High Failure Modes Research Articles

Failure Mode and Effects Analysis of Accessibility in Frigid Zone Campus Buildings

With the progress of China’s economy, there is an increasing focus on accessibility systems. Enhancements to accessibility infrastructure are being implemented in all types of structures, with a particular focus on educational institutions such as college campuses. This research was carried out to examine the campus accessibility system of Northeastern University’s Nanhu and Hunnan Campuses in Shenyang City, China, using failure mode and effects analysis (FMEA) as a methodology and using incorporating fuzzy control, which overcomes the limitations of traditional FMEA. Fuzzy-FMEA integrates the fuzzy linguistic assessment to assist the analysis process, in contrast to standard analysis which mainly relies on subjective judgment. Through calculations, it is known that ramps, barrier-free toilets, and barrier-free entrances are the items with the highest failure modes. The construction of the campus accessible environment needs to prioritize solving the problems of these facilities. The research results also found that there is a lack of research specifications for accessible environments in China’s cold regions, and universal specifications are not fully suitable. The accessibility of the new campus was improved and management was improved, reflecting the school’s increased awareness of accessible environment construction in recent years. However, there are still many common problems in the old and new campuses, proving that they are not aware of the importance and urgency of improving these problems. In addition, the construction of barrier-free facilities in the administrative office buildings where management and faculty are located on both campuses is generally in good condition. The accessible design of dormitories and canteens commonly used by students is often ignored. Moreover, the rough detailing in many buildings prevents these facilities from being used properly. These are the challenges faced by the Northeastern University in building an accessible environment.

Implementing failure mode and effect analysis to improve the safety of volumetric modulated arc therapy for total body irradiation.

Volumetric-modulated arc therapy for total body irradiation (VMAT-TBI) is a novel radiotherapy technique that has been implemented at our institution. The purpose of this work is to investigate possible failure modes (FMs) in the treatment process and to develop a quality control (QC) program for VMAT-TBI following TG-100 guidelines. We formed a multidisciplinary team to map out the complete treatment process of VMAT-TBI following the AAPM TG-100 guidelines. This process map gives a visual representation of the VMAT-TBI workflow from the CT simulation, image processing, contouring, treatment planning, to treatment delivery. From the process map, potential FMs were identified. The occurrence (O), detectability (D), and severity of impact (S) of each FM were assigned according to scoring criteria (1-10) by the multidisciplinary team. A risk priority number (RPN) was calculated from average O, S, and D of each FM (RPN=O x S x D). High risk FMs were identified as 20% of the FMs having the highest RPN scores. After the FMEA analysis, fault-tree analysis (FTA) was performed for each major step of the treatment process to determine the effects of potential failures to the treatment outcome. Effective QC methods were identified to prevent the high risk failures and to improve the safety of the VMAT-TBI program. We identified a total of 55 sub-processes and 128 FMs from the VMAT-TBI workflow. The top five high-risk FMs were: (1) Prescription and/or OAR constraints changed during planning and not communicated to the planner, (2) Patient moves or breathes too heavily during the upper body CT scan (3) Patient moves during the lower body CT scan, (4) Treatment planning system not calculating total body DVH metrics correctly for TBI, (5) Improper optimization criteria used or not sufficient optimization, resulting in suboptimal dose coverage, OAR sparing or excessive hotspots during treatment planning. Two FMs have average severity scores ≥8: Incorrect PTV subdivision/isocenter placement and Prescription and/or OAR constraints changed during planning and not communicated to the planner. Quality assurance and QC interventions including staff training, standard operating procedures, and quality checklists were implemented based on the FMEA and FTA. FM and effect analysis was performed to identify high-risk FMs of our VMAT-TBI program. FMEA and FTA were effective in identifying potential FMs and determining the best quality management (QM) measures to implement in the VMAT-TBI program.

Fuzzy analytic hierarchy process‐based risk priority number for risk assessments of commissioning process of a ring gantry LINAC

We propose a fuzzy analytic hierarchy process (AHP)-based risk priority number (RPN) method in failure modes and effects analysis (FMEA) to overcome the shortcomings of traditional RPN-based FMEA. Our research group has previously published the FMEA to mitigate the failure modes (FMs) for the commissioning process of a ring gantry LINAC. However, inter-relationships among FMs were observed in high ranked FMs due to a heavy reliance on imaging system. Fuzzy AHP was applied to determine relative weights of risk impacts based on inter-relationships among FMs. Since the time sequence dependency is a major factor for risk factors, a hierarchical structure of AHP was used to reflect the directional impacts such as causal influence and feedback loop. Two fuzzy weighted RPNs, called (RPNW and FRPNW , were calculated depending on the input values of severity (S), occurrence (O), and probability of not being detected (D) from the evaluators. The RPNW used numerical values, whereas the fuzzy values were used for FRPNW . Both RPNs were calculated by multiplying the weighted O, S, and D using the fuzzy AHP method. The differences between the two fuzzy RPN rankings are due to inherent fuzzy uncertainty and deviations in O, S, and D values submitted by the evaluators. Considering all results of traditional and fuzzy-based FMEA, the two most highly ranked FMs were identified: errors in determining the non-isocentric SSD and SSD from MV images because of the unique features of the ring gantry LINAC. This study has demonstrated the feasibility of the use of a fuzzy AHP-based RPN to perform comprehensive analysis and prioritization of FMs. The risk analysis using fuzzy AHP can be improved and/or refined based on the department's specific workflow and clinical preferences taking various priority weighting approaches into account.

