities for implementation. Where the priority of a recommendation is downgraded or the recommendation is rejected, this shall be supported by a sound justification. Alternative recommendations shall be provided to justify rejection of recommendations.
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PTS 60.2209 DECEMBER 2010
Some of the HAZOP recommendations may require the MOC process be invoked. The Facility/Project Owner shall ensure that the MOC system is applied for the agreed project scope. If another alternative is being proposed or if the recommendation is cancelled upon detailed study, this shall be formally documented by the Facility/Project Owner. This is important to record the justification or assumptions. At an established and agreed period after the recommendation has been implemented, the Facility/Project Owner shall be responsible for assessing the effectiveness of the recommendation (i.e. did it adequately address the risk?). If the recommendation is found to be ineffective, remedial action shall be taken. The Facility/Project Owner shall monitor the ongoing implementation of the safeguards. All the recommendations arising from the HAZOP studies shall be tracked in accordance with the Facility/Project Owner’s plan and progress reported to the HCU/OPU Management on a regular basis. If recommendations cannot be implemented in a timely manner, the Facility/Project Owner shall provide a rationale and revised timeframe to the HCU/OPU Management. 5.0 ASSURANCE HCU/OPUs shall assess the quality, adequacy, and effectiveness of the HAZOP study through Assurance process. The purposes of the Assurance are to:
Determine whether HCU/OPU’s HAZOP procedures and practices are complete, up-todate and compliant with applicable governmental regulations, policies and good HSE management practices. Determine whether HAZOP study is conducted, effective, apply good engineering practices and meet the requirements of the HAZOP methodology. Determine the status and quality of HAZOP recommendations versus identified objectives, goals and/or other targets.
6.0 GLOSSARY A glossary of commonly used terms in HSE is given in both PTS 60.0101 HSE Management Systems and PTS 60.0401 Hazards and Effects Management Process. 7.0 REFERENCE The following references are considered to provide useful guidance to support the HAZOP process.
PTS 60.0401 Hazard and Effect Management Process Guideline for Hazard Evaluation Procedures, CCPS PTS 60.0101 Health, Safety, and Environmental Management Systems Manual PTS 60.0107 Design PTS 60.2206 Design Integrity PTS 60.2204 Process Hazard Analysis PTS 60.2203 Process Safety Information PTS 60.2201 Management of Change
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PTS 60.2209 DECEMBER 2010
APPENDIX 1 – DETAILS OF HAZOP TYPES IN PROJECT LIFE CYCLE HAZOP Types
HAZID
COARSE HAZOP
MAIN HAZOP
Description
Timing & Documentation
Scope & Purpose
Results
This is a hazards and effects identification technique using similar analysis and brainstorming techniques to HAZOP, but designed to be used at a much earlier stage in the project. Concentrates on wider health, safety and environmental issues with less of a process focus. HAZID is included here because it is complementary to Coarse HAZOP and in certain circumstances the two study types can be combined.
Described in PTS 60.2004 Hazards Identification (HAZID)
Described in PTS 60.2004 Hazards Identification (HAZID)
Described in PTS 60.2004 Hazards Identification (HAZID)
This uses the full HAZOP methodology but is intended to be used early in a project's life where there is still the 'ability to change the design, operating and maintenance policy'. The plant is divided into a small number of large nodes appropriate for an early stage in the design development. This study has the objective of making the plant inherently safe before many detailed engineering decisions have been made. It is particularly useful before the award may be of particular use prior to the letting of a design contract to ensure that the consultant/contractor is provided with a sound design.
The requirement for a coarse HAZOP is that the design has progressed to the point where the Process Flow Scheme (PFS) has been developed showing all major lines and equipment. Typically this is at the end of the development of the project's basis for design. The documents required are:
The Coarse HAZOP would usually be the first HAZOP study for a project. It often represents the first opportunity for all the design disciplines, project management and operations to be involved in a complete review of the project. The key objective is to optimise the design and minimise any significant rework, which would cause slippage of the schedule. All the project disciplines should have senior representation and the composition of the team is critical to the HAZOP's success. This study presents the best opportunity to challenge many of the basic process assumptions used in the design. It may be a relatively short study applying the full HAZOP technique to large nodes appropriate to the limited engineering details that are available
This project stage is the most appropriate time to call for detailed QRA studies or other supporting investigations. Qualitative Risk Analysis is helpful in identifying the issues or giving major concerns.
