scholarly journals Analyzing the Long-Term Service Life of MEP Using the Probabilistic Approach in Residential Buildings

2018 ◽  
Vol 10 (10) ◽  
pp. 3803 ◽  
Author(s):  
Sanghyo Lee ◽  
Yonghan Ahn
Keyword(s):  
Decision Making ◽  
Service Life ◽  
Residential Buildings ◽  
Probabilistic Approach ◽  
Life Time ◽  
Probabilistic Methods ◽  
The Cost ◽  
Maintenance Plan ◽  
Term Maintenance

Establishing an effective long-term maintenance plan is essential to ensure the sustainability of a building. Among the various components of a building, the mechanical, electrical, and plumbing (MEP) components are complexly affected by various parameters, such as quality and user pattern, with respect to the service life. Besides, these components are replaced at different points in time, which becomes one of the main risks when establishing a maintenance plan for the building. Therefore, it is very important to consider the uncertainty in calculating the service lives of MEP components in a systematic and reasonable way. This study aims to systemize the MEP components of residential buildings and analyze their service life patterns using a probabilistic approach for long-term maintenance planning. The analysis was performed on 54,318 maintenance cases from 1998 to 2017 at 65 twenty-five-year-old rental apartment buildings in South Korea. Before performing the analysis, a service life matrix was established by classifying the MEP components into 12 types and setting the service life time at 6–25 years. Then, the service life distribution was derived for each MEP component. The probabilistic approach can provide information for rational maintenance decision-making regarding each MEP component as well as basic service life settings. Since the performance of the MEP components deteriorates due to various reasons, de facto uncertainty exists in the service life of each component; thus, the probabilistic approach can serve as an important decision-making method. If probabilistic methods are developed by acquiring the cost data in addition to the frequency of maintenance activity used in this study, a more effective long-term maintenance plan can be established.

scholarly journals Analysis of the Repair Time of Finishing Works Using a Probabilistic Approach for Efficient Residential Buildings Maintenance Strategies

2021 ◽  
Vol 13 (22) ◽  
pp. 12443
Author(s):  
Youngduk Cho ◽  
Sanghyo Lee ◽  
Joosung Lee ◽  
Jaejun Kim
Keyword(s):  
Decision Making ◽  
Residential Buildings ◽  
Probabilistic Approach ◽  
Residential Building ◽  
Repair Time ◽  
Probabilistic Methods ◽  
Maintenance Strategies ◽  
Building Components ◽  
The Republic ◽  
Maintenance Plan

In general, the long-term maintenance planning of residential buildings is performed based on uniform repair times. However, in fact, various factors, such as the quality and user patterns, affect the performance of residential building components in the Operation and Maintenance (O&M) phase. Hence, various residential building components are repaired at uncertain times, acting as a risk for the residential building maintenance plan. Therefore, an efficient maintenance plan should be established considering maintenance uncertainty. In this regard, this study aims to analyze the uncertainty of repair times for various finishing works in residential buildings based on a probabilistic methodology and outline the implications for the establishment of efficient maintenance strategies in these buildings. Hence, 47,344 repair data for 63 buildings in 12 public residential building complexes completed between 1991 and 2001 in the Republic of Korea were used for analysis. Before the analysis, a repair time matrix was constructed by classifying the finishing works in 25 types and setting service life times to 6–26 years. The repair time distribution for each finishing work was then derived. Results confirmed that basic repair time setting can be performed and various information for reasonable maintenance decision making regarding each finishing work can be provided through a probabilistic approach. The probabilistic approach can be used as a critical decision-making method because there is uncertainty associated with the repair time of each finishing work owing to the performance degradations of various finishing works due to complex causes. Although this study focused on repair time owing to data collection limitations, maintenance strategies with strategic flexibility can be established by developing probabilistic methods that simultaneously consider frequency and cost by securing additional high-quality cost data.

scholarly journals Analyzing the Finishing Works Service Life Pattern of Public Housing in South Korea by Probabilistic Approach

