scholarly journals Sneak Circuit Analysis: Lessons Learned from Near Miss Event

Author(s):  
James Li

Sneak Circuit Analysis is intended for critical applications which are essential to mission success and safety. A sneak condition will occur when a designed circuit inhibits a wanted function or results in an unwanted function. Sneak conditions originate from one of the four following scenarios: a sneak path resulting in a flow of electrical current along an unexpected route; a sneak timing that may cause the activation of some desired/designed functionality at an unexpected time; a sneak indication in monitoring functions that may result in an ambiguous or false display of system operating conditions; and lastly, a sneak label which may induce operator error due to inappropriate instruction. This paper introduces a near miss event that occurred in the Sao Paulo monorail which was caused by a sneak time condition. Root cause analysis and design modifications are also discussed in the paper.

2021 ◽  
Author(s):  
Alvin Ivan Handoko ◽  
Henry Edward Khella ◽  
Erwan Couzigou ◽  
Adel Abdulrahman Al-Marzouqi

Abstract Since the implementation of the Drilling Performance Department in late 2017, ADNOC Offshore has been able to develop a company performance-oriented culture among the drilling teams. This performance culture is reflected in 25% ILT reduction in 2018 and 12% in 2019. Furthermore, 37 NPT RCA cases were investigated and concluded in 2019, which resulted in 57 actions for tracking and closure. With 5 (five) concessions, 9 (nine) different shareholders, and 39 (thirty-nine) rigs, drilling performance management is challenging. ADNOC Offshore created a centralized Drilling Performance Team to capitalize on this diversity as an opportunity to improve the traditional drilling performance role. This paper describes the team's approach on Drilling Performance and the consecutive result. The team enhances the typical drilling performance role of Key Performance Indicator (KPI) management and reporting by adopting the Performance Opportunity Time (POT) and Root Cause Analysis (RCA) Process. At the same time, the Drilling Performance Team facilitates the flow of information between teams to ensure effective knowledge transfer within such a large organization. The POT concept tackles the well duration reduction through the reduction of Invisible Lost Time (ILT) and Non-Productive Time (NPT). To reduce the ILT, the team took advantage of the extensive technical background in the various drilling teams. Performance improvement initiatives were proposed by taking references from different teams within ADNOC Offshore and evaluating the application in other concession. Other approach is to compare with out-of-company references. For NPT reduction, the innovative approach was to use the HSE Root Cause Analysis (RCA) concept. This RCA process led by the Drilling Performance Team was implemented to standardize the approach and have a systematic investigation analysis. This process resulted in identifying root causes and effective corrective action plans. As per HSE, addressing the root causes of incidents would result in the most significant impact in NPT. This approach also allows an independent and more detailed look on the subjects, where commonly these tasks are done in a limited manner by drilling teams alone with their ongoing operational workload. Finally, results are communicated to the drilling organization through lessons learned portal and technical bulletins.


Author(s):  
Juan C. Ramirez ◽  
Mark Fecke ◽  
Delmar Trey Morrison ◽  
John D. Martens

An explosion occurred in the firebox of an industrial boiler with a nominal fuel input rate of 100 MW (340 million Btu/hr), in a processing plant during final commissioning of the burner systems. This paper describes the investigation of the incident, root cause analysis, and lessons learned from the incident. The original burners in the boiler had recently been replaced with low NOx burners, and the facility was in the process of commissioning the new burner system. The boiler was running only on natural gas igniters at the time of the incident. While firing on igniters, an undetected stoppage of the control equipment occurred, which led to a restriction of airflow through the secondary air dampers. The boiler controls included programmable logic controllers (PLCs) for both the combustion control system (CCS) for regulation and the burner management system (BMS) for safety functions. The BMS was intended to detect a loss of control such as this and immediately stop fuel to the boiler; however, it did not. The BMS PLC was not configured to detect the dangerous states and allowed the igniters to continue to fire. An explosion subsequently occurred within the boiler firebox that caused extensive damages to the facility and equipment. This paper will describe the incident investigation and determination of multiple root causes for failure of the BMS to prevent the explosion. The inadequate configuration of the control systems was likely present for some time prior to the incident, and the explosion was eventually caused when the right conditions occurred during this commissioning. We found through the investigation that the BMS deficiencies could have been detected and prevented (and almost were) through standard hazard analysis techniques common in the chemical processing industries. This paper will also discuss how hazard analysis can be applied to detect and prevent similar system failures.


