Archive | May/June


6:00 am
May 1, 2007
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Advances In Arc-Resistant Motor Control Equipment

Arc flash is responsible for about 80% of electricalrelated injuries. It occurs when an arc fault superheats the air around it, expanding and creating a pressure wave within the enclosure. The resulting arc plasma then vaporizes everything with which it comes in contact.

In industrial settings, many things could compromise the air space that acts as insulation to prevent electrical energy from igniting an electrical arc. The conductor could be as simple as a rodent, snake or water accidentally entering the electrical equipment, or human error—like leaving a tool in the equipment or forgetting to tighten a connection.

“The best prevention is an in-house safety program with compliance to NFPA 70E standards,” says Joe Sheehan, P.E, principal electrical engineer at The National Fire Protection Association (NFPA). “Then my most important advice is ‘shut it off.’ Electrical equipment should never be worked on live, unless it’s for diagnostic testing for correct amperage. It’s the culture in industry that we’re trying to change to keep workers safe.”

Another important safety measure is appropriate personal protective equipment (PPE). While PPE can be effective, it also can be heavy and cumbersome.

While prevention is the best possible solution, sometimes an arc fl ash explosion occurs regardless of best intentions. That’s where technology can help protect employees. As part of their arc fl ash prevention programs, companies now can install arc-resistant motor control equipment and intelligent control systems that offer enhanced safety features and remote operation and monitoring capabilities.

The way of the future
Arc-resistant motor control centers (MCCs) are designed to contain the arc energy and direct it away from personnel— they cannot prevent an arc fl ash. “Arc-resistant” describes equipment designed to control arc fl ash exposure by extinguishing the arc, by controlling the spread of the arc or by channeling the arc pressure wave away from personnel.

John Kay, manager of Medium-Voltage MCC Engineering at Rockwell Automation Canada, has over 20 years experience working with MCCs. He compares advances in this technology to advances in automobile safety features.

“Fifty years ago, seatbelts didn’t exist,” Kay notes. “Eventually, they became standard in new vehicles, and are now legally mandatory. Newer safety features include anti-lock brakes and air bags, which will eventually become mandatory. The same can be said for arc-resistant MCCs. Arc-resistant designs represent enhanced safety technology and, therefore, an enhanced level of safety.”

According to Kay, Rockwell has a unique design in its Allen-Bradley ArcShield medium-voltage (up to 7,200 volts) arc-resistant MCC. The design redirects arc fl ash energy out relief vents at the top of the unit and away from personnel through an overhead plenum. These products have been successfully tested in accordance with ANSI C37.20.7: IEEE Guide for Testing Medium-Voltage Metal- Enclosed Switchgear for Internal Arcing Faults. During testing, cotton squares (similar to 4.5 oz/yard untreated T-shirt material) are mounted a meter from the ArcShield MCC. Acceptance criteria require that none of the cotton indicators ignite during or following a test.

“One of the key differentiators of the medium-voltage ArcShield MCC is that it maintains IEEE C37.20.7 Type 2 protection, even with the low-voltage door open for maintenance purposes,” says Kay. “The controllers are compartmentalized and the low-voltage panel is reinforced and sealed to prevent arc fl ash materials from entering it.” Specifi c testing is done to meet the requirements of each level of “arc-resistant accessibility” based on appropriate codes and standards. IEEE Type 2 accessibility means that all four sides offer protection, therefore anywhere within the perimeter of the equipment—not just in front of the door. The risk level is reduced for normal tasks to a Zone 0 category, which results in a reduced level of PPE.

To contain the pressure blast, the ArcShield controller’s cabinet is heavily reinforced with additional support members and plates, and uses 12-gauge steel for all doors, side, roof and back sheets. Extra strength, multipoint latches and robust door hinges add to the security of the unit’s main doors.

To redirect the arc exhaust gases, specialized silicone coated, aluminum pressure relief vents on the unit’s roof open to release the pressure. A plenum system above the enclosure channels the superheated gas and vaporized copper and steel to a safe and controlled location.

Kay also points out that Rockwell is the fi rst equipment manufacturer to apply arc containment features to NEMA® low-voltage motor control centers (up to 600 volts). These MCCs do not use a plenum system, instead, they release the arc gases and pressure out the front of the cabinet in a lateral direction, away from personnel.

