Archive | 2002

219

12:55 am
December 2, 2002
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Share What You Know

Every employee has a wealth of knowledge to offer, and systems must exist where this knowledge can be transferred to someone else.

One of the major concerns haunting every corporation is how to capture human knowledge, experience, and expertise before it walks out the door. When employees retire or accept employment elsewhere, they leave with detailed information or “history” that is often difficult to transfer to their replacements.

This knowledge or human interpretation of people, processes, products, services, and client relationships is undoubtedly invaluable to determining future actions for those that carry on the legend and continue the practices of any organization. Although a wealth of data is stored in computer systems, even the most sophisticated computer systems cannot reveal human interpretation for potential action, also known as interpretive thinking: “the ability to do more than recite what was said; going further than parroting information; adding one’s own opinion to the information being displayed.”

Crossing the barriers of interpretive thinking can occur only in environments where human beings are recognized as having the central role of knowledge creation, where information is gathered and recorded continually, hence the term knowledge management.

What items should be included in the knowledge management process? Key elements are the company’s history, specific procedures and processes an employee follows, and the working environment.

A company’s history
Vast amounts of useful information can be found in a company’s history including changes in corporate hierarchy, policy changes, product success and failures, and process revisions. This information provides assistance in determining plans for products and/or services, without repeating unnecessary costly errors or wasting time.

More importantly, this information can assist new hires, regardless of position, in learning the company’s history, such as what individuals were behind the greatest successes, the creation of products, the design of the infrastructure, growth, losses, and changes in the organization. Many individuals refer to the company history as the “treasure map” because of the opportunity for uncovering valuable information.

Procedures and processes
Consider the wealth of information you have been exposed to, and multiply that by the number of years you remained in any organization or position, and imagine trying to convey that to someone following in your footsteps. You have mastered many processes and procedures and are likely able to perform some of them robotically or subconsciously at times. Transferring that information requires becoming consciously aware of every thing you do and know.

Identifying the elements is a good place to start. These elements include:

  • Specific procedures you follow
  • Written documentation included in your role
  • Key activities you perform
  • General outline of daily, weekly, and monthly duties
  • Minimum skills needed to perform the job
  • Educational requirements
  • Experience necessary such as key technology systems, processes, etc.
  • Skills and abilities as related to mathematical needs, verbal and written requirements, reasoning/troubleshooting skills, and physical requirements
  • Key relationships such as direct contacts, direct reports, and people you communicate with regularly and sporadically

Working environment
To transfer the picture fairly, you also must include information related to the working environment, keeping in mind that you probably have become immune to some of these items:

  • Amount of stress related to this position
  • Level of noise that is present daily
  • Exposure to hazards, regardless of how safe the environment is
  • Factors related to isolation, if any
  • Resources available including materials, people, and infrastructure

It also is important to document commitments you make to meetings, teams, and projects.

Establish a documentation trail
Creating a documentation trail is the next step. Some organizations have created their own “yellow page” type of directory to assist employees in knowing the skills and backgrounds of the organization’s human assets. In this directory, each employee is listed along with a picture and biography that includes education, work history with the current organization, previous employers if valuable to the current organization, career highlights, special skills, and unique project knowledge or experience. This database then can be sorted to aid in locating a person best suited for internal needs as they arise.

A similar database can be created for processes, strategies, objectives, organizational culture, and core values.

Role of communication
The documentation trail is dependent upon your ability to identify details. The following unrelated question demonstrates this point:

Question: How has the Internet affected the young adults of today? Write your answer on a piece of paper in bulleted points. Now, take a look at your answer. How much of your answer was based on fact vs opinion?

Opinion might include the following:

  • Young adults use the Internet only to play games and chat in chat rooms.
  • All young adults using the Internet will eventually isolate themselves from society and become depressed and introverted.
  • The Internet is breeding a generation of nonsocial robotic people.

Fact would include the following:

  • 67 percent of Americans ages 18-24 live in households that use the Internet to access essential information
  • Almost 83 percent of new freshmen at American colleges (4 out of 5) say they are using the Internet for research and homework.
  • 47 percent said they would consider taking an educational course through the web.

According to Webster’s dictionary, the following definitions exist for opinion and fact: Opinion = view, judgment or appraisal formed in the mind; Fact = something that has actual existence, reality, or truth.

The point of this exercise is to help you see the value of documenting only the facts related to your role, not your opinion of the duties, role, responsibilities, etc.

Separate fact from opinion
To separate fact from opinion, you need to remove the emotion from your commentary, remain objective, and think outside the box.

Stored information can be turned into useful and valuable tools when an individual is challenged to begin looking at the same picture a different way. This is similar to the drawing many of us have seen where viewed one way, a young beautiful woman is visible, and after studying the picture for a few seconds, an image of an old, witch-like woman appears. Taking an objective look at the same information can produce different perspectives.

Employees are people, and people become immune to maintaining greater perspectives on those functions they perform routinely. The synergy needed between data and people can come from the person least likely to come across the data in any other part of his job.

I was working as a consultant in an organization and happened upon some information related to the sales and marketing department. The information included clients, products sold, and total sales dollars. The information was provided to me as a matter of record, but I chose to inspect it for new insight into the overall picture to enhance my effectiveness on the project. Looking at this information objectively, I began to draw unbiased conclusions and shared those conclusions with the sales/marketing department. In doing so, I presented information that influenced future product decisions. Unknowingly, I had assisted them through my objective view.

Beyond the job description
How objective can you be in describing your job beyond the job description? Let’s try another exercise to demonstrate this point. We will use the role of a receptionist since most individuals are familiar with this role. A job description for this position might be as follows:

Essential duties and responsibilities: Answers phone, greets visitors, handles walk-in job applicants, maintains an inventory of front office supplies, and restocks supplies when needed. Hours: 9 to 5 Monday-Friday

Qualifications: Extroverted personality, good phone skills, and able to perform basic mathematics

Duties NOT mentioned: Proficient with computer and e-mail, multiple task expert, flexible on work hours, exceptional organizational skills, stress free/positive attitude, jack-of-all-trades.

The point is this: in order for you to transfer what you know, you have to look at the overall picture, not just the job description.

The pertinent relationship is 50 percent collecting and recording data and 50 percent interpreting what has been collected. Then document what you have collected.

Using a knowledge transfer journal
You can purchase an existing journal or create one yourself. Either way, you should have both a manual version and an electronic version, using the manual version to jot down thoughts or comments as they arise, eventually entering the data into the electronic version. See accompanying section “What To Include in a Knowledge Transfer Journal.”