Author(s):  
Silvia Khurrum ◽  
Michael Catapano

This paper presents a case history of problems experienced with a replacement HP feedwater heater that was manufactured with Type 439 stainless steel tubing. The subject heater was installed after numerous problems during manufacturing and was commissioned for service in February 2007. The first failures were experienced after only 2 years of operation. Reports indicate that after the discovery of the first leaks, maintenance groups servicing the heater were never able to get the heater completely leak-tight. Ultimately, the frequency and magnitude of subsequent leak incidents that followed caused the power generating company to fully bypass the heater in September 2009. The paper offers a full chronology of events that ultimately led to the demise of subject heater. The primary objective of the paper is to share the lessons learned during the root cause analysis of the problem, including the inherent limitations related to subject tube material. Specific steps identified herein were taken by the power generating company to ensure that the technical specification for the next replacement heater would preclude any similar problems from occurring.


2017 ◽  
Vol 52 (8) ◽  
pp. 1292-1295 ◽  
Author(s):  
Nadja Apelt ◽  
Joshua Schaffzin ◽  
Christina Bates ◽  
Rebeccah L. Brown ◽  
Marc Mecoli ◽  
...  

2011 ◽  
Vol 135 (11) ◽  
pp. 1436-1440 ◽  
Author(s):  
Maxwell L. Smith ◽  
Stephen S. Raab

Context.—Methods to improve surgical pathology patient safety include measuring the frequency of error in specific steps of the surgical pathology testing process, root cause analysis of active and latent components, and implementation of quality improvement initiatives. Objective.—To determine the frequency and cause of near-miss events in the specimen accessioning, setup, and biopsy-only gross examination testing steps of anatomic pathology. Design.—We used an observational checklist method to identify near-miss events. We performed root cause analysis to determine latent factors contributing to near-miss events. We conducted observations for 45 hours during 5 days, involving the accessioning and processing of 335 specimens. Results.—We detected a total of 2310 process-dependent and 266 operator-dependent near-miss events, resulting in a near-miss–event frequency of 5.5 per specimen. Root cause analysis showed that all process and operator near-miss events were associated with multiple system latent factors, including lack of standardized protocols, appropriate knowledge transfer, and focus on safety culture. Conclusion.—We conclude that the increased focus on surgical pathology near-miss events will reveal latent factors that may be targeted for improvement.


Author(s):  
Katherine E. Walker ◽  
David D. Woods ◽  
Michael F. Rayo

In 2013 NASA nearly drowned an astronaut during an Extravehicular Activity (EVA 23) on the International Space Station due to spacesuit water leakage. Indicators of trouble on the preceding EVA (22) were discounted. NASA carried out an investigation of the near miss event that is a sample of how root cause analysis is carried out in actual organizations (National Aeronautics and Space Administration, 2013). This paper contrasts the root cause analysis with a new analysis the authors carried out that captures how multiple systemic contributors combined to create the conditions that led up to the near miss. The new analysis illustrates the original finding from the late 1980s that accidents arise from multiple factors each necessary but only jointly sufficient (Reason, 1990; Woods, 1990; Cook, 2000; Woods, Dekker, Cook, Johannesen, & Sarter, 2010). Many of these contributors are system factors that have been present (latent) in the organization for some time prior to the specific sequence of events. In other words, the accidents arose from organizational or systemic factors (Reason, 1997). In contrast, the traditional root cause analysis focuses on the human roles closest to the adverse event and only raises systemic issues in terms of vague generalities that are difficult to address in systemic improvements (Dekker, 2014; Woods et al., 2010). The paper provides this contrast for two purposes. The first goal of this paper is to provide a concrete technique and diagram for identifying systemic contributors to adverse events (Systemic Contributors Analysis and Diagram or SCAD). The second goal is to highlight how the current practice of root cause analysis is unable to come to grips with systemic issues, misses the interactions between contributors, and misses emergent system properties. Using this systemic technique reveals that adverse events are very often due to production pressure at the blunt end, not human error at the sharp end of systems.


2012 ◽  
Vol 5 (2) ◽  
pp. 132-136 ◽  
Author(s):  
Eileen Y. Evanina ◽  
Nicole L. Monceaux

The Joint Commission on Accreditation of Hospital Organization (JCAHO) has handoff requirements to create the safe and effective transfer of patient information between providers. Multiple studies have investigated standardized nurse-to-nurse handoffs and nurse-to-physician handoffs. However, very few studies have examined handoff communication between anesthesia providers. A near-miss scenario during a sitting craniotomy procedure is reviewed, and a root cause analysis conducted to demonstrate the importance of communication and how a standardized anesthesia handoff tool can facilitate patient safety.


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