Preventive Maintenance Work Research Articles

퍼지 집합을 활용한 건물 사전 보수작업 대상 선정 지원모델

건물의 사전 보수작업은 시설물이 제 기능을 발휘할 수 있도록 성능을 유지하고 향후에 발생할 수 있는 결함을 미연에 방지할 수 있다는 점에서 관심과 중요성이 증가하고 있다. 효과적인 사전 보수작업 수행을 위해 보수작업이 필요한 대상을 명확히 선정해야 하며 이를 위해 작업 대상이 가지는 상태에 대한 정확한 분석과 평가가 선행되어야 한다. 작업 대상의 성능 측정은 하나의 평가 기준에 대한 평가 보다는 여러 개의 평가 기준들을 동시에 고려한 평가가 측정의 정확성을 향상시킬 수 있다. 하지만 의사결정자의 주관적인 판단에 의해 측정값이 부정확한 평가 기준들이 존재할 수 있다. 이를 보완하고자 본 연구는 다양한 평가 기준을 이용한 사전 보수작업 대상의 성능 측정과 효과적인 작업 대상 선정을 위한 의사결정 지원 모델을 제시한다. 본 연구는 작업 대상 선정을 위한 평가 기준을 선정하고 기준별로 측정값을 종합하여 의사결정 과정에서 활용할 수 있도록 한다. 또한 건물의 상태 측정 시, 평가자의 주관적인 판단의 애매함으로 인해 발생하는 결과의 불확실성을 보완하고자 퍼지 집합을 사용하여 측정을 실시한다. 본 연구를 통해 의사결정자는 보수작업 대상 선정 과정에서 객관적인 평가를 위한 도구로 활용할 수 있다. 또한 본 모델은 의사결정자의 주관적인 의도에 따른 다양한 절충값을 얻을 수 있어, 의사결정자별 상이한 평가 방식을 반영할 수 있다. Preventive maintenance of buildings has increased the importance of interest in that it is able to maintain the performance building has and to prevent a problem occurred in future. For improved preventive maintenance work, it should be performed to select works order clearly and preceded the accurate measurement for the state of works order. when measuring the conditions, measurement of the state of work order considering the various criteria is more effective than to measure by only criterion. But, there are something hard to evaluate exactly between the criteria because of decision-maker's subjective judgments. To solve these problems, this research proposes decision making support model to determine preventive maintenance works order using Fuzzy-sets. By using Fuzzy-sets when measuring state of work objects, it can be reduced vagueness of judgments by decision-makers. This model can be used as a tool for objective evaluation of preventive maintenance work orders and offer the guideline to perform decision-making.

Segregating Preventive Maintenance Work for Cycle Time Optimization

Preventive maintenance (PM) plays an essential role in keeping the equipment in control and performing in the long term in semiconductor manufacturing. However, the impact of this activity on the cycle time of a specific toolset or even the entire fab can be detrimental. Hence, there is a strong incentive for determining the best way to carry out the required PM work content so as to optimize cycle time. In this paper, a model is proposed that optimizes the number and frequency of PMs for a predetermined PM work content, with the consideration of attached setups.

A probe into the facilities maintenance data of a hotel

The performance of facilities in buildings has profound influence on end-user satisfaction. This, in turn, would affect the buildings’ income and hence the level of resources available for maintaining their facilities. Probing into the computerised maintenance management data of a quality hotel, the study reported here identified a strongly positive correlation between the facilities’ downtime and the quantity of maintenance work orders. Work efficiency, which measures the effectiveness of the hotel’s maintenance workforce, was found to decline with increasing utilisation levels of the workers. Scrutinising the utilisation and efficiency levels of the workers enabled a review of their workloads and performances. The benchmarking curves developed based on the downtimes of the hotel’s facilities can help measure the quality of maintenance works. Further research works are needed to study the effects of low and moderate occupancy rates on maintenance demand, the utilisation and efficiency levels of workers in performing preventive maintenance works, and the availabilities of unreliable facilities and those which are hard to maintain. Practical applications: It has been shown how the data stored in a computerised maintenance management system can be analysed to examine the demand for facilities maintenance, the effectiveness of a maintenance workforce and the performance of facilities. The study findings are useful for facilities management (FM) practitioners. Pursuing more studies of this kind would make further contributions to performance evaluation and benchmarking in the FM field.

