Inspection Repair Cost

The inspection repair cost will include all the expenses incurred to carry out the inspection and corrective action taken (if necessary). This will include the cost of maintenance engineers, spares consumed and loss of operational time. The expected cost for corrective action under 

Predicting Costs Associated with Inspection Tasks (Costk) 

The cost associated with inspections carried out on the equipment, Costk, is given by  

Costi = operational cost for task group i (includes inspection task for failure k) Costk = cost rate for crew. mtti = inspection duration. 

The inspection duration indicates the mean time taken to inspect the item. This time is only used to calculate the maintenance crew costs. A task group is used to group together different maintenance tasks, which are to be performed at the same time. Performing an inspection task on a group of items at the same time can often be more cost effective than inspecting the items at different intervals. The values of the cost rate for crew and scheduled call-out cost for crew should be the same as the values used in Equation (8.19). 

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This model estimates the expected cost per unit time of maintaining the equipment on an inspection regime of period T. The probability of a defect arising as a breakdown failure is given in Equation (8.1) as b(T). As an inspection repair cost applies to all components even if the component is in good condition, the probability of fault arising as an inspection repair is 1 -b(T). 

To analyse the effect of the change in the cost elements that were difficult to quantify, a sensitivity analysis is performed on the optimal inspection period by altering the inspection repair cost Costm) and the inspection cost (Costk). The following five cases were considered ... 

The result of this analysis is shown graphically in Figure 8.13 and the expected cost and optimal inspection period for each case are given in Table 8.3. From the sensitivity analysis, it can be seen that the optimal inspection period is around 7 to 8 operating hours. The variation in T is observed to be small when inspection repair cost and inspection cost are varied. 

In the simplest terms, a fault-tree for risk analysis requires the following information probabiUty of detection of a particular anomaly for an NDE system, repair or replacement decision for an item judged defective, probabiUty of failure of the anomaly, cost of failure, cost of inspection, and cost of repair. Implementation of a risk-based inspection system should lead to an overall improvement in the inspection costs as well as in the safety in operation for a plant, component, or a system. Unless the database is well estabUshed, however, costs may fluctuate considerably. 

Many organizations fail to appreciate the scale of their quality failures and employ financial systems which neglect to quantify and record the true costs. In many cases, the failures are often costs that are logged as overheads . Quality failure costs represent a direct loss of profit Organizations may have financial systems to recognize scrap, inspection, repair and test, but these only represent the tip of the iceberg as illustrated in Figure 1.7. 

While boiler explosions fortunately do not occur too often today because of the existence of extensive safety devices as well as the regular program of inspection, their effects can be catastrophic. Similarly, sudden and unforeseen damage caused by the overheating of multi-tubular steam boilers due to lack of water can lead to eventual furnace collapse, with very extensive repair costs as well as lost production. 

Here we will present a simulation model for determining the inspection policy for SRVs in a typical petrochemical plant, based on experience. In my opinion, it minimizes the total inspection and repair costs without jeopardizing the safety. The model is simply a result of 20 years of observation in the chemical, petrochemical, power and oil and gas industries. 

The EPA has proposed an enhanced IM program that would require a dynamometer test under varying engine loads, would test evaporative emissions, and would raise the repair cost limit substantially. The enhanced IM program still has some serious defects. Most notably, it lacks the necessary components of significant on-road, in situ, remote sensing to validate the emission reductions and to catch cars that have been tampered with between inspections. 

These costs are easily calculable when the omission has led to unintended consequences well identified and with a clear cause-effect relationship and are usually documented in the records of the reparative activity executed. For example, repair costs of a product under warranty as a result of not having executed the final inspection of the product or administrative penalty for breach of statutory duty in environmental management due to not having identified this legal requirement. 

This paper focuses on how to model the deterioration of static pressurized process equipment to enable efficient inspection and maintenance planning. Such equipment tends to gradually deteriorate over time from erosion, corrosion, fatigue and other mechanisms, and at some point of time inspection, repair or replacement is expedient with respect to safety, production and costs. The deterioration of the equipment is influenced by many factors such as type of equipment, system design, operation and process service, material and environment. For hydrocarbon systems, the most critical deterioration mechanisms are corrosion due to CO2 and H2S, microbially influenced corrosion, sand erosion and external corrosion (DNV 2002). In general, CO2 is the most common factor causing corrosion in oil and gas system of low alloy steel (Singh et al. 2007). 

Another utility ( 2 billion in annual revenues) reduced its inspection and repair costs by 30 percent annually by implementing a strategic sourcing process. 

Often the success of a decontamination operation is expressed in terms of a cost-benefit analysis, i. e. a comparison of the expenses incurred during execution of the total procedure to the cumulative dose exposure (man-rems) which can be expected to be saved as a consequence of the reduced radiation levels. The problem with such an analysis, which is mainly in use in the USA, lies in the difficulty in translating radiation dose exposures saved into an equivalent amount of money. The result of such an analysis, therefore, depends highly on the equivalent assumed. On the basis of such cost-benefit analyses, substantial radiation exposure savings to the staff have been calculated, in particular when decontamination was carried out prior to inspection, repair or replacement work. As was shortly mentioned above, the initial concerns of the plant owners with regard to the costs, the potential success and the potential hazards of such an action have been largely dissipated and, at many plants, decontamination of particular systems has become a standard technique. However, as the measures taken for reduction of plant contamination buildup (see Sections 4.4.3. and 4.4.4.) will prove to be more and more successful in the future, the need of operational decontamination in the plants is expected to decrease. 

