Maintenance Management

Transcription

1 Maintenance Management 16/11/2016 Emad Elbeltagi 1 Definition Current Practices Types of Failures Agenda Maintenance Strategies Types of Maintenance Repair and Maintenance 16/11/2016 Emad Elbeltagi 2 1

2 Definition Maintenance is the routine and recurring process of keeping a particular asset in its normal condition so that it can deliver the excepted performance or service without any loss or damage 16/11/2016 Emad Elbeltagi 3 Definition Maintenance Management all the activities that determine the maintenance objectives, strategies and implementation by means of maintenance planning, control, supervision and considering economical aspects 16/11/2016 Emad Elbeltagi 4 2

3 Current Practice Maintenance is the actions associated with facilities after it is broken While maintenance should be actions taken to prevent a facility from failing or to repair normal degradation to keep it in proper working order However, data obtained in many studies indicates that facilities owners do not expend the necessary resources to make maintenance in proper working order 16/11/2016 Emad Elbeltagi 5 Current Practice Rather, they wait for the failure to occur and then take whatever actions are necessary to repair or replace the facility Nothing lasts forever and all facilities have predefined life expectancy or operational life For example, equipment may be designed to operate at full design load for 5,000 hours and may be designed to go through 15,000 start and stop cycles 16/11/2016 Emad Elbeltagi 6 3

4 Failures Failure inability to produce work in appropriate manner Equipment / machine failure on production, failure of power supply, air-conditioned system, computer network, photocopy machine Vehicle failure brake, transmission, engine, cooling system Building, bridge, road failure, etc. 16/11/2016 Emad Elbeltagi 7 Types of Failures Failures can be grouped into three categories, understanding these is critical when assigning maintenance tasks: Induced Intermittent Wear out 16/11/2016 Emad Elbeltagi 8 4

5 Types of Failure (Induced) Induced failures are a result of an outside force causing the failure mode For instance, extra loads on a given structure Monitoring may help detect these potential failures Failure must be recognized and analysis performed to determine the root cause As such, we acting proactively and making the transition into a Reliability-Based Maintenance 16/11/2016 Emad Elbeltagi 9 Types of Failure (Intermittent) Intermittent failures can happen at any time "random, time between failures cannot be determined Failures can best detect through process and predictive maintenance monitoring Many plants find that preventive maintenance are not effective in determining the onset of failure in either induced or intermittent failures and, therefore, a waste of capital 16/11/2016 Emad Elbeltagi 10 5

6 Types of Failure (Wear Out) Wear-out failures have a known time between failures and they occur when the useful life of a component is expended These types of failure modes are often detectable through process and predictive maintenance monitoring However, time-based refurbishment usually proves to be the most effective maintenance strategy 16/11/2016 Emad Elbeltagi 11 Failure Against Life Cycle The failure rate against a facility life cycle can be represented as follow: 16/11/2016 Emad Elbeltagi 12 6

7 Failure Against Life Cycle The initial period of the curve is characterized by high failure rate which may be linked to poor design, poor installation, or misapplication The infant mortality period is followed by a nearly constant failure rate period known as useful life There are many theories on why components fail in this region, most acknowledge that poor O&M often plays significant role 16/11/2016 Emad Elbeltagi 13 Failure Against Life Cycle It is also generally agreed that exceptional maintenance practices encompassing preventive and predictive elements can extend this period The wear-out period is characterized by a rapid increasing failure rate with time In most cases this period encompasses the normal distribution of design life failures 16/11/2016 Emad Elbeltagi 14 7

8 Maintenance in Service Industry Hospital Restaurants Transport companies Banks Hotels and resorts Shopping malls / retail Gas station 16/11/2016 Emad Elbeltagi 15 Questions? Why do we need maintenance? What are the costs of doing maintenance? What are the costs of not doing maintenance? What are the benefits of maintenance? How can maintenance increase profitability of company? 16/11/2016 Emad Elbeltagi 16 8

9 Maintenance Objectives Ensure that facilities and their associated services are in a safe condition Ensure that facilities are fit to use Ensure that the condition of the facilities meets all statutory requirements Maintain the value of facilities stock Improve the quality of a facility 16/11/2016 Emad Elbeltagi 17 Maintenance Strategies Maintenance can be divided into the following strategies: Reactive (day-to-day repair) Preventive, which includes cyclic and condition-based maintenance Predictive, modernization and maintenance which include additional works needed as a result of new legislation and regulations 16/11/2016 Emad Elbeltagi 18 9