On an ongoing basis, send out questionnaires and surveys periodically to document and assess knowledge. Share these results with everyone.

Train your replacement
The shadowing process is the best method for training a replacement because it provides a direct opportunity to transfer knowledge from one person to another through actions as well as words. Side-by-side study allows for more observation vs explanation, and makes the tasks or duties being observed more easily understood. Once the observation is completed, a debriefing process should take place in order to determine what questions remain unanswered. Assessing the learning experience then becomes the last step in which the new hire, or person new to the position, can actually apply what was observed, and uncover where assistance may still be needed.

In the shadowing process, the objective is to capture the “who, what, when, where, and why” of the job. It provides for an opportunity to share solutions that help solve everyday work issues, and to focus on useful bits of information that can be easily digested and retained.

During this interactive process where participative training takes place, the employee conducting the training can assess the variables in the new hire’s skill set, and adjust as needed to fit those variables.

It is imperative, however, to monitor the saturation level—the point at which it becomes apparent that your protégé exhibits less energy and interest than witnessed prior to this time. Keep in mind that a new hire, or person new to the position, is not likely to openly share when he or she feels overwhelmed or saturated with information. It can be difficult to learn as well as decipher what value each observation has while taking notes, especially when trying to make a positive impression.

The communication process
In training any replacement, the communication process or “effectiveness of the communications” is what determines the success of the training itself. One of the greatest challenges in communicating what you know is recognizing that your perspective, mind set, and expectations have likely been skewed by your experiences.

In addition, your personal feelings, past experiences, and values also have played a role along with degrees of respect related to title, authority, and credibility. Freedom to respond and environmental issues such as noise, interruptions, and privacy, along with cultural barriers, all can affect your ability to drive the communication process. These factors coupled with the trainee’s own communication barriers can easily spell disaster.

See accompanying section “Ensuring Communication” to see the steps you can take to ensure positive communications during the training experience.

Attitude sells it all
Maintaining a positive mindset during the training process is critical to the success of the experience as well as the transferring of knowledge. Two critical points include:

  • Incorporate the truth. Be honest about co-workers, vendors, and customers. Avoid making excuses.
  • Set up for success. Eliminate complaining and/or negative commentary. Keep personal matters out of the equation, and take initiative. Be the motivator.

Remember that individuals perform at their best when their surroundings are positive and non-threatening. Those who are the most involved with each process are the most likely to create the greater product. Establish a solid procedure for the utilization of new ideas.

Keys to ongoing success of knowledge management
Managing and sharing knowledge will occur naturally in organizations if the following practices are applied:

  • Create groups of internal and external networks. Socialization of relative interests can create innovative ideas and opportunities for information sharing. Strengthen networking groups by using facilitators who can encourage and massage ideas into reality.
  • Establish synergy between data and people. Human interpretation of information is where the synergy begins. Opinions will enable organizations to add value to the bottom line.
  • Generate ideas from stored data. Challenge your staff to use recorded information to create new ideas. Break the routines of patterned thinking—doing things the same way. Objective parties should periodically review data. Objective perspectives can add insight.

Employees viewed as human assets are the center of knowledge creation. Every employee has a wealth of knowledge to offer, and systems must exist where this knowledge can be shared. Rigid rules and limited parameters will keep the thinkers in the box. Above all, remember that information is worthless without interpretation. MT


Nancy Mercurio is co-owner of Training Systems Network, producers of The Professional Development Channel providing training to corporations and government agencies via satellite. She is a globally televised author and trainer and specializes in human relations and organizational behavior, providing consulting and coaching services. She can be reached at 11266 E. Hillsborough Ave., #180, Tampa, FL; (813) 818-1883

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19505

10:26 pm
December 1, 2002
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Understanding Shaft Alignment: Basics

Part one of a four-part series that will cover alignment fundamentals and thermal growth, and highlight the importance of field measurements through two case studies.

Despite the best efforts to precisely align rotating machinery shafts, dynamic movement (commonly believed to be due to the thermal growth of the machine casings) has resulted in machines operating at less than optimum alignment conditions. This vexing problem has plagued machine reliability professionals for decades.

What is shaft alignment?
Shaft alignment is the positioning of the rotational centers of two or more shafts such that they are co-linear when the machines are under normal operating conditions. Proper shaft alignment is not dictated by the total indicator reading (TIR) of the coupling hubs or the shafts, but rather by the proper centers of rotation of the shaft supporting members (the machine bearings).

There are two components of misalignment—angular and offset.

Offset misalignment, sometimes referred to as parallel misalignment, is the distance between the shaft centers of rotation measured at the plane of power transmission. This is typically measured at the coupling center. The units for this measurement are mils (where 1 mil = 0.001 in.).

Angular misalignment, sometimes referred to as “gap” or “face,” is the difference in the slope of one shaft, usually the moveable machine, as compared to the slope of the shaft of the other machine, usually the stationary machine. The units for this measurement are comparable to the measurement of the slope of a roof (i.e., rise/run). In this case the rise is measured in mils and the run (distance along the shaft) is measured in inches. The units for angular misalignment are mils/1 in.

As stated, there are two separate alignment conditions that require correction. There are also two planes of potential misalignment—the horizontal plane (side to side) and the vertical plane (up and down). Each alignment plane has offset and angular components, so there are actually four alignment parameters to be measured and corrected. They are horizontal angularity (HA), horizontal offset (HO), vertical angularity (VA), and vertical offset (VO).

Shaft alignment tolerances
Historically, shaft alignment tolerances have been governed by the coupling manufacturers’ design specifications. The original function of a flexible coupling was to accommodate the small amounts of shaft misalignment remaining after the completion of a shaft alignment using a straight edge or feeler gauges. Some coupling manufacturers have designed their couplings to withstand the forces resulting from as much as 3 degrees of angular misalignment and 0.075 in. (75 mils) of offset misalignment, depending on the manufacturer and style of the coupling.

Another common tolerance from coupling manufacturers is the gap tolerance. Typically this value is given as an absolute value of coupling face TIR (as an example, a specification migh read “face TIR not to exceed 0.005 in.”). This number can be deceiving depending on the swing diameter of the face dial indicator or the diameter of the coupling being measured. In fairness, it should be noted that the tolerances offered by coupling manufacturers are to ensure the life of the coupling with the expectation that the flexible element will fail rather than a critical machine component.

If this angular tolerance was applied to a 5 in. diam coupling, the angular alignment result would be 1 mil/1 in. of coupling diameter or 1 mil of rise per 1 in. of distance axially along the shaft centerline. If the coupling was 10 in. in diameter, the result of the alignment would be twice as precise (0.5 mil/1 in.). This would lead one to conclude that an angular alignment tolerance based on mils/1 in. would be something that could be applied to all shafts regardless of the coupling diameter.

