This document defines the procedure to be used for Hazard and Operability (HAZOP) Reviews.
This specification is prepared in order to precisely define the organization and the implementation methods and procedures of the HAZOP reviews to be conducted for all projects executed by CONTRACTOR.
The objective of the HAZOP review is to check and investigate the design of all facilities in order to identify any potential hazard and operability problems which could arise particularly through deviations from the design intent. A set of lists of necessary actions and recommendations to improve and mitigate the consequences to the identified problems or hazards will be recorded and presented in the form of the HAZOP report.
The HAZOP review is based on the PFD, plot plans, P&ID and other PROJECT DOCUMENTS. The latest issue of the documents shall be used for the HAZOP study. These documents will be submitted to the HAZOP team in advance (in accordance with applicable PROJECT SPECIFICATION/procedures) so that they may review them prior to the HAZOP study.
These documents shall be issued at an advanced stage of engineering, (ie. IFH P&ID) issued for HAZOP.
The P&IDs used for the HAZOP shall be fully drafted in CAD or equivalent as per the PROJECT SPECIFICATION and show all equipment, instruments, check valves, safety valves, controllers, pressure and level switches etc. that are included in the limits of the supply.
The P&ID set used for the HAZOP review shall be marked "HAZOP REVIEW P&ID" and shall be included in the HAZOP report.
Apart from the P&IDS which shall be used for the HAZOP review, the HAZOP team shall have access to any other available information required for the study (process data sheets, cause & effect diagrams, etc.).
The following documents are applicable and shall be considered to be a part of this specification.
API 750, Section 2 Process Safety Information (29 CFR 1910-119)
API 750, Section 3 Process Hazard Analysis (29 CFR 1910-119)
The method consists of a systematic study of all process and utility lines and equipment included in the PROJECT.
Each line will be studied as a whole, from battery limit to battery limit or to the equipment connected to the end of the line, whichever is applicable. Materials handling equipment shall be similarly treated as process lines and shall be studied in the same manner.
The HAZOP Review shall cover all the process lines and systems that are part of, or may be affected by the PROJECT facilities. This shall include EXISTING FACILITIES, both upstream and downstream that may be affected by the new PLANT. The following shall be reviewed as a minimum:
Process Lines
Process Vessels
Process Equipment
Off-Site Systems
Utility Systems
Fire Detection Systems
Fire Protection Systems
ESD Systems
Isolation at Battery Limits
Interface with other Facilities
For each line, the study will investigate the appropriate process parameters and the guidewords as listed in Table 1. For each guideword, the HAZOP team will list the possible causes and the consequences regarding the operating procedures and the safety aspects from both a personnel and material point of view.
If the consequences are considered as being out of the normal operating range or design intent of the system, the HAZOP team will investigate the installed safeguards:
The detection devices, to ensure that the operator will be aware that something abnormal is happening.
The safety devices installed, to limit the consequences of the process upset.
