KCF Technologies Blog

Many Mills Now Make Most of Predictive and Preventive Maintenance

Founded in 1915 as the Technical Association of the Pulp and Paper Industry, TAPPI is today "the world's largest professional association serving the pulp/paper, nonwovens, converting, and packaging industries."  From 2001 to 2006, TAPPI published Solutions!, a slightly overenthusiastic-sounding monthly journal on all things pulp and paper.  Its August 202 issue included a five-page study "Benchmarking Maintenance Practices at North American Paper Mills," the joint effort of a team of seasoned maintenance professionals drawn from five different states.

The article is an eye-opening look at the state of maintenance at the turn of the 21st century, drawn from an industry-wide survey begun in 1997 of 571 U.S. and Canadian pulp and paper mills.  Of these, 141 (25 percent) took part.  Mills were of all types, and "ranged in tonnages from less than ten tonnes per year to one million tonnes per year, and from less than 100 employees to greater than 1,200 employees."

Annual maintenance budgets at 86 percent of these mills ran from $1 million to more than $25 million.  Much of that cost was labor, accounting for "30 to 40 percent of total maintenance budgets at more than two-thirds of...mills."  In fact, "Respondents reported that the number of maintenance employees equaled an average of about 20 percent of total mill employment," which actually was a drop of two to three percent since the mid-1980s.

"Since earlier paper industry surveys, mills have made substantial progress in the areas of preventive maintenance (PM) and predictive maintenance (PdM).  [Circa 1990], preventive maintenance was becoming was becoming a recognized best-practice, and predictive maintenance was seen by most as 'a nice theory.'  In fact, the earlier surveys did not even mention PdM.  However, with advances in sensor technologies and reduced costs of measuring and diagnostic equipment, PdM has become practical and cost-effective."

Mill budgets for PM and PdM soared accordingly.  Whereas "preventive maintenance had ranged from nine to 22 percent of the total maintenance budget" in the mid-1980s, "a few of the recently surveyed mills indicated budgets for both PM and PdM covered up to 100 percent of the total maintenance budget, with an average of nearly 40 percent."  Earlier surveys from 1993 to 2001 also showed the 85 to 90 percent of mills "rely on Computerized Maintenance Management Systems (CMMS) to track machine repair histories, schedule PM tasks, and provide a means of cost control."

"Most mills ranked quite high in their ability to control unscheduled downtime, with 72 percent...having less than five percent unscheduled downtime and 51 percent of the total reporting less than three percent.

Asked to rank 19 maintenance practices according to which gave the best value, vibration monitoring ranked far above the rest at 97 percent, followed by lube oil and wear analysis (64 percent), walk-down inspections (61 percent), alignment checks (54 percent), and temperature inspections (52 percent).

Even with near-unanimous agreement that vibration monitoring was valuable, actual practices varied wildly.  Ninety mills measured vibration at an average of 1,939 points in the paper machine area, but others monitored as few as ten points and others still up to 11,730 points.  Most mills did the monitoring on a monthly basis (54 mills) or a weekly basis (27 mills), but some monitored daily (17 mills), others annually (9 mills). And, 42 percent of mills reported that they outsourced the gathering of vibration data altogether.

Finally, mills were asked to report the effect of predictive and preventive maintenance on reducing unscheduled downtime to service mechanical and electrical problems.  Some 70 to 81 percent reported that PM and PdM "significantly" reduced downtime, 18 to 28 percent said that PM and PdM activities and programs had only a minimal effect, and only one to two percent felt they had no role whatsoever in reducing unscheduled downtime.

Predictive Maintenance Becomes a Bigger Bargin and a Better Bet

Pumps at a wastewater treatment plant.

Maintenance Strategies: Predictive Maintenance vs. Run to Fail was a five-page paper on water and wastewater treatment published five years ago by Multitrode, "a total solution provider for the municipal water and wastewater pump station industry worldwide."  This firm of some 60 employees, founded in 1986 in Melbourne, Australia, was acquired last month by Xylem Inc., "a leading global water technology company," itself formed in ITT Corporation's spinoff of its water and wastewater business in 2011.

The unattributed paper begins, "One of the most common questions from water and wastewater utilities when they are asked about their maintenance practices in lift stations is 'What do other organizations do?'....Maintenance practices for utilities include run to fail, preventive maintenance on a schedule of time or time in service, and predictive maintenance by monitoring leading indicators of pump and motor problems."