This study should be held at the end of the project specification phase (front end engineering phase) of a project. Its objective is the assurance of the HSE safety of the current design ('Will it Work?') rather than making radical recommendations for change. This is the primary HAZOP study for any project using the full technique and addressing all the details of the plant. objective is to look in detail at all aspects of the design, and the main HAZOP will be the most comprehensive HAZOP study within the project.
The study should be held at the end of the project specification phase. The Process Engineering Flowsheets (PEFS) or Process and Instrumentation Diagram (P&IDs) should almost be of Approved For Design (AFD) quality and signed off by the Project Manager as suitable for HAZOP purposes. Any changes to the PEFS or P&IDs following this HAZOP should be covered by formal Management of Cchange control procedures, which itself should potentially include a Minor Change (Mini-) HAZOP. The documents required are: Process Engineering Flowsheets (PEFS) or P&IDs Process Flowsheets (PFS) Plot Plans Cause and Effect Diagrams
The main HAZOP is the most comprehensive study in the project and examines in great detail all aspects of the design.
The detailed report of the study should catalogue all the hazards identified and all areas where there was insufficient information or gaps in the knowledge of the team. It should be remembered that the Main HAZOP is usually too late to start challenging basic concepts in the design of the plant.
Process Flow Schemes (PFS) full mass balance information plot layout process description including all operating modes project definition including lifecycle issues and planned plant flexibility HSE policy preliminary operating and maintenance philosophy and product off-take constraints.
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PTS 60.2209 DECEMBER 2010
HAZOP Types
Description
Timing & Documentation
Scope & Purpose
Results
Process Safeguarding Drawings Interconnection Diagrams and old PEFS legend details Local population densities and infrastructure, areas of particular sensitivity (local rivers, marshes, etc). Operating Philosophy HSE Safety Policy Philosophy Evacuation Philosophy previous HAZOP meeting minutes/action lists
FINAL HAZOP
This study is held at the end of the detailed design stage when drawings are ready to Approve for Construction. The technique is the same as the Main HAZOP except that the study focuses on changes since the Main HAZOP, rather than reviewing the agreed design. The final study is required to look at changes made to the Approved For Design (AFD) drawings resulting from the contractor's detailed design effort and the availability of vendor's information. The technique is the same as the Main study but the team is limited to looking at changes rather than reviewing the agreed design
The PEFS or P&IDs should be of preApproved For Construction (AFC) standard and signed off as agreed for the HAZOP. Any changes to the PEFS or P&IDs following this study should use a Variation Change Control (VCC) procedure which itself should include a Minor Change (Mini) HAZOP
The concept is to extend the Main HAZOP, picking up on details that were not available at the last meeting, and concentrating on the changes to the design, and the additional vendor details. This should be a shorter meeting than the Main HAZOP but the time required depends significantly on the quality of the AFD drawings used for the Main study and the number and control of subsequent design changes
At the end of this meeting the design should be frozen and the HAZOP exercise complete. The AFC drawings should be frozen once the recommendations of this study have been reviewed and incorporated.
The documents require are similar to MAIN HAZOP but focus on the change.
MINOR CHANGE MINIHAZOP
This study, usually linked to a Management of Change control procedure, can be applied at any stage in the design development or subsequent operation of the facility to assess proposed changes or vendor package details. The methodology is similar to that of a HAZOP for a brown-field development A safety statement should be issued on each change to confirm that it does not affect the safety of the main plant. Several minor changes can be studied together once the net effect is seen to have a significant effect on the design or operation of the plant.
