Kelly Maintenance Strategy

1. Auflage 1997
ISBN: 978-0-08-093839-4
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 272 Seiten

Devising optimal strategy for maintaining industrial plant can be a difficult task of daunting complexity. This book aims to provide the plant engineer with a comprehensive and systematic approach, a framework of guidelines, for tackling this problem, i.e. for deciding maintenance objectives, formulating equipment life plans and plant maintenance schedules, designing the maintenance organisation and setting up appropriate systems of documentation and control. The author, Anthony Kelly, an experienced international consultant and lecturer on this subject, calls his approach BUSINESS-CENTRED MAINTENANCE (BCM) because it springs from, and is driven by, the identification of business objectives, which are then translated into maintenance objectives and which underpin the maintenance strategy formulation. For the first time maintenance management is analysed from the perspective of the whole company and thus makes sense not only technologically but also in economic and business terms. - Complete guide to maintenance from a whole-company perspective - Best-selling and world-renowned author - Complementary to RCM (Moubray) and TPM (Wilmott)

Zielgruppe

Academic/professional/technical: Undergraduate. Academic/professional/technical: Postgraduate. Academic/professional/technical: Research and professional

Autoren/Hrsg.

Kelly, Anthony

Inhaltsverzeichnis

1;Front Cover;1
2;Maintenance Strategy;4
3;Copyright Page;5
4;Table of Contents;6
5;Preface;8
6;Acknowledgements;10
7;Chapter 1. Maintenance and the industrial
organization;12
7.1;Organizations and the role of management;12
7.2;References;17
8;Chapter 2. Plant acquisition policy and maintenance life-cycle costs;18
8.1;Life-cycle costing;18
8.2;Capital asset management;19
8.3;Summary;26
8.4;References;28
9;Chapter 3. Formulating maintenance strategy, a business centred approach;29
9.1;The maintenance system;29
9.2;Application of the approach;39
9.3;The effect of 21-shitt operation on maintenance;39
9.4;The strategic thought process;40
10;Chapter 4. The structure of plant;42
10.1;Introduction;42
10.2;Modelling industrial plant;42
10.3;The reason for maintenance;48
10.4;Capital replacement policy;50
10.5;Maintenance strategy;50
11;Chapter 5. The reliability of plant components;54
11.1;Introduction;54
11.2;Engineering reliability, probability and statistics;55
11.3;Item reliability;55
11.4;Statistical analysis of component lifetimes;57
11.5;Probability density functions;59
11.6;Measures of component reliability;61
11.7;Time-to-failure;66
11.8;The whole-life item failure profile;66
11.9;Diagnosis of recurrent failures and prescription of the remedy;69
11.10;Weibull analysis of item lifetimes;69
11.11;Weibull probability paper;72
11.12;Small data samples, possibly incomplete, or large multi-censored samples;74
11.13;References;76
12;Chapter 6. The reliability of plant systems;77
12.1;Introduction;77
12.2;Reliability block diagrams;78
12.3;Series reliability;79
12.4;Active-parallel reliabiIity
;81
12.5;Active parallel reliability with partial redundancy;82
12.6;Inactive parallel, or standby reliability;83
12.7;Reliability analysis of complex or large systems;84
12.8;System reduction;86
12.9;References;88
13;Chapter 7. Maintenance objectives;90
13.1;Introduction;90
13.2;Alumina refinery: operating characteristics;90
13.3;The maintenance objective;94
13.4;Maintenance resources and plant output factors;94
13.5;General statement of a plant maintenance objective;99
13.6;A procedure for formulating maintenance objectives;101
13.7;Maintenance objectives in practice;104
14;Chapter 8. Principles of preventive maintenance;108
14.1;Introduction;108
14.2;The plant item — a definition
;110
14.3;Maintainability diagrams;110
14.4;Maintenance procedures and their selection;112
14.5;The maintenance actions;115
14.6;Reconditioning — internal versus contract;118
14.7;In situ repair techniques and the repair versus replace decision;118
14.8;The timing of the maintenance action;118
14.9;Condition-based maintenance (CBM);123
14.10;Operate to failure (OTF);132
14.11;Guidelines for establishing the best timing of a maintenance action;132
14.12;Examples of maintenance procedure selection;135
14.13;Universal maintenance procedures;144
14.14;Assembling the maintenance life plan for a unit;144
14.15;References;151
15;Chapter 9. Determining the life plan and schedule — the top-down bottom-up approach;152
15.1;Introduction;152
15.2;The top-down bottom-up (TDBU) approach;155
15.3;TDBU application;169
15.4;Comments;174
15.5;Using the TDBU approach;177
16;Chapter 10. Controlling plant reliability;178
16.1;Reactive control of plant reliability;178
16.2;Pro-active control of unit reliability;179
16.3;Incorporating reliability control systems into the organization;180
16.4;Reference;186
17;Chapter 11. Case studies in maintenance strategy;187
17.1;Introduction;187
17.2;The station and its

