Archive | January, 2005


8:04 pm
January 1, 2005
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Common-Sense CMMS: Combine Software and Handhelds

A computerized maintenance management system (CMMS) is an essential operational and management tool for managing asset preservation, ensuring that production systems operate as required, and minimizing downtime. An effective CMMS should be able to support these functions by automating administrative tasks, as well as by gathering relevant information in order to perform these processes. A CMMS also needs to be able to manage a strategic plan for proper maintenance, replacement, and upgrade of major assets.

If you do not have a CMMS, should you be considering one? If your organization has a CMMS, are you optimizing its benefits and its return on your investment?


Technician at tier-1 automotive manufacturing facility uses a handheld to verify data input, suggest possible outcomes to a task, suggest a course of action, or print a report.

Why use a CMMS?
The primary purpose of a CMMS is to manage, capture, and track inspection, maintenance, and repair activities of an organization. In real terms, most CMMS solutions perform the basic function of providing work orders to cover repairs and maintenance of buildings, plant, and equipment. They provide a scheduling facility for maintenance for planned preventive work on maintainable assets. And they also generally collect costing details for the labor and materials related to the work performed.

However, advanced CMMS solutions also can improve many other aspects of daily activities, as well as provide the tools to understand and analyze maintenance and repair processes and trends. They can eliminate manual data entry; incorporate alerts, triggers, and escalation procedures; and shift the focus from unnecessary administrative tasks to performing maintenance activities. They also can assist in planning and predicting future needs, prolonging the life expectancy of assets, and managing processes.

Combining CMMS software with proven technologies such as handheld devices and personal digital assistants (PDAs) can substantially increase the realized benefits from a CMMS solution:

• Incorporate barcodes to increase accuracy and efficiencies
• Update information electronically, eliminating unnecessary paperwork and data entry
• Capture timestamps and signatures
• Provide maintenance personnel, engineers, and inspectors with electronic intelligent work orders
• Automatically track and manage inventories and timesheets
• Equip staff with easy-to-use tools that enable them to focus on their expertise and work activities, rather than on administrative tasks and paperwork.

Justifying the need
The first consideration in choosing a CMMS is whether to keep maintenance information in a computerized database. Some will say that it depends on the size of the organization and its assets. Others will say that it depends on the number and quality of staff available to resource the CMMS. Also there are those who would argue that it can all be done on paper.

Only a well-designed and easy-to-use CMMS solution can improve daily activities as well as index and sort through years of information related to the maintenance, cleaning, and strategic planning of buildings, plant, and equipment. In reality, regardless of the size of an organization, it needs to maintain a database of the work performed. Automation includes improvement of daily activities, automatic tracking of inventories, better work assignments, and shift of focus toward exceptions, not routine matters.

Breakdown maintenance
It could be that the entire maintenance plan is one of breakdown maintenance. Breakdown maintenance defers repairs and allows damage to accumulate, compounding an organization’s problems. On the other hand, regularly scheduled equipment inspection and maintenance not only prevent sudden and unexpected equipment failure, but also reduce the overall cost of the building and equipment.

The management of these programs, in particular reporting their current status and future needs, requires a CMMS. Managing the operation of on-site maintenance staff and contractors is a daunting and difficult task; however, if there is a corresponding record in the CMMS then tracking and management is much easier.

Even if you are duplicating data that is in your contractor’s CMMS, it is extremely important to have your own copy of data. The contractor may cease to exist and for the sake of future reference and reporting it is essential you have your own CMMS populated with your own data.

What should be captured?
Further consideration should be given to what information you want to keep, and, more importantly, what has to be kept.

In addition to manufacturers’ specifications and management requirements, there are statutory requirements and regulations that impact this question including fire, health and safety, and environmental legislation.

Statutory requirements could be entered into a CMMS as a scheduled maintenance plan with labor, materials, and costs for projecting estimated future costs. By keeping a corresponding record in the CMMS and using the job number as a cross reference to the paper record, the organization is able to quickly report on the status of statutory work in preparation for annual signoffs and/or audits.

Those who have had workplace safety audits are aware that the first question asked is “Where are the maintenance records?” A maintenance plan that includes estimated costs can be compared with the actual costs to ensure the effectiveness in the cost of asset preservation.

Using PDAs
Additional considerations include the use of handheld devices. By extending the use of standard PDAs to business applications or using handheld devices with mobile-based operating systems, users can quickly improve their daily activities.

Handheld devices can verify data input, suggest possible outcomes to a task, suggest a course of action, or print a report. They also can automate specific processes, include information about assets and equipment, automate inventory cycle count processes, and provide easy-to-navigate functionalities, minimizing keystrokes and maximizing productivity.

Selection process
So how does one start looking for the right CMMS package?

• Look within your own organization and determine what is happening with the maintenance and inspection functions. Check if there is an existing maintenance program in place; check its functions and who manages the information-gathering process.

• Determine what maintenance is required to be performed on the building, plant, and equipment in the facility.

• Prepare a brief of the facility’s minimum and optimum requirements for a CMMS, the resources to manage the database, and time frame for implementation.

• Research three to five providers. Have them present their product to assess the package in terms of ease of use, functionality, and ability to meet your requirements.

• Evaluate each proposal for specific CMMS functionalities:
–Does it address your specific requirements?
–Does it minimize unnecessary or duplicate data entry?
–Can it automate administrative tasks, reminders, and notifications of upcoming events?
–Does it have built-in dynamic escalation procedures?
–Can it incorporate inspections and other activities in the CMMS?
–Can it manage and track inventories?
–Is there an ability to collect requests for work to be done directly into the CMMS via electronic means such as PDAs or Web portals?
–Is there the ability to transfer work assignments to technicians via electronic means?
–What is its return on investment?

This is a simplistic approach to the selection process; however, it will give most managers a good starting guide to the selection of a CMMS.

Information provided by Eitan Shibi, president, Techs4Biz Corp., 60 Columbia Way, Ste. 300, Markham, ON L3R 0C9; telephone (800) 361-8725

Benefits of Using Enhanced CMMS Solutions

• Guarantee that all required tasks and activities are completed on time.

• Incorporate various mechanisms to ensure execution of tasks, including auto- matic listing of activities, reminders, alerts, escalation procedures, and easy access to information.

• Improve reporting and analysis capabilities.

• Comply with health and safety regulations.

• Improve strategic and business planning and make informed decisions; ana- lyze records, needs, and patterns.

• Improve operational efficiencies.

• Increase productivity and profitability.

• Perform activities effectively; simplify repeatable tasks; provide staff with easy- to-use tools that focus on performing tasks.

• Allow staff to spend more time performing service activities and less time on paperwork and data entry.

• Identify trends and highlight potential problem areas.

• Improve controls and accountability, leading to better quality of work.

