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AMAZON multi-meters discounts AMAZON oscilloscope discounts There are many approaches to performing maintenance and engineering activities at an operating facility. The type of process, plant size, location, and business conditions at a particular time are all variables that can affect this approach. The system must fit the basic overall corporate goals. The final evaluation of success, however, for whichever system selected, is achieving the lowest possible product cost over extended periods of time at varying business conditions. This segment of our text will concentrate on plant maintenance and engineering service in a multi-plant corporation operated on a combination centralized-decentralized basis. However, the reader will quickly discern the applicability of this approach to many aspects of equipment maintenance in "stand-alone" plants. Organizational control methods are all planned for an optimum approach to cost economy. Basically, then, we are presenting corporate management's approach to an overall maintenance strategy. This approach is as valid in 2004 as it has been in the 1965-1970 time period. Type of Operation: To understand the organizational approach to maintenance and engineering described here, it’s first necessary to understand the size and type of operations involved. We should assume that the facilities would fall into virtually all size categories. The plants are quite autonomous and may select maintenance organizations to fit their particular needs. Through their own unique experiences of plant maintenance and engineering problems and studying alternative approaches used by others, a mature organization will have gradually formulated an operations control system, including plant maintenance and engineering services, which best serves its type of operation and is flexible for future needs. This implies that large plants, which have the technical and maintenance support resources to be totally self-sufficient, may opt to deviate from the organizational and implementation-oriented setups we are about to describe. However, for best results, the deviation should not be very drastic because the basic principles of effective maintenance organization and control hold true for any plant environment. Before discussing plant maintenance specifics and engineering functions, we will discuss why this multi-plant corporation went to the present approach. Like many companies, the corporation started with an approach wherein the plant manager was autonomous in his responsibility for production, maintenance, and most engineering services. He depended largely on the equipment manufacturer to help solve problems. As more plants were added to the network and more significant operational and mechanical problems were encountered, it was gradually recognized that the most economical solution to critical problems was to quickly interject the best technical specialists within the company, regardless of location. However, it was not possible or economical to have these highly skilled specialists at each facility or to adequately train the plant manager in all areas when the facility normally operated at an extremely high on-stream factor. Again, as a higher degree of technical knowledge was gained, equipment improvements made, and sophisticated process and machinery monitoring devices introduced, it was found that the periods between major equipment maintenance could be significantly extended without risking costly equipment failures. The use of a relatively small group of mobile, technical specialists from within the company was the key to better plant performance and lower costs. Equipment manufacturers and vendors' representatives have neither the incentive nor the responsibility to provide the prompt technical services required. Manager's Role: Yet, it was strongly desired to have these specialists report to and work solely under the guidance of the individual plant manager in order not to confuse the chain of command. Thus, a decentralized system of giving the plant manager responsibility for general operations, cost performance, and maintenance performance, but with a strong centralized approach to all aspects of monitoring plant performance and providing specific maintenance and engineering services as required, was evolved as the fundamental organizational concept. Once this basic concept was reached, efforts were then devoted to understanding and establishing specific methods of accomplishing plant maintenance and engineering services under the general system concept. Since the plant managers' responsibilities on a decentralized basis rep resented a rather conventional approach to day-to-day operation, we will dwell on considerations relative to the centralized aspect of plant maintenance and engineering services and the monitoring function. These centralized services were provided by a group of specialists located for the most part at the home office or at the location of the largest affiliated plant. Some advantages of this centralized approach to plant maintenance and engineering services are: 1. Better solutions to important technical problems. With the varied plant problems, the ability to use key specialists will normally result in the best technical solution. 