operating characteristics;187
17.3;The meintenence strategy in use when the station provided base load;189
17.4;Maintenance

strategy review for two-shift operation;190
17.5;The station and its

operating characteristics;192
17.6;Production and maintenance objectives;192
17.7;Maintenance strategy before privatization;193
17.8;Maintenance strategy after privatization;193
17.9;The plant and its operating characteristics;200
17.10;Maintenance strategy;203
17.11;Observations;204
17.12;The plant and its operating characteristics;205
17.13;Modelling fleet operation and maintenance;206
17.14;Observations;207
17.15;Overhauls and major

repairs;214
17.16;Observations;214
18;Chapter 12. Exercises in maintenance strategy;216
18.1;Introduction;216
18.2;Exercise 1. An aluminium smelter: the anodemaking

plant;216
18.3;Exercise 2. A gold mine milling process;220
18.4;Exercise 3. An alumina refinery;222
18.5;Solution guidelines;224
19;Chapter 13. Reliability Centred Maintenance;228
19.1;Introduction;228
19.2;History and basic philosophy of the RCM approach;229
19.3;The RCM procedure;230
19.4;RCM in civil aviation;236
19.5;RCM in industry;236
19.6;The benefits of RCM;239
19.7;RCM and the TDBU approach;240
19.8;References;240
20;Chapter 14. Total Productive Maintenance – its uses and limitations;242
20.1;Introduction;242
20.2;What is total productive maintenance?;242
20.3;An early case study;244
20.4;Fundamentals of TPM;248
20.5;European applications by non-Japanese companies;252
20.6;Conclusions;257
20.7;References;260
21;Chapter 15. Conclusions;261
21.1;(i) Reliability Centred Maintenance (RCM);261
21.2;(ii) Total Productive Maintenance (TPM);262
21.3;(iii) Business Centred Maintenance (BCM);262
22;Appendix 1 Maintenance terminology;264
23;Appendix 2 In situ repair techniques;265
24;Index;272

Leseproben

2

Plant acquisition policy and maintenance life-cycle costs*

Life-cycle costing

One way of considering the profitability of plant is on the basis of its complete Figure 2.1 models the principal phases of this, and Table 2.1 lists the main cost-influencing factors. The importance of these various phases and factors will vary with the technology concerned, e.g. in power generation fuel costs may be the overriding factor, in petroleum refining the plant availability, in the provision of buildings their anticipated useful life.

Table 2.1

Factors influencing life-cycle profitability

Capital cost

Installation cost and time

Commissioning coat and time

Useful life

Plant performance

Product quality

Plant availability

Production cost

Maintenance cost

Fuel cost

Product demand

Product price

Obsolescence

Table 2.2

Capital Asset Management

Figure 2.1 Plant life-cycle and costs

Figure 2.2 A life-cycle cost profile © H. S. Riddell

Figure 2.3 Factors in the build-up of total life costs © H.S. Riddell

Figure 2.4 Comparison of (a) actual costs and (b) present value costs for LLS and PRS, batch chemical plant

Figure 2.6 Opportunities for maintenance and life-cycle cost improvement © H. S. Riddell

Figure 2.7 Capital asset management control system ©

Investment in the plant occurs from its conception to its commissioning, and perhaps into its early years of operation. If all goes well, the return on this investment begins soon after the plant comes into use and continues until the plant is disposed of. An example of a life-cycle cost profile is shown in Figure 2.2.

The data of this example have been used to plot Figure 2.3, which demonstrates that in some cases the total maintenance cost can be considerably greater than the capital cost.

