Application and Limitation of Safety Valves Inspection Codes in China

2021 ◽  
Author(s):  
Jian Xing ◽  
Zhiyuan Han ◽  
Shuping Ai
Keyword(s):  
Failure Modes ◽  
Engineering Application ◽  
Chemical Equipment ◽  
Oil Refining ◽  
Risk Level ◽  
Chemical Plants ◽  
Accident Rate ◽  
Inspection Interval ◽  
Application Data ◽  
The Difference

Abstract Safety valves are important devices to protect system by relieving pressure in oil refining and chemical equipment. According to API 576-2017 and API 510, the inspection interval for safety valves should not be more than 10 years. Also, TSG ZF001–2006 in China specifies the inspection interval for safety valves is only 1 year. However, the maintenance interval for petrochemical units normally is 3∼5 years, which thus results in the inconsistency between its inspection interval and the maintenance interval. This study firstly conducts contrastive analysis about the difference of major regulations and standards for safety valves inspection between China and API standards, and then performs thorough investigation of the operational management and regulation about the extension for safety valves inspection interval in the typical Chinese petrochemical enterprises. Besides, the failure modes and risk level of safety valves are investigated by quantitative analysis of 44,692 safety valves engineering application data in oil refining and chemical plants based on Risk-Based Inspection (RBI) technology. The result indicates that the overall risk level of safety valves is low, as the percentage of safety valves with a high-risk level is less than 1%, and the accident rate caused by safety valves failure is less than 0.005%. In addition, this study analyzes the limitations of specification such as TSG ZF001–2006 in terms of safety valves inspection and the application of regulation extension. Based on above analysis, the specifications and standards about safety valves should be revised and introduce the RBI technology to extend the inspection interval.

scholarly journals Fatigue Resistance and Failure Behavior of Penetration and Non-Penetration Laser Welded Lap Joints

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Xiangzhong Guo ◽  
Wei Liu ◽  
Xiqing Li ◽  
Haowen Shi ◽  
Zhikun Song
Keyword(s):  
Fatigue Resistance ◽  
Failure Modes ◽  
Plate Thickness ◽  
High Stress ◽  
Lap Joints ◽  
Failure Behavior ◽  
Passenger Cars ◽  
Plate Fracture ◽  
The Difference ◽  
Railway Passenger

AbstractPenetration and non-penetration lap laser welding is the joining method for assembling side facade panels of railway passenger cars, while their fatigue performances and the difference between them are not completely understood. In this study, the fatigue resistance and failure behavior of penetration 1.5+0.8-P and non-penetration 0.8+1.5-N laser welded lap joints prepared with 0.8 mm and 1.5 mm cold-rolled 301L plates were investigated. The weld beads showed a solidification microstructure of primary ferrite with good thermal cracking resistance, and their hardness was lower than that of the plates. The 1.5+0.8-P joint exhibited better fatigue resistance to low stress amplitudes, whereas the 0.8+1.5-N joint showed greater resistance to high stress amplitudes. The failure modes of 0.8+1.5-N and 1.5+0.8-P joints were 1.5 mm and 0.8 mm lower lap plate fracture, respectively, and the primary cracks were initiated at welding fusion lines on the lap surface. There were long plastic ribs on the penetration plate fracture, but not on the non-penetration plate fracture. The fatigue resistance stresses in the crack initiation area of the penetration and non-penetration plates calculated based on the mean fatigue limits are 408 MPa and 326 MPa, respectively, which can be used as reference stress for the fatigue design of the laser welded structures. The main reason for the difference in fatigue performance between the two laser welded joints was that the asymmetrical heating in the non-penetration plate thickness resulted in higher residual stress near the welding fusion line.

Safety Assessment of Long Term Serviced Pressure Vessels: A Case Study of Typical Refining and Chemical Plants in China

2021 ◽  
Author(s):  
Zhiyuan Han ◽  
Guoshan Xie ◽  
Haiyi Jiang ◽  
Xiaowei Li
Keyword(s):  
Pressure Vessel ◽  
Safety Assessment ◽  
Failure Modes ◽  
Pressure Vessels ◽  
Time Dependent ◽  
Chemical Plants ◽  
Safety Specification ◽  
Detailed Assessment

