HAZOP

by

David Gossman

In 1998 we published a GCI Tech Notes that summarized the HAZOP process.  Recently I had the opportunity to teach a class on performing HAZOPs to a group of safety professionals in Shanghai, China.  As a result of that experience further information on the process of performing HAZOPs will be presented in a new series of GCI Tech Notes starting with this issue.

Introduction

A Hazard and Operability (HAZOP) study is a structured and systematic examination of a planned or existing process or operation in order to identify and evaluate problems that may represent risks to personnel or equipment, or prevent efficient operation.  The HAZOP technique was initially developed to analyze chemical process systems, but has later been extended to other types of complex systems including, as examples, transportation systems and software systems.  The  HAZOP process is just one of a large number of different techniques available to the safety professional for analyzing systems to identify and prevent hazards. It has the further advantage that it also identifies and helps to prevent operational problems.  HAZOP studies require more details regarding the systems under consideration, but produce more comprehensive information on hazards and errors in the system design.  As with any of these processes there are pros and cons to using a specific technique for a particular circumstance.  HAZOPs are not the best technique for every circumstance and it is important to understand the benefits as well as the costs and limitations of the method before making the decision to use it in a particular circumstance.

HAZOP Pros

• The HAZOP process is a systematic examination.
• The team approach to a HAZOP makes it a multidisciplinary study.
• The HAZOP team utilizes operational experience.
• The process covers safety as well as operational aspects.
• Solutions to the problems identified may be indicated.
• HAZOPs consider operational procedures.
• HAZOPs cover human errors.
• The HAZOP study led by independent person.
• HAZOP study results are recorded.
• For team members the process is easily learned and performed.
• A HAZOP does not require considerable technical expertise for technique formulation.
• As a systematic process it provides rigor for focusing on system elements and hazards.
• The HAZOP process is a team effort with many viewpoints.
• Commercial software is available to assist in HAZOP analysis.

HAZOP Cons

• A HAZOP focuses on single events rather than combinations of possible events.
• The HAZOP focus on guide-words allows it to overlook some hazards not related to a guide-word.
• Training is essential for optimum results, especially for the facilitator.
• HAZOPs are typically very time consuming and thus expensive.

Discussion

HAZOP is a hazard identification technique which considers system parts separately and systematically examines the effects of deviations on each part. Sometimes a serious hazard will involve the interaction between a number of parts of the system. In these cases the hazard may need to be studied in more detail using techniques such as event tree and fault tree analyses.  Many systems are highly inter-linked, and a deviation at one of them may have a cause elsewhere. Adequate local mitigating action may not address the real cause and still result in a subsequent accident.  Many accidents have occurred because small local modifications had unforeseen knock-on effects elsewhere. While this problem can be overcome by carrying forward the implications of deviations from one part to another, in practice this is frequently not done.  As with any technique for the identification of hazards or operability problems, there can be no guarantee that all hazards or operability problems will be identified in a HAZOP study. The study of a complex system should not, therefore, depend entirely upon a HAZOP. It should be used as a compliment to other suitable techniques. It is essential that other relevant studies are coordinated within an effective overall safety management system.  The success of a HAZOP study depends greatly on the ability and experience of the study leader and the knowledge, experience and interaction between team members.  HAZOP only considers parts that appear on the design representation. Activities and operations which do not appear on the representation are not considered.

Conclusion

An important benefit of HAZOP studies is that the resulting knowledge, obtained by identifying potential hazards and operability problems in a structured and systematic manner, is of great assistance in determining appropriate remedial measures.  While a HAZOP is not appropriate in all circumstances one of the major benefits that can be used to help justify the cost and time investment is that it also helps to avoid operating problems and can thus provide a clear return on the investment beyond the reduction in hazards.

Development of a surgically implantable, artificial kidney

Development of a surgically implantable, artificial kidney—a promising alternative to kidney transplantation or dialysis for people with end-stage kidney disease—has received a $6 million boost, thanks to a new grant from the National Institute of Biomedical Imaging and Bioengineering (NIBIB), one of the National Institutes of Health, to researchers led by UC San Francisco bioengineer Shuvo Roy, PhD, and Vanderbilt University nephrologist William Fissell, MD.

A team of university scientists has developed the world’s first artificial kidney technology to be implanted in the body. Their bio-hybrid approach uses living kidney cells in tandem with a series of specialized microchips powered by the human heart to filter waste from the blood stream.

The National Kidney Foundation estimates that over 100,000 patients are on the waiting list for a donor kidney, and over 3,000 are added list each year.  The average patient spends 3.6 years waiting for a viable transplant, and may be treated with dialysis while they wait, but only one in three dialysis patient survives longer than five years without a transplant.

Transplanted organs from deceased or living donors must be carefully matched in order to avoid tissue rejection, but an artificial solution could potentially bypass these complications and be manufactured to better meet the demand.  To address this unmet need, William Fissell from Vanderbilt and Shuvo Roy from the University of California, San Francisco (UCSF) launched The Kidney Project.

“This project is about creating a permanent solution to the scarcity problem in organ transplantation. We are increasing the options for people with chronic kidney disease who would otherwise be forced onto dialysis,” Fissell told the UCSF News Center.

In November 2015, The Kidney Project received a $6 million grant from the National Institute of Biomedical Imaging and Bioengineering (NIBIB). According to Fissell, the group also reached out to both the National Institute of Health (NIH) and the FDA in a more coordinated effort to bring the artificial kidney to clinical trial. Under a cooperative agreement with the NIBIB’s Quantum Program, the NIBIB will oversee funding for The Kidney Project’s research for another four years.

The prototype is roughly the size of a coffee cup and uses a combination of silicon nanotechnology and living kidney cells to filter blood. A series of 15 microchips serve as scaffolding for the living cells to grow on and around, creating a bio-hybrid device.

“We can leverage Mother Nature’s 60 million years of research and development and use kidney cells that fortunately for us grow well in the lab dish, and grow them into a bioreactor of living cells,” explained Fissell in a recent article published by Research News @ Vanderbilt.  Fissell described the device as a “Santa Claus System,” because it can reliably distinguish between waste chemicals and those nutrients a body should reabsorb.

According to Fissel, the device is powered naturally with the patient’s own blood flow, and his team is working to ensure that blood can flow through the device without clotting or causing damage. Vanderbilt biomedical engineer Amanda Buck is using computer programs to study the device’s fluid dynamics and further refine the channels for maximum blood flow efficiency.

The team announced that they were ready to begin pilot tests of their silicon filters, and they intend to launch the first human clinical trials for the artificial kidney technology as early as 2017.

Last year, CNN reported that the University of California, Los Angeles (UCLA) had introduced technology that would allow patients to receive continuous dialysis treatment; an advance that scientists claim reduces many of the side-effects and inconveniences of the treatment. This technology, said lead researcher Victor Gura, could be available in two years.

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