2. More efficient use of talent. With extremely high onstream factors, chemical and mechanical engineering specialists at each facility cannot be fully justified, since the rate of problems and/or severity would not normally warrant their continuous presence. Minimum staffing at each plant to handle normal day-to-day problems, plus a mobile technical and maintenance organization will result in lower overall costs. The question of overstaffing at a particular facility to take care of "first year" startup problems is a very real one. The ability to have this same mobile specialist group help in quickly solving first year operation problems allows a flexible and easy method of reducing a facility to its minimum labor cost at the earliest time. 3. Better communication. Technical solutions, procedures, and other important factors which have a direct and immediate effect on on-stream factors and costs can be more readily transmitted from one plant to another. The use of plant shutdown and maintenance reports prepared by the plant manager allows the central technical organization to evaluate and disseminate information pertinent to other facilities. 4. Better response to management and business outlook. Constantly varying market conditions change product demand and value. These important factors often become the overriding consideration in scheduling maintenance work and turnarounds. Centralized overall maintenance planning can more readily assimilate these factors in considering a large number of plants at different locations. This is an important consideration in minimizing peaks and valleys in major maintenance work and allowing a smaller specialist group to handle a broader scope of activities. 5. More consistent organizational policies, procedures, and better methods of making comparisons on general performance, cost, production, prompt action, and managerial talent. To keep the centralized organization current on the facts of life at plant facilities, a program of specialist and management visits to each facility must be established. These visits, coupled with careful production monitoring, normal maintenance, and general cost performance are necessary prerequisites for the system discussed herein. The extra travel and communication costs are far outweighed by better personnel utilization. Maintenance Total plant profitability is obviously affected both by onstream factors and maintenance costs. One cannot be separated from the other. Any system, therefore, must account for how cheaply maintenance can be performed from an organizational setup, and also what must be done and how often. The ability to update maintenance requirements and improved planning based on experience at a group of plants has a large bearing on overall maintenance costs. Other than breakdown maintenance, all maintenance work is planned. Some can be done while the plant is operating and the rest during shut down. The effectiveness of this planned or preventive maintenance (PM) program to reduce breakdowns and the organizational methods used to accomplish the planned major maintenance work will determine maintenance costs. Preventive maintenance as discussed here covers all planned maintenance work, whether major or minor, regardless of whether the plant is running or shut down. The selection of what shall be done as part of the PM program and how often it shall be done is one of the most important factors affecting corporate maintenance costs and the realization of an optimum onstream factor. It’s a generally accepted practice to let each plant manager handle the PM program for his facility. In some plants, this is being done with individual check sheets or production boards using equipment manufacturers' recommendations and the limited experience of plant personnel. However, the demand for plant operation attention often prevents timely maintenance performance. Another defect is that it lacks uniformity and does not provide compliance reports to home office management. And, there is often no effective way to compare the PM performance at similar plants or equipment at different locations. Most important of all, equipment failures may occur because proper consideration and judgment is not given to maintenance items whose significance is best understood by qualified specialists. Central Control System In view of this, major corporations will frequently opt to incorporate a centrally controlled PM system into the Operations Department. This allows mechanical and process specialists to make the key cost decisions on what kind and how often maintenance should be accomplished at all affiliate plants by coupling it to an electronic data processing monitoring system. This will serve as a management tool in evaluating conformance to the maintenance system. Thus, the plant manager is made responsible for efficiently executing the PM work as outlined by the program, and is monitored for performance by centralized management. The data processing system can be easily adapted to any facility, is inexpensive to install and operate, and lends itself to overall reduced costs as the corporation expands. Some of the system advantages are: 1. The PM performance and frequency program is prepared by the centralized group of qualified engineering specialists based on equipment manufacturers' recommendations, experience, and historical records. The program is reviewed and approved by the plant manager. Program updating to take advantage of new technical knowledge and both good and bad experience is important to ensure continued cost savings. 2. A definite schedule is presented to plant managers so they know what is expected of them. 3. Operations management is advised of system conformance and is made aware of rescheduled tasks. 4. The system identifies overall corporate maintenance requirements so that work can be staggered enabling a minimum mobile group of technical and maintenance specialists to handle the overall program. 5. Historical data are accumulated for analysis. 6. Reduction in clerical work more than offsets the cost of computerization. Principal Applications Areas for the Maintenance Computer Conceptual discussions of the past and more recent systems development work have concentrated on six general areas of maintenance support. Systems are, of course, called by different names, according to the company which is developing and implementing them. Systems of any one type may also have differing emphasis, according to the specific company's requirements for maintenance support. The general applications areas are: 1. Materials inventory/stock cataloging. 