Preventive breakdown maintenance

If maintenance is performed, there are two principal maintenance strategies preventive and breakdown maintenance. These are not mutually exclusive, and may be combined even in the same piece of equipment. Take for example a private motor car. The owner performs a mixture of preventive maintenance (by adding lubricating oil, topping up the battery fluid, hydraulic fluid and coolant) with breakdown maintenance (e.g. only replacing the starter motor when it fails, rather than at regular intervals). 

Breakdown maintenance is suitable for equipment whose failure does not threaten production, safety or the environment, and where the cost of preventing failure would be greater than the consequence of failure. In this case, the equipment would be repaired either on location or in a workshop. Even with this policy, it is assumed that the recommended lubrication and minor servicing is performed, just as with a motor car. 

Preventive maintenance includes inspection, servicing and adjustment with the objective of preventing breakdown of equipment. This is appropriate for highly critical equipment where the cost of failure is high, or where failure implies a significant negative impact on safety or the environment. This form of maintenance can be scheduled on a calendar basis (e.g. every six months) or on a service hour basis (e.g. every 5,000 running hours). 

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

Scheduled prevenhve maintenance is performed to prevent breakdowns or mal-fiinchons, to prolong the hfe of an instrument, and to maintain ophmum operating characlerishcs. For automated immunostainers, the performance and documentahon of maintenance/funchon checks should be done as defined by the manufacturer with (at least) the frequency as specified. In general, common laboratory equipment such as pipets, centrifuges, and balances need to be serviced or cahbrated twice yearly. 

Maintenance is not merely called upon to repair failed equipment (breakdown maintenance). Over the course of time, maintenance workers have teamed with plant operations personnel to develop preventive maintenance (PM), predictive maintenance (PdM), and condition-based maintenance (CBM) programs, all in an effort to get ahead of problems occurring in plant operations, and to do so as efficiently as possible. 

Inspections of rotating equipment could be accomplished by Preventive Maintenance Programs, which assures that equipment and machine behavior follow some sort of statistical average based upon weeks of operation or throughput in the process stream. Preventive maintenance (PM) programs—the planned, periodic inspection of equipment—reduces the occurrence of unexpected problems. Preventive Maintenance Programs are much more efficient to conduct than the old-fashioned breakdown maintenance programs of previous years in which failures often occur at undesirable times, interfere with production, and may prove to be more costly to correct. [2]... 

The major benefit to be realized from Fieldbus and intelligent instruments is primarily due to the ability to obtain on-line diagnostic information. This provides information on the performance of a control valve, for instance, or on the expected lifetime of a seal material based on the number of hours installed and the duty. These features lead to better planned maintenance (rather than preventative or run-to-breakdown maintenance), which in turn leads to lower overall maintenance costs and fewer unplanned losses of production. Validation of the on-line diagnostics will assist in the ongoing review of the validation status of the OCS. 

Critical operations will be identified where backup equipment or systems are economically justified. Redundancy of critical equipment and systems will ensure that continuous operation is achieved when something fails. Maintenance will focus attention on critical operations in order to increase equipment effectiveness, reduce unplanned breakdown tmd increase the effectiveness of preventive/predictive maintenance. 

Effective preventive/predictive maintenance programs will be used to anticipate and predict maintenance problems in order to eliminate the uncertainty of expected breakdowns and high repair costs. Predictive maintenance wiU not be limited solely to the detection of failure but will proactively identify and eliminate the root causes of chronic problems. Preventive/ predictive maintenance programs will be adequately staffed to cover adl major assets within the operation. Maintenance wiU maintain current techniceil knowledge and experience for applying a combination of predictive technologies that is best suited for the specific application or system. 

The development of more effective planning and scheduling systems will be a top priority for the future capable maintenance operation. As reductions in breakdown repairs occur through more effective preventive/predictive maintenance, the opportunity to increase planned maintenance work will result. Maintenance and operations work closely to schedule rcpai rs at the most convenient time. Maintenance will become more customer oriented tmd focus on achieving greater customer service by completing scheduled repairs on time. The utilization of craft time will increase as levels of planned work increases and as the uncertainties and inefficiencies associated with breakdown repairs arc reduced. 

Condition monitoring, preventive maintenance, and breakdown maintenance shall be well planned, organised, and safely executed in consultation with production team. Some essential tools and facilities shall be available in-house. 

Even in factories where planned maintenance is not officially applied the first method of breakdown maintenance is rarely followed completely. When a given item of equipment has failed several times in the same way or after similar intervals of time, someone is sure to suggest that some preventative action should be taken before the time that the next failure is due. This may be as simple as saying that a particular pump, gearbox, or motor is overhauled in the annual shutdown because it is known from past experience that it will not last for another year . 