It is necessary to carry out formally HAZOP studies for minor changes to the drawings following the Main HAZOP. Such a meeting would not require the full team used for the Main HAZOP but just the core members involved in that area of the plant.
The detailed report of the study should catalogue all the hazards identified and all areas where there was insufficient information or gaps in the knowledge of the team.
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PTS 60.2209 DECEMBER 2010
APPENDIX 2 – HAZOP TEAM MEMBER FUNCTIONS Team Member
Type of HAZOP
ROLE
Process Engineer
Provide expertise on the process design and intended operation of the plant. It is important that the individual has a full knowledge of the design history of the part of the plant being studied as well as a deep overall understanding of the whole plant. For large projects it may be advisable to include the process discipline supervisor who has knowledge of the whole plant, supported by the appropriate lead engineers who may have more detailed knowledge of the area under study for each session.
Project Engineer
To ensure that the objectives of the project are understood throughout the study. These may include commercial as well as technical constraints on the plant.
Operations and/or Maintenanc e Personnel
Representation from the eventual operators of the plant is essential. They can contribute in providing key information on intended work practices as well as experience of operating issues on similar equipment. If the study is undertaken during a contractor's design phase, the client should supply the operational input rather than the Contractor.
Instrument (Control Systems) Engineer
The instrument engineer has a far wider involvement in the plant design and operation than the other 'specialist' engineers. Many of the control and automatic protection devices are plant-wide in their application and it is therefore often advisable that he is a member of the core team contributing to the whole study.
HSE Engineer/ specialist
For many studies the HSE engineer is included in the core team. If the project or process engineer is responsible for undertaking the QRA studies and assessing the overall level of process risk, then part-time involvement of the HSE engineer is adequate. He may provide the expertise to the team on consequence assessment (flame length, etc) and on historical failure probabilities.
Machinery specialists
Machinery and packaged equipment issues rarely extend far beyond the machine itself, hence the machinery specialist is only required whilst the individual equipment issues are discussed.
Vendor's representati ves
Once vendor designs are available it is advisable that a vendor representative is present whilst the package is studied. The level of representation will depend on the size and complexity of the package. It is often advisable to hold Mini-HAZOPs of complex packages during the vendor's design rather than wait to review a completed design. In most HAZOP studies the requirement for civil engineers is limited and it is usual for them to be called upon when required or for specific sections of the plant, e.g. drainage routing.
Civil/Struct ural Engineers Specialist Engineers (piping, instrumentat ion, electrical, corrosion, etc)
The requirement for specialist engineers is similar to civil engineers or machinery specialists. Examples would be the need for electrical engineers when considering the interface between power utilities and the plant, and the potential for common mode failures.
Coarse
Main
Mini
Final
Batch
C
C
C
C
C
C
C
P
C
C
C
C
C
C
C
C
C
C
C
C
C
C
P
C
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
Procedural Activities
C
P
P
P
P
C = Core team member P = Part time team member 25
I&C
PTS 60.2209 DECEMBER 2010
P
P
APPENDIX 3 – GUIDELINE FOR HAZOP STUDY SCHEDULING
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PTS 60.2209 DECEMBER 2010
APPENDIX 4 – LIST OF PARAMETERS AND GUIDEWORDS Guideline for Guideword Selection for Various Types of HAZOP
DEVIATION PARAMETER FLOW
PRESSURE LEVEL TEMPERATURE TIME
STEP
ACTION
SEQUENCE INFORMATION
CURRENT
AIR VOLTAGE INTRUMENTATION RELIEF CONTAMINATION PROPERTIES RUPTURE / LEAK IGNITION SERVICE FAILURE ABNORMAL OPERATION SAMPLING SPARE EQUIPMENT MAINTENANCE CORROSION / EROSION SAFETY
HAZOP TYPE
GUIDEWORDS
CONTINUOUS PROCESS
NO MORE LESS REVERSE MORE LESS MORE MORE LESS NO MORE LESS WRONG SAME TOO LATE TOO EARLY LEFT OUT BACKWARD NONE REVERSE (WRONG) MORE LESS OTHER THAN NONE REVERSE (WRONG) MORE LESS NO REVERSE MORE LESS NO MORE LESS OTHER THAN OTHER THAN OTHER THAN OTHER THAN OTHER THAN OTHER THAN OTHER THAN OTHER THAN OTHER THAN OTHER THAN OTHER THAN OTHER THAN OTHER THAN
