SWRO desalination shall comply with the international safety standards covering equipment pieces and systems working under pressure. Such equipment and systems shall be periodically tested. CP enforces this "testing mode of operation" into any equipment module under pressure. CP compares the pressure ratings of the equipment pieces in the pressure testing group and sets the testing pressure. Finally CP generates the pressure testing report with all relevant data.
The aim of the hazard and operability (HAZOP) analysis is to identify potential hazardous events and significant operability problems associated with the desalination or water treatment project.
Nobody will argue that the results of HAZOP depends heavily upon the human factor - experience and attitudes of the team members and the leadership style adopted.
The second factor to success is previous HAZOP experience. It cannot be neglected even in cases when the plant is of established design with a number of similar plants being operated throughout the world. The EPC contractor shall maintain the customized hazards checklist and the risk database storing the lessons learned from the previous projects, field service safety issues, and even failure reports.
The third factor to be reckoned with is limited time available for HAZOP analysis. For the SWRO project of above 150 MLD, for instance, its "coarse" variant requires about 600 man-hours of brainstorming sessions and another 400 man-hours for off-session paperwork and preparation. So big load is explained by a volume of "what if" questions to be answered during brainstorming sessions. Worse, the project engineering is frozen for the duration of HAZOP.
Implementation of the HAZOP findings may substantially affect the project schedule and the budget and adds to the project risk. So it has to be conducted as early as possible. In practice it means that out of a maze of the engineering documents only two are available with certainty for HAZOP – process flow diagram (PFD) and piping and instrumentation diagrams - P&IDs. Lack of others is substituted with the good engineering practice assumptions of the experienced engineers participated in brainstorming.
The criticality of the information availability is explained by the fact that in desalination plants more than 80% of HAZOP recommendations are operability problems and are not hazards. Feasible deviations from the design intent cover the whole specter of the plant design and operation starting from corrosion to system failure to batch processes recharging, and the operator training. This information cannot be deduced from the P&ID graphical symbols or the plant plot. Even if all the documents are submitted for HAZOP review as the word, excel or image files, the required information is hidden amongst thousands of non-relevant pieces. For example, instrument index may contain more than 1500 entries, and only 3% may relate to the control loops searched for.
The lack of required information (or partial availability) and a big volume of work explain the HAZOP probabilistic nature (Monte-Carlo method) and its reliance on the human factor mentioned above. This is in sharp contrast to the wide-spread opinion that HAZOP is a systematic study.
Besides the risk identification, the other pole of HAZOP is safeguards – operating procedures and devices that detect and give early warning, prevent, or mitigate the consequences of hazard occurrences. Ironically enough, engineering practice has not yet developed requirements for documenting the safeguards in consistent manner. Taking unwarranted credit for non-documented safeguards is a common mistake of HAZOP sessions.
Finally, the HAZOP analysis is accompanied by mechanistic check-list review and the status review of the plant functionality implementation. In that respect HAZOP is by far the most important milestone of any project.
From the above-mentioned one may conclude that the HAZOP results and, consequently, the plant engineering quality may be drastically improved by solving the problems of information availability and accessibility.
Crenger resolves these problems by offering a unique HAZOP interface for searching, recording, editing and storing the HAZOP findings, fast-linking to any piece of information, creating high-quality reports and metrics. Crenger makes HAZOP part of the FEED package.