scholarly journals RELIABILITY ANALYSIS OF FIRE SUPPRESSION SYSTEMS

2019 ◽  
pp. 127
Author(s):  
Dejan Ristić ◽  
Milan Blagojević ◽  
Nermin Haznadarević ◽  
Milena Simić
Keyword(s):  
Reliability Analysis ◽  
Fire Suppression ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Sprinkler System ◽  
System Failure ◽  
Event Tree ◽  
Fire Extinguishing ◽  
Alarm Systems ◽  
In Fire

The methods of fault tree and event tree are well-known methods for reliability analysis of technical systems. However, these methods are rarely applied in fire protection systems including fire alarm systems and fire extinguishing systems. The aim of this paper is to use the hypothetical values of event probability, obtained through qualitative fault tree analysis, in order to obtain results that would indicate which individual events cause sprinkler system failure and which events are the most significant for, or contribute the most to, sprinkler system failure.

scholarly journals Evaluation of the Level of Reliability in Hazardous Technological Processes

2020 ◽  
Vol 11 (1) ◽  
pp. 134
Author(s):  
Darja Gabriska
Keyword(s):  
Reliability Analysis ◽  
Failure Rate ◽  
System Reliability ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Entire System ◽  
Event Tree ◽  
Event Tree Analysis ◽  
Technical Standards ◽  
Tree Analysis

In an automated systems environment is very important to predicted failures or unexpected situations to achieve system reliability. Failure of such systems can cause serious property damage, the environment, damage to human health or cause death. The essential task is to determine the tolerable and acceptable risk. The required level of risk for safety-critical systems can be achieved by using international technical standards and applying safety functions. Safety functions are implemented using an electrical/electronic/programmable electronics (E/E/PE) safety-related system. Technical standards offer the aspect of balancing risk tolerability according to the relevant, reliable safety functions. Based on the specific architecture of the whole system, it is possible to determine the maximum failure rate of the probability of failure on demand (PFDSYS) of the selected architecture. Subsequent application of reliability analysis using the event tree analysis (ETA) and fault tree analysis (FTA) methods can optimize the failure rate of the entire system. Application of reliability analysis using event tree analysis (ETA) and fault tree analysis (FTA) methods can only theoretically optimize the failure rate of the entire system with constant initial conditions and constant parameters of the reliability functions. The article proposes a new methodology for dynamic analysis of the state of system reliability as a function of the system operation time, maintenance frequency and system architecture. As a result of the methodology is a library of standard element architectures and simulation models which allows predicting and optimizing the reliability of E/E/PE safety-related systems.

scholarly journals Hardware Reliability Analysis of a Coal Mine Gas Monitoring System Based on Fuzzy-FTA

2021 ◽  
Vol 11 (22) ◽  
pp. 10616
Author(s):  
Jingtian Xu ◽  
Man Yang ◽  
Shugang Li
Keyword(s):  
Reliability Analysis ◽  
Monitoring System ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Gas Monitoring ◽  
Hardware Failure ◽  
Minimum Path ◽  
Fuzzy Fault Tree Analysis ◽  
Hardware Reliability ◽  
Tree Method

The hardware reliability of a gas monitoring system was investigated using the fuzzy fault tree analysis method. A fault tree was developed considering the hardware failure of the gas monitoring system as a top event. Two minimum path sets were achieved through qualitative analysis using the ascending method. The concept of fuzzy number of the fuzzy set theory was applied to describe the probability of basic event occurrence in the fault tree, and the fuzzy failure probabilities of the middle and top events were calculated using fuzzy AND and OR operators. The results show that the proposed fuzzy fault tree is an effective method of reliability analysis for gas monitoring systems. Results of calculations using this method are more reasonable than those obtained with the conventional fault tree method.

Developing an Efficient Approach for Unmanned Aerial Vehicle Reliability Analysis

2020 ◽  
Author(s):  
Ahmad Khayyati ◽  
Mohammad Pourgol-Mohammad
Keyword(s):  
Reliability Analysis ◽  
Block Diagram ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Dynamic Fault Tree ◽  
Safety And Reliability ◽  
Time Dependencies ◽  
Aerial Vehicle ◽  
Redundant Component ◽  
High Level

Abstract Unmanned Aerial Vehicles (UAV) are increasingly get popularity in many applications. Their operation requires high level of safety and reliability to accomplish successful missions. In this study, the reliability was comparatively analyzed by different available approaches to select the efficient method. First, failure model of the system is developed. Then, three different scenarios are considered to study the effect of redundancies on the system reliability results. In the first scenario, there is no redundancy where in the second scenario there is only one redundant component and in the third scenario, there are three redundant components. Static reliability analysis such as Fault Tree Analysis (FTA), Reliability Block Diagram (RBD), Markov Chain (MC), and Bayesian Networks (BN) are applied on proposed scenarios and results are obtained. Regarding to time dependencies between redundant components, a dynamic-based methodology is also developed in this study through applying Dynamic Fault Tree (DFT) analysis. Proposed static and dynamic approaches are applied on an UAV as a case study and results are discussed. Finally, characteristics of each methodology and related conditions are clarified for selecting the efficient reliability analysis approach.

scholarly journals Maintenance modelling for computer-based systems

2001 ◽  
Vol 215 (3) ◽  
pp. 221-231 ◽  
Author(s):  
L Meshkat ◽  
J B Dugan ◽  
J Andrews
Keyword(s):  
Fault Tree ◽  
Fault Tree Analysis ◽  
System Failure ◽  
Time Schedule ◽  
Functional Capabilities ◽  
Dynamic Fault Tree ◽  
Analysis Methodology ◽  
Expected Performance ◽  
Dependability Analysis ◽  
Computer Based