2018 ◽  
Vol 10 (12) ◽  
pp. 4469 ◽  
Author(s):  
Soyeon Park ◽  
Yonghan Ahn ◽  
Sanghyo Lee
Keyword(s):  
Service Life ◽  
Public Housing ◽  
Probabilistic Approach ◽  
Housing Developments ◽  
Life Patterns ◽  
South Korean ◽  
Service Lifetime ◽  
Life Pattern ◽  
Term Maintenance

Over recent decades, it has become essential to establish preventive long-term maintenance plans for public housing developments. Also, deterministic maintenance strategies have been increasingly replaced by those based on reliability and risk, which are probabilistic. Efforts to obtain optimized long-term maintenance plans have included management of service life and prediction of service lifetime. Accordingly, the present research develops a system for various finishing works of public housing and analyzes the service life pattern of each component using a probabilistic approach. For the analysis, this research analyzed 46,201 South Korean public housing maintenance records from the last 21 years and determined the maintenance frequency distribution. The purpose of the research is to suggest efficient long-term maintenance plans using the analyzed results of service life patterns. Results from the analysis showed that each component has a different service life pattern that can be applied to establish the service lifetime and decision making for floating maintenance. Since the interaction between finishing works is affected due to various components and parameters, the results are useful to reduce the uncertainty and risk of deterministic maintenance plans. The meaning of this research is to analyze the service life pattern using a probabilistic approach and recommend how to establish an efficient maintenance system.

scholarly journals Probability Calibration Of Load Duration Modification Factor For Timber Roofs In The Polish Mountain Zones

2014 ◽  
Vol 60 (2) ◽  
pp. 195-208
Author(s):  
T. Domański
Keyword(s):  
Limit State ◽  
High Stress ◽  
Life Time ◽  
Probabilistic Methods ◽  
Limit States ◽  
Term Limit ◽  
Load Duration ◽  
Maximum Likelihood Methods ◽  
Short And Long Term

Abstract The resistance parameters of timber structures decrease with time. It depends on the type of load and timber classes. Strength reduction effects, referred to as creep-rupture effects, due to long term loading at high stress ratio levels are known for many materials. Timber materials are highly affected by this reduction in strength with duration of load. Characteristic values of load duration and load duration factors are calibrated by means of using probabilistic methods. Three damage accumulation models are considered, that is Gerhard [1] model, Barret, Foschi[2] and Foshi Yao [3] models. The reliability is estimated by means of using representative short- and long-term limit states. Time variant reliability aspects are taken into account using a simple representative limit state with time variant strength and simulation of whole life time load processes. The parameters in these models are fitted by the Maximum Likelihood Methods using the data relevant for Polish structural timber. Based on Polish snow data over 45 years from mountain zone in: Zakopane – Tatra, Świeradów – Karkonosze, Lesko – Bieszczady, the snow load process parameters have been estimated. The reliability is evaluated using representative short – and long –term limit states, load duration factor kmod is obtained using the probabilistic model.

scholarly journals Probability calibration of deformation factor for timber roofs in the Polish mountain zones

2018 ◽  
Vol 163 ◽  
pp. 07003
Author(s):  
Tomasz Domański ◽  
Kamil Kmiecik
Keyword(s):  
Limit State ◽  
High Stress ◽  
Life Time ◽  
Probabilistic Methods ◽  
Limit States ◽  
Term Limit ◽  
Load Duration ◽  
Maximum Likelihood Methods ◽  
Short And Long Term

The resistance parameters of timber material structures decrease with time, depending on the type of load and timber classes. Strength and Modulus of Elasticity reduction effects, referred to as creeprupture effects, due to long term loading at high stress ratio levels are known for many materials. Timber materials are highly affected by this reduction in strength and deflection with duration of load. Characteristic values of load duration and deformation factors are calibrated by means of using probabilistic methods. The reliability is estimated by means of using representative short-and long-term limit states. Time variant reliability aspects are taken into account using a simple representative limit state with time variant strength and simulation of whole life time load processes. The parameters in these models are fitted by the Maximum Likelihood Methods using the data relevant for Polish structural timber . Based on Polish snow data over 45 years from mountain zones in: Zakopane – Tatra, Świeradów – Karkonosze, Lesko – Bieszczady, the snow load process parameters have been estimated. The reliability is evaluated using representative short – and long –term limit states. The deformation factor kdef is obtained using the probabilistic model.