2. Preventive maintenance/equipment records. 3. Work order costing. 4. Fixed equipment inspection. 5. Planning/scheduling of major maintenance projects. 6. Work order planning and scheduling. The various computer systems have been developed both separately and as integrated groups through exchange of data between systems. Moreover, maintenance systems generally are designed for data exchange with a conventional accounting system. Materials inventory/stock catalog systems are designed to support maintenance by making certain that required materials and spare parts are available at the right time, at the right place, and at minimum cost. Well-designed systems in this category provide better availability of parts and materials by supplying up-to-date catalogs, generated in multiple sorts. Some systems allow stock items to be reserved for future usage in major construction projects or for scheduled plant or unit turnaround projects. A well-designed inventory/stock catalog system also may maintain a history of materials and parts usage. This enables maintenance to evaluate service demand patterns or vendor performance and to adjust inventory levels according to materials/parts usage. Some companies place emphasis on the purchasing function in design of inventory systems. Such systems automatically signal the need for materials or parts reorders on whatever basis the purchasing department wishes to establish (such as order point/order quantity or minimum/maximum quantities). The system may also be designed for automatic purchase order generation and to maintain a file of open purchase orders. It also can report unusual situations such as changes in a manufacturer's parts number, price increases beyond a prescribed limit, or alterations in delivery time requirements. Ordinarily, an inventory/catalog system produces the majority of its reports on a weekly or monthly basis. Systems also may be run daily for adding new materials or parts, for daily stock status reporting or for processing receipts and issues information. Maintenance people have long recognized the need for adequate inventory control and cataloging procedures. Without such procedures, the maintenance department runs the risk of having its work planning and scheduling controlled by materials availability. The computerized inventory/catalog system, thus, offers the benefits of improved manpower utilization and unit downtime reduction. Preventive maintenance and equipment records systems not only bring a highly organized approach to scheduling of periodic inspections and service connected with a preventive maintenance program, but also provide a mechanism for compiling a complete equipment performance and repair history-including costs-for equipment within a processing facility. The well-designed preventive maintenance and equipment records system is built around failure of equipment description data. Through this file, equipment inspection intervals are assigned according to criticalness or in accordance with laws or safety and environmental protection codes. Service intervals are also assigned-sometimes according to manufacturer's recommendations and sometimes on the basis of experience in extension of equipment life. Overhauls are scheduled in the same way as service intervals. Some types of service and all overhauls must also be backlogged for performance during equipment shutdown periods. Most preventive maintenance systems produce a periodic listing of PM work to be performed-including specifications, service, and overhauls due. Jobs are entered into the plant's regular work order planning and scheduling system. PM jobs not performed on schedule are then reported-perhaps at a higher priority-for inclusion in the next PM work list. The equipment records function, a natural extension of the preventive maintenance scheduling function, usually is not limited to equipment covered by the PM program. All equipment may be placed in this system's file. Through feedback cards from the field, the system can compile and maintain a complete repair file on all equipment of interest. Repair history and cost data may be reported in several different ways. Repair history by specific equipment or equipment type, for example, aids maintenance in setting or adjusting inspection, service, or overhaul intervals for equipment. Other reports may aid maintenance in identifying equipment which is costing most to maintain or has the poorest performance history. Some systems also support repair/replace decisions by maintenance or engineering department as well as equipment selection decisions. Equipment interchangeability information, and reports on equipment spare parts, are also available from some systems. The preventive maintenance/equipment records systems is also called the "reliability maintenance system" by some companies and plants. Work order costing systems are vital for analysis and control of plant maintenance costs. These systems provide a framework for the capture of cost-related information and processing capability for analyzing such information and producing reports required by cost-conscious maintenance management. Work order cost systems accumulate costs by work order. Usually, cost-related data from time sheets, contractors' invoices, journal vouchers, and spare parts inventory are compiled by the system and analyzed to produce: 1. Detailed and summary listings of costs, by work order. 2. Detailed listings of all current month cost transactions for each work order. 