BATCH PROCESS
PROCEDURAL / ACTIVITY
I&C
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PTS 60.2209 DECEMBER 2010
APPENDIX 5 – SAMPLE GUIDEWORDS AND CAUSES PARAMETER
GUIDEWORD NO
MORE FLOW LESS
REVERSE
MORE PRESSURE
LESS
LEVEL
MORE
INSTRUMENTATION
OTHER THAN
RELIEF
OTHER THAN
CONTAMINATION
OTHER THAN
PROPERTIES
OTHER THAN
EXAMPLES Block valve closed , wrong line up, slip blind installed, incorrectly installed check valve, equipment failure (control valve, isolation valve, pump, vessel, Instrumentation, etc.),control valve fails closed , incorrect pressure differential, isolation in error, power failure - etc. Bypass valve open, increased pumping capacity, operation of pumps in parallel , reduced delivery head , change in fluid density, exchanger tube leaks, worn or deleted restriction orifice plates , cross connection of systems, control faults, control valve trim changed, control valve fails open, burst pipe, large leak, wrong valve open, fugitive emissions, slug flow Line restriction, filter fouled , defective pumps , fouling of vessels, lines, valves, or orifice plates , density or viscosity changes , competing pump heads and flows , inadvertently throttled valve , etc. Malfunctioning or omitted check valves (note that check valves are not usually bubble tight or positive shutoff devices) , siphon effect , incorrect differential pressure , two way flow , emergency venting , wrong lineup , in line spare equipment , etc. Design pressures, specification of pipes, vessels, fittings, and instruments , surge problems , leakage from interconnected high pressure system , gas breakthrough (inadequate venting) , inadequate or defective isolation procedures for relief valves , thermal over pressure , positive displacement pumps , pressure control valves failed closed or open , increased centrifugal pump suction pressure , more reaction , plugged pressure tap , etc. Generation of vacuum condition , condensation – gas dissolving in liquid , restricted pump/compressor suction line , undetected leakage , vessel drainage procedure , blockage of blanket gas , vacuum relief , etc. Outlet isolated or blocked , inflow greater than outflow , control failure , faulty level measurement , condensation in vapor lines , vessel overflow , deactivated level alarm , inadequate time to respond , etc. Control strategy , location of instruments , lack of instrumentation , information overload , response time , set points of alarms and trips , time available for operator intervention , alarm and trip testing , confusing alarms , fire protection , panel arrangement and location , auto/manual facility and human error , sample devices , failure mode of transmitter , failure mode of control valve or final control element – failure mode for out-of-range input , lack of documentation , computer control , mechanical and PLC interlocks , bypassed interlocks – failure of safety instrumented system , defeated alarms , etc. Path for relief protection , design basis for relief (Process/fire, startup/shutdown conditions, etc.) , type of relief device and reliability – inspection/testing results , relief valve discharge location , environmental implications , two phase flow , effect of debottleneck on relief capacity requirements , start-up conditions , materials of construction , temperature of rupture disks, preventive maintenance and isolation philosophy , failure of administrative controls , blocked relief valves, restricted inlet/outlet lines , plugging in relief system , frequency of relief valve use , relief device not exposed to operating temperature or pressure , location of relief device , near miss incidents , etc. Leaking valves , leaking exchanger tubes , incorrect feed stock /specification , inadequate quality control , process control upset reaction intermediates/by-products , improper mixing ,ingress of air, water, or rust ,inadvertent mixing , explosive mixtures , interconnected systems (especially services, blanket systems) , wrong additives or catalysts , preparation for shutdown and start-up operations , solvent flushing , etc. Reactivity , stability/decomposition , runaway reactions, vapor pressure , saturation points of chemicals , solubility , crystallization , particle size , settling of solids , sublimation , viscosity , inadvertent mixing , phase change , phase separation , flammability , toxicity , MSDS information , etc.