Harmonic forces are dangerous
When shafts are misaligned, forces are generated. These forces can produce great stresses on the rotating and stationary components. While it is probably true that the coupling will not fail when exposed to the large stresses as a result of this gross misalignment, the bearings and seals on the machines that are misaligned will most certainly fail under these conditions. Typically, machine bearings and seals have small internal clearances and are the recipient of these harmonic forces, not unlike constant hammering.

Excessive shaft misalignment, say greater than 2 mils for a 3600 rpm machine under normal operating conditions, can generate large forces that are applied directly to the machine bearings and cause excessive fatigue and wear of the shaft seals. In extreme cases of shaft misalignment, the bending stresses applied to the shaft will cause the shaft to fracture and break.

Bearing life expectancy
The most prevalent bearings used in machinery, ball and roller bearings, all have a calculated life expectancy, sometimes called the bearing’s L-10 life— a rating of fatigue life for a specific bearing. Statistical analysis of bearing life relative to forces applied to the bearings has netted an equation (see “How Bearing Life is Affected by Misalignment“) describing how a bearing’s life is affected by increased forces due to misalignment.

As the force applied to a given bearing increases, the life expectancy decreases by the cube of that change. For instance, if the amount of force as a result of misalignment increases by a factor of 3, the life expectancy of the machine’s bearings decreases by a factor of 27.

Quite a bit of research in shaft alignment has been conducted over the past 20 years. The results have led to a much different method of evaluating the quality of a shaft alignment and to increasingly accurate methods of correcting misaligned conditions. Based on the research and actual industrial machine evaluations, shaft alignment tolerances are now more commonly based on shaft rpm rather than shaft diameter or coupling manufacturers’ specifications. There are presently no specific tolerance standards published by ISO or ANSI, but typical tolerances for alignment are shown in the table “Typical Tolerances for Alignment.

Another common method of determining shaft alignment tolerances is to ensure the machine feet are within a specified distance from what is considered “zero”. This method also can be misleading. If a machine is considered to be aligned when the foot corrections are less than 2 mils at both the front feet and back feet, serious misalignment can sometimes be present. As a general rule, the smaller the machine footprint (distance from front feet to back feet), the worse the alignment condition based on these criteria for alignment tolerance.

In Fig. 1, the motor foot distance front to back is 10 inches. The distance from the front feet to the center of the coupling is 8 inches. If the front foot of the motor is left 2 mils high and the back feet are left 2 mils low, the shaft alignment results will be as follows: vertical angularity of 0.4 mil/1 in. open at the top of the coupling, and a vertical offset of 5.2 mils high at the plane of power transmission. If this machine operates at 1800 rpm, it would be outside the acceptable shaft alignment tolerances. Again, this reinforces that a set of shaft alignment tolerances based on shaft rpm would apply to all machines regardless of their footprint. MT


Contributors to this article include Rich Henry, Ron Sullivan, John Walden, and Dave Zdrojewski., all of VibrAlign, Inc., 530G Southlake Blvd., Richmond, VA 23236; (804) 379-2250; e-mail info@vibralign.com

How Bearing Life Is Affected By Misalignment

1202_shaftalign_equation

Formula notes: This formulation is credited to the work done by Lundberg and Palmgren in the 1940s and 1950s through empirical research for benchmarking probable fatigue life between bearing sizes and designs.

For ball bearings: L10 = (C/P)3 x 106; For roller bearings: L10 = (C/P)10/3 x 106

where:

L10 represents the rating fatigue life with a reliability of 90 percent

C is the basic dynamic load rating—the load which will give a life of 1 million revolutions which can be found in bearing catalogs

P is the dynamic equivalent load applied to the bearing

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Typical Tolerances For Alignment

1202_shaftalign_tolerances

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Misalignment Using Machine Feet Distances

1202_shaftalign_misalign

Fig. 1. Using machine feet distance to align a machine to acceptable tolerances can give misleading information.


 

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254

10:19 pm
December 1, 2002
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Why a CMMS Needs General Ledger Integration

In order to accurately track costs, measure the benefits of implementation, and produce high-quality management reports, a computerized maintenance management system must be tied to the business manager’s main tool.

By any objective standard, manufacturing plants and facilities have wide-ranging and deep-seated problems with computerized maintenance management systems (CMMS):

  • Surveys indicate that 90-95 percent of all CMMS users feel their systems fail to deliver desired results.
  • Fewer than 10 percent of the 300,000 commercial, industrial, and institutional organizations in North America have ever achieved demonstrable, positive results from a CMMS implementation.
  • More than 50 percent of CMMS implementations are abandoned in less than 6 months.
  • According to a 2000 CMMS survey conducted by the Plant Maintenance Resource Center, only 20 percent of responding organizations attempted to formally quantify the benefits obtained from their CMMS implementations. In the same survey, the percentages of respondents who reported significant savings in the areas of labor, materials, and other costs were 9.2 percent, 11.5 percent, and 10.3 percent, respectively.

What is wrong with CMMS? According to Terry Wireman, a widely published author in the field of facility and plant management, when the failures of strategic maintenance initiatives are closely analyzed, the root cause usually falls into one of two main categories: lack of understanding of the strategy or lack of measurable or quantifiable results.

Wireman also says that measurable financial indicators drive executive managers. Whether measured by return on net assets, return on fixed assets, stock price, shareholder value, some other indicator, or a combination of indicators, their performance is judged in financial terms. This measurement system in turn drives how their organizations are managed. Unless departments within a company can link to a financial measurement system, their performance will not be measured correctly.

Study the accounting cycle
What is a financial measurement system and why is the failure to link to it so lethal to the success of a CMMS implementation? The problem may be seen graphically in Table I.

When you examine the 10 steps in the accounting cycle, note that drafting the financial statements is Step 8. A CMMS will carry only through Step 3. The obstacles this presents when trying to draft high-quality management reports are painfully obvious—you cannot get there from here.

CMMS software has a fatal flaw in its conceptual design and real world implementation because the software creates transactions journals for labor and materials, components, and inventory, but never posts them to a general ledger. CMMSs are unable to capture the true cost of work, and/or measure the true benefits of the CMMS implementation, because they lack a general ledger roll-up structure (Step 4 in the accounting cycle). Managers cannot balance the books because they literally do not have any books to balance. As a result, the high-quality management reports (Step 8) that characterize other types of business organizations are virtually impossible for the overwhelming majority of plants.