3. Reports which list, for each work order, costs incurred for the current month as well as during the life of the work order. Using these and other reports, maintenance management can compare actual costs against estimates or budgets and can pinpoint costs which are outside policy guidelines or rising at a rate faster than anticipated. The work order cost system also may be designed to provide input for other systems. It can generate equipment cost transactions for a preventive maintenance/equipment records system, for example, or can provide summarized accounting entries for a general ledger system. In summary, work order cost systems provide cost information in a form that is fully usable by maintenance management in identification and definition of cost-related problems within the maintenance function. With this information, control efforts may be concentrated on areas where potential savings exist. The fixed equipment inspection system adds consistency, comprehension, and effectiveness to a plant's inspection program. It’s designed to support the plant inspection department and is structured around a data base of information on equipment critical to a plant's operation, such as piping, pressure vessels, heat exchangers, and furnaces. Fixed equipment may be designated as critical because of its potential for creating safety hazards, its position within the processing train or because of laws or codes governing equipment inspection in certain cases. The system aids in scheduling inspection activities. Each piece of equipment covered by the system is scheduled for periodic inspection. Inspections that can be performed while the equipment is operating are placed on a monthly schedule for routine execution by the inspection team. Inspections which must await equipment shutdown are placed on a standing work list for coordination with operating and maintenance departments. Inspection systems also may provide inspection history for particular pieces of equipment, standard inspection procedures for the equipment, forms for recording equipment conditions and thickness measurements, and automatic computation of corrosion rate (based on multiple inspections). The well-designed inspection system also can accommodate thickness measurement data produced by inspection tools such as ultrasonic, infrared, or radiographic devices. Using results from system computations, inspection groups may report equipment condition to maintenance groups if repair, service, or replacement is required. Maintenance, in turn, would generate a work order consistent with the inspector's requirements. Information also may be routinely provided to engineering personnel to plan equipment replacement or to improve equipment and parts selection as equipment is replaced. Planning and scheduling major maintenance projects using computer supported Critical Path Method (CPM) techniques was one of the earliest applications of computers in support of the maintenance function. The central idea behind development and use of such systems was to identify opportunities for parallel execution of tasks associated with a turnaround project so that available manpower and resources may be utilized as efficiently as possible to minimize equipment downtime. In spite of the CPM system's "head start" in use by maintenance groups, this potentially profitable tool soon was abandoned by a surprisingly large number of plants and companies. Most companies said the available CPM systems were too complex or too cumbersome for effective use in maintenance turnaround projects or small construction jobs. There is, however, a resurgence of computer-based CPM systems today. Systems currently designed and used for planning and scheduling major maintenance projects are simplified versions of the earlier systems. They are, in fact, designed specifically for use by process industry maintenance personnel. They incorporate terminology readily understood by maintenance people and combine simplicity of operation with flexibility. Typically, the well-designed CPM system produces reports which show how limited resources may be used to complete a project in the shortest possible time. Alternatively, the system may show the manpower necessary for completion of a project in a given length of time. Maintenance work order planning and scheduling continues to be a largely manual set of procedures throughout the hydrocarbon processing industry. There are, however, several systems which support daily work planning and scheduling. One such system is a skills inventory file that provides daily information on available personnel for use in manual planning and scheduling of maintenance work. Another is the computer-based file containing standard maintenance procedures that can be retrieved for preparation of work orders and in estimating manpower time requirements. Additionally, other maintenance-related systems, such as preventive maintenance systems and inspection-support systems, may generate work orders for inclusion in daily maintenance schedules. Work order planning and scheduling also is supported by materials and parts inventory systems. The actual computer-based scheduling of daily maintenance manpower resources, however, has remained an elusive goal. Recent systems work has aimed at scheduling shop work where forecasting work requirements is easier than forecasting field work. Incentives for Computer Systems The primary incentive for design and implementation of maintenance related support systems is the potential for reducing maintenance-related costs. The cost of keeping hydrocarbon processing plants running includes maintenance expenditures. These typically range from 1.8 to 2.5 percent of the estimated plant replacement value. Justification of Systems Although process industry companies generally agree that maintenance support systems* are a viable means of reducing maintenance costs, there is no general agreement on the size of benefits available or the source of these benefits. For this reason, there are probably as many ways to justify computer installation as there are computer applications: 1. Reduced clerical effort. 