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PTS 60.2209 DECEMBER 2010
PARAMETER
GUIDEWORD
RUPTURE / LEAK
OTHER THAN
IGNITION
OTHER THAN
SERVICE FAILURE
OTHER THAN
ABNORMAL OPERATION
OTHER THAN
SAMPLING
OTHER THAN
MAINTENANCE
OTHER THAN
CORROSION / EROSION
OTHER THAN
SAFETY
OTHER THAN
NO TIME
MORE LESS
EXAMPLES HAZARDS: Toxicity , fire/explosion potential , high pressure , temperature , potential off-site impact, possible RMP worst case or alternate release scenario, impact on surroundings, DETECTION: methods, time required, detectors, visibility, odour thresholds, video monitors, routine checks, MITIGATION: methods available, isolation points, duration of leak, containment methods, emergency operations in spill area, procedures/training, inventory reduction, PROTECTIVE SYSTEMS: turret coverage, fire crew availability, deluge system, fire fighting strategy, required response, alarms, evacuation procedures, emergency showers/eyewash stations, location of SCBA , PREVENTION: root cause elimination, materials of construction, maintenance/mechanical integrity procedures, mechanical stress – overhead lifting procedures, overpressure protection – defect identification, inspection methods. STATIC ELECTRICITY, grounding arrangements, insulated vessels/equipment, low conductance fluids, splash filling of vessels, insulated strainers and valve components, dust generation and handling, hoses, temporary grounding for loading/unloading, PM for grounding systems, OPEN FLAMES, flares, pilot lights, fired heaters, OTHER SOURCES – vehicle entry, electrical classifications, lightning, hot surfaces, hot work/welding, hot work permits, people in area, FLAMMABILITY - Auto ignition, upper and lower flammability limits, flash point, fire triangle, SURROUNDING AREA Failure of instrument air/steam/nitrogen/cooling water/hydraulic power/water or other , contamination of instrument air, nitrogen, etc., telecommunications, heating and ventilating systems, computers, backup systems, protection systems, previous failures, etc. Purging, flushing, start-up, normal shutdown, emergency shutdown , operations under emergency conditions, severe weather conditions, spills, fire, turnarounds, off shift operations, shift change, flaring, bypassed safety devices, time (sequence), startup following emergency shutdown, regeneration, decoking, spills/spill containment, evacuation plans, bypassing procedures, using extraordinary effort, extended shift schedules, previous incidents and near misses, use of contractors, etc. Personnel exposure, purpose of sample, sampling apparatus, environmental, spill and leakage monitoring, sampling procedure, time for analysis result, calibration of automatic samplers, reliability, accuracy, or representative sample , diagnosis of result, industrial hygiene (personnel exposure/monitoring), sample disposal, operator intervention, process changes because of sample result, etc. Maintenance procedures (verbal, written), working on operating ("live", "hot", "active") equipment, preventive maintenance, predictive maintenance, isolation philosophy, drainage, purging, cleaning, drying, blinding, hot bolting, hot and cold taps, access, rescue plan, training, pressure testing, work permit system, breaker identification, confined space, contractors, installed/non-installed spare equipment, availability of spares, modified specification, storage of spares, catalogue of spares, etc., test running of spare equipment, etc. Engineering specifications , internal/external corrosion protection, corrosion under insulation, cathodic protection arrangement, embrittlement, stress corrosion cracking, fluid velocities, inspection (testing/monitoring of piping, vessels, heat exchangers, etc.), etc. Training , written operating and maintenance procedures (accurate, updated, enforced), fitness for duty, fire and gas detection systems/alarms, emergency shutdown arrangements, contingency plans, previous near miss incidents, effluent disposal, hazards created by others (adjacent storage areas/process plants), testing of emergency equipment, compliance with local/national regulations and codes, chemical storage excess inventory, lighting, industrial hygiene: personal protective equipment (PPE), location of safety showers/eye wash, community awareness and emergency response program (CAER), material safety data sheets (MSDS), fire fighting response time, emergency training, threshold limit values (TLVs) of process materials and methods of detection, first aid/medical resources, noise levels, lifting (back injury), etc. Skipped step, event does not occur, e.g., valve does not open/close, timer fails/malfunctions, service failure, relay logic prevents occurrence, etc. Valve malfunction, timer fails, more reaction, accumulation, improper batch recipe, product quality, unwanted by-products, interruption, etc. Improper settings on controls, failure/malfunction batch logic, increased production rates, shift change, improper instructions, operator preference, inadequate mixing, shortcuts, etc.