ArcShield products also can incorporate intelligent motor control solutions, including remote monitoring and isolation features to help prevent accidental exposure to energized parts. For example, networking these MCCs with Rockwell’s IntelliCENTER software permits realtime monitoring, confi guring or troubleshooting of both medium- and low-voltage products. This information can be accessed from anywhere in the world via a secure Internet link.

Both medium- and low-voltage models can be specifi ed with built-in DeviceNet™ wiring for remote monitoring of the equipment’s operating parameters, which keeps personnel out of the MCC room.

Rockwell Automation 
Milwaukee, WI

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6:00 am
May 1, 2007
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Joining The FSI Team


Ken Bannister, Contributing Editor

The most successful series on television these days is the CSI (Crime Scene Investigation) franchise. Modeled on the classic Sherlock Holmes “whodunit” format, this modern series uses a seductive mix of cutting-edge forensic technology and common sense to quench our quixotic need to provide simple answers and solutions for complex problems. (OK…I admit it…I’m a CSI junkie!)

Over the past few years working with my Maintenance clients, I’ve conducted many informal “water cooler” polls, trying to learn which CSI program is favored most and what attracts so many maintainers to regularly watch these shows. Apart from morbid curiosity as to how each week’s victims meet their demise, the majority of respondents point to the series’ attention to crime scene details as its most compelling aspect. That’s not too surprising, when you consider how a maintainer conducts troubleshooting.

Whenever a system or component fails, it leaves behind an evidence trail that will lead not only to the failure cause, but to a strategy to help you understand and/or predict and prevent future failure events. Even though we CSI junkies know we must “protect the crime scene at all costs,” in our haste to “keep the equipment running at all costs,” we often destroy the “crime” scene and either contaminate or throw out the evidence. Sound familiar?

I submit that we all are “failure scene investigators” (FSIs) within the Maintenance profession— that we all are responsible for equipment reliability through better understanding of equipment failure. If we are to reduce our levels of maintainability while increasing both availability and reliability, we must follow the CSI lead and investigate all equipment failures via a systematic approach, much like the seven-step approach below:*

  1. Secure the scene. Work with Operations to perform a quality evaluation of the failure before beginning repairs and/or restarting the equipment.
  2. Photograph the scene. The old adage that “a picture is worth 1000 words” could not be truer in a failure investigation. Photos allow the scene to be revisited well after the equipment is back up and running, and act as good training materials for preventing future failures.
  3. Perform on-scene forensics. The Maintenance/ Reliability group can perform many technical diagnostics at the failure scene, including infrared signatures, oil analysis signatures, etc.
  4. Bag and tag all physical evidence of failure or tampering. Once all local physical evidence of tampering and breakage has been photographed, bagged and tagged, the actual failed components can be dismantled and replaced. Any parts for repair must be photographed, and any parts requiring replacement must also be bagged and tagged.
  5. Interview witnesses. Operators can describe any abnormal sound, smell or vibration emanating from the equipment prior to failure.
  6. Perform laboratory forensics. Examine all past failure records and vibration readings and conduct necessary metallurgical and oil testing.
  7. Analyze findings. Write up the FMEA report and recommendations and distribute to the appropriate audience.

Taking a CSI-inspired approach will enhance your reliability program while adding new value to your predictive toolset. Good Luck!

Ken Bannister is managing partner and principal consultant for Engtech Industries, Inc. E-mail:; or telephone: (519) 469-9173.

*Adapted from materials for “Achieving Reliability Through Effective Failure Scene Investigation.” ©

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6:00 am
May 1, 2007
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Lubrication Management & Technology News

Chevron’s Lubricants University, an online training resource offering information on relevant technologies and trends in the lubrication and maintenance industry, has announced that it will offer its “Fundamentals of Lubrication” training course in Spanish, for free. The course targets Spanish-speaking industrial maintenance professionals and maintenance departments with Spanish-speaking employees who are interested in gaining an understanding of lubrication and its role in preventing wear and friction in mechanical equipment.

“We have seen the number of Spanish-speaking maintenance professionals grow with the increasing Hispanic population in the United States,” says Virginia Moser, training coordinator, Chevron North America Lubricants. “To reach this developing market, it made sense to offer our most popular course in Spanish.”

Invensys Process Systems has announced a significant expansion of its overall customer sales, engineering and support capabilities in Western Canada. As part of this expansion, the corporation recently began construction of a new, 15,500 square foot regional headquarters facility in South East Calgary. The complex will be twice as large as Invensys’ present Calgary facility, providing three times the area to accommodate staging, testing and verification of customers’ automation systems. Scheduled for completion next fall, the new site also will include a state-of-the art customer center, complete with meeting spaces, a training facility and a fully equipped demonstration area.