10 Maintenance Strategies (Reactive) Reactive maintenance is basically the run it till it breaks maintenance mode No actions or efforts are taken to maintain the facility to ensure design life is reached Studies indicate this is still the predominant mode of maintenance in the United States, more than 55% of maintenance resources and activities of an average facility are still reactive Emergency or nonplanned 16/11/2016 Emad Elbeltagi 19 Maintenance Strategies (Reactive) If our maintenance program is purely reactive, we will not expend manpower dollars, we could view this period as saving money In reality, during the time, we are spending more dollars associated with capital cost because, while waiting for the facility to deteriorate, we are shortening the life of the facility resulting in more frequent replacement 16/11/2016 Emad Elbeltagi 20 10

11 Maintenance Strategies (Reactive) Advantages Low cost Less staff Disadvantages Increased cost due to unplanned downtime of a facility Cost involved with repair or replacement of components Possible secondary damages from failure of main components Inefficient use of staff resources 16/11/2016 Emad Elbeltagi 21 Maintenance Strategies (Reactive) Breakdown maintenance, in this system the facility is allowed to function / operate till no failure occurs; ie no maintenance work is carried out in advance to prevent the failure As long as the facility is functioning at a minimum acceptable level, it is assumed to be effective This approach is ineffective and extremely expensive due to: poor planning and incomplete repair 16/11/2016 Emad Elbeltagi 22 11

12 Maintenance Strategies (Preventive) Preventive maintenance is a maintenance program committed to the elimination or prevention of corrective and breakdown maintenance A comprehensive preventive maintenance program involves periodical evaluation of critical equipment to detect problems and schedule maintenance tasks to avoid degradation in operating conditions Planned or scheduled 16/11/2016 Emad Elbeltagi 23 Maintenance Strategies (Preventive) Preventive maintenance defined as actions performed on a time or run-based schedule that detect or mitigate degradation of a component or system with the aim of sustaining or extending its useful life through controlling degradation to an acceptable level Expending the necessary resources to conduct maintenance activities intended by the designer, life is extended and reliability increased 16/11/2016 Emad Elbeltagi 24 12

13 Maintenance Strategies (Preventive) Dollars are saved over that of a program just using reactive maintenance Studies indicate that this savings can amount to as much as 12% to 18% on the average Preventive maintenance will run facility more efficiently resulting in dollar savings While we will not prevent catastrophic failures, we will decrease the number of failures 16/11/2016 Emad Elbeltagi 25 Maintenance Strategies (Preventive) Advantages Cost effective in many capital-intensive processes Adjustment of maintenance periodicity Increased component life cycle Reduced equipment or process failure Disadvantages Catastrophic failures still likely to occur Includes performance of unneeded maintenance Potential for incidental damage to components in conducting unneeded maintenance 16/11/2016 Emad Elbeltagi 26 13

14 Maintenance Strategies (Predictive) Predictive maintenance is a management technique that uses regular evaluation of the actual operating conditions of equipment, production systems to optimize total operation Condition-based or reliability 16/11/2016 Emad Elbeltagi 27 Maintenance Strategies (Predictive) Predictive maintenance defined as measurements that detect the onset of system degradation (lower functional state), thereby allowing causal stressors to be eliminated or controlled prior to any significant deterioration in the component physical state Results indicate current and future functional capability 16/11/2016 Emad Elbeltagi 28 14

15 Maintenance Strategies (Predictive) Basically, predictive maintenance differs from preventive maintenance by basing maintenance need on the actual condition rather than on some preset schedule Preventive maintenance is time-based Activities such as changing lubricant are based on time, no concern is given to the actual condition and performance capability of the oil It is changed because it is time 16/11/2016 Emad Elbeltagi 29 Maintenance Strategies (Predictive) Unusual sounds coming out of a rotating equipment predicts a trouble An excessively hot electric cable predicts a trouble Simple hand touch can point out many unusual equipment conditions and thus predicts a trouble Cracks on the Skelton of a buildings or steel rust show problems that need to be fixed 16/11/2016 Emad Elbeltagi 30 15

16 Maintenance Strategies (Predictive) Advantages Predictive maintenance is used to define needed maintenance task based on quantified condition Eliminate catastrophic failures Allows for preemptive corrective actions Decrease in equipment or process downtime. Decrease in costs for parts and labor Better product quality 16/11/2016 Emad Elbeltagi 31 Maintenance Strategies (Predictive) Disadvantages Increased investment in diagnostic equipment Increased investment in staff training Savings potential not readily seen by management 16/11/2016 Emad Elbeltagi 32 16