Problems with reports
Some of the most intractable problems—including incoherent reports and the lack of standard costs—may be attributable to the lack of a general ledger roll-up structure in CMMS. For example, in the area of reports:

  • The May 2002 issue of MAINTENANCE TECHNOLOGY magazine (Extracting Specialized Information from Your CMMS/EAM, by Christopher N. Winston, HSB Reliability Technologies, p 13) noted that CMMSs come with a set of standard reports. Generally, the number is increased with each major release of new software. Still they never seem to be enough.
  • Leading CMMS vendors advertise that their software comes packed with reports, and invite their users to expensive training classes on how to build reports.

Packed with reports but they’re never enough? Can a CMMS really be this complicated?

During World War II, General Eisenhower ran the war based on a two-page report that his staff prepared before breakfast. The business world has an Eisenhower-style, two-page report, too—the balance sheet and the income statement. While the terminology for plants might be different, the plant manager is responsible for a balance sheet and income statement, too. Instead of cash, the plant manager might have an asset called budget appropriation on his balance sheet, and instead of sales, he might have a revenue item called budget appropriation used on his income statement.

Without the right tool for the job—a general ledger—plant managers cannot accurately track their costs and measure the benefits of their CMMS implementation. Ignoring the imperatives of double entry accounting will result in the kind of operational muddle and financial confusion that plagues CMMSs and plant management today.

Under the circumstances, it is no surprise that 90-95 percent of plants cannot accurately measure their costs; the real mystery is how the other 5-10 percent do it. The answer is that their CMMS is integrated to a general ledger.

Work order processing and contract accounting
From an accounting point of view, the proper handling of a work order is a relatively complex process because work order processing bears a very strong correlation to contract accounting. A work order may be thought of as a miniature contract—a contract in a microcosm. (See accompanying section “Contract Accounting and Work Order Processing Analogies.”)

For example, when preventive maintenance work orders are scheduled, the job should be bid by estimating the time and materials costs. Otherwise, you will never know your proper staffing levels. How many people are needed, and when are they needed? What is in the backlog, and how long will it take to catch up?

At the end of an accounting period, the plant manager must make some adjusting entries to his general ledger to accurately track his costs. For example, some uncompleted work orders will have some charges to them, and accordingly, they should not be closed out. Similarly, what is the change in the backlog? If the backlog grew from two to four weeks, the liability should be provided for currently. Both of these situations call for adjusting entries to be made in the general ledger.

Despite the analogies between new construction and plant management, the plant manager has a harder job than the construction supervisor. By the nature of a work order, a plant manager has many more “contracts” to administer than a construction supervisor. In terms of pure number crunching, there is no comparison. The plant manager has many more “transactions” to process because costs are allocated over many more cost centers—the work orders and the components—than construction accounting where the contractor will have relatively fewer contracts to track and administer.

An ice storm can shut down a construction project for a day. Relatively speaking, this is no big deal, the crew gets a day off. However, an ice storm can shut down the critical and indispensable operations of a hospital or a university. Accordingly, the plant manager must perform under time pressure on another order of magnitude compared to a construction supervisor.

The construction supervisor is given the most sophisticated computer tools that capitalism can envision and technology can provide. In contrast, however, the over-worked and under-appreciated plant manager, while saddled with accounting problems similar to a construction supervisor, must try to make financial sense without even the most basic and essential tool of the business manager: a general ledger.

Do I have to do this?
Just how much number crunching does the plant manager need to do? There are various levels that can be done in a CMMS and someone needs to do it. However, that does not mean it has to be you, and in fact, it probably should not be you.

Remember, your accounting issues—your income measurement problems—are very similar to a construction company’s, only more difficult because they are more abstract. The construction company has compliance issues that drive the accounting process, and at the end of the year it needs accurate information for financial statements, tax returns, bonding, insurance, and credit purposes.

These compliance issues are powerful motivators to get the job done—but these factors are not in play in the plant manager’s world. The construction industry employs legions of accountants, and although the accounting industry may be blind to the needs of manufacturing plants, an accountant should lead your efforts in gathering the appropriate financial information.

Since you are reading this article, you probably have been very disappointed with your CMMS. It must be galling to know that, in some respects, your job was Mission Impossible; without a general ledger, you never had a chance. The CMMS lies at the intersection of three powerful and complex technical disciplines: functional engineering, computer, and accounting technology. It cannot be easy to summon new enthusiasm for something that disappointed you so badly in the past, but if you fix your general ledger problem, your CMMS can finally start to deliver on its promise.

In order to accurately track your costs, measure the benefits of your CMMS implementation, and produce high-quality management reports, your CMMS must be integrated to a general ledger. The good news is that the payoff for a successful CMMS implementation can be substantial. According to the January 2002 issue of MAINTENANCE TECHNOLOGY magazine (Reaping the Benefits of CMMS, by Derold Davis and Joe Mikes, Westin Engineering, p 13), a successful CMMS implementation may reduce overall maintenance costs 20-40 percent and inventory valuation may be reduced by 20-30 percent; other authorities cite savings and benefits that are just as compelling. To get there, however, you need the time-honored, singular, and imperative tool of the business manager—a general ledger. MT


Frank P. Ward, CPA, is the controller at QBIC III Systems, Inc., 22-D Montgomery Village Ave., Gaithersburg, MD 20879; (301) 330-6812

Table I. Accounting Cycle Vs. CMMS

The Accounting Cycle

  1. Collect and verify source documents
  2. Analyze each transaction
  3. Journalize each transaction
  4. Post to the general ledger
  5. Prepare a trial balance
  6. Adjusting entries
  7. Adjusted trial balance
  8. Financial statements
  9. Closing entries
  10. Post closing

CMMS

  1. Collect and verify source documents
  2. Analyze each transaction
  3. Journalize each transaction
  4. A CMMS never gets to Step 4, Post to the general ledger

Contract Accounting and Work Order Processing Analogies

The Accounting Cycle
Contract
“Take off” the bid
Estimate the contract
Costs incurred to date
Estimated costs to complete
Budgeted vs actual
Completed contracts
Uncompleted contracts
Cost over-run
At year end, carry over costs on uncompleted contracts

Work Order
Work order
Plan the work request
Estimate the job
Costs incurred to date
Estimated costs to complete
Budgeted vs actual
Completed work orders
Uncompleted work orders
Cost over-run
At year-end, carry over costs on uncompleted work orders

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211

8:58 pm
December 1, 2002
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The Common Failure of Recycled Improvement Initiatives

Is your company guilty of continually creating new improvement initiatives every few years or, even worse, what we sometimes hear as the next management flavor of the month?