As the title suggests, the study discards at its outset the long-cherished concept of preventive maintenance, using the critique in Thompson and Granger's monograph What Price Preventive Maintenance?, published in 2004:
"For years companies have been performing the preventive maintenance recommended by manufacturers without question...reasoning...that manufacturers have done all the research needed to ensure their equipment will operate properly in any environment.  Most companies also want to ensure that equipment warranties are maintained during the initial install period.  Once these maintenance actions are entered into the CMMS [computerized maintenance management system] or work routine, no one challenges their validity or periodicity because 'that is the way we have always done it.'  This can be a very costly way of doing business."
The Multitrode study found that "across the majority of utilities in the U.S. and Australia the most common methodology was run to fail.  Manpower shortages and/or lack of a budget for better monitoring and control were by far the most common explanation for this choice..."

"The major problem with run to fail is that it is a choice to fly blind as to the state of the assets.  While there are many reasons why pumps and motors can deteriorate faster than historical data shows, there isn't space in this article to detail them all.  However, an excellent example is given in article in Pumps & Systems ["Unbalanced Voltages and Electric Motors," July 2008] by Thomas H. Bishop."

Bishop looked at the effects of slight voltage imbalances--"around 10 percent below nominal"--on the life expectancy of pumps in the United Kingdom "at a large regional municipal utility that introduced a predictive maintenance into the lift stations..."

"[B]ecause the 3-phase supply wasn't remotely monitored, no one was aware of it.  The supply reduction was causing higher running currents, but not enough to trip any panel components or the pump thermistor.  Still, the pumps were running too hot, causing a big reduction in lifetime."  Pumps that should have lasted 25 years were burned out after less than a third of that--only seven to eight years--because of a seemingly trivial voltage shortfall.

Not only can miscalculations like the preceding make "run to fail" extremely costly, but at the same time, predictive maintenance has become much more affordable, practical, and easy to install and operate; that is, cost-effective.  Once regarded skeptically as a cross between sorcery and algebra, predictive maintenance is now making a home where pumps, motors, compressors, fans, and any other rotating machinery is in operation.

Photo by Christopher Shannon/KCF Technologies.  All rights reserved.

Vibration Monitoring for HVAC - Part 2

Part 2 of 2...Vibration Analyst, Mike Hoy discusses vibration monitoring and predictive maintenance in a HVAC plant.

Mike Hoy is the lead vibration analyst at a major university in Pennsylvania. He is charged with a range of HVAC/R related vibration analysis duties, including predictive and proactive maintenance, laser shaft alignment, fan balancing, and installation of wired and wireless remote vibration monitoring systems. Mike has over 30 years of experience installing, monitoring, and maintaining industrial equipment.

SmartDiagnostics® Feature Highlight: Adding Notes to Data Points

A simple but powerful feature of SmartDiagnostics® is the ability to add notes to data points.

An application of this feature is that it would allow a plant manager to document any maintenance activity undertaken regarding a piece of equipment, let a maintenance specialist supply vital information about the service undertaken, or let any authorized SmartDiagnostics® useradd a note on some other significant issue.  This can be extremely helpful when more than one person is looking at the data.

For example, if a plant worker greases some bearings, it's very simple to "add a note"to a data point to inform everyone who looks at the data precisely what has been done, which could help explain a different result in observed vibration.

To add a note for a particular point in the data trend chart:
  1. Click on the anomalous data point in the trend chart.
  2. Click the yellow Note button between the upper and lower graph.
  3. A new Edit Note Details pop-up window (seen at top right) will open.
  4. Enter a title for your note into the Title entry field.
  5. Enter any information you need for the note in the Text box.
  6. Click the Save button.
The note title will be displayed in a box that is anchored to the vibration data point that was selected when you clicked the Add Note icon.

To see all the notes that have been made on a monitoring location, click on Notes in the navigation tree and a Notes Log view will be displayed in the Working Pane.  From this view, you can delete or edit existing notes by clicking on the respective icons.

Predictive Maintenance Tip: Predictive and Preventive Mixture May Be Best for HVAC

The Air Conditioning Contractors of America (ACCA) is a U.S. national trade association that represents heating, ventilation, air conditioning, and refrigeration contractors.  The ACCA chapter located in Houston has more than enough experience with sweltering midsummer heat to make it worthwhile to take a look at the tips that they recommend for both commercial and residential HVAC users.

The first of their recommendations: "Don't ignore your heating and cooling system.  Your HVAC/R system is a great big mechanical system, just like your automobile.  You know that you need to keep you car tuned up and get your oil changed regularly.  Your comfort system also requires regular maintenance from qualified specialists."

Their tools of choice are preventive maintenance agreements (PMAs), "agreements between you and your ACCA quality contractor for scheduled inspections and maintenance of your heating, ventilation, and air conditioning system.  PMAs are generally scheduled semi-annually to maintain peak efficiency, prevent utility overpayment, and avert system failures through predictive maintenance that can help extend the life of your HVAC system."