• Ensure that service is performed according to warranties, guidelines, and reg- ulations.

• Receive customized reports delivered to e-mail.

Additional benefits come with using handheld devices in comparison with manual or paper-based processes: minimizing errors, increasing accountability, and having the ability to quickly turn data into useful information.

Solutions must be cost effective and providers must be able to demonstrate their business case and return on investment.

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6:00 am
January 1, 2005
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How Much Reliability Can You Afford?

0105hillmanSome months ago I was working in the building products industry. The company for which I worked saw a need for their maintenance managers to have a better understanding of equipment asset management and reliability. We contracted for training through a well-known training company. The instruction was very good and we all gained much knowledge from the training.

However, there was one comment made by the instructor of the training company that left me scratching my head. During one of the training sessions a student asked the instructor how far we needed to go with reliability. His answer was “How far do you want to go? How much can you afford?”

I am now in business doing training in asset management and predictive maintenance technologies and I frequently hear similar statements concerning reliability.

Many times I have maintenance managers tell me that the reliability talk all sounds good but their companies can’t afford to spend big bucks on reliability. Sometimes their comments are something like, “It would cost us too much to get there.”

Another comment that I frequently hear is, “We aren’t ready for reliability. We have other maintenance issues that we need to take care of first.” These last two statements are like saying “we need to get well before we visit the doctor.”

I see these comments as a fundamental misunderstanding of the value of pursuing reliability. Trying to determine how much reliability you can afford or how much it would cost to get your assets to a certain level of reliability is the wrong approach. A proper way to look at the issue is to look at your goals and let these goals decide the needed levels of asset reliability.

If we look first to our goals, the fundamental question is no longer “How much reliability can we afford?” The question now becomes “How much reliability do we need to reach our goals?”

Suppose we have a goal to increase company profits by a certain percentage. What is the reliability level that we require of our equipment assets in order to reach this profit goal? When looked at in this light it is easy to see that reliability doesn’t have a cost. Reliability is an investment that generates profits.

I am not saying or even implying that there won’t be some up front costs incurred in improving plant reliability. Improvement costs will be largely determined by the added reliability required and the condition of the equipment assets when the improvement initiative is implemented.

If only a small increase in reliability is needed to meet profit goals and the assets are already in fairly good condition, the costs may be small. If a large increase in reliability is needed and the equipment is in very poor condition, the costs may be much larger.

Some companies don’t have the discipline or courage to get over the “hump” of the initial investment in order to reap the big rewards of good equipment reliability. These companies are the ones whose people say “We tried reliability but it doesn’t work with our processes because we are different.”

A good counter to my argument that reliability doesn’t cost would seem to be in the area of redundancy. Redundant equipment can sometimes add a certain amount of reliability to a process. This redundancy comes with the added cost of purchasing two assets to perform the function of one.

Let’s suppose that your company would like to add a back-up pump to a production process in order to increase the reliability of the process. There is no denying that the additional pump and its installation will cost money. You are adding the pump to increase reliability, so reliability costs money, right? If the costs incurred by adding the back-up pump are more than the increase in profitability due to the increased reliability, you probably didn’t need to add the pump. The reliability wasn’t needed.

We don’t pursue reliability because it’s fun or because we are told that reliability is the way to go. Nor should we pursue reliability to achieve best in class or the much talked about world class status. We pursue reliability in order to meet our profit goals.

How much reliability do we need? We need just enough to meet our profit goals.

How much reliability can you afford? If reliability costs you money, you don’t need reliability.—Bill Hillman

Bill Hillman, CMRP, is managing partner of Asset Management Specialists Co. His equipment asset management career spans 30 years in the steel industry and 6 years in the wood products industry, the last 20 of which has been in predictive maintenance. He has been certified in lubrication, infrared, vibration, ultrasonic, and magnetic particle testing technologies.

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6:00 am
January 1, 2005
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The Voice of Experience


Robert C. Baldwin, CMRP, Editor

Last month, I had the opportunity to meet with two practitioners whose knowledge and judgment I respect. Both have significant experience in the maintenance and reliability field and have made significant contributions to the body of knowledge.

One was Charles Latino, perhaps the first person to institute equipment reliability practice in a major industrial company. The other was Jack R. Nicholas, Jr., one of the early practitioners of reliability centered maintenance. Both shared some ideas they believe fundamental to success.

I spoke with Latino at the offices of The Reliability Center (, Hopewell, VA, a company he founded 20 years ago when he entered private practice as a teacher and coach for equipment asset reliability.

I met with Nicholas, CEO of Maintenance Quality Systems, who is developing an approach for evaluating RCM activity, at the International Maintenance Conference in Florida where he delivered the keynote address.

Both conversations, which took place within a couple days of each another, touched on some of their work experience and included key factors they deemed important for success. Here are some of the points that stuck in my head:

  • Lasting solutions to reliability problems come from paying attention to detail and using proven methods for systematic identification and analysis of reliability issues.
  • Many of the latent causes of equipment failure can be traced to management policy decisions such as emphasizing speed over quality in repairs and failing to invest in skills training.
  • Many elegant solutions lie hidden because workers fear to come forward with suggestions. They don’t want to get in trouble for mistakes or errors, or get their coworkers in trouble.
  • Technology is a tool rather than a solution. Too many companies reach for the technology without developing the process first.
  • It is important to minimize intrusive maintenance because it leads to the infant mortality failure profile, the most common type. If it ain’t broke, don’t fix it.
  • Invest in the development of written procedures for precision maintenance to help insure that work is done right the first time, every time. Workers retire and leave, but the procedures remain.

We will be bringing you more helpful exprienced-based information from these two practitioners and others this year. I hope you also will share your experiences with the maintenance and reliability community in e-mails, conversation, and articles so all can gain from your voice of experience. MT


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6:00 am
January 1, 2005
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Using Pareto Analysis to Focus Reliability Improvements

This approach helps uncover reliability problems obscured by the volume of plant work requests.

Progress Energy’s Harris nuclear power plant in New Hill, NC, is taking a proactive approach to identify and improve equipment performance. Power plants such as Harris have more than 100,000 components. Personnel perform thousands of maintenance activities annually.

With large organizations and personnel turnover, many equipment reliability issues can go unnoticed or even become “expected” maintenance. It is not always easy to identify equipment that degrades prematurely when it occurs over many years with different people involved.

All plant components require some level of maintenance over time. Some contribute more than others to the maintenance workload. To minimize operation and maintenance costs, plant equipment needs to operate at a maximum maintenance interval. Harris’s Component Engineering group is employing a simple statistical method known as a Pareto analysis that, when applied to maintenance work requests, can identify the equipment that contributes the most to the plant maintenance work load.