Abstract The safety and risk of the long term serviced pressure vessels, especially which serviced more than 20 years, has become one of the most concerned issues in refining and chemical industry and government safety supervision in China. According to the Chinese pressure vessel safety specification TSG 21-2016 “Supervision Regulation on Safety Technology for Stationary Pressure Vessel”, if necessary, safety assessment should be performed for the pressure vessel which reaches the design service life or exceeds 20 years without a definite design life. However, the safety and risk conditions of most pressure vessels have little changes after long term serviced because their failure modes are time-independent. Thus the key problem is to identify the devices with the time-dependent failure modes and assess them based on the failure modes. This study provided a case study on 16 typical refining and chemical plants including 1870 pressure vessels serviced more than 20 years. The quantitative risk and damage mechanisms were calculated based on API 581, the time-dependent and time-independent failure modes were identified, and the typical pressure vessels were assessed based on API 579. Taking the high pressure hydrogenation plant as an example, this study gave the detailed assessment results and conclusions. The results and suggestions in this study are essential for the safety supervision and extending life of long term serviced pressure vessels in China.

scholarly journals Research on Failure Characteristics of Concrete Three-Point Bending Beams with Preexisting Cracks in Different Positions Based on Numerical Simulation

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Liuqun Zhao ◽  
Li Zheng ◽  
Hui Qin ◽  
Tiesuo Geng ◽  
Yonggang Tan ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Bearing Capacity ◽  
Failure Modes ◽  
Failure Process ◽  
Engineering Application ◽  
Tensile Failure ◽  
Engineering Structures ◽  
Failure Characteristics ◽  
Three Point Bending ◽  
Wide Range

Concrete three-point bending beams with preexisting cracks are widely used to study the growth process of I-II mixed mode cracks. Studying the failure characteristics of preexisting cracks at different locations on concrete three-point bending beams not only has important scientific significance but also has a wide range of engineering application backgrounds in the safety assessment of engineering structures. In this paper, through several numerical experiments, the influence of preexisting cracks at different positions on the failure characteristics of concrete three-point bending beams is studied, and three typical failure modes are obtained. The failure process of the specimens with three typical failure modes is discussed in detail, and it is pointed out that the crack failure mode is tensile failure. The change trends of bearing capacity, acoustic emission quantity, and acoustic emission energy of three typical failure modes are analyzed. The maximum bearing capacity, the maximum acoustic emission quantity, and energy of three failure modes of concrete three-point bending beams generally show an increasing trend.

scholarly journals The Analysis, Discussion and Suggestions for the Mesh Reinforcement Technique of Polymer Mortar Wire Rope

2012 ◽  
Vol 5 ◽  
pp. 271-276
Author(s):  
Shu Ren Zhang ◽  
Zhong Long Li
Keyword(s):  
Engineering Application ◽  
Wire Rope ◽  
Practical Significance ◽  
Strengthening Effect ◽  
Technical Standards ◽  
Healthy Development ◽  
Mesh Reinforcement ◽  
Polymer Mortar ◽  
The Difference ◽  
Correct Understanding

The mesh reinforcement technique of polymer mortar wire rope is a new reinforcement technique used more in the domestic fittest reinforcement project recent years. Recently, there is no unified technical standards, the detailed practice is not same in practical work. There are big differences among the reinforcement effects. The key issue of wire rope is whether add prestressed or not. If add, how much should be prestressed? The difference of the actual practice and reinforcement effect reflects the understanding gap polymer mortar wire rope of mesh reinforcement technique action principle of the designer. A correct understanding of polymer mortar wire rope of mesh reinforcement technique the mechanism and the objective analysis strengthening effect and actively explore research in engineering application problems have a practical significance to promote the healthy development of the structure strengthening technology.

Continual improvement of the pre-analytical process in a public health laboratory with quality indicators-based risk management

2019 ◽  
Vol 57 (10) ◽  
pp. 1530-1538 ◽  
Author(s):  
Canan Karadağ ◽  
Nafi Nevrez Demirel
Keyword(s):  
Public Health ◽  
Risk Management ◽  
Quality Indicators ◽  
Failure Modes ◽  
Public Health Laboratory ◽  
Risk Level ◽  
Continual Improvement ◽  
Risk Levels ◽  
Analytical Process ◽  
Risk Treatment