Calculational-Experimental Monitoring of Radiation Damage Parameters on VVER Equipment and Their Application During Equipment Residual Life-Time Estimation

2018 ◽  
Author(s):  
Pavel Borodkin ◽  
Azamat Gazetdinov ◽  
Nikolay Khrennikov
Keyword(s):  
Service Life ◽  
Residual Life ◽  
Time Estimation ◽  
Life Time ◽  
Point Of View ◽  
Fast Neutrons ◽  
Fluence Rate ◽  
Radiation Load ◽  
Reactor Pressure

The problem of ensuring the integrity of VVER type reactor equipment integrity is now most significant in connection with justifying the safety of the NPP units and the extension of their service life-time to 60 years and more. This issue primarily first of all concerns long term operated NPP power units with VVER-440s and VVER-1000s. The justification of the VVER equipment integrity depends on the reliability of estimation of the degree of the equipment damage. One of the mandatory requirements [1], providing the reliability of such estimation, and also the evaluation of VVER equipment life-time, is the monitoring of equipment radiation loading parameters. Relative to this requirement there is a problem the challenge of justification of such the normative parameters, used for an estimating of the reactor pressure vessel (RPV) metal embrittlement, as the fluence and fluence rate of fast neutrons with energies above 0,5 MeV. Compliance with these requirements is analyzed during regular monitoring of radiation load parameters, which is performed by SEC NRS for all Russian NPP from the regulatory point of view. As a result of this activity, SEC NRS has recently elaborated one of the new approaches aimed to monitoring the radiation load of all equipment of Russian VVERs. The paper describes these approaches and shows the way of their implementation during monitoring procedures.

The necessity of conducting repairs, or the Economic paradox

2021 ◽  
pp. 12-22
Author(s):  
V. A. Sidorov ◽  
A. V. Sidorov ◽  
N. V. Gichun
Keyword(s):  
Working Condition ◽  
Probabilistic Approach ◽  
Spare Parts ◽  
The Other ◽  
High Rate ◽  
Technical Diagnostics ◽  
Mechanical Equipment ◽  
Maintenance And Repair ◽  
The Cost

The increase in the total number of machines in the middle of the 20th century led to a rise in the number of repair services and served as an impetus for the start of work to improve the reliability of mechanical equipment based on the statistical probabilistic approach, the provisions of terotechnology and methods of technical diagnostics. Maintaining machines and mechanisms in working condition has become quite expensive. On the other hand, reducing the cost of maintenance and repairs leads to a violation of the continuity of the technological cycle. Existing trends in mechanical engineering and in the general paradigm of the development of civilization indicate a tendency to reduce the durability of parts and units. The manufacture of products with a long service life becomes economically unviable, which is the essence of the paradox. The article considers the examples of implementation of various approaches to the operation of equipment during maintenance and repair. The prerequisites for the necessity of conducting repairs are analyzed. It is recommended to try to reach a compromise between the manufacturer and the consumer on the basis of long-term contracts for the supply of spare parts or the provision of equipment maintenance services. The urgency of the problem is further justified by the high rate of robotization, since robots also need to be repaired. In this regard, the authors express the hope that this article will be useful in solving the problem of the repair.

scholarly journals Condition-Based Maintenance of HVAC on a High-Speed Train for Fault Detection

Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1418
Author(s):  
Lorenzo Ciani ◽  
Giulia Guidi ◽  
Gabriele Patrizi ◽  
Diego Galar
Keyword(s):  
Decision Making ◽  
High Speed ◽  
Failure Modes ◽  
Air Conditioning System ◽  
Suggested Approach ◽  
Reliability Centered Maintenance ◽  
High Speed Trains ◽  
Optimal Maintenance ◽  
The Cost ◽  
Maintenance Plan

