Process Safety Metrics Research Articles

Process safety consequence modeling using artificial neural networks for approximating heat exchanger overpressure severity

One challenge in accounting for process safety incidents is that accurate modeling is complex, time-intensive, and requires many inputs. Process safety consequence modeling using first principles can be complicated. At the same time, setting up experiments is not always practical. This work proposes an artificial neural network (ANN) framework to predict process safety metrics to prevent overpressure during tube rupture scenarios with reasonable accuracy. Specifically, we apply a feed forward neural network to predict heat exchanger safety rating that is proportional to the heat exchanger pressure normalized with respect to the maximum allowable pressure. By training ANN to a set of tube rupture simulation data, we are able to bypasses the need for solving tedious dynamic and non-smooth system of equations. The ANN-based models yield safety rating predictions that comply with API 521 overpressure standards. We further demonstrate how these predictions can be used to perform real-time monitoring for a network of heat exchangers in a plant setting.

Safety and quality metrics for process hazard analysis

AbstractCompanies use metrics to monitor their process safety performance. Process safety metrics may relate to any aspect of a process safety program but many metrics are developed for individual process safety elements, such as process hazard analysis (PHA). Traditional metrics for PHA mostly address aspects of managing PHA studies, such as the timely completion of corrective actions. However, there are other types of metrics that are of interest, specifically those that characterize the level of safety achieved for a process and the level of quality achieved in a study. This article describes the use of such metrics in PHA and provides examples of their use.

Do not let your safe operating limits leave you S‐O‐L (out of luck)

AbstractCollection and utilization of process safety metrics is an important tool for driving improved safety. Tier three leading indicators (challenges to safety system) indicate failures of process safety management systems and highlight areas that should be improved to prevent a more serious event. Safe Operating Limit (SOL) exceedances are a commonly used Tier 3 leading indicator. Surprisingly, there are many different approaches used in industry to calculate safe operating limits and to apply them. This inconsistency potentially diminishes the usefulness of SOL exceedances as an effective indicator.This paper discusses current industry practices around safe operating limits as established by a recent global benchmark survey of over 150 safety practitioners. Areas explored in the survey of SOLs include; methodology for calculating, how/where information is stored, how/when established values are reviewed and audited, usage as a leading indicator, integration with operations (training, documentation), identification and tracking of when exceedances have occurred, and actions taken on exceedance. Key results and conclusions will be presented as well as recommendations on where industry should focus on improvement.

Risk assessment and risk reduction of an acrylonitrile production plant

Reducing accident occurrence in petrochemical plants is crucial, thus appropriately allocating management resources to safety investment is a vital issue for corporate management as international competition intensifies. Understanding the priority of safety investment in a rational way helps achieve this objective.In this study, we targeted an acrylonitrile plant. First, Dow Chemical's Fire and Explosion Index (F&EI) identified the reaction process as having the greatest physical risk. We evaluated the severity of accidents in the reaction process using the Process Safety Metrics advocated by the Center for Chemical Process Safety (CCPS); however, this index does not express damages a company actually experience. To solve this problem, we proposed a new metric that adds indirect cost to CCPS metrics. We adopted fault tree analysis (FTA) as a risk assessment method. In identifying top events and basic events, we attempted to improve the completeness of risk identification by considering accidents from the past, actual plant operation and equipment characteristics, natural disasters, and cyber-attacks and terrorist attacks. Consequently, we identified the top events with high priority in handling because of serious accidents as fire/explosion outside the reactor, fire/explosion inside the reactor, and reactor destruction. The new CCPS evaluation index proposed in this study found that fire and explosion outside the reactor has the highest severity. We considered the creation of the fault tree (FT) diagram of the top event, estimating the occurrence probability, and identifying the risk reduction part and capital investment aimed at risk reduction. As an economically feasible selection method for risk reduction investment, using the difference in loss amounts before and after safety investments indicated investment priority.