There are some very good reasons why this happens:

1. Due to growing healthy appetites for better and more, the expectations of consumers (that’s us) for products and services continue to rise.

2. The suppliers of these products and services continue to try to differentiate themselves, in competing for our demands, by coming up with not only more products and services, but also different and new ones.

3. All things being equal, we will always prefer to purchase the lower priced product or service.

4. While this market frenzy continues, the regulators of the world will make sure that growth in materialism does not compromise the sustainability of the earth and its people. This will be accomplished by increasing environmental and safety requirements of the providers of goods and services.

As long as these factors continue to hold true, the companies where we work will always be looking for ways to improve output, quality, cost, safety, and the environment. Hence the never-ending flow of improvement initiatives which deal with the common idea of defect elimination. Defects are like bugs eating away at the value an organization is trying to create. Unquestionably, these historical improvement initiatives have been successful in achieving some degree of result, within certain time periods.

Unfortunately, these common initiatives all have adopted a top-down rather than bottom-up approach to improvement. A top-down approach is reactive, in that it assumes the existence of a problem that requires a solution.

A bottom-up approach makes no assumptions; it proactively identifies all potential defects before they occur and ensures corrective steps are taken.

This latter approach has been articulated best by Winston Ledet, the visionary behind “The Manufacturing Game.”

His research uncovered a case where an asset that generated 6500 repair work orders in a year had 20,000 underlying equipment defects, culminating in 10 substantial business losses and one major catastrophic incident.

We can conclude that in order to avoid major incidents at the top, defects at the bottom must be eliminated. Any defects at the bottom that go unchecked could become a more severe problem at the top, with greater ramifications. In fact, in order to reduce the incident rate by 50 percent at the top, 10,000 defects must be eliminated from the bottom.

Most organizations that adopt a top-down approach to improvement initiatives can, at best, target only a few hundred defects. These organizations, by nature, continue to be vulnerable and hence continue to experience major incidents and business losses.

Ledet’s findings support other research that relates to failure modes. Having been involved in reliability improvement for 20 years now, I have found that for every $1 million in equipment value there are at least 100 failure modes. Similarly, for every $100 million in equipment value, there are as many as 10,000 equipment conditions that need to be monitored regularly to avoid the business consequences associated with potential failures.

Many improvement initiatives stall because of the requirement to manage this data-intensive process. Most organizations have not put in place the competencies and the reliability information systems required to manage the condition data and to thereby avoid the many potential failures.

A Canadian brewery has been successful in implementing both reliability practices and technology to collect, analyze, and respond to condition data. This company educated its employees with a broad range of practices. As a result, the company made a sustained shift to a reliability focus within maintenance. Additionally, it provided plant floor employees with the technology to perform failure mode identification and conduct equipment condition inspections. This combination has allowed the company to reduce downtime by 50 percent and increase throughput by 10 percent, saving millions of dollars a year.

By continuing to look at problems from the top-down, and only dealing with them after they occur, organizations and their employees will forever experience an ongoing series of recycled improvement programs.

However, when approached from the bottom up, reliability improvement can be very effective in both achieving results and sustaining the improvement momentum. MT
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190

8:55 pm
December 1, 2002
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What's the Hottest Performance Initiative?

bob_baldwin

Robert C. Baldwin, CMRP, Editor

Maintenance and reliability leaders in every industry and in all sizes of plants are searching out best practices and the processes that will help them close the gap between their current position and the department goals that will contribute most to corporate objectives. If not, they won’t remain leaders for very long.

What practices are they installing? To find out, we tacked on a question to our annual salary survey (see page 30) asking a representative sample of Maintenance Technology readers to tell what they are doing in this area.

Respondents were provided a list of performance improvement initiatives and asked to indicate those that have been implemented at their plant in the past 18 months. Here they are in decreasing order of popularity:

  • Preventive maintenance (PM) analysis and improvement, 59 percent
  • Reliability centered maintenance (RCM), 38 percent
  • Operator performed maintenance tasks, 36 percent
  • Total productive maintenance (TPM), 27 percent
  • Outsourcing specialized maintenance, 27 percent
  • Supplier consolidation, 21 percent
  • Knowledge transfer, 20 percent
  • Lean manufacturing, 18 percent
  • Kaizen initiative, 10 percent

Now that the votes are counted, we have a leader but we don’t have a winner. Dividing the number of votes by the number of respondents who have recently launched improvement initiatives shows an average of 3.1 initiatives for each respondent. That seems like a lot at first glance, but the choices were far from mutually exclusive. Knowledge transfer and supplier consolidation, for example, do not necessarily have any connection to PM analysis.

It would seem that the respondents are doing the right thing by focusing on PM analysis and improvement because preventive maintenance is the foundation to almost any maintenance strategy.

The data shows that half the groups who are addressing PM also are employing RCM, whose structured approach leads to the selection of the most appropriate tasks for ensuring the continued function of the equipment to required specifications.

It also must be noted that three-quarters of the groups using Kaizen continuous improvement initiatives also are installing TPM.

Overall, 82 percent of the respondents have installed at least one of the listed improvement initiatives.

The real challenge is not the identification of the hottest new initiative, but keeping your current initiatives fired up and not letting them cool down before you get the results you are after. MT

rcb

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255

7:39 pm
December 1, 2002
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Revitalizing an Aging Grounding System

Checking, testing, and updating installations improves overall electrical parameters.

Jersey City-based New Jersey International & Bulk Mail Center (NJI-BMC), one of the largest United States Postal Service facilities, was concerned about effectively maintaining its aging grounding system for 26kV, 5kV, and 600V primary, medium, and low voltage power distribution systems. The safety and security of employees and equipment in the 1.7-million-sq-ft facility were primary goals.

We have been collecting harmonics and power factor data for the past three years, using Power Measurement Ltd. (PML), Saanichton, BC, meters at the 5kV bus. Data showed that voltage total harmonic distortion (THD) varied from 35 to 1 percent. The current THDs displayed a drastic variation from 727 to 3 percent. The power factor varied from 53 to 93 percent. These figures concerned us.

Background of the facility
NJI-BMC, the largest among 21 bulk mail centers, is located on 142 acres of marshland; its three main buildings—bulk, foreign, and administration—occupy approximately 1.7 million sq ft. The bulk and foreign buildings contain about 1100 conveyors, parcel sorting, and sack sorting machines that, if placed end-to-end, would stretch up to 25 miles.

These conveyors and machines sort and distribute sack and parcel mail on a 24/7 basis. Mail then is distributed to various postal facilities and international shipping docks via 2000 trailers. These trailers are dispatched on a daily basis from 296 truck bays.