Table1 : HAZOP Guidewords and Definitions
Guide Words | Meanings | Comments |
NO. NOT OR NONE | The completenegationof the design intentions | No part of the intentions is achieved and nothing else nappers. |
MORE OF | Quantitative increases ofany relevantPhysical parameters | These refer to quantities - relevant physical properties such as flow rites and temperatures as well as activities like 'HEAT and 'REACTION'. |
LESS OF | Quantitative decreases of any relevant Physical parameters | These refer to quantities - relevant physicalproperties such as flow rates and temperatures as wellas activities like 'HEAT and 'REACTION'. |
AS WELL AS | A qualitative increase | All the design and operating intentions are achieved together with some additional activity. |
PART OF | A qualitative decrease | Only some of the intentions are achieved; some are not. |
REVERSE | The logical opposite of the intention | This is mostlyapplicable to activities forexample, reverse flow or chemical reaction. It can also be applied to substances e.g. 'POISON' instead of 'ANTIDOTE' of 'D' instead of ' L' optical isomers. |
OTHER THAN | Complete substitution | No part of the original intention is achieved. Something quite different happens. |
Apply to All Piping section | |
NO FLOW | Wrong routing - blockage - incorrect slip plate - incorrectly fitted check valve -burst pipe - large leak-equipment failure (C.V., isolation valve, pump, vessel, etc.) -inconect pressure differential - isolation in error. |
LESS FLOW | Line restrictions - filter blockage - defective pumps - fouling of vessels, valves, orifice plates - density or viscosity changes. |
REVERSE FLOW | Defective check valve - siphon effect - incorrect pressure differential - two-way flow - emergency venting - incorrect one ration - in-line spare equipment. |
MORE FLOW | Increased pumping capacity - increased section pressure - reduced delivery head - greater fluid density - exchanger tube leaks - restriction orifice plates deleted -cross connection of systems - control faults - control valve trim changed - running two pumps. |
APPLVTO VESSELS AMD TANKS ONLY | |
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APPLY TO PIPELINES AS WELL AS VESSELS AND TANKS | |
HOFE TEMPERATURE | Ambient conditions - fouled or failed exchanger tubes - fire situation - cooling water failure - defective control - heater control failure - internal fires - reaction control failures - heating medium leak into process. |
LESS TEMPERATURE | Ambient conditions- reducing pressure - fouled or failed exchanger tubes - loss of heating - depressurisation of liquefied gas-Joule/Thompson effect. |
MORE PRESSURE | Surge problems - connection to high pressure system - gas breakthrough (inadequate venting) - defective isolation procedures for relief valves - thermal overpressure - positive displacement pumps - failed open P.C.V.'s - design pressures, specifications of pipes, vessels, fittings, instruments. |
LESS PRESSURE | Generation of vacuum condition - condensation - gas dissolving in liquid - restricted pump/compressor section line - undetected leakage - vessel drainage- blockage of blanket gas reducing valve. |
MORE VISCOSITY | Incorrect material or composition - incorrect temperature - high solids concentration - settling of slurries. |
LESS VISCOSITY | Incorrect material or composition - incorrect temperature - solvent flushing. |
COMPOSITION CHANGE | Leaking isolation valves - leaking exchanger tubes - phase change - incorrect feedstock/specification - inadequate quality control - process control upset - reaction intermediates/by-products - settling of slurries. |
CONTAMINATION | Leaking exchanger tubes - leaking isolation valves - incorrect operation of system - interconnected systems (especially services, blanket systems) -effect of corrosion - wrong additives - ingress of air - shutdown and startup conditions - grade change. |
APPLYONCE TO EACH ENTIRE UNIT OPERATION | |
ABNORMAL OPERATIONS | Purging - flushing - start-up - normal shutdown - emergency shutdown -emergency operations - inspection of operating machines - guarding of machinery. |
SAMPLING | Sampling procedure and operator safety - time for analysis result - calibration of automatic samplers - reliability/accuracy of representative sample - diagnosis of result - loss of sample flow. |
SERVICE FAILURE | Failure of instrument air/steam/nitrogen/cooling water/hydraulic power/electric powers rate or other - contamination of instrument air, nitrogen, communications - heating and ventilating systems - computers. |
INSTRUMENTATION | Control philosophy - location of instruments - response time - set points of alarms and trips and ability to change - time available for operator intervention -alarm and trip testing - fire protection – trip/control amplifiers - panel arrangement and location - auto/manual facility and human error - fail safe philosophy. |
RELIEF | Relief philosophy (process/fire etc) - type of relief device and reliability - relief valve discharge location - pollution implications - two phase flow - effect of de-bottlene cheking on relief capacity - Inlet and outlet piping. |
CORROSION: EROSION | Cathodic protection arrangements – internal/external corrosion protection -engineering specifications - zinc embrittlement - stress corrosion cracking - fluid velocities.
