Preventive maintenance meaning

Breakdown maintenance means no preventive maintenance (i.e., failure is annunciated by the fact of failure). 

Customer supplied products that are issued for incorporation into supplies don t often require maintenance however, items for use in conjunction with the contract may be retained for such a duration that maintenance is necessary. If the products require any maintenance you should be provided with a maintenance specification and the appropriate equipment to do the job. Maintenance may include both preventive and corrective maintenance but you should clarify with your customer which it is. You may have the means for preventive maintenance, such as lubrication and calibration, but not for repairs. Always establish your obligations in the contract regarding customer supplied product, because you could take on commitments for which you are not contractually covered if something should go wrong. You need to establish who will supply the spares and re-certify the equipment following repair. 

Preventive maintenance is probably the most common type of maintenance practiced in chemical manufacturing plants. This usually means carrying out work to ensure that a piece of equipment will operate continuously and efficiently. PM tasks include regularly performed lubrication, parts replacement, and so on. PM is generally carried out routinely at set intervals, usually at a scheduled shutdown. PM has the downside of requiring work that may not be necessary and replacing parts that may still have useful life. 

Water sprays from monitor nozzles and hose lines can be used for vapor mitigation. Tests have been conducted in which monitor nozzles and hose lines have been used to create a chimney effect through which the gas is forced upward and dispersed at a high elevation (Beresford, 1981). Application techniques and flow rates are facility-, installation-, and material-specific. Careful planning, analyses, and testing should be conducted prior to deciding on the use of a mobile water spray as a proven means of mitigation. Preventive maintenance of this equipment is key to reliable operation. Hose lines, typically, are hydrostatically tested annually. Flow tests should also be conducted periodically. 

Inspection and Preventive Maintenance When a steam curtain is to be used to mitigate the consequences of a flammable material release, it must be treated as if it were part of the site s firefighting system. This means that a managerial system must be in place to ensure that the steam curtain system is inspected periodically. Deficiencies should be reported and repaired promptly. Follow-up investigations must be made to ensure that the inspections, deficiency reporting, and repairs occur in a timely manner. If the system must be shut down for the repairs, the same procedures that would be followed for a sprinkler or deluge system shutdown should be utilized. 

The analysis of used lubricating oils is accepted as an effective and practical means of monitoring engine wear. It allows preventative maintenance to be carried out at convenient times when needed and avoids the expense of major breakdowns and excessive lay-offs. Navies, air-forces, air-lines, rail companies and many companies with large truck fleets make use of this diagnostic aid. 

Many of the equipment vendors have developed cost of ownership (COO) models, some traceable, at lease in part, to SEMATECH. These COO models may be used to account for all aspects of amortized costs and provide a user with a highly accurate anticipated cost schedule. At a minimum a COO model should include the cost of the system, utilities, facilitization, mean-time-between-failures, mean-time-to-repair, preventative maintenance, personnel, all consumable safety costs (including that of required support equipment), reactant, and substrate costs. Each of these parameters" should be well defined and guaranteed, and the user of such models should precisely understand how up-time, mean-time-to-repair, and other terms are defined. A 90% uptime schedule is useless if the system is routinely defined to be out of service, for maintenance, 25 % of the time. 

This may mean calibration at predetermined intervals of time or predetermined intervals based on utilization. The requirement for recalibration may well help define a schedule for routine preventative maintenance. 

A. Performance measiires The first step in establishing an effective maintenance basics program is to identify and establish performance measures. Most experienced managers have learned that you get what you measme. Successful pharmaceutical plants develop and implement a series of supportive key performance measures to track and manage improvement of maintenance/reliability. Examples are mean time between failure, maintenance cost per unit of output, percent planned and scheduled maintenance, preventive maintenance tasks completed, expense maintenance cost as a percentage of replacement asset value, etc. These indicators must be available to aU levels of an organization and shoiild be used to maximize individual and group contributions. It would be best if these indicators were part of the reliability-balanced scorecard. 

In addition, other measures, such as mean active corrective maintenance time and mean active preventive maintenance time, are used to measure maintainability. Some of the components of the corrective maintenance tasks are ... 

Indicators may be used to provide an objective, accurate measurement of the different services provided in the department. These can measure specific individual, team, and departmental performance parameters. Typical indicators might include simple tallies of the quantity or level of effort for each activity, productivity (quantity/effort), percentage of time spent performing each activity, percentage of scheduled IPMs (inspection and preventive maintenance procedures) completed within the scheduled period, mean time per job by activity, repair jobs not completed within 30 days, parts order for greater than 60 days, etc. 

Future versions of this application will also consider dynamic risk factors such as user error, mean-time-between failure (MTBF), device failure within 30 days of a preventive maintenance or repair, and the number of years beyond the American Hospital Association s recommended useful life. 

Involves the systematic replacement of components, according to a predetermined schedule. This means the replacement of components whose life span is known. It also includes systematic lubrication jobs as well as minor upkeep work. This definition avoids confusion between systematic checking or even continual checking to determine the state of the equipment (conditional preventive maintenance) and systematic preventive maintenance. 