2. Improved utilization of maintenance work force. 3. Improved equipment reliability. 4. Reduced inventory costs. Reduction of clerical effort is used when filing, recording, and retrieving become excessive. Sometimes a reduction in clerical staff may even be possible after a computer system is installed. However, the relief of key personnel from clerical responsibilities is usually more important as a justification point. For example, a major oil company partially justified installation of a fixed equipment inspection system at a large refinery on the basis that inspectors could be relieved of the clerical duties of filing and retrieving inspection information. This company also found record keeping on inspection, thickness measurement, and corrosion rates to be more consistent and far more accessible. As a result, information com piled by this refinery's inspection department is far more useful today than when such information was kept mostly in filling cabinets in the individual inspector's office. Improved utilization of maintenance manpower is widely used as a means for justifying turnaround scheduling systems, planning/scheduling systems, and inventory control systems. Results from a carefully con ducted analysis of work delays created by existing manual procedures are compared against improvements expected from computerized systems. Man hours saved-multiplied by hourly rates for maintenance personnel-sometimes provide substantial justification for computer systems. Improved equipment reliability, with resulting reductions in equipment downtime and improvements in plant throughput, are obvious justifications for preventive and predictive maintenance systems. Some companies have found that benefits from this source alone can provide a payout as quickly as one year from the initial computer system investment. In the complex process environment of the modern refinery or petrochemical plant, monitoring equipment performance, effective diagnostics, and early recognition of equipment problems require computer speed and support. Improved management reaction to plant equipment problems also has justified computer systems. This is a difficult area to quantify. However, if previous costly equipment failures can be identified as preventable through timely management information, this becomes a very real justification for system installation. Materials inventory and stock catalog systems have been justified by many companies based on reduced inventory. Computer systems have improved inventory management and control, reduced overall stock requirements, and improved warehouse response to maintenance requirements for materials and spare parts. Identification of obsolete parts and materials is far easier and far more thorough when computer support is available. Although many quantitative methods exist for justifying computer based systems in the maintenance area, many such systems are justified by what is called the "faith, hope, and charity" method. Maintenance management simply has faith that maintenance can be made more effective and can be controlled better if maintenance activities and costs can be measured. Through computers, maintenance management also hopes effective record keeping will preserve effective procedures and the maintenance department will be less vulnerable to loss of key personnel because these procedures are recorded within a computer system. The element of charity exists because the accounting or operations departments may have computers which are not fully utilized and are, thus, avail able for maintenance-related applications. Unfortunately, the "faith, hope, and charity" justification technique too often has resulted in installation of systems which were thrown together on a part-time basis by data processing personnel and imposed on the maintenance department in the total absence of any obvious maintenance coverage and/or desire for such systems. The result has been immediate rejection of the system by maintenance personnel and a setback in the maintenance department's acceptance of computer support of any type. Setting Up an Effective System As previously mentioned, there are a variety of computer systems being installed in processing plants. These systems can be installed either as "stand-alone" systems or as systems which exchange data with other related systems. Just where the first system is installed depends mainly on where help is most needed-or where computerization would produce the most significant benefits. With any system, however, there are certain "places to start" which are absolutely vital to system success. The maintenance department which hopes to realize benefits from computer systems must start with a convinced, dedicated management and recognize that system acceptance in the maintenance department must be earned. The manager who has a system designed and installed as "something we can try to see how it works out" has wasted a lot of company money. If the maintenance manager is not solidly convinced the contemplated system is needed and if he is not dedicated to its success, then the system is likely doomed to failure or to only partial realization of potential benefits before the first computer program statement is written. Maintenance management has long recognized that certain management techniques must be used to implement any change. Unfortunately, these techniques are not always applied when the change involves a computer. Communication, participation, involvement, and training all must be used to