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MAINTENANCE | Isolation philosophy - drainage - purging - cleaning - drying - slip plates - access - rescue plan - training - pressure testing - work permit system - condition monitoring - lifting and manual handling. |
IGNITION SUPPRESSION | Grounding arrangements - insulated vessels/equipment - low conductance fluids - splash filling of vessels - insulated strainers and valve components -dust generation - powder handling equipment - electrical classification - flame-arresters - hot work - hot surfaces - auto-ignition - pyrophoric materials. |
SAFETY | Toxic properties of process materials - fire and gas detection system alarms -emergency shut-down arrangements - fire fighting response time - emergency and major emergency training - contingency plans - T.L.V.'s of process materials and methods of detection - noise levels - security arrangements -knowledge of hazards of process materials - first aid medical resources -effluent disposal - hazards created by others (adjacent storage areas/process plant etc.) -testing of emergency equipment - compliance with local national regulations. |
SPARE EQUIPMENT | Installed non-installed spare equipment - availability of spares - modified specifications - storage of spares - catalogue of spares - test running of spare equipment. |
FACILITY LAYOUT | The distance between various units for safety and fire exposure - 'General Recommendations for Spacing' by Oil Insurance Association or Industrial Risk Insurers-API - NFPA, OSHA 1910.119. |
HUMAN FACTORS | Control room layout - alarms - valve access and location - human error - OSHA 1910.119. |
APPLY TOBATCH | |
TIME TOO LONG | Feed continues - agitation continues- reaction continues - pump runs dry - distillation passes end point - material added too slowly - too much material added. |
TIME TOO SHORT | Purge cycle cut short -reaction dies - agitation stops - pump out is stopped - distillation is stopped before end point - component added too quickly - insufficient component added. |
WRONGTIME | Incorrect step is initiated - step is accomplished too quickly - step is permitted to lag. |
STEP TOO LATE | Agitator started late - agitator stopped late - pump started late - pump stopped late - valve opened late - valve closed late - component is charged late. |
STEP TOO EARLY | Agitator started early - agitator stopped early - pump started early - pump stopped early- valve opened early - valve closed early - component is charged too soon. |
STEP LEFT OUT | Pump is not started - pump is not stopped - agitation is not started-agitation is not stopped - system Is not purged - sample is not taken - equipment is not stowed away - component is not charged. |
STEP BACKWARDS | A prior step is repeated - component is double charged. |
PART OF STEP LEFT OUT | Sample not taken - some components not charged - batch Is not cooled -vessel is not depressured. |
EXTRA ACTION INCLUDED | Bath pumps are started - both pumps are stopped - additional valves are opened - additional valves are closed - additional components aie charged to the system. |
WRONG ACTION TAKEN | Wrong piece of equipment is started - wrong piece of equipment is stopped - equipment is started rather than stopped - equipment is stopped rather than started - incorrect valve is opened - incorrect valve is closed -valve is opened rather than closed - valve is closed rather than opened -wrong component is charged. |
Key aspects of the HAZOP review shall include but not limited to the following:
A detailed systematic study of the design and outline operating and maintenance philosophy to identify the consequences of deviation from design intent
Consideration of transient operating conditions during start-up, shutdown, plant upsets and emergencies.
Consideration of potential exposure of employees to chemicals during routine operations including maintenance, decontamination, etc.
Ease of Maintenance.
If the protections indicated on the P&ID are considered unsafe or insufficient, the HAZOP team shall make its recommendation. Recommendations shall be numbered and contain clear alternative designs elaborated to satisfy all the safety and operational requirements. Recommendations shall be recorded and categorized in the HAZOP report as described later in ATTACHMENT.
The review methodology will be the "Guide Word" HAZOP technique and will be performed inaccordance withSections 2 and 3 of API 750 Recommended Practice; i.e., Process Safety Information and Process Hazard Analysis.
The purpose of the review is not to resolve the action items; it is to identify credible deviations from the design intent. The method identifies hazards and postulates possible accident sequences resulting from such hazards; innovative thinking then identifies the consequences of these scenarios. The process shall demonstrate to COMPANY that prudent steps have been taken to provide a safe installation.
HAZOP reviews are not suitable as, nor are intended to be, a follow-up of P&ID reviews. It is acceptable that simple actions, such as adding a check valve, be implemented on the HAZOP REVIEW P&IDs. Prolonged discussions of process or operational philosophies shall not take place during HAZOP reviews. Such discussions shall be carried out outside of the HAZOP review.