How the electrical system is grounded
The high and medium voltage system comprised of 26kV primary high voltage and 5kV medium voltage switchgear is grounded to an underground grounding grid located in the fenced-in outdoor switchyard. The low voltage distribution, 480/277V load centers, power lighting, and receptacle panels, etc., are ultimately grounded to the building’s steel columns. The existing building steel columns are grounded to 46 newly installed ground rods located throughout the outdoor building perimeter. A new main ground-loop cable that runs inside the building perimeter was installed to connect these columns.

The high voltage 26kV system includes main and ground disconnect switches, bus work, two oil circuit breakers, two 10 MVA transformers, surge suppressors, bushings, and connecting bus work. The medium voltage system contains eight 5kV breakers, meters, relays, controls, batteries, chargers, cables, and connecting bus work. This equipment is housed in the outdoor switchgear cubicle. The low voltage distribution system comprises eight load centers (LC). Six contain double-ended 1000 kVA, 4160-480/277V transformers, 12 main breakers, and six tie breakers. Two LC are rated at 1500 kVA, 4160-480/277V transformers, four main breakers, and two tie breakers. The eight LC contain 126 subfeeder breakers that distribute power to various power, lighting, and receptacle panels. These load centers are located in the penthouses of the bulk, foreign, and administration buildings.

Examining the system
In 1997-98, the facility was considering replacing the aging (1972-73) high, medium, and low voltage equipment because of several operational and maintenance problems with the breakers. We also were concerned about the overall grounding scheme of the facility. To find out the existing status of the grounding system, we procured architect/engineer (A/E) services to check and confirm the overall validity of the facility-grounding scheme. The A/E reports indicated:

  • 46 percent of the building’s steel columns lacked adequate grounding and bonding.
  • Inspections in July 1999 showed that the 26kV and 5kV grounding system was acceptable.
  • Several of the building steel columns’ grounding and bonding connections were missing.
  • Some of the steel columns’ grounding cables were disconnected, lost, or had disappeared.

The primary reasons for this situation were ground settling over the past two to three decades that dislodged the ground cables’ connections, and failure of the facility to keep adequate records/data and to maintain the grounding system.

Correcting the situation
Option 1 was to use a traditional grounding scheme of laying the ground cable outside the building perimeter, approximately 6000 ft. This work would require digging trenches, laying the ground cable, and restoring the site to its original status. Digging trenches around our significantly long building perimeter would hamper our routine mail processing operations.

Scheduling and coordinating active bay outages in a safe and secure manner would need additional resources and manpower. Furthermore, prior to authorizing digging around the 30-year-old buildings, we needed to validate that contractors would not inadvertently damage any underground utility lines (water, sewage, electrical, fuel, drains, etc.).

In the past 30 years, the plant had gone through various changes and improvements including the underground utility lines. The as-built drawings retrieved from the library did not represent actual underground topography and piping layout. Checking and validating the underground utility lines layout would also add to the final cost estimate. Any inadvertent breakage in the water, sewage, fuel, or electrical lines would jeopardize safety and security of employees and equipment, and the environmental impacts of breaking these lines could be costly. Subsequently, any one of these incidents could result in shutting down the plant.

Plant shutdown is costly. One USPS contractor, not associated with this project, in the summer of 1999 was billed, and subsequently reimbursed NJI-BMC, $75,000 per hour for an unintentional shutdown. Considering these critical issues, we concluded that this option would be significantly costly, disrupt the plant operation, and might jeopardize safety and security of employees and equipment.

In spite of these grounding problems, the majority of the electrical equipment was working satisfactorily. Somehow, neither operations or maintenance noticed any obvious electrical problems with the plant electrical equipment. The facility kept on processing mail as usual.

Option 2: cable installation inside
When we found out that the overall grounding of the 26kV and 5kV equipment was in acceptable condition, we decided to revitalize the building steel columns’ grounding system. The unique option that we selected for our site was not to use the traditional outdoor building perimeter grounding scheme, but instead install the ground cable inside the building.

Selecting this option saved us digging the trenches, scheduling and coordinating outages of working bays in a safe and secure manner, and restoring the ground. This concept was the key contributor to the faster, less costly, less risky installation of the grounding cables at the NJI-BMC.

Revitalizing the grounding system
In the spring of 2001, we revitalized the grounding system by installing 20-ft-deep ground rods at 46 locations. A bare, 4/0 copper cable was installed that bounded the perimeter steel columns inside the building. This copper cable was located approximately 20-30 ft high to provide adequate access for mail tow truck trafficking and mail processing operations.

As mentioned earlier, we were very much concerned about the safety of employees and equipment, and any adverse impact on mail processing operations. Since this option of laying ground cables inside the building had not been tried on such a large scale, we were slightly apprehensive. To this end, we procured the services of a specialized electrical engineering firm that verified the installation and supervised the overall work and this project.

Unforeseen problems
Of course, we encountered several unforeseen problems in revitalizing the old system. The underground utility as-built drawings were questionable and we were apprehensive when driving 20-ft-deep ground rods without clarifying and validating exact ground rod locations. The contractor faced unique problems in finding adequate manpower (electricians) resources because of the market conditions. We had to delay the overall schedule by several months.

Acorn connections that connect the ground rods to the grounding cable were found to be unacceptable because of the limited contact-surface area. The set screw that grabs the ground cable and rod did not provide adequate connections. CAD-welding these connections was the correct remedy and best solution for this problem. In spite of all issues, the contractor, electrical firm, and NJI-BMC personnel were very resourceful and proactive in resolving major hurdles. The project schedule was extended because of various scheduling issues with the manufacturer, the supplier, the shippers, and our operations department.

Estimating shutdown costs
Since our facility operates 24/7, any shutdowns, regardless of whether intentional or unintentional, impact our revenue. Minimizing the number of shutdowns was extremely critical. Initially, we estimated several major shutdowns for revitalizing the grounding system. However, we successfully completed the project without any shutdowns.

It is difficult to estimate the actual cost of each shutdown because of several factors that directly or indirectly impact total business costs. Some of these factors are: the manpower resource allocation at the time of power interruption, equipment availability, loss of business, type of mail to be processed on that day, customer service impacts, etc. The absence of shutdowns for this project minimized the overall impact on mail processing operations and improved total budgeting allocation for this facility.