Conducting Pareto analysis
A Pareto analysis is conducted by adding the number of work requests for each component type over the time frame of interest. When ordered by the count of work requests for each component, the analysis identifies the “vital few” components that contribute the most to plant maintenance and distinguishes them from the “trivial many” that have a small contribution. The objective is to then take action to reduce the vital few into the trivial many.

Work requests from 2001-2003 were reviewed at Harris and sorted by equipment type. The counts for equipment that comprised 40 percent of all maintenance performed at the plant over the 3-year period are shown in Fig. 1.

There are several hundred equipment types in use at the plant. The benefit of this systematic breakdown is a focused review of a limited number of components. In this case, nine equipment types were involved: Isolation valve, panel, pump, door, fan, motor, pneumatic operator, relief valve, and breaker.

Break down by manufacturer, model
The work requests for a specific equipment type are reviewed then by manufacturer and model. The information for one equipment type, fans, is illustrated in Fig. 2.

Of the 58 fan models at Harris, eight models required nearly 50 percent of the fan maintenance work during the 2001-2003 period. Again this systematic breakdown permits a focused review of a manageable number of fan applications.

Of the 14 work requests on the model SZ-3024 fans (a centrifugal belt driven fan), 36 percent were triggered by vibration and 64 percent by loose belts (Fig. 3). A study of corrective maintenance work orders revealed that bearings had failed.

The cam-lock style roller element bearings were failing on an average of every 2-3 years compared to their L10 design life of 12-15 years. A thorough review was conducted of the maintenance practices for belt and bearing replacements, the preventive maintenance strategy employed on the fan, and the design of the fan.

Discussions with the bearing manufacturer identified a problem with the site maintenance practice which did not require relocking the collar of the bearing after the run-in of fan belts. Additionally, a more reliable bearing was identified for the application that is expected to improve the overall reliability of the fan. The result of these improvements will reduce fan maintenance at the Harris plant by $21,900.

Do same for isolation valves
The same systematic approach was used for isolation valves. Since initial plant operation in 1987, Harris has experienced repeated position indication (i.e., dual indication or loss of indication) with a particular manufacturer’s solenoid valves. The solenoid valves use a reed switch assembly and a magnet mounted on the valve stem to actuate open or closed lights on the main control room panels.

Over the years various root cause analyses focused on the switch assembly and maintenance practices for adjusting the reed switches. Modifications to the reed switch bracket and enhancements to the maintenance procedures did improve reliability. However, a significant number of these position indication problems were still occurring.

A Pareto analysis (Fig. 4) of position indication failures by valve model number was conducted over a 10-year period from 1994-2003. Three models were responsible for 75 percent of the problems. Recognizing this permitted a focused comparison that identified the same three models had a relay in the position indication electrical circuit. The other models did not have the relay.

Mock-up testing verified the relay was causing excessive voltage spikes across the reed switch contacts that resulted in electrical arcing. Over time, the condition would result in micro-welding the reed-switch contacts together thus producing a malfunction of the position indication. The solution was to install a low cost varistor for voltage suppression that will eliminate the electrical arcing. The expected savings in maintenance is $68,000.

Focus the investigation
In both of these examples the Pareto analysis provided a systematic breakdown of work requests to focus on the vital few components that have the highest contribution to plant maintenance. The further breakdown of this data by equipment model number and the cause of the equipment degradation focused available resources on a limited number of applications that required investigation. The investigation of the corrective maintenance procedures, preventive maintenance strategies, and equipment design revealed equipment that was not operating at the optimum maintenance interval.

The Pareto analysis was effective at uncovering the equipment reliability problems. Once the problem is recognized, a solution can be formulated. The systematic application of a Pareto analysis resulted in improved equipment reliability and reduced equipment maintenance.

Daryl R. Gruver is supervisor, component engineering, at the Harris plant of Progress Energy, 5413 Shearon Harris Rd., New Hill, NC 27562; (919)-362-2820



Fig. 1. Breakdown of work requests by equipment type.

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Fig. 2. Breakdown of fan work requests by model number.

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Fig. 3. Breakdown of fan work request triggers for model SZ-3024.

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Fig. 4. Breakdown of solenoid valve position indication failures 1994-2003 by model number.

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6:00 am
January 1, 2005
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Asset Management and Contingency Planning

Maintenance and service managers’ role in providing for emergencies serves day-to-day operations as well.

The attack on U.S. soil in 2001 and ensuing national security alerts around the world drove home the need to improve contingency planning, business continuation, and crisis management. The unexpected continuously taxes the resources of governments and enterprises, yet those organizations are still poorly prepared to respond to such incidents because they focus almost exclusively on cost and efficiency rather than agile response to unplanned events. The ability to respond quickly and effectively in emergencies is the best measure of our readiness to absorb a sudden loss.

By virtue of training and skills, managers responsible for property, plants, technology, fleets, and public infrastructure are well suited to play a central role in managing the risk associated with unexpected impairment of assets and production capacity. How? By focusing on the agility of their business processes, and not just their cost and efficiency.

Enterprises and government agencies must re-examine five core maintenance processes for their ability to recover quickly from unexpected disruptions. Otherwise, those organizations assume additional operating risk most can ill afford. The prescriptions offered not only help to ensure business continuation in emergencies, they can enhance day-to-day operating performance as well.

Managing failure is managing risk
Asset managers know that everything fails and that their role is to manage failure at minimum cost. Preventing all failure is no more likely than eliminating all risk. Accomplished maintenance and service managers understand that planning, predicting, and responding quickly to the unexpected is the surest way to achieve the service levels expected of them.

An often-overlooked component of effective asset life cycle management is contingency planning. Managers plan for and try to predict equipment failure before it happens. They squeeze supply and contracting budgets to eliminate waste. They train personnel to make them more efficient. They prolong effective asset life without undue disruption to operations. It is a tremendous balancing act and much more than a necessary evil the way it is sometimes treated.

Delivering service, whether in-house or as a business, involves the same five core processes. To be fully optimized, those processes must be cost effective, efficient, and agile. Here we look at how to make them more agile—that is, better able to respond quickly and effective when the unexpected happens.

Process 1: Asset documentation
No company operates effectively without extensive information about the technical and financial attributes of its assets including documents such as process maps, system hierarchies, and physical layouts. Engineering bills of material and spares catalogs are needed for troubleshooting and repair.

Asset information is presented by way of drawings, schematics, instructions, checklists, and specifications. Equipment manufacturer and engineering design information is supplemented in time by service and safety bulletins and fault histories. The terms of equipment warranties and service contracts and budgets and operating costs complete the asset documentation picture.

Agile asset documentation insures that such information is available on demand. At a minimum, this means secure asset information in one place, accessible by anyone in the organization. When production capacity is disrupted, asset information in one place means that an organization can quickly assess its loss as well as its ability to re-allocate resources and recover. In daily operations, globally available asset information gives rise to sharing best practices among geographically dispersed locations.