Each system or equipment is divided into subsystems by consensus of the review team. The selected system is identified by a study node number and for easy reference a color code can also be inset on the related P&ID prior to the review and worksheet during the review.
All HAZOP reviews shall be recorded in full and not "by exception", and all guidewords shall be applied appropriately. When the HAZOP team can not identify any significant hazards or causes for any particular guideword, the Chairman shall insert an appropriate record (e.g. no significant causes identified) to demonstrate that the guideword has been considered but no further assessment is required.
An action item is entered on the worksheet if it is the team consensus that the existing precautions, protection, reliability or ease of maintenance are inadequate or there is a concern. Recommendations may be recorded to suggest a prevention or mitigation of the consequences. Recommendations that contain actions that cannot be closed out before IFC P&ID shall be avoided. An action sheet is generated for each action item for recording and tracking responses. The HAZOP Action Items Status Report shall be used to track and summarize the status of all action items.
The HAZOP Report shall be prepared by the HAZOP Secretary and submitted to the HAZOP Chairman before final issue.
A computer software package such as Safeti Hazard Analysis by DNV, PHAWorks by PrimaTech or equivalent, shall be utilized for reporting and tracking the HAZOP study.
The results of the review shall be recorded under the headings of every guide word to demonstrate the process deviation, its possible cause, possible consequences, risk ranking, safeguards, action required, responsible engineer or discipline, and the actions actually taken.
The risk associated with the consequences will be assessed in conformance with WOCRisk Assessment Matrix. HOLD
For the purpose of recording, a HAZOP secretary is nominated to act as team secretary. The secretary shall be familiar with HAZOP procedures and engineering terminology as well as the specific software used.
Recording of recommendations and actions shall be detailed with reference made to the corresponding drawing or document number, and other reference points such as equipment, instrumentation and line numbers where applicable, with clear recording on the reasoning behind any recommendations and subsequent actions.
Recommendations or actions shall be worded such that they describe clearly:
what actions are required (e.g. drawing no. xxx; provide a low-low level trip to vessel xxx)
what is the intended result or improvement (e.g. to protect pump xxx from cavitation)
what are the specific issues, if any, that could not be resolved immediately and needs to be followed up as a result (e.g. SIL of low-low level trip is to be determined in SIL review)
action by whom (or discipline) and with a target close out date.
The recommendations or actions shall be worded such that they can be read and understood by any reader without the need of referencing to the HAZOP worksheets.
All the documents used for the examination, the meeting notes, the list of actions and other documents produced by the team shall be filed and retained by the HAZOP Study Chairman.
The HAZOP summary (which shall include brief descriptions and amount of recommendations categorized in low, medium or high risk).
The HAZOP procedure
The HAZOP team composition and attendance sheet for each participant.
The P&ID set used for the HAZOP
The detailed, computerized report of the HAZOP (HAZOP worksheet), prepared by the HAZOP Secretary during the review session which shall include all the pages of the "HAZOP Study Report Forms" properly numbered and dated.
The HAZOP action sheet which shall be used by the Project Engineer to perform the HAZOP follow up and corrections.
•Copies of the reference documents used during the HAZOP review.
Timely and quality closing out of HAZOP is a necessary part of the HAZOP process. All responsible engineers who have been allocated HAZOP recommendation / actions shall close-out their actions within three (3) weeks of the HAZOP review.
The responsible engineer for the action shall report back to Process Safety the details of how the actions have been assessed, and what actions have been taken, together with evidence to demonstrate how the action has been incorporated in the design (e.g. excerpt of modification made on a P&ID). Actions are not considered closed unless descriptions are accompanied by suitable and sufficient evidence.
The HAZOP Report shall be revised and issued as final revision to show full details of how all HAZOP actions have been closed satisfactorily.
Not updating specific documents and placing the HAZOP action items on a "punch-list" for later development is generally unacceptable as a means of closing out HAZOP actions, and these exceptions shall require specific written approval from COMPANY.