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PTS 60.2209 DECEMBER 2010
PARAMETER
GUIDEWORD WRONG SAME
Other Environmental Hazards
EXAMPLES Out of sequence, procedure/recipe error – software bug, solenoid failure, catalyst activity, operator interruption/error, missed communications, etc. Two or more steps/events occur simultaneously, common cause failure (e.g., service failure), crossed connections, parallel operation, etc. Odour, Noise, Traffic movements
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PTS 60.2209 DECEMBER 2010
APPENDIX 6 – HAZOP WORKSHEET HAZOP Worksheet
Project Title
Company Name Project Contract No.
Meeting Date: Node Details:
G. WORD
Leader: Scribe:
PARAMETER
DEVIATION
No
Flow
No Flow
More
Flow
More Flow
Less
Flow
Less Flow
As Well Flow As Part of Flow
As well as Flow Part of Flow
Reverse
Reverse Flow
Flow
Other than Flow
Other Flow
1.01
Node : PEFS:
CAUSES
CONSEQUENCES
PROTECTION / SAFEGUARDS
RECOMMENDA TIONS
BY
Than
31 PTS 60.2209 DECEMBER 2009
APPENDIX 7 – HAZOP REPORT FORMAT The HAZOP report should contain the following sections: 1.0
Introduction The introduction to the HAZOP report should contain short descriptions of the following:
The background to the project and the scope of the HAZOP
The
The terms of reference given prior to the HAZOP and other safety studies or HAZOP minutes used for reference.
Schedule of the meeting
The composition and affiliation of the team including the attendance of part-time members at each session.
Methodology of HAZOP adopted stating any variations from normal HAZOP practice for the study.
Plant / Facility areas not covered because they were outside the scope of the study or documentation or key personnel were not available.
Description of the plant / facility.
purpose
and
achievements
of
the
meeting
should
be
described.
2.0
Quality of the Study An objective assessment of the quality of the study and the reliance, which may be placed on the results based on team composition, experience and their performance.
3.0
Areas of Potential Weakness Highlights potential weakness of the study such as a lack of specialist knowledge or incomplete drawings.
4.0
Comments Applicable to the whole Plant List and description of the general issues discovered together with their significance to the progress of the project.
5.0
Major and Priority Findings Complex HAZOP meetings may produce very large numbers of action items. Obviously they cannot all be addressed at the same time and the project may have to progress whilst they are being dealt with. The main study findings should be discussed in the report. A list of the (top ten or so) major issues is helpful to the response co-ordinator in expediting the important ones first.
6.0
Further Studies Required List of recommendations that QRA or other studies (FMEA, Reliability) for easy reference and priority action.
32 PTS 60.2209 DECEMBER 2009
7.0
Highlight Areas for Next HAZOP Identification of areas that are unresolved should be made for use by the Leader of subsequent HAZOPs or by the project safety co-ordinator.
8.0
Reports and Comments for Other Safety Reviews Details of issues or action items that in the opinion of the HAZOP team have a direct relevance to other project safety reviews.
9.0
Appendices The appendices should contain the following information:
List of guide words used
Node list
Worksheets
Drawings (master set)
List of background reference documents.
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PTS 60.2209 DECEMBER 2010
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