Process 2: Service supply chain
Supplying a maintenance or service organization requires accurate demand forecasting, a streamlined requisition and approval process, and effective sourcing and procurement of indirect materials and services. Efficient in-bound logistics, materials stores, replenishment, and reconditioning also are needed, not to mention supplier performance measurement.

The agile service supply chain is not dependent on fragile, sole sources of supply. When a supplier is affected by the unexpected, maintenance and service operations are disrupted and revenue may be lost. Even when it means sacrificing some bargaining leverage or additional capital investment, agility means having choices in a pinch. A few years ago, rolling power outages in California left many operations without enough energy to deliver their products and services. Strong supplier relationship management, sophisticated indirect materials sourcing strategies, and optimized stores stocking policies are required for a truly agile service supply chain.

Process 3: Service network management
Nobody does all their own maintenance because it is no more cost effective to hire every technical skill than it is to stock every spare part that might ever be needed. Every maintenance organization, as well as every equipment service business, must occasionally procure services and manage those third parties. Managing such a service network requires not only good service sourcing, procurement, and vendor performance measurement capabilities but also seamless contractor dispatching and tracking of work status, time, expenses, and claims. Ideally, in-house and service provider operations intertwine in ways that allow them to share resources such as tools and stores to minimize costs.

Managing a service network for agility is about responsiveness and accuracy. When disruptions occur, what is your ability to switch providers quickly without errors? For example, electric power companies have a very sophisticated service network that extends well beyond their immediate locale. When four hurricanes hit Florida in a single season last year, electric grid operators from over a thousand miles away responded to restore power according to standing arrangements. Considering the health and safety issues associated with the loss of public services, service network management may be one of the most critical processes of all for a utility.

Process 4: Service incident processing
Whether raised by a call center, a device alarm, a schedule, a meter, or a technician’s report, service requests raise a host of questions that must be answered efficiently.

Does the request represent a revenue opportunity or entail a contracted service-level requirement? Can it be resolved immediately or must we commit additional resources? Does it fit a known fault profile, require reverse logistics, an appointment, or a subcontracted resource? What are my technical skills and depot capacity constraints? All of these questions and more must be answered before any repair, inspection, replacement, or recovery action can be scheduled.

Agile incident processing is the ability to handle any kind of request at any entry point. Rather than a hodgepodge of call centers, help desks, maintenance dispatchers, and property management offices (or their self-service equivalents), the agile maintenance enterprise can profile, resolve, and/or dispatch the full gamut of service, support, and maintenance requests. Like asset documentation, agility of this kind requires necessary information in one place, secure but readily accessible by everyone. When operations are disrupted in one department or location, others can quickly pick up the slack. In daily operations, a 360-deg view of service requests, resources, and commitments also facilitates outsourcing and efficient dispatch.

Process 5: Workforce management
Once dispatched, efficient and cost-effective workforce management entails planning, estimating, and approval either on a job-by-job basis or with more involved project management techniques. Prior to issuing the first work order, we must address safety, hazards, permitting, and regulatory compliance. We must identify specific resources, often in crews that may include specialized equipment, tools, and contractors.

After the make up of labor and materials requirements is determined, we must coordinate the work with plant operating schedules, occupancy constraints, and public access needs. All the while, supervisors must attend to technician training and certifications tracking to insure work quality and compliance. And when work is finally completed, extensive reporting is required.

We facilitate workforce agility by enhancing technician knowledge on the ground. A tremendous amount of experience is locked up in workers’ heads. Capturing that information and reporting it out as useful, context-sensitive business intelligence gives supervisors much more flexibility in choosing specific resources. When the most qualified technician is not available, another will do because he is supported by excellent information.

This is not the business intelligence of the off-line, data-warehouse variety but real-time information. Workforces benefit most from knowledge of events and patterns that may have occurred only days or hours ago. Knowledge delivered daily to the shop floor or field makes a service workforce agile.

Foster agile maintenance and service practices
There are three initiatives that every maintenance and service organization can undertake which will improve its ability to handle operational threats and the unexpected:

• Consolidate and secure asset information in one place
• Develop an inside-out view of resources and commitments
• Enhance service supply chain resilience

Consolidate and secure asset information in one place. Aside from making it much easier to disseminate and enforce maintenance best practices, consolidating asset documentation in online repositories makes it possible to secure and replicate important documentation so that it is available when critically needed. Companies that rely too much on what is in people’s heads are ill prepared to replace that knowledge quickly.

Replacing a single piece of equipment is one thing. Re-constituting an entire plant process is quite another. If either the people or the information has been lost, such a task can be lengthy, costly, and painful to the business.

Develop an inside-out view of resources and commitments. Knowing your resources and the commitments against them, not only for in-house but also throughout your network of service providers, does not just improve service levels generally. It also allows you to divert work quickly back and forth between network and in-house resources when disruptions occur in one or the other.

Even in the best of times, you cannot go it alone. In an emergency, there may be nowhere else to turn besides the service network. Make certain that they are engaged in and familiar with your operations. Best of all, manage the service network with self-service and collaboration capabilities so that service providers can swing into action on their own, accurately and effectively, when your own operations have been disrupted.

Enhance service supply chain resilience. Rather than being satisfied with the lowest nominal cost, seek the best value from suppliers including those times when supply lines are unexpectedly compromised. Sacrifice a little bargaining leverage to insure back-up sources, not only to deal with temporary shortages, but also to insure reliable supplies when needed.

Rather than potentially fragile sole-sourcing, rotate preferred providers regularly. Cultivate multiple suppliers’ familiarity with your operation and unique needs. Develop contingency labor and materials sourcing agreements with key vendors including terms and conditions for emergency as well as everyday response. That way, you will always be in a position to adjust quickly when either you or an individual supplier is affected by an unexpected event.

How agile are you?
How would you assess your current level of agility? Do you focus on cost and efficiency at the expense of improving your ability to adjust quickly in emergencies? Is your business vulnerable to security threats and unexpected events either in-house or in your service network and supply chain?

Is asset information consolidated, replicable, secure, and accessible quickly from any part of the organization? Do you have a complete view of both in-house and service provider resources and commitments? Is your service supply chain robust enough to withstand the loss of a key supplier or to support your operation in the event that critical stores were suddenly lost?

Agility is not free. But the cost of agility is a reasonable hedge against disruptions caused by unexpected events. Purchasing agility requires balancing its cost against the production margin, occupancy, and public access that it insures.

A nation is as secure as the ability of its enterprises and government agencies to absorb catastrophe with minimum disruption. Are you doing your part in that effort?