ensure that need for the system is generally recognized through out the maintenance department and that the system is accepted by maintenance personnel as a problem solver. One of the more effective techniques for implementing a computerized system is to build upon existing, manual systems in order to permit minimal change in the information input activity even though major improvements are effected in available reports and analyses. A common misconception is that a computer application requires a large volume of additional routine data. If a good manual system exists for preventive maintenance scheduling, inventory control, or other functions, the computer system often requires no more routine input information. As reports are produced, the volume should be carefully limited to necessary information. Report formats should be developed with the ultimate user's participation. Finally, results should be thoroughly communicated throughout the maintenance organization. A plant also should be careful to allocate the resources necessary to support the system's implementation effort. Computer applications often require a one-time data entry-such as equipment specifications or material descriptions-which imposes a short-term load on available personnel. These tasks may be assigned to existing personnel or contracted to outside firms. The temptation to use existing personnel on a part-time basis has often proven counter-productive to final system success. After programming, implementation, and training it’s also essential that the system be supported. The new maintenance system's "credibility" among maintenance personnel is extremely fragile during the first few months of its existence. Hardware problems, computer priorities and program "bugs" can be disastrous to system acceptance. Parallel operation of existing manual procedures with the computer system for a period of time has been used to prove the computer system and to demonstrate the improvement in information availability and analysis. Finally, when implementing a computerized maintenance program, it’s important to progress from one system to the next at a speed that won’t create confusion or misunderstanding. If multi-system maintenance support is a plant's goal, then a long-time strategy for system implementation is necessary to ensure logical growth compatible with needs (and abilities) of plant personnel. To overcome the "too much, too soon" problem, one major chemical company has designed a modular system for eventual installation at all of its plant sites. The modules are made avail able to the plants-but not forced upon them. Each plant is encouraged to formulate a long-term strategy for use of these systems and to use the techniques of communication and personnel involvement in implementing systems at its own pace. This modular, but preplanned concept of computer system installation at plant sites permits growth into a totally integrated system, even if years separate the installation of individual systems. Manuals Prepared To accomplish the preventive maintenance control system, in a large multi-plant environment, manuals are prepared by technical specialists listing the specific maintenance tasks for each equipment item at the operating plants. The manufacturer's recommendations and a plant's own experience are considered in determining the extent of coverage for maintenance procedures and frequency. Differentiation between running maintenance and shutdown maintenance is also made. As operating requirements change, these procedures are improved and updated and revised pages are issued to keep the manuals current. Needless to say, these "manuals" are kept and updated on computers. Paper printouts are produced, as needed. Maintenance tasks range in frequency from daily shifts to several years, depending on the equipment type, its loading, and serviceability. Maintenance tasks are monitored by the staff at the home office and passed through the data processing equipment that performs the following functions: 1. Prints schedules and feedback cards. 2. Digests feedback information on completed or rescheduled maintenance. 3. Prints reports showing tasks performed or deferred. 4. Calculates percent compliance. 5. Accumulates actions taken and total time expended. 6. Prints addenda to the schedule and addenda feedback cards for uncompleted tasks. The percent compliance to the schedule for each plant is separated into "normal" and "downtime" categories. This separation permits evaluation of the schedule portion controlled by the plant manager-that portion he can do only during an emergency or planned shutdown. Central management is thus automatically given the opportunity to pass judgment on the desirability of rescheduling "downtime" PM items. Compliance reports are issued monthly and sent to plant managers and the home office. At the beginning of each month, the computer prints work schedules for all maintenance tasks due in the particular month. These schedules cover machinery and equipment for each plant in the system. Copies are sent to each plant manager and to the home office staff. The schedules list all the PM tasks that must be done during the coming month. An advance schedule of downtime tasks, covering the next three months, is also included. This advance notice assists the plant manager in planning down time task performance in case an emergency shutdown occurs. The computer schedules are accurate because maintenance task timing is based on the date they were last performed and the frequency assigned. Many inter national design contractors offer maintenance services that integrate other aspects of asset management. Along with the schedules, the data processing equipment prints out a data log to feed back completion or rescheduling information. This mode of tracking is