In recent years, the emphasis of power line operators is on predictive/preventive maintenance to ensure reliable and safe operation. Breakdown maintenance is becoming a thing of the past. Crucial elements of this approach are consistent application of the most up-to-date technological know-how and systematic surveillance of the power lines. 

A preventive maintenance program starts with a survey of maintenance needs. It should be developed to get the work done before repair or replacement is required. Don t wait for breakdown maintenance. As described in the process safety management (PSM) standard (refer to OSHA 29 CFR 1910.119), do not wait for something to break down until... 

Preventive Maintenance is the most important routine function that maintenance personnel can accomplish. The reactive, breakdown maintenance mode will never be gotten away from if PMs are not performed consistendy and properly on a regularly scheduled basis. 

This approach (SOAP) is now used for fleet vehicles, aircraft engines, as well as locomotives and can prevent breakdowns by scheduling maintenance in relation to wear at predictable parts of an engine. 

All work equipment must also be adequately and suitably maintained in an efficient state to prevent breakdown and/or risks of fire, health or safety. A programme of planned preventive maintenance (PPM) must be implemented to ensure that work equipment is kept in efficient working order and in good repair and the fire risks are reduced to a reasonable level. The frequency of maintenance should be determined by ... 

There is little or no attention paid to preventive maintenance breakdown maintenance is the rule... 

Downtime, and particularly the risk of unplanned downtime, is a key cause of the need for safety stocks in a process. Other JIT tools and techniques can help to minimise the problems here. For example, total productive maintermnce CFPM Nakajima, 1989) seeks to answer the question What can everyone do to help prevent breakdowns Regular planned preventive maintenance, closer cooperation between production and maintenance persormel, and equipment sourcing for ease of maintenance are some of the actions that can be taken in response. In other words, increasing planned maintenance costs often results in reduced overall costs of machine downtime. Minimising changeover time is a JIT tool that can be used not only to reduce lost production time but also to improve production flexibility. Inflexible facilities delay the rapid production of customer orders. 

If the concentration of hydrazine is observed carefully, to prevent breakdown of the excess to ammonia, its use instead of sodium sulfite has a number of advantages. Salt content does not increase as it does when sulfite is added. Another advantage is that alkalinity can be controlled with a proper excess of hydrazine. Maintenance of a hydrazine residual in the water protects the boiler against occasional increases in dissolved oxygen content that result from variations in operating conditions. Finally, much smaller dosage levels are required. 

A PPM program is needed to avoid equipment failures, utiHty outages, and production intermptions. From a cost savings angle it is extremely important to do preventive maintenance in order to avoid breakdowns. Periodic inspections and a good lubrication program uncover conditions that could lead to breakdowns. When problems are found eady, they can be taken care of without work intermption and costly repairs. Sometimes faciHty managers are so afraid of downtime that preventive maintenance is done too often. In other cases production does not allow adequate time to provide proper maintenance. 

Monitoring by Electromechanical Instrumentation. According to basic engineering principles, no process can be conducted safely and effectively unless instantaneous information is available about its conditions. AH sterilizers are equipped with gauges, sensors (qv), and timers for the measurement of the various critical process parameters. More and more sterilizers are equipped with computerized control to eliminate the possibiUty of human error. However, electromechanical instmmentation is subject to random breakdowns or drifts from caUbrated settings and requires regular preventive maintenance procedures. 

Combining the practice of preventive maintenance and total quality control and total employee involvement results in an innovative system for equipment maintenance that optimizes effectiveness, eliminates breakdowns, and promotes autonomous operator maintenance through day-to-day activities. This concept known as Total Productive Maintenance (TPM) was conceived by Seiichi Nakajima and is well-documented in his book Introduction of TPM and is highly recommended reading for all involved in the maintenance area. 

Maintenance embraces regular inspection, periodic examination by competent persons , and repairs. Accidents may arise as a result of the lack of maintenance, during maintenance, and as a consequence of faulty maintenance. Preventive maintenance can be a legal requirement for, e.g., pressure vessels/boilers, lifting gear, power presses. A system is required for monitoring compliance witli scheduled preventive maintenance programmes, backed up by in-service inspection. Breakdown... 

Planned or preventative maintenance is not necessarily the best for all installations. If the service is not essential, and spares are known to be available within a reasonable time, nothing is done beyond obvious routine servicing work. Then, when a breakdown occurs, it is repaired. This approach, although not widely accepted, is an option which should be considered. 

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