Milton Bevington is senior director, enterprise asset management, and Hemant “Sunny” Gosain is director, enterprise asset managment, for Oracle Corp., 500 Oracle Pkwy., Redwood Shores, CA 94065; (650) 506-7000

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6:00 am
January 1, 2005
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Condition Based Operations for Manufacturing

Open OpenO&M Framework is the key. It is an open integration solution facilitating the sharing of information among all plant information systems, including maintenance, reliability, and asset management functions.

Manufacturing companies are continually striving to achieve and maintain a high level of operational excellence. Operational excellence requires continual improvement of a company’s manufacturing operations, driving them to become increasingly lean and agile.

To meet the goals of operational excellence, manufacturers must be able to fully utilize the information in all of their control and information systems. Achieving this level of utilization requires the ability to easily integrate various control and information systems. Significant advances supporting information exchange have been made in recent years within the application areas of advanced process control, finite scheduling, asset management, statistical process control, and supply chain integration. However, the integration of operations and maintenance (O&M) related information has lagged behind these other areas of information exchange, limiting opportunities to make business operating decisions that depend on integrated O&M information.

In today’s world of interdependent supply chain partners and O&M outsourcing models, the limitations also have significant implications that reach beyond the bounds of any single enterprise into the extended enterprises of which they are a part.

In a more practical scenario, this problem can be represented by an unexpected equipment failure during the execution of a planned production order. It is clear that this is going to impact operations in the enterprise. However, that same impact is now propagating up and down the entire supply chain with potential financial implications including penalty costs and loss of business.

This is an overview of how three industry organizations—MIMOSA, the OPC Foundation, and the ISA’s SP95 Committee—are working together to provide the process industries the capability to openly and securely exchange O&M information.

Maintenance: Ever increasing importance
As today’s business environment of lean manufacturing sites, build-to-order manufacturing models, just-in-time delivery of parts and ingredients, and integrated supply chains combine to permit reduced inventory levels, they also cause the costs of unexpected equipment failures to skyrocket.

If an equipment failure causes a key part or ingredient to be delivered late or at diminished quality, an entire production run can be negatively impacted with a significant loss in profitability. In this context, failure includes any change in equipment performance resulting in unacceptably low production quantity or quality, as well as equipment performance resulting in unacceptably high safety risks, manufacturing costs, or environmental impact.

Inventory can be used as a buffer to partially offset the risk of diminished production, but in the pursuit of operational excellence, this is a costly step backward. The ability to anticipate and prevent unexpected equipment failures by performing maintenance based upon actual equipment condition information and operating parameters can lead to both reduced maintenance costs and lower equipment failure rates. It also enables superior operational decision-making because equipment availability forecasts are more reliable, making production schedules more accurate. Enhanced decision support systems (DSS), leveraging all enterprise information, are the key to economically managing these issues.

The ability to perform maintenance based upon actual asset condition information is called condition based maintenance (CBM). Using CBM-related information along with other operating inputs to optimize operating decisions for an effective enterprise is known as condition based operations (CBO). The discussion that follows focuses on the use of CBO in process industries to enable more economically efficient production.

Condition based operations
Condition based operations involves using current O&M information to make the best economic decision for the business.

From the production operations management perspective, scheduled production is viewed as a time window (e.g., two shifts, one week) where production runs are scheduled on equipment, or assets. Production in a given period is often constrained by equipment availability during the same period. Production plans and detailed production schedules, even when created based upon planned maintenance schedules, are often disrupted by asset failures. In addition, even the most careful maintenance scheduling usually only includes coarse input from operations and on-going business requirements (e.g., critical and highly profitable orders on tight schedules).

As a result of these lurking threats, the confidence in meeting a production schedule decreases as one looks further into the future. This loss of confidence (or reduced visibility) is partially a result of not being able to accurately predict asset health and maintenance requirements during the schedule period.

Figure 1 represents this scenario by depicting the expected capacity of a manufacturing facility plotted over time. The variations in height of the expected capacity indicate changes due to projected asset availability. The horizontal dashed line indicates the maximum capacity for the facility if all the assets are available. Therefore, the area between the expected capacity and the maximum capacity indicates capacity that is not expected to be available for production. The loss of confidence in the expected capacity in the future is represented by the brown shading (degree of uncertainty). It becomes more pronounced over time, indicating an increasing chance that unexpected disruptions to the schedule could occur in the future.

The aim of CBO is to enable better informed operational decision-making, resulting in optimal production by leveraging CBM-oriented information. At the enterprise level, CBO extends both the accuracy and the time period of the forecasts that are critically dependent on equipment resources in order to enable the economic optimization of the entire production process. Individual users, such as production planners, may wish to see a more accurate capacity forecast only within their normal planning horizon.

Figure 1 illustrates such a capacity forecast with decreasing visibility into the future, similar to the decreasing visibility of a long-term weather forecast. CBO will clear the shadow as much as possible to enhance the visibility and reduce the uncertainty of the forecast. A capabilities forecast would extend the concept to include qualitative production information and possibly provide options to use other manufacturing resources with similar capabilities in order to enable economically optimized operating decisions.

Industry solution
The OpenO&M For Manufacturing Joint Working Group was formed by three nonprofit organizations—MIMOSA, the OPC Foundation, and the ISA SP95 Committee. They are collaborating to provide the standards and technology that form an interoperable framework for the exchange of O&M information—the OpenO&M Framework. The OpenO&M Framework enables the exchange of operations and maintenance information horizontally and vertically within an enterprise as well as between supply chain partners as appropriate. The collaborative approach will harmonize the various existing standards from these organizations and jointly develop future standards as needed.

MIMOSA and the OPC Foundation have established the OpenO&M initiative as an industry-neutral approach for enabling the open enterprise integration of O&M information. ISA’s SP95 Committee is the key industry partner to enable OpenO&M standards to be properly applied to the manufacturing and processing industries, thereby enabling CBO for industrial enterprises. This approach to harmonize these standards enables both end-users and solution providers to take advantage of the proven standards and specifications from the three organizations today while providing a clear path forward to richer capabilities in the future without the risk of obsolescence.

Within a commercial enterprise, individual manufacturing sites will benefit from the OpenO&M Framework, which is an enabler for CBO, CBM, and collaborative asset lifecycle management (CALM) strategies. The wider application of the framework can also be made to the entire enterprise supply chain and supporting infrastructure covering fleets, facilities, and manufacturing plants in both public and private sectors.

Industry standards enable integration
The implementation of CBO in a single manufacturing site, or throughout an enterprise, requires the broad-based integration of O&M information from a variety of sources. Without a widely accepted standard for O&M information this implementation requires the development of numerous point-to-point interfaces as shown in Fig. 2.