A case study on improving the effectiveness of preventive maintenance

This paper employs a mathematical model to improve the effectiveness of preventive maintenance. The study focuses on using real data of a feed pump (FP) in a petroleum refinery plant to test the effectiveness of the PM model and its impact on both reliability and maintainability. The model is tested for different scenarios by changing one of the main variables each time. These scenarios are developed using different values of failure rate to determine the steady state probability at normal operation. This will allow obtaining the best scheduling time for PM and improving the reliability of the feed pump. The timing of the preventive maintenance is essential to reduce system failure and corrective maintenance. The model helps to find good and decisive time, when the preventive maintenance work is superior rather than having a corrective action to repair the feed pump. This model supports the plant for sustainability and cost effectiveness with good timing and effective PM. Therefore, at high failure rate the probability of the Feed Pump failure will increase. In this case the availability of the Feed Pump will decrease, indicating that there is a need to perform PM works on the system. The results show that the life span of the system is extended with proposed PM model. Accordingly, increasing the reliability will increase the operational life cycle by reducing failures during operations, hence reducing the total costs by improving the availability.

Managing Road Maintenance Using Geographic Information System Application

The development and economic growth of a nation is closely related to its available transportation system. Good and efficient road transport infrastructure facilities will promote industrial and socio-economic development. To provide safety and comfort to road users, a comprehensive road maintenance schedule must be formulated and adopted to ensure those roads are in good condition at all times. Preventive maintenance works, such as road rehabilitation will help to reduce the major road repairs and expenditure. Prior to this, a good database, gathered through GIS will be necessary in order to ensure maintenance is done effectively. Geographic Information System (GIS) is said to be one of the useful tools that can be utilized to manage database in road maintenance engineering. This system is capable of storing, managing, analyzing, computing and displaying all forms of geographical data for road maintenance works. In this study, the author has adopted GIS application software – ArcView, and has reviewed and analyzed its effectiveness in managing road database. These data are then used to assist the management to ensure effective and systematic road maintenance. A typical model of roads in Penang, Malaysia is used as a case study to further clarify the application of GIS in road maintenance.

Comprehensive Audit Process Guides Facilities in Focusing Priorities

How do you consistently and effectively manage biomed programs spread across 27 hospitals under three different supervisors? The team at the University of Vermont Technical Services Program (TSP) has spent the last few years developing and refining a system to do exactly that. Their solution—a comprehensive audit program—ensures that managers regularly review key organizational metrics at every site, systematically assessing the quality of the program and identifying opportunities for improvement. The results: better-trained employees and an improved program.

Cost-effectiveness analysis of a rural/urban first-responder defibrillation program

Objective. To analyze the cost-effectiveness of a proposed first-responder defibrillation program in a small rural area in comparison with a recently initiated first-responder program in an adjoining urban center in southwestern Ontario. The purpose of the analysis was to quantify the expected benefits of the proposed program to determine whether the costs are justified. Methods. This analysis was conducted on the city of Waterloo (population 80,000 over 25 square miles) and the adjoining rural township of Wellesley (population 8,000 over 105 square miles). The township has volunteer fire department first responders with basic life support (BLS), and basic life support/defibrillation (BLS-D) ambulances as the second tier; whereas the city's full-time fire department has recently adopted a first-responder defibrillation (BLS-D) program backed up by the same BLS-D ambulance service. The most relevant costs identified were the capital costs of the defibrillators, ancillary equipment, and biomedical service for preventive maintenance and routine nonwarranty work. Response intervals and percentage of patients found in ventricular fibrillation were projected and sensitivity analysis was applied. Results. The projected cost per life saved is $6,776 (C) in the urban area and $49,274 (C) in the rural area using an incremental save rate of 6%. Applying sensitivity analysis to the data, the save rate varied from 2% to 10%, resulting in a cost per life saved of $20,328 (C) and $4,066 (C), respectively, in the urban community. For the rural area, the cost per life saved ranged from $147,821 (C) (2%) to $29,564 (C) (10%). Even the worst-case save rate for the urban center [2%; $20,328 (C)] is significantly less than the best-case save rate [10%; $29,564 (C)] for the rural area. Conclusions. The cost per life saved for a rural first-responder defibrillation program is significantly more expensive than one for an urban center. However, the cost per life saved is still economical compared with common treatments for other life-threatening illnesses. PREHOSPITAL EMERGENCY CARE 2000;4:43-47

A DYNAMIC APPROACH FOR PLANNING PREVENTIVE RAILWAY MAINTENANCE ACTIVITIES

This paper provides some useful methods for finding optimal track possession intervals for carrying out preventive maintenance works. The objective is to minimize the inconvenience fro the train operators and the infrastructure possession time. In these models the train free periods are mostly used for this purpose, name the hours between two consecutive train operations. This approach can be useful for some European railway companies for carrying out preventive maintenance works.