Abstract Background Quality indicators (QIs) and risk management are important tools for a quality management system designed to reduce errors in a laboratory. This study aimed to show the effectiveness of QI-based risk management for the continual improvement of pre-analytical processes in the Kayseri Public Health Laboratory (KPHL) which serves family physicians and collects samples from peripheral sampling units. Methods QIs of pre-analytical process were used for risk assessment with the failure modes and effects analysis (FMEA) method. Percentages and risk priority numbers (RPNs) of QIs were quantified. QI percentages were compared to the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) performance specifications and RPNs were compared to risk level scale, and corrective actions planned if needed. The effectiveness of risk treatment actions was re-evaluated with the new percentages and with RPNs of predefined QIs. Results RPNs related to four QIs required corrective action according to the risk evaluation scale. After risk treatment, the continual improvement was achieved for performance and risk level of “transcription errors”, for risk levels of “misidentified samples” and “not properly stored samples” and for the performance of “hemolyzed samples”. “Not properly stored samples” had the highest risk score because of sample storage and centrifugation problems of peripheral sampling units which are not under the responsibility of the KPHL. Conclusions Public health laboratories may have different risk priorities for pre-analytical process. Risk management based on predefined QIs can decrease the risk levels and increase QI performance as evidence-based examples for continual improvement of the pre-analytical process.

Investigation of the Effectiveness of Boulevard Roadways

1998 ◽  
Vol 1635 (1) ◽  
pp. 147-154 ◽  
Author(s):  
Salvatore Castronovo ◽  
Paul W. Dorothy ◽  
Thomas L. Maleck
Keyword(s):  
The State ◽  
Accident Rate ◽  
Left Turn ◽  
Significant Difference ◽  
The Mean ◽  
Accident Rates ◽  
The Difference ◽  
The 1960S

The state of Michigan has been constructing directional crossovers in the medians of boulevard roadways since the 1960s to alleviate the congestion and interlocking that were occurring at bidirectional crossover locations. The objective of this research is to investigate the safety benefits of divided roadway and directional crossover median designs. An investigation of the mean accident rates of roadways with boulevards compared to the mean accident rates of roadways with continuous center left-turn lanes revealed that there is a significant difference, with boulevard roadways having a lower mean accident rate for those Michigan roadways investigated. Investigation into the difference of the mean accident rates for boulevard roadways with medians of different widths indicated that roadways with medians greater than 9.15 m (30 ft) but less than 18.30 m (60 ft) had the lowest mean accident rate of the three median categories investigated. The difference was significant for most accident types when compared to roadways with medians less than or equal to 9.15 m (30 ft) and greater or equal to 18.30 m (60 ft). The investigation of the accident rates for boulevard roadways with directional and bidirectional signalized crossovers, while not conclusive, indicated that boulevard roadways with direction crossovers had a lower mean accident rate than boulevard roadways with bidirectional crossovers for signalized roadways.

Comparison of Failure Modes of Piping Systems With Wall Thinning Subjected to In-Plane, Out-of-Plane and Mixed Mode Bending Under Seismic Load: An Experimental Approach

2007 ◽  
Author(s):  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Shiratori
Keyword(s):  
Failure Modes ◽  
Seismic Load ◽  
Piping System ◽  
Shake Table ◽  
Shake Table Tests ◽  
Wall Thinning ◽  
Piping Systems ◽  
Out Of Plane ◽  
Plane Bending ◽  
The Difference

In order to investigate the influence of degradation on the dynamic behavior and failure modes of piping systems with local wall thinning, shake table tests using 3-D piping system models were conducted. About 50% full circumferential wall thinning at elbows was considered in the test. Three types of models were used in the shake table tests. The difference of the models was the applied bending direction to the thinned wall elbow. The bending direction considered in the tests was either of the in-plane bending, out-of-plane bending, or mixed bending of the in-plane and out-of-plane. These models were excited under the same input acceleration until failure occurred. Through these tests, the vibration characteristic and failure modes of piping models with wall thinning under seismic load were obtained. The test results showed that the out-of-plane bending is not significant for a sound elbow, but should be considered for a thinned wall elbow, because the life of piping models with wall thinning subjected to out-of-plane bending may reduce significantly.

Structural Integrity Assessment for Various Failure Modes Using a Risk-Based Maintenance Method

2004 ◽  
Author(s):  
Hiroyuki Horikawa ◽  
Masaki Yoshikawa ◽  
Nobuo Takasu
Keyword(s):  
Failure Modes ◽  
Structural Integrity ◽  
Ground Deformation ◽  
Degradation Mechanism ◽  
Risk Level ◽  
Integrity Assessment ◽  
Evaluation Approach ◽  
Actual Damage ◽  
Maintenance Plan ◽  
Good Agreement

In this paper, a newly developed system called RBM (Risk-Based Maintenance) is presented. The system is used to describe the structural integrity of buried pipeline based on the index of risk that is defined in the product of the failure frequency and the consequence. Various failure modes corresponding to each degradation mechanism are included, and the estimation of failure probability that the external load exceeds the structure resistance is carried out. As the result of trial evaluation compared with the past earthquake incident, it is in good agreement with actual damage of pipeline subjected to liquefaction and large ground deformation. Furthermore, the system enables operators to maintain the structural integrity for service life by providing the most optimized maintenance plan according to the risk level. The features of the quantitative risk evaluation approach and the benefits of the developed RBM system as a means of structural integrity assessment are also discussed.