Recommendations
Based on our limited experience, we recommend considering the following key items:

  • Strongly suggest completing proactive PMs of the existing grounding system.
  • Measure and record power quality parameters: harmonics, power factor, etc.
  • Install new ground cables inside the building perimeter to save capital cost and resources.
  • Perform extensive testing of existing equipment and grounding system.
  • Assess need for an on-site standby-by power source if shutdown is inevitable.
  • Emphasize CAD welding when necessary.
  • Prepare detailed planning and step-by-step procedures to minimize operational impact.
  • Review safety and environmental issues with an on-site expert prior to initializing the project.

After revitalizing the grounding system, addressing the power panels, and retrofitting low voltage circuit breakers, our present electrical readings have improved significantly. The voltage THDs vary from 2 to 3 percent, the current THD varies from 11 to 15 percent, and the power factor fluctuates from 74 to 99 percent. At present, we do not know, or have any records, of equipment malfunctioning directly related to power quality issues.

In general, our equipment operated satisfactorily in spite of drastic variations in THDs. We believe that our limited exposure or know-how of power quality issues might have unknowingly impaired some equipment operation or life expectancy. Nevertheless, our site offers opportunities for diagnosing, testing, and validating power quality products and their impact on the existing electrical distribution system.

Checking, testing, and revitalizing this aging grounding system did improve overall electrical parameters. At this stage, we do not know or do not have the expertise to assess and validate if these improvements, in fact, had any impact on our daily mail processing operations. MT


Joseph C. Pearson has been the manager of maintenance at the United States Postal Service’s New Jersey International & Bulk Mail Center for the past 12 years. The facility’s maintenance department consists of approximately 500 managers, engineers, and craft employees. Dilip A. Pandya has been an electrical engineer at NJI-BMC for the past four years; he manages electrical requirements for the plant and is responsible for investigating and implementing innovative cost-effective technologies. Pandya can be contacted at (201) 714-6727

Acknowledgments
The authors appreciate the support they received from the following organizations and U.S. Postal Service personnel. Without their timely efforts and assistance the project could not have been completed as successfully and within the allotted budget:

  • USPS NJI-BMC: Joe Russo, MMO; Ed Pfeiffer, PM engineer; all electricians, senior supervisors, and managers of maintenance and operations; and Plant Manager Frank P. Tulino
  • Hoboken FSO: Ashok Verma, project coordinator, and Ralph Champa, manager
  • New York Area Maintenance Support: Nick Borg and Guy Miata, manager
  • Sunmar Electrical Contractors: Joseph Caciano and Mark Wright
  • Triad Engineering: Paul Witwick and Ron Regan
  • Lockwood Greene: Ben Yazbek and Simon Cattan
  • Longo Industries: Joe Lebar and John Ziomek
  • Public Service Electric & Gas Palisade Division: Paul Durak, Reggie Jones, Bill Critchley, Andy Gleichmann, and Arthur Dolacke
  • Public Service Enterprise Group-Energy Technology: Mike Halsey and John Sloan

 

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277

1:59 am
November 2, 2002
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Information Management System Helps Meet Maintenance Goals

Augusta Service Co. Inc. (ASCI), Augusta, GA, is a maintenance organization that serves two parent companies and their subsidiaries. During the past 10 years, we have met regulatory challenges—and the unique challenges of the companies we serve—by installing, adapting, and expanding an automated system to manage the information required for predictive and preventive maintenance.

ASCI is a nonprofit company owned by DSM Chemicals North America, Inc. and PCS Nitrogen Inc. DSM is the world’s largest merchant supplier of caprolactam monomer for Nylon 6 polymer, which is used in carpets and textiles. PCS Nitrogen is the world’s largest producer of nitrogen fertilizers and its Augusta facility is the largest nitrogen fertilizer producer on the East Coast. Two other production facilities owned by DSM and one owned by W.R. Grace also operate on the 150-acre site in Augusta served by ASCI.

To serve all of these facilities, we maintain a maintenance shop with 25-person electrical and instrumentation (E&I) crews on site at each company’s main facility. A back-shift crew and several utility shops assist in providing preventive and predictive maintenance. A maintenance-engineering group provides engineering support to the parent companies through assigned area-maintenance engineers, as well as base support through its mechanical and pipe groups and E&I.

Certification and compliance top priority
ASCI purchased its automated system, DocuMint Solution, in 1992 from Loveland Controls Co., which later became part of Honeywell. Our goal was to develop a test history database to help DSM and PCS attain ISO 9000 certification.

In addition to providing a means of compiling, storing, and organizing test histories, the automated information management system captures crucial details for certification, including “as found” and “as left” test points, environmental conditions at time of calibration, NIST traceable test equipment, and out-of-tolerance specifications on field instruments and test equipment.

DSM now holds ISO 9000 (2000) certification. DSM Resins US, Inc. earned QS-9000 certification and PCS earned ISO 9002 (1994) certification. We expanded our use of the system in 1997 to address the Occupational Safety and Health Administration’s (OSHA) Process Safety Management (PSM) standard 1910, particularly to document compliance with the standard’s mechanical integrity rule.

Organizing and managing data
The organization of ASCI’s database reflects our need to manage assets for two separate companies, document history on instrumentation loops, and maintain records on individual instruments and equipment. The database hierarchy is Cost Center (a group of equipment in a particular area of the plant), Loop (all instrumentation related to a single function), and Tag ID (each instrument or piece of equipment).

Currently, the database includes 83 cost centers, more than 8600 loops, and more than 38,500 tags. It holds more than 30,000 test results—each linked to specific tag IDs and specific pieces of test equipment.

Test equipment is tracked as well. ASCI maintains three-point, one-point, and certification histories on all 340 pieces of test equipment. Prior to use, each piece of test equipment receives a one-point check for accuracy. The database also designates which test equipment ASCI should segregate for use on ISO 9000 devices. We maintain check standards for one-point and three-point checks in each instrument shop.

Each process calibrator has a test setup for every function it performs, which means ASCI tests a total of 687 functions. We maintain a test equipment function database, which designates each function of each calibrator as an individual record with a test setup assigned.

Creating shortcuts for routine tasks
We also use the software to create quarterly reports for each facility’s production staff. These reports reveal specific deficiencies related to past-due or untested instrumentation. Production staff also may use reports to plan for shutdowns, audits, and daily schedules. To expedite these and other routine information needs, we use the Fastask function of the system. Reports include:

  • Production update report: Issues a list of all delinquent or untested devices by cost center to update a specific area of the plant.
  • Cost center performance: Searches all ISO cost centers to determine the number of devices untested or past due based on date guidelines.
  • Scheduler report: Searches for tag IDs or test equipment between chosen dates to allow reports to cross reference with maintenance schedules.
  • Plant structure for ISO: Searches and displays only ISO tags, in only ISO loops, in only ISO cost centers, instead of all tags in all loops in all cost centers, which may include instruments that are not ISO quality critical instruments.

