Process Safety Management
As Chemical Engineers, we have to assess, and as practicable, quantify the risks inherent in the processes we are designing, commissioning and operating.
How's Your Safety?
Chemical Engineers have a pivotal role in reducing the risks on plant to acceptable or tolerable levels. As professionals that probably understand the plant best from a holistic viewpoint, we can play a vital role in the continuous improvement in safety standards - essential in this climate of ever more stringent health, safety and environmental legislation.
- How do you gauge your process safety performance and how do you know you are performing adequately from a process safety management perspective?
- Does your site have effective process safety leadership? How do you know this?
- Are operational expectations clearly defined and communicated to the workers?
- Is the firm too focussed on personal safety rather than process safety?
- Are leading safety indicators used and not just lagging indicators?
- Does the safety culture foster a trusting environment in which people are encouraged to report incidents, however minor?
- What are the minimum requirements for effective process safety management
The Context
Process Safety is different to Occupational Safety. Process safety is pro-active and centres on the safety integrity of the process; occupational safety focuses more on injuries to workers – i.e., very much a reactive focus. Often, firms focus too much effort on occupational safety when in fact, process safety should be given more attention, commensurate with risk.
Effective Process Safety Management is a function of:
- Effective process safety leadership, including representation at site and board level
- A trusting, open culture that is conducive to safety and where workers’ views are taken into account
- Suitable training and the unhindered transfer of knowledge and good practices
- Plant that is fit for purpose and the application of suitable technology
- Adequate repairs and maintenance expenditure
- Necessary and sufficient process monitoring and control
- Timely rectification of faults
- Effective change management
- A satisfactory balance between production and safety orientation
- Adequate levels of staffing
- A long-term, rather than short-term focus on safety
- Stability – high turnover at safety management level can be damaging
- Effective communication
- Etc.
Good Process Safety Management (PSM) requires effective Process Safety Leadership, therefore leaders have to foster an environment conducive to safety through the Safety Culture. Unfortunately, good safety leadership is not always apparent in organisations. At various management levels, such leadership requires a good level of knowledge and experience with the processes in question. And critically, at board-level, an ethos of safety has to be articulated with a consistent, compelling and meaningful message to all employees. Too many firms pay lip service to process safety management with hollow statements or strap lines.
The safety culture is made of up of shared set of beliefs, norms and practices, documented and communicated though a common language. Shared is the keyword: if the safety values are not shared consistently, safety performance will probably not be acceptable, leading to the potential for process incidents and accidents. The shared experiences of an organisation (or site), such as previous incidents, or defining periods, tend to shape the safety culture. Hence, very different safety cultures can be seen at sites or within companies operating broadly the same process, e.g. a refinery.
The two major disasters at the Buncefield oil terminal and BP’s Texas City refinery were the result of a loss of containment. But poor safety leadership was one of the main underlying reasons that these disasters occurred.
Accidents like these continue to shape the requirements of PSM and have brought to the forefront key issues such as:
- Safety leadership
- Safety culture
- Change management
- Mechanical integrity
- Primary containment
- Best practice
- Emergency preparedness
- Leading and lagging indicators
As Chemical Engineers, we have to be aware of these emerging issues and design and manage our processes accordingly. Through this web site, we aim to bring to your attention these emerging issues, pooling ideas from industry-accepted and credible sources, and suggest ways of continually improving your process safety management performance. As Chemical Engineers, we can make a difference. We have an obligation to society make our plants and places of work as safe as is reasonably practicable. Disasters such as those at Buncefield and Texas City could have easily been avoided.
We welcome you to share your experiences and views. You can do this by using our submissions page.
Following best practice in process safety management doesn’t just protect employees, the general public and the environment from harm, it also has the capacity to increase profitability of the company. The “triple bottom line” of people, planet and profit – a corporate social responsibility ethos – will play an increasing role in peoples’ expectations. The Chemical Engineer is well-equipped to deliver on these expectations.
Tools and Techniques
Employers must assess the risks in the workplace and take all reasonably practicable precautions to ensure the safety of their employees and others who could be affected. The general principles of an appropriate risk assessment are identified in EN 1050 Safety of machinery - Principles of Risk Assessment and in The Management of Health and Safety at Work Regulations 1999 (Management Regulations).
Through the risk assessment process employers should identify the potential hazards and determine their significance. They should then take appropriate precautionary measures to reduce the risk from the hazards to an acceptable level that is as low as reasonably practicable.
Assessment of risk should be carried out at key stages of the project from feasibility study through design, construction and to commissioning.
A useful five-stage risk assessment will include the following (Ref. HSE):
- Identify the hazards
- Decide who might be harmed and how
- Evaluate the risks and decide on precaution
- Record your findings and implement them
- Review your assessment and update if necessary
About HAZID
A Hazard Identification Study (or HAZID) is a useful too for eliciting relatively high-level risks within an organisation of process. The study is normally presented as a simple table.
A HAZID is a semi-quantitative process which classes hazards into various keyword categories such as temperature (high, low), level (high, low), pressure (high, low), etc. The process starts by examining, for example, the process flow diagram (PFD) or piping and instrumentation diagram (P&ID). The diagram is split into manageable chunks (nodes) and each hazard category is discussed to elicit possible (credible) hazards.
The HAZID process can also be applied to business risks and business processes as such. The tool is under-utilised in that respect.
Key Steps
- For each particular hazard category or keyword, a credible scenario is elicited and the raw risk (i.e., un-mitigated) of the hazard is ranked from 0-5 (negligible effect to severe effect).
- The un-mitigated consequences of the hazard are then assessed.
- The mitigating factors that are deemed to reduce the raw risk are then discussed and noted in the table. These are generally broken down into basic process control systems, human intervention and other mitigating factors.
- The mitigated risk is then evaluated and scored.
- The residual risk is then evaluated and ranked according to whether acceptable (green), tolerable (yellow) or unacceptable (red). This risk is evaluated using a simple 2x2 matrix which clearly displays the colours of the risk zones.
Application of HAZID
The HAZID is a simple, yet powerful tool for evaluating risks inherent in a process or business.
The HAZID study will form an important input to the Hazard and Operability studies (HAZOP) and the layers of protection analysis (LOPA) - see later.
To make the most of the tool, he HAZID requires a competent chairperson and a technical secretary within the team. The novice should generally seek advice from an experienced HAZID technician before attempting to use the tool in a real-life case. The HAZID tool can easily be developed using MS Excel, however, proprietary software is available. There are a number of consultants out there who can provide HAZID consultancy services.
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