Embracing Inpatient Radiopharmaceutical Therapies in Radiation Oncology: An Example With Commissioning Pediatric I-131 MIBG Therapy

<h3>Purpose/Objective(s)</h3> Radiopharmaceutical therapy is rapidly expanding in radiation oncology and nuclear medicine. Iodine-131 metaiodobenzylguanidine (I-131 MIBG) is an inpatient therapy involving long infusion times and special consideration for radiation exposure and contamination control. In this study, we outline our process for commissioning pediatric I-131 MIBG therapy with a multidisciplinary team and perform a failure modes and effects analysis to assess the robustness of our procedures. <h3>Materials/Methods</h3> To commission pediatric I-131 MIBG therapy, we (1) created a multidisciplinary team with the appropriate skills, (2) located a space that met the needs of this intensive inpatient therapy, and (3) developed procedures that maximized safety. We identified failure modes (FM) from room design to patient/room release and scored them (1-10) according to their risk for occurrence (O), severity (S), and lack of detectability (D), per AAPM Task Group 100. The risk-priority number (RPN) is the product of these scores and identifies the FMs with the greatest risk. <h3>Results</h3> Our multidisciplinary team includes an authorized user (radiation oncologist/nuclear medicine physician), pediatric oncologists, radiation therapists, nurses, therapy medical physicists, and radiation safety staff. The space has a dedicated restroom and shower with appropriate plumbing, shielding built into the patient room/restroom construction, appropriate ventilation/filtration, and enough space for the patient, the infusion team (3-5), equipment, and mobile shields. The procedures meet regulatory and institutional safety standards and allow for appropriate radiation exposure and contamination control. 149 FMs were identified. The FMs with the greatest RPN were related to training deficiencies: (1) training of staff was inadequate (O = 5, S = 8, D = 4, RPN = 160), (2) caregivers did not understand radiation safety training (O = 5, S = 7, D = 4, RPN = 140), and (3) saline bag line and other dose lines (if multiple vials) were not clamped properly during dose infusion (O = 4, S = 8, D = 4, RPN = 128). 36/149 (24%) FMs had a high severity (S≥7). Of those, 11 (7% of all FMs) had a moderate risk of occurrence or going undetected (O or D > 3 but < 7) and none had a high risk of occurrence or going undetected (O or D ≥7). The remaining 25 high severity FMs were associated with commissioning, training, and room design/construction (14/25); drug ordering and patient preparation (7/25); and dose infusion (4/25). We attribute these FMs' relatively low risk of occurrence or going undetected to extensive checklists and redundant procedures. <h3>Conclusion</h3> Pediatric I-131 MIBG therapy is a complex treatment that requires careful consideration during commissioning. With a properly trained multidisciplinary team, robust procedures and checklists, and appropriate resources, it can be implemented safely and effectively.

Production Machine Maintenance System Design Using Reliability Centered Maintenance

One of the indicators in increasing productivity is the level of reliability of production machines. The reliability level of a production machine is determined by the effective and efficient maintenance process of the company. A case study was conducted in a manufacturing company. In the period January until June 2019, the percentage of machine downtime is more than 3.0% (ideal benchmarking downtime for the manufacturing industry). Research carried out using Reliability Centered Maintenance (RCM). It starts with determining critical objects, then identifies each function of the assets, carries out FMEA analysis and calculates the highest risk of each failure mode, calculates proper maintenance intervals for the five highest failure modes, then ends with making a maintenance strategy by considering risk based inspection. This study aims to develop a maintenance strategy model that is better than what is currently used. By applying Reliability Centered Maintenance, machine reliability can be increased by an average increase of 39.34% and the right maintenance strategy can be found. Furthermore, it will get a new framework to become a new maintenance policy for the company.

Critical Re-Evaluation of a Failure Mode Effect Analysis in a Radiation Therapy Department After 10 Years

PurposeFailure mode effect analysis (FMEA) is a proactive methodology that allows one to analyze a process, regardless of whether an adverse event occurs. In our radiation therapy (RT) department, a first FMEA was performed in 2009. In this paper we critically re-evaluate the RT process after 10 years and present it in terms of a lesson learned. Methods and MaterialsA working group (WG), led by a qualified clinical risk engineer, which included radiation oncologists, physicists, a radiation therapist, and a nurse, evaluated the possible failure modes (FMs) of the RT process. For each FM, the estimated frequency of occurrence (O, range 1-4), the expected severity of the damage (S, range 1-5), and the detectability lack (D, range 1-4) were scored. A risk priority number (RPN) was obtained as RPN = OxSxD. The data were compared with the 2009 edition. ResultsIn the 2020 analysis, 67 FMs were identified (27 in the 2009 series). The absolute risk values of the previous 3 highest FMs were generally reduced. The patient identification risk (highest value in the 2009 analysis) was reduced from 48.0 to 6.9, becoming the 51st RPN score, thanks to a patient barcode recognition within the bunker. The 2020 highest risk values regarded: (i-2020) the patient’s inadequate recollection and reporting of his/her medical history (ie, anamnesis) during the first medical examination and (ii-2020) the incorrect interpretation of tumor and normal tissue in computed tomography images. The WG proposed corrective actions. ConclusionsIn this single institution experience, the 10-year FMEA analysis showed a reduction in the previous higher RPN values thanks to the corrective actions taken. The new FMs and subsequent RPNs reveal the need for a continuous iterative improvement process.