The MIMOSA organization, the OPC Foundation, and the ISA’s SP95 Committee intend to provide a framework to enable the integration of operations and maintenance systems by harmonizing their standards and specifications. This framework will permit system vendors and manufacturing companies to build one interface for each operations and maintenance system. This single interface, called OpenO&M, will enable the system to exchange O&M information with any other control or information system resulting in lower integration costs and deployment time. The numerous point-to-point interfaces in Fig. 2 will be replaced by the single interface shown in Fig. 3.

MIMOSA’s Open Systems Architecture for Enterprise Application Integration (OSA-EAI) defines XML schemas for the exchange of maintenance information critical for implementing CBM and CBO such as condition based monitoring, asset based registry, and maintenance work and parts management.

The OPC Foundation’s OPC interface specifications are the de facto standard for exchanging data between disparate systems in the manufacturing industries. By using OPC technology, OpenO&M will be using the most popular method of communication at the control and manufacturing execution system level thereby reducing the amount of work required to adopt it. The use of OPC also enables the use of state-of-the-art technologies such as Web services and the ability to provide secure data exchange.

The ISA-95 Enterprise-Control System Integration standard provides a standard definition for the vertical exchange of manufacturing data between business and control systems as well as on-going work to define a manufacturing operations standard. The ISA-95 standard has been accepted by the IEC and ISO as the joint-logo international standard IEC 62264. The ISA-95 standard will enable OpenO&M information to be exchanged with manufacturing operations and business systems.

The collaboration effort among these three organizations will integrate the MIMOSA and ISA-95 data exchange formats and will utilize the OPC interface specifications as the “pipe” to transport the information between systems.

In the complex environment of a plant, O&M information needs to be exchanged horizontally and vertically as shown in Fig. 4. The client-server technology of OPC will be used to exchange OSE-EAI and ISA-95 format data as required by an enterprise’s information needs.

Key enabler for world class manufacturing
By providing the right CBO information to the right person at the right time, the implementation of the OpenO&M Framework enables manufacturing organizations of all sizes to become world class—delivering high-quality products on-time and at a lower cost. This enables their enterprises to be more effective, profitable, and competitive in the marketplace. The Framework accomplishes this by dramatically reducing the cost of implementing and maintaining integrated multi-vendor O&M solutions.



Fig. 1. Confidence in the forecast decreases with distance into the future.

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Fig. 2. Without a widely accepted standard for O&M information, the implementation of condition based manufacturing requires
the development of numerous point-to-point interfaces.

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Fig. 3. The acceptance of the OpenO&M Framework will permit system vendors and manufacturing companies to build a single interface
for each system for information exchange.

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Fig. 4. The client-server technology of OPC will be used to exchange OSE-EAI and ISA-95 format data as required by an enterprise’s information needs.

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The OpenO&M For Manufacturing Joint Working Group

Three nonprofit organizations—MIMOSA, the OPC Foundation, and the ISA SP95 Committee— comprise the working group. They are collaborating to provide the standards and technology that form an interoperable framework for the exchange of O&M information—the OpenO&M Framework.


The Machinery Information Management Open Systems Alliance (MIMOSA) is a not-for-profit trade association dedicated to developing and encouraging the adoption of open information standards for operations, maintenance, and collaborative asset lifecycle management in commercial and military applications. MIMOSA is composed of process and discrete manufacturing corporations, facility management companies, military organizations, capital equipment OEMs, and suppliers of asset management software systems including human-machine interfaces, manufacturing execution systems, plant asset management systems, enterprise resource planning systems, enterprise asset management systems, operational data historian systems, and condition monitoring systems. Information is available at

The OPC Foundation is dedicated to ensuring interoperability in automation by creating and maintaining open specifications that standardize the communication of acquired process data, alarm and event records, historical data, and batch data to multi-vendor enterprise systems and between production devices. Production devices include sensors, instruments, programmable logic controllers, remote terminal units, distributed control systems, human machine interfaces, historians, trending subsystems, alarm subsystems, and more as used in the process industry, manufacturing, and in acquiring and transporting oil, gas, and minerals. Information is available at

The Instrumentation, Systems and Automation Society (ISA) is a global, nonprofit, educational organization connecting people and ideas in automation and control. ISA is a publisher of books, magazines, and standards. The ISA’s SP95 standards committee is responsible for creating enterprise-control system integration standards to define the interface between control and enterprise functions. The first two parts of the standard have been released as ANSI/ISA-95.00.01-2000 Enterprise-Control System Integration, Part 1: Models and Terminology and ANSI/ISA-95.00.02-2001 Enterprise-Control System Integration, Part 2: Object Model Attributes. The international counterpart to Part 1 is IEC/ISO 62264-1. Information is available at

O&M is a trademark of MIMOSA. ISA and the ISA logo are registered trademarks of The Instrumentation, Systems and Automation Society. OPC Foundation and OPC are registered trademarks of OPC Foundation. Other marks may be the property of their respective owners.

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6:00 am
January 1, 2005
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Maintenance and Reliability Tools

The Internet never ceases to amaze me. This great “thing” is owned by no company and controlled by no government, and it just keeps getting better and better.

Every Web publisher is self-appointed but ultimately is voted on and validated by Web surfers—for without surfers, there is no real point to publishing. AOL, MSN, and Yahoo! all make it easy to set up blogs, groups, and personal Web sites so anyone can add his voice to the Internet. You do not need fancy graphics to have a great Web site; in fact, simple site designs are often more appreciated by visitors. Two such sites are listed below.

I recently came across (no, it is not one of my sites) created and managed by Sy Friedman, president of Probabilistic Software. Its claim to fame is that it does not sell you software to create mean time between failure (MTBF) and mean time to repair (MTTR) and other availability and reliability reports. It actually creates the reports for you right online—instantly.

An “Instant MTTR” is the MTTR and availability (Ai) of your equipment delivered instantly in a Maintainability and Availability Prediction Report. The report is prepared in accordance with MIL-HDBK-472, Notice 1, Procedure V, Method A, “Maintainability Prediction;” and MIL-STD-470B, “Maintainability Program for Systems and Equipment,” Task 203, “Maintainability Predictions.”

All you need to do is enter average corrective maintenance task times for each replaceable assembly in your equipment. It’s that simple. The site processes your data, enters it into a Maintainability and Availability Prediction Report, and e-mails it to you within minutes.

The report you will receive includes a title page, table of contents, introduction and summary, resulting MTTR value, maximum corrective maintenance time (Mmaxct) value, availability (Ai) value, mathematical models supporting these values, and a MIL-HDBK-472 and MIL-STD-470B methodology discussion. The Maintainability Prediction Report also contains an appendix which presents the “Maintainability Analysis Worksheet” tabulations showing the average corrective maintenance task times that support the MTTR and availability calculations. There is a cost of $500 for this service.

If you are too busy to fill out the “Instant MTTR” data input sheets and want assistance, just send your equipment packaging design to and they will do it for you and send you the report within a few days. Report examples are available in pdf format so you can preview what you will get.

