We provide plant safety review and our safety reviews for process plants involved a holistic approach which covers the entire spectrum of the process plant whilst employing various tools and technologies. Despite the complexity of safety reviews, in general our safety reviews can be broken down into five major steps, namely:
This step involves reviewing the plant designs. Information required to commence this step includes a detailed process descriptions accompanied by process flow diagram (PFD) that contains major equipment, pipes, critical control and mass & energy balance. We also require piping and instrumentation diagrams (P&IDs) that contains all of the equipment, pipes, valves, instrumentation & controls. These P&IDs should be accompanied by functional specifications, safety interlock tables and should exhibit the layers of protection, eg HAZOP, LOPA included in the design. We will also review engineering calculations, datasheets & specifications to ensure these are adequate and appropriate for the intended operations. Finally, we will need to review the plant layout to determine how the equipment will be clustered, the relevant distant employed, the height of equipment and locations of safety equipment. With these information, we will review and benchmark against industry standard, our in-house design checklist and audit the design against relevant standards, regulations and/or government requirements.
Chemical Exposure Index
The chemical exposure index (CEI) was developed by The Dow Chemical Company, used to identify and rank the relative acute health hazards associated with potential chemical releases and its impact to the people in neighbouring plants or communities. This CEI system will provide a method of ranking one hazard relative to another and it is not intended to define a particular design as safe or unsafe. This CEI method is employed for conducting an initial process hazard analysis (PHA), in the distribution ranking index (DRI) calculations, to provide opportunity to make recommendations for eliminating, reducing or mitigating releases and in emergency response planning. The CEI is calculated from five factors: a measure of toxicity; the quantity of volatile material available for a release; the distance to each area of concern; the molecular weight of the material being evaluated; and process variables that can affect the conditions of a release such as temperature, pressure, and reactivity. Hence, we will require chemical and physical properties of all chemicals used in the plant of interest.
Standard Operating Procedures
In this step, we review the standard operating procedures (SOPs), including startup, shutdown, normal, and emergency procedures. The operating procedures should be clear, specific and highlight the limitations of the process, such as temperature, pressure and give the consequences when such limitations are exceeded. In this review, we look for areas such as vague instructions that may result in human errors. We will also select random operators and assess the operator’s ability in executing SOPs. Training records that show operators being equipped with the knowledge to perform risky tasks will also be reviewed. Lastly, we also look at those tasks that should have been incorporated in the design or automated from the outset instead of relying on human actions.
For plant already in operation, we will review accident investigations of previous and relevant incidents that are shared throughout the company and between companies. The purpose is to characterise and understand the weakness of the plant. Apart from review the data stored in either SCADA/PLC or DCS systems, we will also perform statistical process control (SPC) analysis on the plants past performances. Too often, plants simply rely on control system informing when the process variables hit a limit which then triggers actions. Unfortunately, most of such a method devoted far too little attention to variability reduction. A plant in which the process is not stable or has low process capability index is unpredictable and may be unsafe. If the process is centred and has low standard deviation, it will operates within upper and lower limits all the time until a disturbance occurs. And when this occurs, SPC will detect so much earlier before any of the limits are breached giving the control system and/or operators more time to address to the disturbance.
Hazard Identification & Mitigation
In some cases if warranted, in addition to employing the steps outlined above, we may employ computational fluid dynamics (CFD), finite element analysis (FEA) or fluid structural interactions (FSI) simulation technologies. The use of such simulation technologies help to pin-point where the issues are and may further reveal hidden issues. Once we have identified the hazards present in the plant of interest we will develop appropriate recommendations to improve the design and operating procedures to eliminate hazards and prevent accidents. As a plant safety consultant, we will also develop and review the management system to ensure that all of the safety review recommendations are implemented and documented before startup or modifications.
Finally, whilst there are several firms offering plant safety consulting services, we differentiate ourselves from other plant safety consultants in the way we approach a problem. Our standard approach involves safety analysis that goes beyond simply adopting rule-of-thumb guidelines. Whilst rule-of-thumb provides a starting point for most plant safety reviews, in some cases, it may lead to overcompensation. In a nutshell, our conventional plant safety review services are supported by in-house advanced engineering technologies to ensure effective & efficient solutions.