used by plant maintenance personnel to record actions taken, time expended, date completed, and any pertinent remarks concerning findings when the task was done. The log issued to the plants at the beginning of the month must be answered on the last day of the month. Performance Reports The preventive maintenance performance report shows the tasks which are performed on time, performed late, are rescheduled, or remain in a deferred state. It allows the plant manager and home office management to evaluate performance. The number of tasks scheduled, rescheduled, and completed is listed at the end of the report along with the compliance percentages and the total time in hours for normal and downtime categories. Preventive maintenance performance reports are generated by any of the commercially available CMMS software programs. Preventive maintenance tasks that were not completed as scheduled are summarized in addenda to the schedule and sent to plant managers as reminders. The addenda are printed monthly by the computer, based on noncompliance of tasks previously scheduled. Deferred tasks continue to appear on these addenda until completed. A set of feedback requests accompanies the addenda for the reporting of work completed. Data reported via the feedback requests are accumulated by the computer. This includes time expended for each maintenance task and the number of times actions such as cleaning, filling, lubricating, overhauling, or testing are performed. A report of accumulated maintenance statistics is produced by the computer and is used by the operations management to make an audit of work done. FIG. 1. Maintenance as part of Asset Management. Breakdowns Reduced Since the incorporation of this system at large multi-plant corporations there has been a very definite trend of reductions in breakdowns. This allows nearly all maintenance work to be performed on a planned basis and on an optimized time schedule to provide the best possible on-stream factor. In the actual performance of planned maintenance work, there can be several approaches. One approach is to have complete in-house maintenance and supervisory ability at each plant with occasional subcontracting for large peaks. A second is to subcontract all maintenance work, thus eliminating the requirement for maintenance personnel at individual plants. Each system has obvious advantages and disadvantages depending on plant size, location relative to other area plants, etc. Recognizing good planning and skilled supervision as the key elements in low cost major maintenance, an intermediate approach has been taken at some plant locations. Some of the main considerations of this approach are: 1. The plant manager is fully responsible for normal maintenance. Each plant employs an absolute minimum number of resident maintenance people consistent with the day-to-day requirements, plus a normal backlog of work which can be accomplished while the plant is running. 2. The responsibility for planning major maintenance and turnarounds would come under the jurisdiction of a corporate maintenance manager working in close conjunction with the plant managers. His group of mobile planners, technicians and maintenance staff represent a well-trained nucleus for supervising major maintenance work to supplement the normal plant maintenance group. These individuals travel from plant to plant as required. This makes it unnecessary to have skilled supervision at each facility capable of handling planned major maintenance work. By scheduling the total corporate maintenance requirements, this same skilled group can handle a large work volume at a number of facilities at overall lower cost and inject a higher than normal experience factor into the supervision aspect of maintenance. The major maintenance work is performed using standard critical path scheduling, manpower and tooling planning, cost control procedures, inspection reports, etc. 3. Supplementary maintenance manpower is provided by using care fully selected local contractors. However, by having a well-trained nucleus of supervisory and maintenance personnel available from within the company, overall manpower efficiency is kept at a higher level than normal, thus resulting in lower costs and reduced outage time. Operators are used where possible during turnarounds which involve plant shutdown. 4. The travel and living costs for the flexible, rotating group of maintenance technicians and planners is a minor cost factor compared to the more efficient use of personnel and reduced outage time. In many cases, the technician and central maintenance group are geographically located near key facilities, since this is where they spend most of their time. Discussion of any maintenance concept is incomplete without including a method of spare parts control. The goal of an effective spare parts program is to keep the investment in capital spares to a minimum without seriously jeopardizing the plant on-stream factor, and administering the spare parts program at the lowest possible cost. Only experience, after an extended operating period, will determine the adequacy of decisions made in this regard. The spare parts program at a multi-plant corporation should most certainly be administered on a centralized basis. The commonality of equipment makes this a prerequisite for low total spare parts investment. The same central mechanical engineering organization responsible for monitoring field mechanical problems is also responsible for the initial selection of spare parts and the approval for reordering major spares. Initial spare selections are based on equipment manufacturer recommendations, operating experiences, and careful analysis of what is in existence. To obtain the best possible price, major spare parts are negotiated as part of the original machinery