This phase, fundamental for the RCM approach, consists in analyzing the operating experience. It provides information on the failures and degradations which have actually occurred on current systems. It is the only mean of showing that an expected failure or degradation has only rarely occurred and that a given preventive maintenance task is therefore not needed and may even be harmful. 

According to the major incident/accident reports of nuclear power plants in Korea, the contribution of human errors takes up about 22% of the total events (KINS). The previous study presents that most of the human-related unplanned reactor trip events during the normal power operation are associated with the test and maintenance activities (63%), which are comprised of the plant maintenance activities such as a periodic preventive maintenance , a plannedmaintenance and a corrective maintenance (Kim Park 2008). This means that the test and maintenance activities should be a major subject that needs to be focused on. The hiunan errors intervened during a periodic preventive maintenance and a corrective maintenance mostly lead directly to a trip event, while the hmnan errors during a planned maintenance , which are performed during the period of a plant overhaul, are mostly dormant imtil a triggering event occurs. 

To evaluate the maintenance policy and to compare both proposed improvement functions Gi and G2, the average cost on the finite time span, denoted by E[C(7 ] is computed. Each time a maintenance action or an inspection is performed on the system, a cost is incurred. Let us denote by Cprev the cost of a perfect preventive maintenance action. It is supposed that the cost of the imperfect maintenance action performed at time tp is proportional to the improvement function G(tp). It means that the cost of the imperfect preventive maintenance action which is performed at time tp, denoted by Cp cv, is equal to ... 

In an operational context, there is a need to adjust and optimize existing maintenance programs. In order to facilitate this, one has to be specific on failure causes and mechanisms. A Failure Mode Effect and Criticality Assessment (FMECA) module has thus been included in the RAM tool. With the FMECA module in place, the ageing and downtime modelling are further improved compared to the basic RAM model in Section 5.1. Critical failures are split into different failure modes with the related Mean Time to Failures (MTTFs) and failure causes. A description of maintenance measures is linked to each of the failure modes. Information regarding the different cost elements of maintenance and operation are registered in the maintenance-planning module, or the Reliability Centred Maintenance (RCM) module. Interval optimisation for each of the preventive maintenance tasks is derived as the interval that produces the minimum total cost. 

A means to indicate the nature and due date of the various inspection and maintenance operations to be performed (the preventive maintenance schedule for the vehicle) and... 

Do you have a means for gauging the effectiveness of your preventive maintenance procedures ... 

Some companies interpret MI to mean only preventive maintenance and therefore assign MI solely to the maintenance group. Actually, because MI includes a wide variety of tasks and activities, the responsibilities for MI activities are spread widely across a facility and many personnel may not realize that their Jobs involve a portion of a regulated MI program. 

MTBPM mean time between preventive maintenance... 

PM mean power polarization-maintaining (optical hber) preventive maintenance ... 

In the case of an OR linkage, it follows from qiit) = < A0 that maintenance in the manner considered is without influence. This is understandable if it is considered that the failure of one component can in itself lead directly to the undesired event and cannot be prevented by subsequent repairs. In real terms, results can be achieved when maintenance is preventive, possibly in such a way that wear phenomena, identified before component failure, are eliminated. Related to the theoretical formulation observed here, this means that preventive maintenance can keep component failure rates at a low level. 

Maintenance and inspection Two kinds of maintenance, viz. corrective maintenance and preventive maintenance have direct impact on cost element. The frequency of maintenance or inspection directly affect availability and the operating cost in terms of cost toward man-hours spent, spare part consumption, etc. Turnaround time, mean time to repair (MTTR), etc., are measures for maintenance costs for modeling. 

These measurements provide a means to monitor coatings in the field and permit steps to be taken before serious damage results due to atmospheric corrosion. Early preventative maintenance is less costly than extensive repair work resulting from a failed coating. 

It is often necessary to archive process-related information. Archived data are used to track defects as a means of process control. These data can assist in quickly determining the root cause of an out-of-control process. Process information can also be used to monitor long-term equipment performance, indicating the need for periodic preventive maintenance or machine replacement. Easy access to historical process information can also facilitate the reintroduction of a particular product line with a minimum investment in process development efforts. 

Mean time between failures (MTBF) is determined using the technologies and processes hsted previously. This will allow for proper planning of preventive maintenance based on information, not just on recommended schedules. Using these technologies and SPC should reduce the cost of equipment maintenance over time. 

These Regulations require that maintenance is carried out to prevent danger. This means that some form of inspection, test and repair has to be done in advance so as to anticipate dangerous faults and to ensure that they do not occur, so far as is reasonably practicable. It is evident that neglecting an installation or equipment until an incident occurs and then taking remedial action does not constitute preventive maintenance and does not eomply with the law. 

The two main elements of fixed interval preventive maintenance are procedure and discipline. Procedure means that the correct tasks are done, the right lubricants applied, and consumables replaced at the best interval. Discipline requires that all the tasks are planned and controlled so that everything is done when it should be done. Both these areas deserve attention. The topic of procedures is covered in detail in following sections. 

The earlier the threshold is set and effective preventive maintenance done, the greater is the assurance that it will be done prior to failure. If the mean time between failures (MTBF) is 9,000 miles with a standard deviation of 1,750 miles, then proper preventive maintenance at 5,500 miles... 

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