Effective process safety management for highly hazardous chemicals

Process safety management (PSM) has been a critical consideration in the plants that handle highly hazardous chemicals (HHCs), flammable gases and liquids. This article introduces PSM standard by OSHA's 29 CFR 1910.119. Further, it highlights an effective PSM for HHCs and provides PSM practices of the industries in Thailand. Effective PSM can prevent or mitigate catastrophic releases of HHCs which can cause health problems, fires, explosions, and fatalities. It is a disciplined framework for managing the integrity of operating systems, safety critical equipment (SCE) and safe work practices. Effective implementation and audits of PSM system and the continual improvement are important. It requires the industries to execute suitable leading and lagging process safety metrics. The inclusive and integrated PSM intents, human factors, good design principles, recognized and generally accepted good engineering practices (RAGAGEPs), engineering and administrative controls, and integrity of operating and maintenance practices are substantial key roles. It is important that the PSM system should be risk-based under the ALARP concept because hazards and risks are not equal, and there are multiple risks and consequences to consider. In summary, the PSM effectiveness depends on, for example, process safety metrics, management review, audit findings and particularly workforce involvement.

Incident Investigation on the Basis of Business Process Model for Plant Lifecycle Engineering

The process safety incidents are directly caused by defects of protection layers, and process safety management (PSM) system should maintain the soundness of the protection layers. In general, the weakness of the PSM system is identified through the incident investigations, and the performance of the PSM has to be improved through the PDCA cycle using process safety metrics. However, PSM business process is comprehended in the plant lifecycle engineering business processes, so that even if the weakness of PSM system is identified, the key engineering business processes for that weakness cannot be recognized, so far. To overcome the above mentioned problem on process safety metrics, we propose the business process model based process safety incident investigation for process safety metrics.

The probability circular ruler “PCR” (process safety metrics)

The explanation of process safety protection layers and related probability of failure does not need to be complicated. This article shows visuals that can be used to explain the complexity of safety layers and their relationship to reduce the risk of an overall incident. It is proposed that the “Swiss Cheese Model” be replaced with a more realistic probability wheel referred to as the probability circular ruler, leading to usable information to be included in the P&ID as tagging labels with safety data of the process protecting device. © 2016 American Institute of Chemical Engineers Process Saf Prog 35: 124–136, 2016

Process safety common lead metrics: implementing and learning

No matter which major accident event investigation is looked into, some common themes concerning the requirements for process safety metrics present themselves. For example, the recent Macondo investigation by the US Chemical Safety Board (CSB) examined both API 754 and IOGP 456, and re-iterated that metrics need to be developed to capture the health of barriers and management systems. The effectiveness of barriers and management systems needs to be assessed, as does the frequency that these barriers are being called upon to make sure that the risk is being properly managed. Both API 754 and IOGP 456 use the four-tier system, where the top two tiers are lagging, and tiers three and four are more leading. Both standards focus on reporting and benchmarking the lagging metrics; however, the selection of leading metrics is left to be determined by individual companies. Recent work completed by the IChemE Safety Centre (ISC) focuses on these leading metrics, but takes a different approach by developing a suite of 21 common lead metrics that allows for developments to occur. By having common metrics across companies and across industries, ISC and its member companies are at the groundbreaking point where benchmarking and identification of best practice can begin. APPEA is leading the charge with a unanimous agreement by the CEOs at the April CEO meeting to implement the common lead metrics across the APPEA companies. Quadrant Energy is well underway with its journey, and this extended abstract discusses the process being undertaken to commence reporting on all 21 of these process safety common lead metrics.

So we all have been implementing process safety metrics-what next?

Industry over the last two to three years has put a lot of effort into implementing Process Safety Metrics. This is a good practice but, now that we have metrics data, how are we utilizing them to improve process safety performance? Air Products has been monitoring process safety performance for the last five years using combined Center for Chemical Process Safety and American Petroleum Institute RP 754 metrics. This article will highlight the approach we have applied, both through our lagging and leading indicators, to drive our process safety performance improvement programs. It will review the programs we initiated, leading indicators we identified, and how it also helped to improve our process safety culture. This article will also look at the importance of measuring severity and its impact in driving leadership behaviors. We will also discuss future opportunities to improve process safety performance via metrics analysis and follow-up initiatives. © 2013 American Institute of Chemical Engineers Process Saf Prog 33: 172–178, 2014

Normalization of process safety lagging metrics

This article explores new process safety metrics for measuring process safety performance in the chemical processing industry. While Process Safety Management enables an operation to optimize their process safety programs and organizational risks, there is an emerging need to evaluate process safety implementation across an organization through measurement of key indicators. Lagging metrics utilize process safety incidents as the numerator and divide it by an appropriate process‐related denominator or “normalization factor.” Currently, work hours is used extensively as a normalization factor to evaluate safety performance in the process industries. However, this lagging metric does not directly reflect process safety information and may not accurately reflect the safety performance of the process. Modified denominators are explored in this study and compared with the existing time‐based denominator to validate the effectiveness and applicability of the new metrics. Each proposed normalization factor was validated using available industry data. A statistical unitization method has been used to convert incident rates of different ranges for the convenience of comparison. Results show that some proposed process‐related metrics have potential as alternatives, used along with the time‐based metric, to evaluate process safety performance within organizations. © 2013 American Institute of Chemical Engineers Process Saf Prog 32: 337–345, 2013