Rational design and materials selection must be based on an economic analysis of alternatives. In order to determine the actual costs of the alternatives, projected system life and the need for inspection, maintenance, and repair costs must be known. While there is a great deal of information available on the performance of a wide variety of materials in marine environments, these data are difficult to apply to the projection of system life. Most of the quantitative information on corrosion performance is for isolated specimens and does not address the interzone interactions and effect of design features that occur on real structures. Most of the limited amount of published information derived from the evaluation of actual structures is not quantitative and thus is difficult to use in the design of new structures. 

Preventive maintenance provides more operational rehabihty however, it also involves higher inspection and maintenance costs, if the inspection strategy is appHed, or higher repair costs if the exchange strategy is applied. Which maintenance strategy will be applied depends on a number of factors, such as Hfespan, personnel structure etc, and will be determined by company management... 

Repair costs of the component include the costs of access vessels, spare parts and technicians to perform initial inspection, repair or replacement. Moreover, lost production and revenue losses due to the disturbed functionality of the wind turbine(s) are a part of the corrective maintenance costs. 

Cost of preventive maintenance can be carried out in the scheduled intervals during inspections Expected cost of inspection and preventive maintenance Cost of repair Number of events... 

The rate of failure for steam is very high, even though there are no major failures. It has to be stressed that, a number of major defects, resulting after periodical inspections have been accounted as failures , because the significant consequences on repair costs or plant availability. As in other studies major defects are not included, the rate is not so worrying. Furthermore the age of failed equipment end the type of industry are essential for understanding the data. 

Fig. 3 Distribution of damage ratio (ratio of claims amount or repair cost and building replacement cost) distribution as a function earthquake intensity as observed in Northridge earthquake, (a) Post-75 single-family wood-frame buildings, (b) Steel-frame buildings inspected in SAC project...

The predicted cost associated with inspection repair from Equation (8.20) is calculated to give,... 

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. 

Maintenance and Reliability Preventive maintenance requires that all engines be shut down at periodic intervals for inspection and repair. For properly maintained heavy-duty engines availability is over 97 percent, with maintenance costs of 2.50 to 5 per horse-power-year and lubricating-oil consumption of 1 to 2 gal/hp-year. While this represents a high degree of reliability, outages of heavy-duty engines are more frequent than those of electric motors or steam turbines. 

Maintenance is not a glamorous procedure however, its importance is second to none. Maintenance procedures are always controversial, since the definition of upkeep varies with the individual interpretation of each maintenance supervisor. The latitude of maintenance ranges from strict planning and execution, inspection and overhaul, accompanied by complete reports and accounting of costs, to the operation of machinery until some failure occurs, and then making the necessary repairs. 

As with any power equipment, gas turbines require a program of planned inspections with repair or replacement of damaged components. A properly designed and conducted inspection and preventive maintenance program can do much to increase the availability of gas turbines and reduce unscheduled maintenance. Inspections and preventive maintenance can be expensive, but not as costly as forced shutdowns. Nearly all manufacturers emphasize and describe preventive maintenance procedures to ensure the reliability of their machinery, and any maintenance program should be based on manufacturer s recommendations. Inspection and preventive maintenance procedures can be tailored to individual equipment application with references such as the manufacturer s instruction book, the operator s manual, and the preventive maintenance checklist. 

Local repair of delamination originally caused by non-durable surface treatment is only temporarily successful at best. The surface treatment on the unrepaired portion of the assembly remains susceptible to attack and the area of delamination will likely continue to grow once the assembly is put back into service and exposed to moist conditions. Replacement or complete remanufacture of the component is the only way to permanently address this type of damage. However, time-limited repairs using bonded or mechanical methods can be used to extend the life of the component until a major overhaul is scheduled. In some cases such as widespread disbond of fuselage doublers, mechanical repairs (rivets and fastened doublers) and continued inspection are used to extend the life of the skin indefinitely because of the high cost of replacement. 

Diagnosis of defects by inspection of visible causes or more sophisticated means (tracer-dye inundation to find sources and routes of leaks, infrared photography, etc.) is a prerequisite for correct repair specification. Greater skill in detailing and specifying suitable materials and methods are required in the design of flat roofs and the same applies to repairs. Here, too, durability and effectiveness are, to some extent, cost related. 

In 1854, the Manchester Steam Users Association was formed to help with the prevention of explosions in steam boilers and to find efficient methods in their use. To achieve this, the Association employed the first boiler inspectors, whose services were then made available to the Association s members. Within a short space of time, the members became convinced that insurance to cover the high cost of repair or replacement of damaged boilers was desirable, and this resulted in the first boiler insurance company (The Steam Boiler Assurance Company) being formed in 1858. The scope of the services for inspection and insurance later extended to include pressure vessels, steam engines, cranes, lifts and electrical plant, the insurance protection in each case being supported by an inspection service carried out by qualified engineer surveyors. 

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