17 Maintenance Strategy Model Different dimensions should be looked at when planning maintenance work 16/11/2016 Emad Elbeltagi 33 Maintenance Strategy Model (Decision Diagram) 16/11/2016 Emad Elbeltagi 34 17

18 Types of Maintenance Other View 16/11/2016 Emad Elbeltagi 35 Types of Maintenance Maintenance Decision 16/11/2016 Emad Elbeltagi 36 18

19 Repair Generally, the maintenance scheduling embraces the following activities: Inspection Repair Overhauling Hence the term repair reflect the time duration consumed to perform the corrective action Based on the time the repair may be minor like adjustment of something or major 16/11/2016 Emad Elbeltagi 37 Repair and Maintenance Repairs Repair activities are reactive Breakdowns and malfunctions occurs when system in use Cost is high Preventive Maintenance Based on regular scheduled inspection Performed before failure and during ideal time 16/11/2016 Emad Elbeltagi 38 19

20 Repair and Maintenance Trade-off between Repair and Maintenance At minimum level of preventive maintenance (remedial policies) Do repair only when breaks occur Cost of breakdowns, interruptions of service and repair is high As the preventive maintenance efforts increased, breakdown and repair costs decreased At some point, the total maintenance cost reached its minimum value 16/11/2016 Emad Elbeltagi 39 Repair and Maintenance Trade-off between Repair and Maintenance Annual Cost Minimum Level of Preventive Maintenance Low Minimum Total Maintenance Cost Total Maintenance Costs Preventive Maintenance Cost Breakdown and Repair Cost Degree of Preventive Maintenance High 16/11/2016 Emad Elbeltagi 40 20

21 Repair and Maintenance How Speedy Should Repairs Be? Cost Minimum Total Cost of Repairs 0 Slow Speed of Making Repairs Fast Cost of Repair Crews & Spare Parts Cost of Interruptions to Service 16/11/2016 Emad Elbeltagi 41 Structural Health Monitoring SHM is defined as the use of in-situ, nondestructive sensing and analysis of structural characteristics, including the structural response, for detecting changes that may indicate damage or degradation It is a move from visual inspection to data collection base inspection and monitoring 16/11/2016 Emad Elbeltagi 42 21

22 Structural Health Monitoring Basic components of SHM 16/11/2016 Emad Elbeltagi 43 Structural Health Monitoring SHM aims to provide quantitative data on the real conditions of a structure and detect the appearance of degradations By installing a number of sensors, continuously measuring parameters relevant to the structural conditions and other environmental parameters SHM can be used for load estimation (e.g. traffic, wind) and validate design assumptions regarding the static and dynamic behavior of structures 16/11/2016 Emad Elbeltagi 44 22

23 Design for Life-Cycle The promotion of a design that decreases a facility cost over its life-cycle The ASCE is currently preparing guidelines for promoting design for life-cycle The life cycle cost (LCC) of an asset is defined as the present value of the total cost of that asset over its operating life, including initial, occupation, operating costs, and the cost or benefit deriving from disposal of the asset at the end of its life 16/11/2016 Emad Elbeltagi 45 Design for Life-Cycle The broad objectives of a life cycle costing may be: To enable more effective investment decisions, taking into account all costs that may arise from it To consider the impact of all costs, rather than just capital costs Too provide information that can contribute to the more effective management of the completed facility To assist in the evaluation of alternative solutions to specific design problems 16/11/2016 Emad Elbeltagi 46 23

24 Design for Deconstruction The usage and end of life impact of construction activities on the ecosystem are to be accessible at the design stage Design activities must be beneficial to the ecosystem during building usage and end-of-life The focus of AEC practitioners has shifted from the traditional methods of end-of-life building disposal to modern methods such as deconstruction 16/11/2016 Emad Elbeltagi 47 Design for Deconstruction DfD could serve multiple purposes, material recovery for building relocation, component reuse, material recycling and remanufacture DfD are more concerned with building relocation and component reuse rather than recycling or manufacturing More challenge is to design buildings that can be deconstructed and its components reused with minimal reprocessing 16/11/2016 Emad Elbeltagi 48 24

25 Design for Deconstruction DfD Factors 16/11/2016 Emad Elbeltagi 49 25