They may give ACCA members work, but PMAs have a pretty significant advantages for the consumer, too: "PMAs typically more than pay for themselves through higher efficiency, less utility overpayment, and contractor discounts.  PMA customers typically receive a discount on all parts and services performed during the entire year....Should a system failure occur during the heat of the summer or cold of the winter, customers with PMAs generally receive priority service."  Finally, "...contractors are often able to assign technicians to the specific customers.  That way, you get to see and know the same service technician, and he or she becomes more familiar with you and your equipment."

If regular preventive maintenance check-ups by general practitioners are good to safeguard the health of and HVAC system, then--to follow the medical analogy further--predictive maintenance may be the equivalent of the diagnostic tests, like X-rays and MRIs, that are used to track the more subtle signs that attention may be needed.  Or, as the ACCA put it, you get "Peace of Mind: Predictive maintenance will mean fewer system failures and a longer life for your HVAC equipment."

And, the stakes certainly are substantial.  "The HVAC system is most likely the single biggest use of energy in your home.  In commercial applications where refrigeration is applied (combined with HVAC systems), huge amounts of energy are used in the building.  In fact over 1/3 of the energy used in the United States is used to heat and cool buildings.  According to the Consortium of Energy Efficiency (CEE) up to 50 percent more energy can be saved with proper installation, sizing, and maintenance of commercial central air conditioning and heat pumps."

That's as true if you're freezing in Fairbanks as it is if you're overheated in Houston.

Predictive Maintenance Spends Pennies Today to Save Dollars Tomorrow

Founded in 1966, the Goodway Products Corporation "has built a reputation for manufacturing the highest quality cleaning systems in the world."  Goodway products include--"a wide range of tube/pipe cleaners, duct cleaners, vacuums, floor machines, high-pressure washers, and other maintenance related equipment" and a host of HVAC maintenance products, too--are "in over 125 countries and on every continent, including Antarctica."

In 2008, the corporation introduced "Just Venting" as "a blog for HVAC professionals and others who want to learn more about the environmental, technological, social, economic, and personal aspects of this industry."  A year later, that blog published "Predictive Maintenance Saves Energy, Time and Money," by Rich Silverman.

Silverman quickly arrives at the key advantage offered by predictive maintenance: "Reactive maintenance is always too late--the problem has already occurred.  And, preventative maintenance, while better than reactive, still offers no guarantee that the work is being done at the optimal time."  By contrast, predictive maintenance, "can maximize system performance and uptime, reduce maintenance costs for both labor and materials, enhance indoor air quality, and lengthen the life of your equipment" through "ongoing, continuous measurement of key performance parameters of your equipment, such as voltage draws, or vibration levels, or the particulate contamination of oil to determine when equipment needs to be maintained."

Like any system, predictive maintenance has costs.  "Sometimes," Silverman observes, " 'the powers that be' hesitate to approve these types of expenses because of the do-more-with-less requirement they work with every day.  Maintenance can often times be viewed as an overhead line item, and overhead is something to be reduced."

That may be penny wise and pound foolish.  Using a compressor as an example, the author notes, Predictive maintenance...will eliminate the need for expensive emergency repairs.  You'll be able to do maintenance on a weekend, when no one is in the building to complain about the heat.  And, you will extend the usable life of the compressor by eliminating the [excessive] vibration before it causes catastrophic damage."

According to the U.S. Department of Energy, buildings consume almost 40 percent of the electricity used in the entire country.  As Silverman notes, "It's entirely possible that a fine-tuned HVAC system will save more money than the cost of fine-tuning....And, that should persuade management that predictive maintenance makes good business sense."

You might even say that predictive maintenance in a Goodway of doing business.

Photo illustration by Christopher Shannon/KCF Technologies.  All rights reserved.

Vibration Monitoring for HVAC - Part 1

Part 1 of 2...Vibration Analyst, Mike Hoy discusses vibration monitoring and predictive maintenance in a HVAC plant.

Mike Hoy is the lead vibration analyst at a major university in Pennsylvania. He is charged with a range of HVAC/R related vibration analysis duties, including predictive and proactive maintenance, laser shaft alignment, fan balancing, and installation of wired and wireless remote vibration monitoring systems. Mike has over 30 years of experience installing, monitoring, and maintaining industrial equipment.

Condition-Based Maintenance Can Mean Smooth Sailing for Wind Turbines

A SmartDiagnostics® vibration sensor mounted on a gearbox inside a wind turbine.
A 17-page study by four researchers from the University of Massachusetts and one from the Electric Power Research Institute in Palo Alto, Calif., "Condition monitoring and prognosis of utility scale wind turbines" appeared in 2006 in the quarterly Energy Materials, printed jointly by Maney Publishing and the Institute of Materials, Minerals, and Mining in London, England. The study's goals were to review, "The state of the art in condition monitoring in wind turbines, and related technologies,"and to summarize, "technology needs and future challenges for the development of condition monitoring and prognosis for large wind machines, both onshore and offshore."