Effect of Chlorhexidine Pretreatment on Bond Strength Durability of Caries–affected Dentin Over 2-Year Aging in Artificial Saliva and Under Simulated Intrapulpal Pressure

2011 ◽  
Vol 36 (6) ◽  
pp. 649-660 ◽  
Author(s):  
EH Mobarak
Keyword(s):  
Bond Strength ◽  
Failure Modes ◽  
Artificial Saliva ◽  
Water Control ◽  
Control Groups ◽  
Silver Precipitation ◽  
The Difference ◽  
Microshear Bond Strength ◽  
And Control ◽  
Composite Cylinders

SUMMARY Objective To evaluate the influence of 2% and 5% chlorhexidine (CHX) pretreatment on bond durability of a self-etching adhesive to normal (ND) and caries-affected (AD) dentin after 2-years of aging in artificial saliva and under simulated intrapulpal pressure (IPP). Methods One hundred twenty freshly extracted carious teeth were ground to expose ND and AD. Specimens were distributed into three equal groups (n=40) according to whether the dentin substrates were pretreated with 2% or 5% CHX or with water (control). Clearfil SE Bond (Kuraray) was applied to both substrates and composite cylinders (0.9 mm diameter and 0.7 mm height) were formed. Pretreatment and bonding were done while the specimens were subjected to 15 mm Hg IPP. After curing, specimens were aged in artificial saliva at 37°C and under IPP at 20 mm Hg until being tested after 24 hours or 2 years (n=20/group). Microshear bond strength was evaluated. Failure modes were determined using a scanning electron microscope (SEM) at 400× magnification. Data were statistically analyzed using three-way analysis of variance (ANOVA); one-way ANOVA tests, and t-test (p<0.05). Additional specimens (n=5/group) were prepared to evaluate interfacial silver precipitation. Results For the 24-hour groups, there were no significant differences among the ND groups and AD groups. For ND aged specimens, the 5% CHX group had the highest value followed by the 2% CHX and control groups, although the difference was statistically insignificant. For AD aged specimens, the 5% CHX group revealed statistically higher bond values compared to the 2% CHX and control groups. Fracture modes were predominately adhesive and mixed. Different interfacial silver depositions were recorded. Conclusions Two percent or 5% CHX pretreatment has no adverse effect on the 24-hour bonding to ND and AD. Five percent CHX was able to diminish the loss in bonding to AD after 2years of aging in artificial saliva and under simulated IPP.

scholarly journals THE MANAGEMENT OF PROCESS LEAD TIME IN THE RELEASE OF STERILE PHARMACEUTICAL BATCHES: A CASE STUDY OF OPTIMIZATION IN AN OFFICIAL BRAZILIAN PHARMACEUTICAL LABORATORY

2021 ◽  
Vol 16 (1) ◽  
pp. 42-51
Author(s):  
Maria Tereza de Sousa Silva ◽  
Edison Nunes da Silva Junior ◽  
Jorge Magalhães ◽  
Vanessa da Silveira dos Santos Pacheco
Keyword(s):  
Risk Management ◽  
Failure Modes ◽  
Pharmaceutical Product ◽  
Release Time ◽  
Risk Level ◽  
Management Tools ◽  
Release Process ◽  
Quality Program ◽  
Batch Release ◽  
Fmea Method

Medicines must comply with quality, safety, and efficacy pillars. Nowadays, organizations seek to incorporate new management models encouraged by quality program following the world trend regarding the technological revolution. The present research aims to improve the sterile pharmaceutical product batches release process, using the Failure Mode Effects Analysis (FMEA) method. This study addresses the gap in literature on quality risk management during batch release. The methodology uses a form adapted to the process in order to systematize the information, improving its comparison and analysis, thus estimating, the identification of potential failure modes and their effects on their performance. Made it possible to assign values for the severity, occurrence, and failure modes detection, to then determine the risk level and the priority of risk level. The results obtained showed the mitigation and elimination of failures in the process, as well as opportunities for improvement and causes of failures identification, improvement in the process performance indicators, greater reliability, and reduction in batch release time. Keywords: good manufacturing practices pharmaceutical industry, risk management, risk management tools

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