FMEA of MR-Only Treatment Planning in the Pelvis

PurposeTo evaluate the implementation of a magnetic resonance (MR)-only workflow (ie, implementing MR simulation as the primary planning modality) using failure mode and effects analysis (FMEA) in comparison with a conventional multimodality (MR simulation in conjunction with computed tomography simulation) workflow for pelvis external beam planning. Methods and MaterialsTo perform the FMEA, a multidisciplinary 9-member team was assembled and developed process maps, identified potential failure modes (FMs), and assigned numerical values to the severity (S), frequency of occurrence (O), and detectability (D) of those FMs. Risk priority numbers (RPNs) were calculated via the product of S, O, and D as a metric for evaluating relative patient risk. An alternative 3-digit composite number (SOD) was computed to emphasize high-severity FMs. Fault tree analysis identified the causality chain leading to the highest-severity FM. ResultsSeven processes were identified, 3 of which were shared between workflows. Image fusion and target delineation subprocesses using the conventional workflow added 9 and 10 FMs, respectively, with 6 RPNs >100. By contrast, synthetic computed tomography generation introduced 3 major subprocesses and propagated 46 unique FMs, 15 with RPNs >100. For the conventional workflow, the largest RPN scores were introduced by image fusion (RPN range, 120-192). For the MR-only workflow, the highest RPN scores were from inaccuracies in target delineation resulting from misinterpretation of MR images (RPN = 240) and insufficient management of patient- and system-level distortions (RPN = 210 and 168, respectively). Underestimation (RPN = 140) or overestimation (RPN = 192) of bone volume produced higher RPN scores. The highest SODs for both workflows were related to changes in target location because of internal anatomy changes (conventional = 961, MR-only = 822). ConclusionsFMEA identified areas for mitigating risk in MR-only pelvis RTP, and SODs identified high-severity process modes. Efforts to develop a quality management program to mitigate high FMs are underway.

Failure Modes and Effects Analysis of Electrical System at Indoor Wires and Wiring Appliances

본 연구에서는 옥내 배선 및 배선기구에 대하여, 통계자료, 관련법, 실태조사 등의 분석을 통하여 그 위험성을 확인하였다. 또한 구성부품을 분류하였고 FMEA 기법 적용이 가능한 신뢰성평가 소프트웨어를 이용하여 고장모드를 발견하고 이를 바탕으로 위험우선순위지수와 중요도를 도출하였다. 옥내 배선 및 배선기구의 구성부품별 중요도는 패널, MCCB/ELB, 커넥터, 스위치, 콘센트, 플러그, 소켓 및 전기배선에서 나타났으며 이중에서 콘센트와 플러그, 전기배선 및 커넥터에서 고장모드가 가장 높게 나타났다. 위험우선순위가 동시에 높은 부품은 콘센트와 플러그, 전기배선 및 커넥터로 중요도와 비슷하게 도출되었다. 특히 콘센트와 플러그 부분에서는 누전 및 접촉불량으로 인한 감전 및 누전화재가 잠재요인으로 나타났으며, 콘센트의 과부하에 의한 과열의 경우도 전기화재를 일으키는 원인으로 작용하고 있고 이 모든 것이 옥내 배선 및 배선기구의 전기재해를 높이는 원인으로 분석되었다.This study analyzed the risks of indoor wires and wiring appliances by looking into statistical data, relevant laws, and actual conditions. In addition, it classified the components to find a failure mode with the use of the reliability evaluation software that can apply the Failure Modes and Effects Analysis (FMEA) technique, and drew a risk priority index and the degree of importance. Regarding the components of indoor wires and wiring appliances, their importance factors were panel, MCCB/ELB, connector, switch, outlet, plug, socket and electric wire, of which outlet, plug, electric wire and connector had the highest failure mode. In addition, it is found that the overheat induced by outlet overload caused an electric fire and increased electric disasters of indoor wires and wiring appliances. The study results are applicable to the fires with the risk of human disaster and the risk of life safety on household items.

Reliability of Optical Fibers, Cables, and Splices

This paper discusses fiber characteristics and cable design considerations that affect cable reliability. Installed cable and splice reliability data are presented, and it is concluded that intrinsic cable and splice reliability is very high. Cable failures are dominated by uncontrollable factors, and the highest failure mode is backhoe blackout. Finally, restoration issues are discussed.