Beginning by noting the great potential of predictive maintenance, the study observes that in the 21st century, "wind energy is a commercial technology;" condition-based maintenance, "must increase the profitability of this technology," and, "must contribute more than the alternative (such as run to failure, or periodic manual inspection)," if it is to be universally embraced by the industry.  And, the bar for that acceptance is set high:
"A condition monitoring system must produce actionable information to be useful.  That is, the indications of fault must be sufficiently specific and credible that the operator will order the maintenance action requested by the condition monitoring system based on its recommendation alone.  The challenge is in raising the fraction of faults detected, detecting these faults as early as possible, and correctly identifying the faulty component, all while reducing false positive indications to an acceptable level."
 Much of the report concerns the relative efficacy of predictive maintenance techniques on the various wind turbine components, and analogies in the high levels of reliability required in comparable U.S. Air Force maintenance standards for rotors, turbines, and gearboxes in fixed- and rotary-wing aircraft.  Also taken into account are different standards for maintenance among insurers in Germany, elsewhere in Europe, and the U.S.

It concludes by reviewing, "each of the four major subsystems of wind turbines: rotors, drive-train and generator, electronic controls and power electronics, and support structure.  In terms of value added by condition monitoring systems, the drive-train has the greatest potential, with the rotor a close second....The value added by monitoring the condition of the other systems is less certain."

While asserting, "Wind energy technology has advanced greatly over the past several decades, reducing the cost of energy to the point where it is competitive with other forms of electric power generation in many situations," the researchers concede, "Further advances in technology are required to enable commercial use of wind turbines in more difficult sites such as offshore locations."

"As wind turbines become larger and are located in more remote areas, both onshore and offshore, the value of condition monitoring increases.  Condition monitoring will be enabling for the largest offshore turbines."

"Cost Effective Predictive Maintenance" a Quarter-Century Later

Back in 1987, "Cost Effective Predictive Maintenance" by B.C. Howes, B.R. Long, and V. Zacharias, was published on eight pages in Pulp & Paper Canada, now in its second century as a digital, annual publication chronicling one of that nation's oldest industries.

The abstract reads, "Predictive maintenance is a concept that is generally accepted in the pulp and paper industry today.  For those mills considering the implementation of such a program, a key consideration should be whether the method chosen will be cost effective.  This paper briefly identifies several alternatives, and attempts to provide a method for evaluating the economics involved."

The study defines the target of its predictive maintenance as "machinery on which increasing vibration is a sufficient indicator of a potential problem and provides enough warning to allow repairs to be made in a timely fashion."

In Figure 1, they display a fanciful timeline showing the "Advance of maintenance practice."  This begins at the bottom with "TECHNOLOGICALLY BACKWARD MILLS" and proceeds through eight stages to TECHNOLOGICALLY ADVANCED MILLS," the latter a veritable maintenance Shangri-La noted for:

(survey everything: computer records & trends)
(use skilled workers to identify solutions)"

What dates the analysis most obviously is that, when it was written, "the state-of-the-art" was one or more maintenance specialists with "a portable instrument...used to take readings," one that "remembers them until they can be transferred back to the computer."  That computer then "keeps track of all the machines, test-points, and recorded data, " in addition to which "trending and historical analysis are done by the computer."

Major concerns of this early iteration of predictive maintenance were the cost of training and the high salaries of the specialized personnel needed to make the system work well, and the substantial expense of the machinery needed to make "periodic planned vibration checks on every piece of machinery" in a plant that could have hundreds of them.

It was felt that "...automation dramatically reduces the tedium of the job.  Fewer people are required to collect data, because using the instrument is so much faster than collecting data by had."

Today, vibration sensors take measurements at intervals chosen by the user, the results of which can, in real time, be fed straight into a computer with the specialized software to display and interpret them almost instantaneously.  With few exceptions, costly, complex, cumbersome manual meters have pretty much gone the way of the dodo bird.

However, the study concludes with words as true today as they were 26 years ago: "Predictive maintenance programs that improve maintenance practice can be a reality in every plant.  It is time to apply/benefit evaluation techniques, in order to make these programs as cost effective as possible.  Only in this way can predictive maintenance make the best contribution to the overall profitability of your plant."

Join KCF Technologies at Reliable Plant 2013!

Visit KCF Technologies at a the Reliable Plant Conference and Exhibition in Columbus, Ohio from April 16-18.  We will be in booth 438 showing how SmartDiagnostics® can help you work towards a goal of a more "reliable plant."

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