Migrating an incident reporting system to a CCPS process safety metrics model

A major chemical company established a formal incident investigation and reporting system several years ago. The original system focused heavily on worker-related injuries, illnesses, and near-misses and was used primarily to track statistics reportable to the Occupational Safety and Health Administration (OSHA). This Occupational Injury and Illness (OII) approach has been recognized to be an ineffective tool for measuring, predicting, and preventing process safety incidents. The Center for Chemical Process Safety (CCPS) recently published guidelines on how to establish safety metrics for the measurement and reduction of process safety incidents. The process safety metrics approach relies upon leading and lagging metrics to improve organization process safety. This paper is a case study of the analysis of one organization’s incident database, which represents approximately five years of data from over a dozen facilities. The aim of this investigation was to extract useful process safety metrics from the incident investigation and reporting system, which would be pertinent to the types of process units and process functions at these facilities. This paper will discuss the approach taken to extract process incident information from an OII-based database and present the difficulties of performing an analysis on such a database. This paper provides guidance on how to migrate an existing OII-based reporting system to a program that includes process safety metrics in accordance with industry best practices.

Cheddar or Swiss? How strong are your barriers?

AbstractThis article describes a company's experience with process safety metrics and describes systematic methods to improve safety performance. As a result of a major accident, an internal investigation identified that although a site may have numerous measures for tracking operational and safety performance, these measures may not focus on leading indicators that could provide early warning of potential major incidents.To systematically reduce incidents, especially, low probability high consequence process safety events, it is necessary to focus on prevention and specifically the strength of the barriers. The approach described in this article, therefore, aims to create a combination of Process Safety Performance Indicators that lead to stronger more robust barriers.While industrial history tells us that such high consequence events are infrequent, this significant process safety risk is always present in production operations, and thus needs to be continuously assessed and reduced through systematic safety management. Within one company, this recognition has resulted in a substantial strengthening of process safety risk management through a more comprehensive system of controls embedded within its new Operating Management System, which is being implemented at the site level across all of its operations globally.This article explores the ongoing methodology and approach being used to select a limited but crucial set of Process Safety Performance Indicators to enable effective measurement and the appropriate management of process safety performance. © 2009 American Institute of Chemical Engineers Process Saf Prog, 2009

Using measured performance as a process safety leading indicator

AbstractPeriodic demands on layers of protection (i.e., prealarms, safety instrumented functions, relief devices, emergency response systems, etc.) are precursors to more serious incidents. The failure of one or more layers of protection is always part of an accident sequence. When they occur documenting these demands and the associated consequences in a way to facilitate analysis, provides a means to measure process safety management performance. Although process safety metrics are still in their adolescence, this article reviews experiences of development and implementation of a “Challenges to Safety Systems” process safety performance indicator. This article includes a discussion of automating significant portions of the data collection process based on the technical work documented by the CCPS PERD (Process Equipment Reliability Database) initiative. The article also recommends various metrics that can be calculated and describes how the initial foundation developed to support improved process safety can be leveraged to achieve other benefits, such as design improvements and improvements in the reliability, operation, and maintenance of the facility. © 2009 American Institute of Chemical Engineers Process Saf Prog, 2009

The evolution and current status of process safety management metrics

AbstractA broad, consistent set of process safety management metrics and leading indicators is important to effectively manage process safety and prevent incidents, help ensure regulatory compliance, meet internal policies, and verify that adequate management attention and resources are allotted to meet program needs. This article will review the development, current state, and future focus areas associated with the use of process safety metrics and leading indicators within The DuPont Company as a global manufacturing organization at a site, business, and corporate level. This includes a historical perspective of past metrics and their technical basis with a primary focus on incident classification and audit results, a review of recent improvements involving an expanded group of current metrics, and a general discussion of forward looking additional improvements. An overview of lessons learned, guidance, and challenges involving the development and use of process safety metrics and indicators within a global enterprise will also be provided. © 2009 American Institute of Chemical Engineers Process Saf Prog, 2009