CONTRACTOR'S Staff
HAZOP Chairman
HAZOP secretary who shall also act as the Scribe
Lead Process Engineer who will also act as HAZOP Secretary
Lead Instrument & Control Engineer
Mechanical Engineer
Other CONTRACTOR engineer's specialists on-call, as required
COMPANY Staff
COMPANY Process Engineer
COMPANY Operations Specialist
COMPANY Loss Prevention(Safety) Specialist
A Preliminary Hazop review shall take place at the beginning of the EPC phase on a preliminary basis to confirm that FEED requirements and any subsequent changes have been covered and hence taken into account during the detailed engineering phase. This review shall be of a desk review type or a coarse HAZOP nature.
The Final HAZOP review shall take place at the end of the EPC Detailed Engineering phase prior to the issue of Approved for Construction (AFC) P&ID. Recommendations from this HAZOP shall be incorporated in all AFC documentation.
The Pre-Start-up HAZOP review shall be held prior to commencement of pre-commissioning activities.
The Preliminary HAZOP shall be conducted by CONTRACTOR to confirm FEED basis and any later changes.
This HAZOP Review shall be conducted as close as is practical to the end of the EPC Engineering phase. The intent is that the engineering is complete and the drawings or at a revision level that reflects the current state of the engineering. This shall generally correspond to the Issue for Design (IFD) stage of development and shall include all COMPANY comments.
This HAZOP shall proceed according to the above methodology utilizing the latest drawings.
As a minimum, the following requirements shall be observed for drawings used for the HAZOP study:
Process data and optimization shall be complete. These data should be more advanced than the Issue for Design (IFD) stage. This implies that the drawings
have been previously issued for design and that the process design and optimization has been developed essentially to the Issue for Construction (IFC) stage.
Drawing presentation shall be complete to the final standard of issue.
All control schemes shall be complete and well reviewed by both the Process and Instrumentation & Control, Mechanical and Piping Departments . There shall be no vendor data outstanding with regard to the function of control loops and all control loops shall be shown on the P&IDs in their final representation.
Fire detection and protection engineering shall be complete. This shall include cause and effect charts, P&IDs for the fire protection systems, location diagrams for fire and gas detectors and plan views that show the specific area covered by each fire and gas detector.
CONTRACTOR shall be responsible for updating all drawings and documents affected by the results of the HAZOP and incorporating the mandatory HAZOP results into the final engineering. Not updating specific documents and placing the HAZOP items on a "punch-list" for later development shall not be allowed under any circumstance.
The pre-start-up HAZOP shall be performed preferably on SITE.
The objective of this pre start-up HAZOP review shall be to cover all modifications occurring during the Detailed Engineering and also to review VENDOR packages which have not been covered in the Final Review carried out under Section above.
The methodology, the resources, and the team shall be normally the same as other HAZOP reviews.
All drawings shall be at the Approved for Construction (AFC) stage of development.
CONTRACTOR will be responsible for updating all drawings and documents affected by the results of the HAZOP and incorporating the mandatory HAZOP results into the final engineering. Not updating specific documents and placing the HAZOP items on a "punch-list" for later development shall not be allowed under any circumstance.
HAZOP REPORTFORM
NODEREF: |
| Date : | REVISION : | |||
DOCUMENTTITLE: | ||||||
DOCUMENT REF : | ||||||
ITEM : | ||||||
DEVIATION | CAUSE | CONSEQUENCE | SAFEGUARDS | RECOMMANDATION | ACTION & RESPENG | |
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ACTION SHEET FOR HAZOP FOLLOW-UP
ACTION SHEET FOR HAZOP FOLLOW UP (TYPICAL)
ACTION ON: | RESPOND BY: |
ACTION NO: | MEETING DATES: |
DOCUMENT REFERENCE: | REVISION: |
TITLE |
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ITEM: | |
CAUSE: |
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1- |
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2- |
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3- |
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CONSEQUENCE: |
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1.1 |
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1.2 |
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1.3 |
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2.1 |
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3.1 |
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SAFEGUARDS: |
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1.2.1 |
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ACTION: |
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1- |
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2- |
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RESPONSE: | DATE:
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Comments