or equipment purchase. Central Parts Depot Specific items not common to other facilities and small, normal spares are maintained at individual facilities. Certain major components common to more than one operating facility and some parts showing high usage are stocked at a centrally located parts depot. This concept allows for a lower total investment in spares. Since spare parts handling, packaging, and long-term storage are so critical and require specialized knowledge, it’s necessary to provide this capability at only one location. It’s possible to ship spare parts from this depot on a 24-hour, seven day a week basis. Transportation arrangements normally keep the total shipping time to less than eight hours. With most maintenance work performed on a planned basis, actual plant startup delays due to the central stocking depot concept are rare. By careful analysis on ordering of initial spares and the central depot concept, major corporations have been able to lower the investment in spares (expressed as a percentage of equipment investment) from approximately 5 percent a few years back to under 3 percent on new plants. To keep the administration of replacement spare parts at a minimum cost, a central data processing system has been established. As parts are used, data are sent to the corporate office for computer input, which automatically generates the parts replacement purchase order. The authorized parts level is periodically and automatically reviewed to prevent reordering of parts with a low turnover. A block diagram showing the spare parts support system is shown in FIG. 2. A composite listing of all parts in the system is available at the corporate office to facilitate the identification of parts interchangeable with other facilities. FIG. 2. Block diagram of operations spare parts support system. Plant Engineering Plant engineering referred to here includes those process and mechanical services required for monitoring plant operations, the prompt resolution of special plant problems, normal debottlenecking, and special engineering assistance as required in performing maintenance work. A centralized organization of specialists within the operations department is charged with this responsibility for the network of facilities. Major engineering design and construction work related to new plants and plant expansions is handled by a separate corporate engineering department and won’t be discussed in this section. The corporate engineering department is also available for special help to the operations department. As indicated previously, the interjection of technical specialists for the quick and efficient resolution of problems was one of the key points to a centralized system of engineering services, and the engineering staff at individual plants has, therefore, been kept minimal. In some plants, a certain need for minimum on-site staffing of chemical and mechanical engineers is required for day-to-day problems, but here special emphasis is placed on coordinating problem issues with the centralized staff. The normal day-to-day minor plant and equipment problems are handled by the plant manager with his staff sized on this minimum basis. The centralized engineering services then encompass these major responsibilities: 1. Aid in resolving specific equipment and process problems as they arise based on information gathered through monitoring techniques or through plant manager request. Suitable engineering or technician help is provided, including site visits when necessary. 2. Getting special services from the corporate engineering department to obtain maximum benefits from understanding the design concepts and to provide a valuable source of field problem feedback for future design considerations. This would also include obtaining recommendations from equipment manufacturers and outside consultants. 3. Monitoring process performance of all facilities including overall production, utility efficiency, and gathering sufficient data to generally identify problem areas. Each facility requires a detailed analysis to determine the minimum key data required. Some monitoring is performed on a daily basis and is transmitted to the home office by e-mail. Other monitoring is performed on a weekly or monthly basis. The computer is used to perform routine calculations required for certain evaluations to determine minimum operating costs. Thus, the computer can be economically used and up-to-date process monitoring and reporting allows for prompt management attention to plant problems. 4. Monitoring of machinery and equipment performance. An example would be the periodic collection of data on all large compression equipment to determine stage efficiencies and intercooler performance since utility costs represent a significant portion of the total operating costs in most petrochemical or air separation plants. Where possible, the performance evaluations are translated into dollars so that business decisions can be made. FIG. 3 shows a simplified computer program used for evaluating compressor efficiencies where the results are translated into cost inefficiencies in dollars/day. Of particular interest, also, is the increased use of field monitoring methods as a key element in evaluating equipment performance. In many cases, this represents the actual guidelines for determining frequency of inspections. 5. Monitoring of plant and equipment performance by regular visits of process and mechanical specialists to the facilities. This provides the necessary final tie of the centralized group with plant personnel. 6. Establishing safety, technical, and operating procedures to provide conformity to all plants. 7. The organization of corporate technical and training sessions for plant personnel based on the management evaluation of need. Next>> |