A framework is presented for incorporating maintenance into a dependability analysis methodology for computer-based systems. Two types of maintenance are considered: failure-driven maintenance and time-driven maintenance. Failure-driven maintenance or repair is carried out when the system (or component) performance deviates from its expected performance and consists of all tasks performed to restore the functional capabilities of failed items, principally diagnosis and repair. Time-driven or scheduled maintenance is conducted on a specific time schedule in order to prevent system failure. There may be dependencies between different components of a system with regard to their maintenance plans. These dependencies arise either because a component has maintenance priority over one or more components or because the maintenance of a certain component implies the maintenance of other components. Constructs are presented for modelling these dependencies in the context of dynamic fault tree analysis and a methodology is developed for solving the fault tree. The dynamic fault tree constructs effectively capture the failure dependencies between components. The approach is illustrated with an example based on a water deluge system.

Reliability of sprinkler system in Australian shopping centres –A fault tree analysis

2019 ◽  
Vol 105 ◽  
pp. 204-215 ◽  
Author(s):  
Khalid A.M. Moinuddin ◽  
Jasmine Innocent ◽  
Koroush Keshavarz
Keyword(s):  
Fault Tree ◽  
Fault Tree Analysis ◽  
Sprinkler System ◽  
Tree Analysis ◽  
Shopping Centres

Preliminary Probabilistic Safety Assessment of the IRIS Plant

2002 ◽  
Author(s):  
Yuko O. Mizuno ◽  
Katsunori Ogura ◽  
Hisashi Ninokata ◽  
Lawrence E. Conway
Keyword(s):  
Safety Assessment ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Heat Removal ◽  
Primary System ◽  
Event Tree ◽  
Secondary System ◽  
Probabilistic Safety Assessment ◽  
Loss Of Coolant Accident ◽  
Probabilistic Safety

A preliminary level-1 probabilistic safety assessment of the IRIS plant has been performed. The first focus is on five internal initiating events, such as primary system break (loss-of-coolant accident and steam generator tube rupture) and transients (secondary system line break and loss-of-off-site power). In this study, the event tree for each initiating event was developed and the fault tree analysis of the event tree headings was carried out. In particular, since one of the IRIS safety systems, the passive emergency heat removal system, is unique to the IRIS plant and its reliability is key to the core damage frequency evaluation, it received more extensive fault-tree development. Finally the dominant sequences that lead to severe accidents and the failures in the main and support systems are identified.

scholarly journals Methodology for tunnel risk assessment using fault and event tree analysis

2021 ◽  
Author(s):  
Zlatko Zafirovski ◽  
Vasko Gacevski ◽  
Zoran Krakutovski ◽  
Slobodan Ognjenovic ◽  
Ivona Nedevska
Keyword(s):  
Risk Assessment ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Economic Consequences ◽  
Event Tree ◽  
Event Tree Analysis ◽  
Tree Analysis ◽  
Geological Conditions ◽  
Hazard And Risk ◽  
Complex Solutions

The intense demand and construction of tunnels is accompanied by uncertainties. The reason for appearance of uncertainties are the complex solutions and conditions for these structures. Location and dimensions are becoming more challenging, and the construction is predicted in complexed geological conditions, leading to application of new approaches, methodologies and technologies by the engineers. Most of the uncertainties and unwanted events in tunnelling occur in the construction phase, which generally leads to economic consequences and time losses. For easier handling of the uncertainties, they should be anticipated and studied within a separate part of each project. One of the newer approaches to dealing with uncertainties is hazard and risk assessment and defining ways to deal with them i.e. management. Hazards and risks can be analysed qualitatively and quantitatively. The quantitative analysis, examines the causes and consequences in more detail way and gives explanation of the dependencies. With the quantitative approach, a more valuable information for decision-making can be provided. There are various models and methods used for the quantification of hazards and risks. This paper presents a methodology in which the fault tree analysis and event tree analysis are used in combination to obtain quantitative results. The fault tree analysis is used for assessment of various hazards and the different ways and reasons that cause them. The event tree analysis is a method for assessing the possible scenarios, which follow after a certain hazard i.e. the consequences that may occur in the project. These trees represent graphic models combined with a mathematical (probabilistic) model, which give the probability of occurrence of the risks.

Reliability analysis of helicopter emergency flotation system

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1001-1009
Author(s):  
Xing Guo ◽  
Jian-Hong Sun ◽  
Ke Liu ◽  
Tong Zhang ◽  
Ming-Qi Li ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Reliability Analysis ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Reliability Design ◽  
Minimal Cut Set ◽  
The Monte Carlo Method ◽  
Cut Set ◽  
Event Based

The reliability of the emergency flotation system of helicopters is analysed by using fault tree analysis and the Monte Carlo method. We constructed a fault tree with the failure of system as the top event and obtained the minimal cut set, the ranking of the structural importance of the bottom events and the probability of the occurrence of the top event. Based on the system fault tree, a Monte Carlo simulation model of the emergency flotation system is established by using Matlab/Simulink. The results show that the Monte Carlo method is feasible and effective for the reliability analysis of the emergency flotation systems of helicopters. Furthermore, the comparison between the criticality importance and mode importance of each subsystem suggests that the control component is the weakest part of the emergency flotation systems, thereby providing a basis for system reliability design and fault diagnosis.

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