If you would rather learn more about developing your own reports, you need to be a regular visitor to H. Paul Barringer’s Web site. In addition to information about consulting and training services, this site offers a boatload of handy reliability tools as well as a lot of free or low-cost software downloads.

Sign up for the reliability problem of the month to keep your reliability wits in shape and fine tuned (you will need them fine tuned to keep up with Barringer).

You will also find a link to Eagle Eye services which gets Weibull guru Dr. Robert Abernathy or Wes Fulton to review your problem data quickly and provide expert comments, conclusions, and recommendations. This service may lead to significant improvements in a timely and cost-effective manner.

Use sites like these to help develop your statistical skills This type of information is often overlooked by maintenance professionals who may lack the proper math skills or have not been trained in how to apply statistical analysis methods in the maintenance context. New software and services can help even the most number challenged of us get value from our data.

Terrence O’Hanlon, CMRP, is the publisher of He is the director of strategic alliances for the Society for Maintenance & Reliability Professionals (SMRP). He is also the event manager for RCM-2005, The Reliability Centered Maintenance Managers’ Forum on March 9-11, 2005 in Clearwater, FL

Free Office Software on the Web

Are you tired of paying hundreds of dollars for word processing, spreadsheet, and presentation software?

Visit E-Press to download a free copy of Easy Office 7.0 or check out my favorite 1.1.2.. If all you need is word processing, try AbiWord 2.0 or Jarte . For presentation software, try Powerbullet Presenter. dbWorx is a very capable database program.

If you have been computing since the 1980s like I have and certain editors of MAINTENANCE TECHNOLOGY, you may remember VisiCalc. It serves well as a simple spreadsheet and, best of all, it’s free.

Send the money you save to a worthy charity!

Internet Tip: New E-mail Client Available

I have written about alternative browsers to Internet Explorer in the past because of all the security issues surrounding Microsoft products. Thunderbird, from Mozilla, is an excellent no-cost alternative to Outlook. It even includes effective junk mail filters and RSS features so you can get blogs like and news delivered directly to your e-mail. Try a copy and e-mail us to let us know what you think.

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January 1, 2005
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Maximizing Chiller Efficiency

Attention to maintenance can help control energy demand. Here is an overview.

Chillers consume more than 50 percent of the electrical usage in many facilities. They use approximately 20 percent of the total electrical power generated in North America, and the U.S. Department of Energy estimates that chillers expend up to 30 percent in additional energy through inefficiency. With more than 100,000 chillers in the United States alone, inefficiency costs industry billions of dollars in energy annually.

Chillers running inefficiently also result in decreased equipment reliability, more frequent maintenance, and shortened lifespan. The slightest decrease in chiller performance can have a major impact on efficiency. For instance, every 1 deg F increase in condenser water temperature above full load design can decrease chiller efficiency by 1-2 percent. A failing or neglected water treatment program can reduce efficiency 10-35 percent, or more in extreme cases.

What is maximum chiller efficiency?
Contrary to popular belief, running the chiller at full load design and achieving the design Kw/ton does not necessarily mean the chiller is running at maximum efficiency. Maximum chiller efficiency is producing the greatest tonnage at the lowest kilowatt usage.

Maximum efficiency occurs with most chillers running at approximately 70-75 percent load and the lowest Entering Condenser Water Temperature (ECWT), based on design. Knowing a chiller’s efficiency and the effects of load and ECWT will help the facility determine the most efficient chiller configurations, saving the maximum on energy costs.

Document chiller data
The first step in maximizing chiller efficiency is to establish a method for recording chiller operational data in a daily log. It is common for facilities to maintain chiller logs, but unfortunately they rarely get reviewed, which is critical.

The daily logs can be entered into a chiller efficiency program. If past chiller logs exist, the data can be input and a baseline can be immediately established. Once the chiller status (baseline) has been determined, operational changes can be made to increase efficiency and measure the results.

Ensure accurate data
Ensuring accurate data can be difficult. One of the most common assumptions made by a facility is that the flow to the chiller is constant and always at design. Unfortunately, this may not be the case and there are several reasons why. Chiller systems are dynamic, ever-changing models, which must adapt to the environment around them. They expand and contract from the original design. They are subject to wear, tear, and age. The best advice is to not assume anything until proven by accurate, continuous verification.

The best way to provide precise data, obtain concrete results, and minimize problems is to verify flow rates to the chiller for tonnage measurements and other calculations to determine efficiency. Four methods for determining flow are inline flow meter, external flow meter, delta pressure, and delta temperature.

Flow meters—turbine type, magmeter (inline), or ultrasonic (external)—provide the most accurate flow readings in gallons per min (gpm). Flow can be determined by delta pressure using a gauge or annubar. Delta temperature cannot actually measure the flow rate in gpm, but it can identify proper flow and problems associated with flow. It also can be affected by other conditions not directly related to flow, such as a scaled or fouled chiller barrel, noncondensable gasses, and refrigerant level, making interpretation more difficult. However, the use of delta temperature along with a flow meter or delta pressure gauge creates a powerful diagnostic tool that can detect problems affecting efficiency in the chiller system.

Along with proper flow, check and calibrate sensors, gauges, and meters for measuring temperature, pressure, and electrical measurements periodically or when a problem is detected.

Adjust water temperature
For constant speed chillers, every 1 deg F increase in chill water temperature can increase chiller energy efficiency 1-2 percent. For variable speed chillers, every 1 deg F increase in chill water temperature can result in a 2-4 percent efficiency increase. However, it may not be possible to increase the chill water temperature to save money due to design constraints, occupant comfort levels, or real-time energy pricing (sacrificing efficiency at one time to improve the efficiency at another time).

Take advantage of wet bulb conditions in the cooling tower system to lower the chiller’s entering condenser water temperature. This can result in a 1-1.5 percent efficiency improvement for every 1 deg F below the chiller full load design. It is important to note that part loads associated with chiller type (high or low pressure) and compressor motor style (constant or variable speed) will affect the chiller’s performance. Consult the chiller manufacturer to establish appropriate guidelines for entering condenser water temperature.

Treat water aggressively
A good water treatment program is a necessity for efficiency. Maintaining the proper water treatment will prevent costly problems. If a problem(s) already exists, take the necessary steps to correct it immediately. The results can provide significant energy savings with greater chiller efficiency, maximized equipment life, and reduced overall maintenance costs. Remember, always wear appropriate personal protective equipment (PPE) when using chemicals or cleaning equipment.

Use biocide and scale/corrosion protection
A water treatment program provides a biocide program that minimizes microbiological growth along with excellent scale and corrosion protection. Microbes, if not properly controlled, can cause numerous problems, such as forming sticky slime deposits in the tube bundle of a chiller, possibly reducing heat transfer efficiency 15 percent or more.