Reliability-centered maintenance (RCM) is a well-established method for preventive maintenance planning. This paper focuses on the optimization of a maintenance plan for an HVAC (heating, ventilation and air conditioning) system located on high-speed trains. The first steps of the RCM procedure help in identifying the most critical items of the system in terms of safety and availability by means of a failure modes and effects analysis. Then, RMC proposes the optimal maintenance tasks for each item making up the system. However, the decision-making diagram that leads to the maintenance choice is extremely generic, with a consequent high subjectivity in the task selection. This paper proposes a new fuzzy-based decision-making diagram to minimize the subjectivity of the task choice and preserve the cost-efficiency of the procedure. It uses a case from the railway industry to illustrate the suggested approach, but the procedure could be easily applied to different industrial and technological fields. The results of the proposed fuzzy approach highlight the importance of an accurate diagnostics (with an overall 86% of the task as diagnostic-based maintenance) and condition monitoring strategy (covering 54% of the tasks) to optimize the maintenance plan and to minimize the system availability. The findings show that the framework strongly mitigates the issues related to the classical RCM procedure, notably the high subjectivity of experts. It lays the groundwork for a general fuzzy-based reliability-centered maintenance method.

scholarly journals Decision-Making on Choosing a Railway Line Option

2019 ◽  
Vol 17 (3) ◽  
pp. 140-151
Author(s):  
V. V. Kazarina ◽  
V. A. Podverbniy
Keyword(s):  
Decision Making ◽  
Initial Data ◽  
Analytic Hierarchy Process ◽  
Residential Buildings ◽  
Additional Analysis ◽  
Analytic Hierarchy ◽  
Railway Line ◽  
The Cost ◽  
Hierarchy Process ◽  
The Village

This article proposes a solution to the problem of choosing an option for routing of a railway line among two previously developed options. As initial data, materials were used for designing Elegest–Kyzyl–Kuragino railway line. On this section, two routing options are considered, which must be compared in order to choose the best one. The first option of the line (Eastern) takes place in a recess outside the village of Podgorny, which excludes the cost of demolition of residential buildings and relocation of residents, but provides for a large amount of earthwork. In the second option (Western), the line is laid through the village of Podgorny. With this development of the line, the volume of earthwork is much smaller, but it is necessary to take into account demolition of residential buildings, relocation of residents, as well as installation of noise barriers.The conclusion drawn by the designers of CJSC Vostsibtransproekt was reviewed and analyzed. During the study, the applied decision-making method required some refinement with regard to this problem and additional analysis. To select the best option, the analytic hierarchy process was used.

scholarly journals A NOVEL MODEL AND TOOL FOR ENERGY RENOVATION PLANNING IN FRENCH RESIDENTIAL BUILDINGS AND DISTRICTS

2018 ◽  
Vol IV-4/W7 ◽  
pp. 11-18
Author(s):  
K. Amokrane-Ferka ◽  
A. Ben Hamida
Keyword(s):  
Residential Buildings ◽  
Existing Buildings ◽  
Short Term ◽  
Energy Consumption Reduction ◽  
Consumption Reduction ◽  
The Right ◽  
The Cost ◽  
Different Characteristics ◽  
Novel Model

<p><strong>Abstract.</strong> Energy renovation of existing buildings is important for energy consumption reduction. In fact, it attracted the interest of governments in several countries for its effectiveness (e.g., 38<span class="thinspace"></span>% consumption reduction by 2020 predicted in France). To achieve such rates, major incentivizing measures were taken by governments to facilitate the funding of energy-oriented renovation projects for final users (e.g., households, communities). Despite all these efforts, a lot of obstacles are yet to be overcome like the lack of interest and involvement of the population, the lack of understanding of the economic equation for renovation, unawareness of governmental aids and support. In fact, most of the population does not fully understand the long-term investment benefits of renovation and look at short term-centered benefits. By taking this into account, the aim of our study is to design, develop and implement a simulation model and decisionmaking tool to assist final users. The first objective of this tool is to shed the light on the advantages and the benefits of renovation to achieve a maximum awareness. To this end, we studied and highlighted three types of incentives: economical, ecological and comfort. The second objective is related to the technical aspects of the project, where users simulate one or several renovations with different characteristics such as insulation materials, space heater, glazing type. Based on the selected parameters, users will be provided with the cost of renovation works, and achievable yearly savings (energy, money, CO<sub>2</sub>, etc.). Consequently, the user can make the right decision that suits his needs.</p>

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