By using the program’s options, ASCI further customized the information management system to meet its needs.

Equipment group searches are simplified. We assign all OSHA PSM loops separate equipment groups for location, rank values for catastrophic failure risk, and rank orders of importance and FMEA numbers, which help calculate ranking values. The loop database stores and indexes these values and orders in a searchable format. When ASCI blocks off equipment groups for calibration, technicians can search for the equipment group number, load the calibrations for all instruments in the group, and go to work.

Calibration sheets expedite turnaround maintenance. During a plant turnaround, technicians must perform hundreds or thousands of tests in a short time period. ASCI also must manually record much of the maintenance information due to the number of temporary technicians on site. To ensure collection of consistent information, we use the information management system to create calibration sheets that can be printed and attached to work orders.

Reverse trace ensures correction of inaccuracies. When we find out-of-tolerance test equipment, we can trace which process control devices the out-of-tolerance equipment calibrated. Technicians then can check and correct affected devices, if necessary.

The payback
Using this information management system, we have been able to ensure our parent companies and their subsidiaries comply with ISO certification and OSHA PSM compliance. Our ability to customize the system and manage the database effectively has also increased profitability.

In addition to supporting routine preventive maintenance, the system also helps increase the efficiency of work performed during turnaround periods.

We have more efficient maintenance schedules. Using the system to track test history such as failure rates of specific models or specific loop configurations, we can use re-engineering to protect equipment and prevent early failures, re-evaluate the tolerance specifications, or adjust the calibration intervals. The evaluations can help determine the appropriate frequency for preventive maintenance.

We can identify specific equipment makes and models that failed repeatedly or frequently drifted out of tolerance. Maintenance histories stored in the information management system provide the rationale for specifying new instrumentation or a wholesale change-out of a particular make or model. This single benefit saves production downtime and contributes to ASCI’s ability to maintain a record of 0.5 percent average production loss of maximum capacity.

The use of the information system as an interlock database has allowed ASCI to identify inoperable and out-of-tolerance interlocks, which are tested during plant outages. It is ASCI’s answer to OSHA 1910 PSM instrumentation documentation requirements for its safety interlocks. The ability of the system to track failures allows engineers to focus on technical requests with a solid historical basis for engineering changes. MT


Information supplied by Tina Spivey, an associate equipment specialist in instrumentation at Augusta Service Co., Inc., 27 Columbia Nitrogen Rd., Augusta, GA 30901; (706) 894-6147. For information on DocuMint, visit www.acs.honeywell.com

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1248

12:46 am
November 2, 2002
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The Trouble with Torque in Electrical Connections

Torque and force are not the same.

The secret to making and keeping reliable electrical connections is contained in two elements: start with clean contact surfaces, and apply high force.

Clean contact surfaces are a function of cleaning procedures, including joint compounds, and will be covered in a future article. Application of high force is the subject here.

The trouble comes about because the terms “torque” and “force” are incorrectly used interchangeably. Force is NOT torque. Force is a function of torque. The expression which describes the relationship is

F = T/K

Note that the equation has a variable, K, that includes the coefficient of friction. The higher the friction, the lower the force for the same torque. Torque is a convenient way to get at force and is usually specified in making an electrical connection. Force is considered inconvenient to measure.

Torque can be misleading

Consider the following. Suppose you are given a torque value for an electrical connection and suppose that the connection is frozen due to corrosion, arcing, etc. Obviously, the recommended torque will not assure a good connection. Thus, relying on torque to judge the quality of an electrical connection can be misleading.

Levels in uncertainty in the accompanying section “Force Variations by Methods of Tightening Connections” are taken from mechanical engineering sources and represent a rough estimate of the percent variation encountered when trying to tighten a connection using different methods.

You can see there is a wide variation in accuracy depending upon the method and that many of them are fairly inaccurate. In fact, when considering life safety, torque values are rarely mentioned.

What is the correct force? When a connection is tightened, the joint electrical resistance drops as the force increases, up to a certain point. Beyond that certain amount of force, a marked decrease in resistance no longer occurs; the resistance remains fairly constant even with increased force. That certain amount of force is the minimum value of force needed.

In bolted connections, I have found that the forces associated with SAE Grade 5 hardware produce this correct value.

Applying proper force
To assure you are applying the proper force in a connection, there are a few methods which can be utilized:

•Low and consistent K factor by the use of lubrication. You can produce repeatable, high forces in the connection. To safely use lubricants, run tests in the shop before applying on the job.

A well-lubricated fastener is stressed to a higher force for the same torque than an unlubricated one. Check that the fastener does not fracture at the higher force. Having conducted tests, then apply the selected torque to the lubricated threads.

•Belleville washers. These are not always required in electrical connections and are often questionable. The washer must flatten at the proper force and many applications do not use a high enough force. In addition, since the bow in the washer is difficult to see, Bellevilles are sometimes installed upside down. If a proper high force is utilized in the connection, I have found that a Belleville is usually not necessary.

But a Belleville is an excellent force indicator and therefore can solve the force/torque dilemma. If you choose a Belleville that flattens at the desired force, you then can proceed with implementing the connections and not worry about a torque value.

•Direct tension indicators. As mentioned previously, in mechanical connections where life safety is a subject of concern (e.g., buildings, bridges, etc.), torque is not mentioned. Instead measurement of force is required.

A common procedure is the use of direct tension indicators. These are washer-like devices that feature protrusions (bumps) which flatten as a function of force applied to the connection. A feeler gauge is used to announce when the proper force is reached. Later inspection is simple through the use of a feeler gauge. Since the indicators are designed for use with steel, make sure the bumps are put against a hardened steel washer, not a copper or aluminum bus.

These devises are available for 1/2 in. hardware and larger. It is possible to use the 1/2 in. indicator with smaller hardware by requesting the force/gap characteristics from the manufacturer and then selecting the proper feeler gauge for the desired force. Make sure the gauge is narrow enough to fit between the bumps. MT


Norman Shackman, P.E., is based in Kent. CT. He conducts in-house seminars on electrical connections and can be reached at http://home.earthlink.net/~elecon/ or (860) 927-4067.

Force Variations By Methods Of Tightening Connections

Method Percent variation (+/-) in force
Feel (experienced installer)* 35
Torque wrench* 25
Turn of nut (snug tight, then 1/2-2/3 turn more)* 15
Lubricated assembly* 10
Belleville washer** 5
Direct tension indicator** 5
*depends on K

**independent of K

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