In preparing an accurate time and cost estimate, it is customary for the client to provide the following information: Up-to-date Piping and Instrumentation Diagrams, Process Flow Diagrams (P&IDs and PFDs), Shutdown Key(s), Design Basis Memorandum (DBM), Plot Plan, and, A description of the process steps or unit operations involved.
By Gobind Khiani – Consulting Fellow-Piping/Pipelines
The importance of using quality drawings for the process hazard analysis (PHA) study cannot be emphasized enough. Without the use of clear, concise, understandable drawings, the PHA study exercise will result in frustrated team members and be drawn out beyond its normal time frame. Engineers review the materials provided and discuss any preferences or special considerations the project manager may have in conducting the study (i.e. limitations on time, desire to use a certain methodology, etc.).
When working with new clients, it is our preference to hold a joint meeting with the client and engineering firm to finalize the project scope and study methodology. This meeting should ideally occur at least two weeks prior to the commencement of the PHA study and include the final drawings to be used in the project. Once the project is awarded, the following information may be requested by the PHA facilitator assigned to lead the study (preferably two weeks prior to the commencement of the PHA study). If the information is not sent to the facilitator, it should be brought to the study for reference, if available.
• Description of general control philosophy (i.e. identifying the primary control variables and the reasons for their selection).
• Special design considerations that are required because of the unique hazards or properties of the chemicals involved.
• Up-to-date Plot Plans concerning building and equipment layouts.
• Up-to-date Piping and Instrumentation Drawings and piping specifications.
• Up-to-date Shut-down keys. Control system and alarm description.
• Vendor drawings, operation and maintenance manuals.
• Design basis memorandum (Facility overview) concerning the relief systems, ventilation systems, safety systems, and fire protection systems.
• Past incident reports.
• Previous HAZOP studies
• Preferred corporate risk matrix (if available).
• Data books (if existing plant).
As it is often difficult to assemble the optimal PHA study team members without advance planning, it is wise to schedule PHA studies at least one month in advance. This also ensures that the engineer has time to properly prepare a time and cost estimate on the project and ensure a PHA facilitator will be available to lead the study.
Proposal Conditions: The proposal is based on P&IDs supplied by the client. Should additional or new materials be provided prior to the commencement of the study, the engineer reserves the right to revise its time and cost estimate for the PHA study. As there may not be sufficient time for a revised proposal to be submitted, the client understands that any change in scope will normally result in additional time being required to complete the study. While Engineer will endeavor to complete the PHA study within the initial proposed time, the client must be aware that this may not always be possible.
The proposal is presented at the request of a client to plan and implement a Process Hazard Analysis study project scheduled. The methodology the engineer proposes to use to conduct the analysis is HAZOP (Hazards and Operability study). We use a sophisticated HAZOP software package run on the facilitator’s computer that works in conjunction with an overhead projection system for large screen viewing. Engineer will provide an experienced HAZOP study leader for the project. Engineer has based this proposal on the proposed study to be conducted at a location mutually agreed upon by and Engineer. A final report will be provided 10 business days following the completion of the study, unless otherwise specified. Following the commencement of the study, the client will indicate the number of final report copies required. The engineer’s time and cost estimate does not incorporate binder and reproduction costs.
The proposal is based on the information and drawings provided by the client to the engineer. It is assumed the client will be responsible to:
1. Provide a comfortable venue for the Process Hazard Analysis study review session(s). Ensure the review team members are available for the duration of the review, with minimal interruption.
2. Provide a white screen for the duration of the study. The objective of the study is to identify potential hazards and/or operability concerns in project scheduled, arising from initiating events (i.e. single contingencies or single jeopardy such as one piece of equipment or instrument failure/malfunction at a given time).
3. To estimate the Severity and Likelihood for each identified hazard and assign a Risk Ranking (RR = S x L) for prioritizing action and document the of consequences considered.
4. To demonstrate due diligence by thorough documentation of the PHA sessions.
5. HAZOP Methodology HAZOP TECHNIQUE the HAZOP multidisciplinary team, guided by an experienced facilitator utilizing sophisticated computer software, uses guideword and parameter structured brainstorming sessions to systematically challenge the unit design.
6. The process is first broken down into nodes – logical and manageable segments that have definable design intent. Each node is studied in detail to identify the potential cause and consequence of hazards and operability problems.
7. Equipment failure, human error, failure of engineering and administrative controls and external events are all considered potential causes. Severity and Likelihood rankings are estimated, and a Risk Ranking is assigned to each identified hazard (S x L = RR).
8. Preliminary recommendations are made to eliminate or reduce risk or to make improvements wherever deemed necessary for the safety of personnel, protection of property and the environment, improved operability and to avoid exposure to third party liability.
9. Each step is documented in worksheets. Existing safeguards are noted and the Risk Ranking prioritizes recommendations.
10. Responsibility for recommendation resolution is assigned and documented in the recommendations section of the report.
11. A comprehensive final report is issued as documentation for decision-making and future reference, and for legal documentation of the resolution of the action items. The technique used and the information recorded complies with US Occupational Safety and Health Administration Regulations OSHA CFR 29 Part 1910.119, 1992.
12. SOFTWARE and HARDWARE for PHA studies is used with up-to-date available technology. Most of the industry prefers the latest release of the leading hazard analysis software, PHA-Pro™ 8 by Dyadem International Ltd. The software is comprehensively set up for mechanical, physical and human error situations and allows for immediate report documentation and distribution, and prompt pre-emptive action where required.
13. Engineer will provide the study team with a copy of the group’s daily recommendations on a DVD; the file will be in MS-Excel. The software is run on a notebook computer which docks with a one-piece LCD desktop projector for comfortable large screen viewing for any number of study participants.
Conducting an efficient and effective Process Hazard Analysis study requires a trained and experienced leader/facilitator and a team of people knowledgeable in disciplines relevant to the process under review. Since studies require perspectives from participants familiar with different processes and the operation of each station being analyzed, team members should be made up of personnel from management, operations, engineering (project, design, process, chemical, facilities), instrumentation and control, safety/environmental, and maintenance.
All team members should have considerable experience in their discipline. It is recommended that no more than seven people participate as Team Members in the HAZOP at one time. Experience has shown that a knowledgeable, experienced team of five to six Team Members often produces the most complete and effective study results. The proposal figures are based on no more than seven participants.
Note: if a team with greater than seven participants be involved in the HAZOP study, the result will be slower progress than if smaller groups of five to six are chosen.
ABOUT THE AUTHOR
Gobind N. Khiani, a UCalgary alumnus with a BSc in Civil Engineering and MSc in Mechanical Engineering has a proven track record in technical and value engineering and holds a Fellowship in Engineering and an MBA. Currently, he holds the position of Vice Chairman of the Standards Council of Canada. He has done peer review on Emissions Management regulatory documents for Environment and Climate Change Canada and participated in research and development initiatives for Emissions Management and Reduction Programs, Alberta and Canada’s Oil Sands Innovation Alliance (COSIA) – a world-leading innovation alliance that set the model for sharing intellectual-property to accelerate environmental performance.