New plants in developing countries are typically more modern and efficient than similar plants in traditional manufacturing countries. Low labor and raw materials costs coupled with subsidies allow a competitive advantage. This global competition also results in reduced value of manufactured products. Building competitive plants is often prohibitively expensive and impacts profits negatively long before any benefits are felt.

Increased expectations
Competitive pressures force customers to demand reliable delivery, low costs, and high quality. Increased sensitivity to environmental and safety factors continue to drive costs, particularly in developed countries. Regulatory requirements significantly increase the construction costs of new plants.

Solutions to challenges
Enhanced supply-chain management is getting the right product to the right place, at the right time, and at the right cost. Efficient supply chain management is impossible without reliability information. The best example is in production planning, where loadings cannot be assessed without machine availability data.

Better service to customers
Increasingly, suppliers are integrating production systems with the procurement departments of their customers. Orders for materials should be acted upon automatically to match production forecasts through electronic data interchange. Better customer service demands better knowledge of the production asset performance, including availability, running rate, and quality.

Greater throughput from assets
Manufacturers must find ways of getting more from existing assets. Consequently, greater throughput from assets explicitly demands improved availability.

Integrated information capability
To implement advanced methods, companies must integrate their information systems to a greater extent than in the past. A response has been the emergence of the enterprise resource planning system--a single database software architecture that enables every operational aspect of a company.

Integrated manufacturing
For maximum efficiency, enterprise resource planning systems must be integrated with production control systems. Interfacing software is called the manufacturing execution system. A manufacturing execution system allows optimized production planning in the presence of realistic reliability data.

Reliability becomes key for companies to meet these challenges--a change from the traditional dismissive attitude toward maintenance departments. There is a change of emphasis taking place: from maintenance as a cost that must be reduced--by reducing head-count--to reliability as a value that increases the company profitability. New reliability methods and systems have a significant effect both on overall cost reduction and increased production.

Value of predictive maintenance
Maintenance costs are often characterized as the tip of an iceberg. Direct costs include personnel, spares, and so on. Although they are measured through percent RAV--annual cost of maintenance divided by total replacement cost of equipment--they are also measured through spares stock turns--annual cost of spares divided by inventory value at the end of the year.

With this model, value issues are grouped together as indirect costs and are not usually addressed adequately even though they may be 10 times greater than direct costs.

The value of reliability model addresses production issues directly by focusing on bottom-line benefits of increasing production capacity through increased reliability. The distinction between cost of maintenance and value of reliability can be seen from the results of the program undertaken by one of the country's largest producers of polyethylene. Five sites ran a reliability project over several years, including a critical condition monitoring element. Benefits fell into 3 groups:
 

•  technical: improved predicted equipment failures
•  maintenance costs: overall costs down $10 million, spares down $3 million
•  value of reliability: increased on-stream and prime production (about $35 million per year)

Role of condition monitoring
Computerized maintenance management systems are the tool of most effective maintenance departments. They are the vehicle for implementing the maintenance management strategy and time-based parts of the technical strategy. It is the basis for integration of reliability systems with other systems in the organization.

The software is modular, with each module covering a set of functions sharing information in a common database. Many implementations are plant-wide based on a local and wide area networks. Condition monitoring supplements maintenance software by providing information on the condition of a specific asset. This allows operators to focus on a very small number of machines out of a very large number.

Diagnosis of the probable fault
This information is obtained either through an in-house human expert, with tools provided by the condition monitoring system, through a consultant, or through some automated system based on artificial intelligence or expert system technology.

Prognosis for the fault
Effective condition monitoring demands integration of information from many sources to allow the expert to make the best analysis of the situation. Condition monitoring provides a maintenance advisory event to maintenance software activating corrective activities. A certain level of maintenance advisory data can be provided directly by the condition monitoring system--for example, machines in alarm--complemented by diagnostic and prognostic comments from a human or automated expert.

Selecting equipment
The range of predictive technologies provides cost effective coverage of nearly all plant equipment. The most common is vibration analysis. Vibration analysis is useful on rotating equipment and may be applied in a variety of ways. Hand-held meters provide simple overall vibration levels. These levels are a general indicator of machine condition and can be recorded and trended to observe how the overall vibration is changing over time.

More detailed vibration data can provide greater detection and diagnostic capabilities required for the majority of plant equipment. This data includes the vibration spectrum, time waveform, and phase information. This is critical because it provides additional diagnostic and prognostic information. The vibration spectrum, time waveform, and phase allows identification of specific machine faults and observation of their development. This information is used to plan repairs by identifying the parts and personnel and setting the required repair date.

Vibration spectrum, time waveform, and phase data can be gathered from commercially available instrumentation. This instrumentation consists of data collectors, surveillance systems, and continuous monitoring systems. The information and technology in each of these instrument categories is similar. The difference is how the technology is used.

Surveillance systems automate the data collection process for critical machinery, remote installations, or when the machinery environment is inaccessible or unsafe. Permanent installation of the vibration sensors on machinery and placement of measurement instrumentation nearby achieves this. Each surveillance module has many channels of vibration sensors connected to it. These modules communicate to a personal computer or network to form an efficient, distributed processing system. This provides automated data collection reducing manpower needs.

Continuous monitoring systems offer a higher level of machinery coverage. In a continuous monitoring system, sensors are installed and measurement instrumentation is placed near the machinery. In these systems though, more instrumentation is dedicated to each measurement channel, providing for continuous, uninterrupted data gathering. Many of these systems include protection monitors that evaluate data as it is gathered and respond instantly to indicate alarms and machine shutdown.

The next most widely used technology is oil analysis. Oil analysis applies to lubricated machinery, as well as machinery with hydraulic systems. It may be performed with instrumentation at the plant site or by drawing samples for analysis by a commercial oil analysis laboratory. On-site instrumentation offers the advantages of immediate results and scheduling flexibility. Contemporary oil analysis systems determine contamination levels, ferrous particle content, and viscosity on-site. Laboratory oil analysis techniques supplement this with information about chemical or elemental content of the oil. Oil analysis allows users to extend the useful life of lubricants and to identify mechanical deterioration.

Other techniques include infrared thermography, motor current analysis, ultrasonic thickness testing, and ultrasonic emission detection. The range of technologies is limited by the resourcefulness and skill of the people managing the assets.

Selecting technologies and planning the data collection is based on the demands of the specific plant equipment and process. Reliability centered maintenance is a proven tool for gaining an understanding of this demand. In a reliability centered maintenance analysis, the production process is broken down to its individual steps and the associated machinery. Using this information, the analyst determines the correct maintenance techniques--time based, condition based, run to failure, or design-out. Where condition-based techniques are used, the reliability centered maintenance analysis identifies the appropriate measurements and interval.

Summary
Reliability is key to making production assets more effective. Condition monitoring is critical in total reliability systems, particularly when used with methods like reliability centered maintenance, total productive maintenance, and so on. The goal is integrating enterprise systems by allowing decisions to be made quickly at the lowest possible level. Future systems will add planning and optimization functions to integrated condition monitoring and maintenance software structures. Such systems will communicate critical information to other systems including the control system, the enterprise resource planning system, and management information services.