Determination of preventive maintenance periodicities of standby devices

This article presents a statistical approach of analysis and decision that uses reliability techniques to define the best periodicity for preventive maintenance of power system protective relays. Relays are standby devices and may stay in the hidden failure state when they are not working. This state of failure generates difficulties in the determination of preventive maintenance periodicities. A case study presented in this work deals specifically with the reliability of the transmission and distribution system protective relays of CEMIG (the state owned Electrical Power Company of Minas Gerais, Brazil). Preventive maintenance data of protective relays obtained during a 4-year period were used in the proposed method. The choice of the periodicities, distinguished by groups of similar relay and voltage operation levels of the protected systems, is made according to the failure risk level that the company is willing to take. The main result obtained by using this method is a substantial reduction of 62% in the amount of preventive maintenance work load for the relays of the distribution system.

C OST -E FFECTIVENESS A NALYSIS OF A R URAL /U RBAN F IRST - RESPONDER D EFIBRILLATION P ROGRAM

Objective. To analyze the cost-effectiveness of a proposed first-responder defibrillation program in a small rural area in comparison with a recently initiated first-responder program in an adjoining urban center in southwestern Ontario. The purpose of the analysis was to quantify the expected benefits of the proposed program to determine whether the costs are justified. Methods. This analysis was conducted on the city of Waterloo (population 80,000 over 25 square miles) and the adjoining rural township of Wellesley (population 8,000 over 105 square miles). The township has volunteer fire department first responders with basic life support (BLS), and basic life support/defibrillation (BLS-D) ambulances as the second tier; whereas the city's full-time fire department has recently adopted a first-responder defibrillation (BLS-D) program backed up by the same BLS-D ambulance service. The most relevant costs identified were the capital costs of the defibrillators, ancillary equipment, and biomedical service for preventive maintenance and routine nonwarranty work. Response intervals and percentage of patients found in ventricular fibrillation were projected and sensitivity analysis was applied. Results. The projected cost per life saved is $6,776 (C) in the urban area and $49,274 (C) in the rural area using an incremental save rate of 6%. Applying sensitivity analysis to the data, the save rate varied from 2% to 10%, resulting in a cost per life saved of $20,328 (C) and $4,066 (C), respectively, in the urban community. For the rural area, the cost per life saved ranged from $147,821 (C) (2%) to $29,564 (C) (10%). Even the worst-case save rate for the urban center [2%; $20,328 (C)] is significantly less than the best-case save rate [10%; $29,564 (C)] for the rural area. Conclusions. The cost per life saved for a rural first-responder defibrillation program is significantly more expensive than one for an urban center. However, the cost per life saved is still economical compared with common treatments for other life-threatening illnesses.

MMMS — A Microcomputer Based System for Maintenance Management

The growing awareness of the critical importance of proper maintenance both at national and sectoral levels has led to the development of the concept of maintenance management systems. This paper outlines the main features of a microcomputer based maintenance management system, called MMMS. The system was developed using dBASE lII and completely menu driven. The main features of the system include the generation of preventive maintenance schedules and work orders for both preventive and breakdown activities, maintenance of all preventive and breakdown activities and generation of practical management reports. It also tracks labor time, cost, and efficiency of various maintenance operations. The system has integrated both the personnel and the spare parts inventory systems with the maintenance system.

Life‐cycle Cost Policy when Equipment Maintenance Is Imperfect

Maintenance‐related costs contribute significantly to equipment life‐cycle costs. In practice, maintenance works are not perfect in the sense that they cannot restore the equipment to a “good‐as‐new” condition. Utilizing the concept of improvement factors to model the imperfect characteristics of most maintenance works, proposes a model which determines the number and timing of preventive maintenance works which are required before the equipment is overhauled. It also determines how many overhauls will be economically required before a decision is made to dispose of the equipment. The equipment disposal decision is based on an analysis of replacements which are constraints to be at the end of time cycles which may have unequal numbers of time‐periods and where the time‐periods do not have to be of equal length. This proposed replacement analysis is an extension of a well‐known replacement model in the literature.

Lime treatment program: an alternative cooling water treatment program for geothermal power plants in the philippines

The National Power Corporation (NAPOCOR) of the Philippines spends millions of pesos annually for treatment of cooling water and preventive maintenance work to ensure the efficient operation of its geothermal power plants supplied by liquid-dominated reservoirs. Therefore, NAPOCOR deemed it worthwhile to look for cheaper water treatment alternatives for the benefit not only of the geothermal power plants, but the whole country as well, in terms of lower power generation costs and improved plant operation. The results of tests on the use of lime in the cooling water of NAPOCOR geothermal power plants are presented in this paper. Initial results show substantial savings in water treatment costs and a significant decrease in corrosion rates on metal parts and equipment.