A company might have as its objective the maximization of its plant’s life-cycle profitability within the constraints imposed by the need for safe operation. Achievement of this would necessitate, among other things, an investment appraisal which sought an economic compromise between such factors as capital cost, running cost, performance, availability and useful life. Figures 2.4(a) and (b) illustrate the use of a life-cycle cost analysis to assist in such an investment appraisal decision.

Capital asset management

Almost invariably, the application of life-cycle cost analysis is rendered difficult by:

(i) the lack of definition of the capital asset acquisition subsystem;

(ii) the complex relationships between the many factors involved in the economic compromise;

(iii) the uncertainty of much of the life-cycle information, i.e. concerning such matters as the projected need for the product, whether and when the plant would become obsolescent, the estimated plant reliability and availability, anticipated costs, and so on.

Because of these and other difficulties the equipment acquisition appraisal is usually dominated by considerations of plant performance and capital cost. Little or no thought is given to reliability and maintainability, the inevitable consequence being that installation and commissioning times and costs will be extended and that plant operation will be dogged by low equipment availability (i.e. high maintenance costs, both indirect and direct).

The question therefore arises as to how this situation can be improved or corrected. Is it via the so-called approach? This evolved in the UK in the early 1970s. It was defined, at first, as follows1:

• A combination of management, financial, engineering and other practices applied to physical assets in pursuit of economic life-cycle costs

A little later, the following was added:

• . its practice is concerned with the specification and design for reliability and maintainability of plant, machinery, equipment, buildings and structures, with their installation and replacement, and with the feedback of information on design, performance and costs.

In short, the idea quite rapidly enlarged from being an approach in which maintenance and unavailability costs were of central importance to one which was much more general, and therefore less tangible. Because of this the concept never took root in British industry.

outlined in Table 2.2, is a more recent approach — preferred by the author — to this area2. It is based on the idea of ‘optimizing total maintenance costs over the equipment life-cycle’. This is best achieved through an understanding of the effects that decisions taken in the plant’s phases can have on the direct and indirect maintenance costs of the phase3 (see Figure 2.5).

Figure 2.5 Factors influencing maintenance costs over the life-cycle

The for new plant must include requirements for reliability and maintainability (i.e. availability) as well as for performance, capital cost and safety. As far as possible, the expected or useful life of the plant should also be specified. In support of this the equipment manuals, drawings, spares lists, spares security-of-supply and training needs should all be specified and, where necessary, this should be included in the contract.

At the stage, reliability, maintainability and useful life are of para-mount importance and should be considered alongside performance. The method of production is particularly important. For example, if a continuous rather than a batch process is adopted, careful consideration should be given to the much higher maintenance costs that inevitably occur. In addition, it must be understood that design-stage considerations of reliability and maintainability can also affect the duration and cost of commissioning. It is self-evident that quality control during the stage will strongly affect the subsequent level of maintenance.

At the stage, maintainability will continue to be an important consideration because it is only then that the multi-dimensional nature of many of the maintenance problems becomes clear.

The stage will not only be a period of technical performance testing but also one of learning — where primary design faults, that might reduce availability, might be located and how they could be designed out. Failure to do this will mean serious maintenance problems and high unavailability early in the operational life. Operating equipment past its useful life stage will result in low availability and high maintenance costs.

Clearly, the best time to influence maintenance and unavailability costs is before the plant comes into use (see Figure 2.6).

• The opportunity for maintenance cost reduction is high at the design stage but drops rapidly — via several key, gateway decisions — to a relatively low level after commissioning.

• It is important that the often conflicting requirements of non-maintenance departments (represented, in Figure 2.6, by the downward-pointing arrows) are balanced against the maintenance requirements (represented by the upward-pointing arrows).

The above arguments suggest the following rules for the effective application of the Capital Asset Management, life-cycle approach to maintenance management.

(i) Decisions to buy new or replacement plant should be based on a present-value life-cycle analysis of costs which should consider both maintenance and unavailability costs, these being estimated, wherever possible, from documented experience.

(ii) The owner–operator of the plant should co-operate with the designer–manufacturer-installer in a full analysis of its reliability, maintainability and safety characteristics. Such an exercise should include assessment of spare part provisioning, of maintenance personnel training and of supplier support systems. The higher the potential costs of maintenance and unavailability the more vital is this exercise.

(iii) The owner–operator should set up a...