The situation can be compounded by the formation of permanent scale or iron deposits on the sticky site. If this occurs, an additional 10-20 percent loss in heat transfer efficiency may result. To fix the problem and restore lost efficiency, an unscheduled shutdown and physical cleaning of the chiller may be required. Furthermore, if no action is taken to improve the water treatment, under deposit corrosion may occur throughout the condenser system, which may create leaks in the transfer piping.

Clean the cooling tower often
Cooling tower system cleaning is essential for peak efficiency. A good time to consider cleaning is fall and spring, just before and after winter lay-up. This usually means part or all of the condenser system may lay-up dormant for several months. Dead legs, sections of the systems with no circulation or stagnate water, in the condenser system are potential areas for producing many types of microbes. One type of anaerobic bacteria of particular importance is sulfate reducing bacteria (SRB) that can cause significant localized pitting corrosion and severe damage in a relatively short period. Treating these areas of a condenser system with biocides and biodispersants prior to lay-up can help minimize microbial problems.

Lay-up treatments also ensure an easier start up in the spring, minimizing maintenance problems. A lay-up treatment is designed to protect the equipment and piping by reducing pipe chip scale (flash corrosion). This chip scale or flash corrosion can have a serious impact on start-up, causing blockage of distribution holes on the tower hot deck, plugged strainers, and in extreme cases, blockage in the chiller. Any of these problems will reduce flow and heat transfer efficiency in the condenser system.

When cleaning the tower basin, all debris should be removed, including sand, silt, trash, and most importantly biofilm. Biofilms are home to many living organisms. Some of the more common organisms include pseusdomonas slime, which can reduce heat transfer efficiency, and SRB.

Tower cleaning also should include inspection of the drift eliminators, fill, and louvers to minimize airflow restriction across the cooling tower system. Make sure the tower fans are working properly to produce the desired airflow for heat transfer removal. Visually inspect the wood and metal construction, looking for signs of deterioration. Wood deterioration may be a sign of microbio problems (mold, yeast, or fungi) or over feeding the oxidizing biocide causing wood delignification or deterioration. Look for white rust on the metal construction caused by either a tower that was never properly pretreated and passivated or a chemical program that may not fit the water chemistry. A thorough spring-cleaning can assist in maintaining maximum efficiency throughout the summer months.

Pretreat new systems
Pretreatment is recommended for a new system (condenser, evaporator, and tower system), or when there is a new add-on to an existing system to ensure heat transfer efficiency and prolong equipment life.

The purpose of pretreatment is to remove oil and grease from new piping and chillers. If pretreatment is not performed, the oil and grease may adhere to the heat exchanger, reducing heat transfer. Oil and grease also can provide food for microbes to bloom, requiring additional costly biocide treatments. Pretreatment should passivate the new metals and minimize white rust and flash corrosion.

Consider passivating chemicals
Galvanic corrosion is associated with dissimilar metal coupling and can exist in all areas of the HVAC system (though it primarily occurs on the condenser side of a chiller), and if severe enough, can affect the life of the chiller. Metal passivating chemicals commonly used in the evaporator minimize galvanic corrosion.

Most chillers have copper tubes with carbon steel tube sheets and end bells, in which a galvanic reaction can occur between the copper and carbon steel. Installing sacrificial anodes and painting the inside of the chiller end bells and tube sheet with an epoxy coating also can minimize this corrosion.

Preserve design flow rates
Maintain condenser and evaporator design flow rates, checking them annually. A rule of thumb is to always maintain flow greater than 90 percent of design because lower flow will reduce chiller efficiency. When the flow is reduced or restricted, it can create undesirable laminar flow (less than 3 ft/sec) through the chiller, which also can cause a water treatment program to fail.

Above design flow (greater than 12 ft/sec) through the chiller may cause vibration wear and erosion or corrosion of the tubes, reducing reliability and life. Cracks and pitting holes can develop, causing leaks in the tube bundle.


Fig. 1. It is important to check the refrigerant level gauge. Low refrigerant levels cause the compressor to work harder and less efficiently.

Curb noncondensable gasses
Noncondensable gasses (air) are associated with low-pressure chillers with evaporators designed to use refrigerants that operate in a vacuum. When a leak develops in the evaporator, air and moisture are pulled in, which affects the compressor and reduces heat transfer efficiency. The compressor is working to move the noncondensable but getting no refrigerant effect.

In fact, noncondensables can blanket tubes in the condenser lowering the overall efficiency up to 6-8 percent at 60 percent load and 8-14 percent at full load. To help minimize the affect of noncondensables, purge units are required.

Maintain refrigerant levels
The ability of a chiller to efficiently remove heat directly correlates to the compressor’s ability to move the refrigerant per unit of time. It is important to maintain proper refrigerant levels because low levels cause the compressor to work harder and less efficiently (Fig. 1). Check for leaks regularly, especially when a chiller shows signs of low refrigerant level. Trending refrigerant levels will help determine if the chiller has a leak(s), a bad purge unit, or refrigerant carryover.

Regular refrigerant analysis is an important part of determining chiller inefficiencies. If oil content in the refrigerant is above the chiller manufacturer’s guidelines, it may be reducing heat transfer. Keeping good maintenance records on oil usage in a chiller will help to avoid this condition.

Schedule preventive maintenance
Compressor oil analysis should be performed annually. Low-pressure chillers may require more frequent analysis, based on purge run hours. This test should include a spectrometric chemical analysis containing information on metals, moisture content, acids, and other contaminants that can affect chiller performance.

Replace oil filters on an as-needed basis on high-pressure drop or when the compressor oil is changed. Consult the chiller manufacturer, lubricant supplier, and/or oil analysis laboratory for oil and filter change intervals.

Monitor refrigerant approach temperature
One of the earliest signs of chiller inefficiency is an increase in refrigerant approach temperature (RAT). The RAT is determined by calculating the difference between the leaving fluid (water) and the saturated temperature of the refrigerant being heated (evaporator) or cooled (condenser). Newer chillers or chillers that have been retrofitted perform this function. Older chillers may require taking the suction pressure (evaporator) and head pressure (condenser), then converting these pressures to temperature from a refrigerant temperature/pressure table.

Every chiller has a manufacturer design RAT. When it is exceeded, a problem with heat exchange in the chiller exists. Problems associated with high RAT include low refrigerant level, noncondensable gasses, low/high flow rates, part loads at low ECWTs, and finally, a scaled or fouled chiller. MT

Don Clark is corporate sales manager for Efficiency Technologies, Inc., 3105 E. Skelly Dr., Ste. 420, Tulsa, OK 74105, developer of energy efficiency programs for commercial/industrial HVAC systems; telephone (866) 333-8321

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