In addition, over the last 18 months, Invensys has doubled its local sales force and more than doubled its local engineering capacity to increase project implementation capabilities and supplement end users’ and EPCs’ own engineering resources. It also has expanded its regional field service team.

Garlock Klozure, a Division of Garlock Sealing Technologies, has acquired the Syntron RP Mechanical Seal line from FMC Technologies, Inc. The Syntron RP seal is a small, cartridge-type, double seal used to seal fluids and gases on various rotating equipment such as pumps, compressors and mixers. The seal itself is constructed of brass or stainless steel, with flexible drive rings and lapped seal faces. The Syntron line and associated assets have relocated to Garlock’s new facility in Palmyra, NY.

Ivara Corporation has entered into two agreements with Dr. Andrew Jardine of the University of Toronto and the Centre for Materials and Manufacturing (CMM) to acquire the rights to advanced reliability technologies developed by Dr. Jardine and commercialized by the CMM. The technologies, which will be embedded into Ivara EXP, offer users powerful statistical capabilities that enable them to make more informed decisions regarding asset repair, replacement and preventive maintenance strategies.

Dr. Jardine, a professor of Industrial Engineering, is a globally recognized authority in the fields of maintenance and reliability who developed these technologies over 25 years of research. The CMM is an Ontario Centre of Excellence that supports research and training within Ontario’s materials and manufacturing sectors. The Centre’s goal is to accelerate new innovations and commercialize new advances through R&D activities.

In the first of the agreements, Ivara has acquired the rights to the “Asset Life Cycle Costing for Mobile and Fixed Equipment” and “PM Optimization” technologies from Dr. Jardine himself. Under the second agreement, with the CMM, Ivara has acquired the rights to “Capital and Emergency Spares Optimation” technology which was developed at the University of Toronto’s Condition-Based Maintenance Laboratory, headed by Dr. Jardine.

Motion Industries has expanded its ability to service customers in Arkansas by acquiring the assets of Jonesboro Bearing & Supply, a wholesale distributor of bearings, power transmission, industrial supplies and fasteners, headquartered in Jonesboro. Founded in 1967 by Harrel W. Ponder, the distributorship employs 33 people in two locations: Jonesboro and Stuttgart.

AMETEK, Inc. has announced its acquisition of Halmar Robicon silicon controlled rectifier (SCR) power controller and related Power Control Systems technology and products of Siemens Energy & Automation. Halmar Robicon’s advanced technology fits well with AMETEK Solidstate Controls, which is recognized as a leader in Uninterruptible Power Supply (UPS) and battery management systems for industrial applications and power generation, and a global supplier of industrial SCR power controllers, custom power supplies and equipment.

A new partnership between Imes Group of Aberdeen, UK, and Optimal Maintenance Decisions, Inc. (OMDEC) of Toronto, Canada, has been announced. Building on the success of the partners’ contracts for government and industries, the new alliance brings together Imes’ global network of facilities in the UK, USA, Europe and Australia that provide risk- and reliability-based asset integrity management services with OMDEC’s advanced equipment reliability technology.

Imes’ has over 20 years experience in providing asset integrity management services to the defense, nuclear, oil & gas and transport industries, ranging from risk and reliability studies, through design and certification consultancy services to full asset management of high-risk, high-value equipment. The company is recognized worldwide for its patented Water Weights load-testing product and for the provision of innovative and tailor-made load measurement solutions in hostile environments. OMDEC develops and markets “EXAKT,” the maintenance decision solution developed at the University of Toronto. EXAKT employs Proportional Hazard Modeling (PHM) to extract critical operating and maintenance knowledge to help users predict and avoid equipment failure and thus assure continuity of operations and mission readiness.

National Technical Systems Inc. (NTS), a provider of test and engineering services, has entered into an agreement with Eaton Corporation to utilize their Southfield, MI vibration laboratory. Managing testing laboratories is NTS’ core business.

Under the agreement, NTS Detroit will provide Eaton’s Southfield facility with on-site testing services, as well as manage Eaton’s 4,600 square-foot test facility, enabling the company to expand its vibration test capabilities by 40%, and increase chamber capacity by approximately 20%.

(Editor’s Note: National Technical Systems serves the automotive, defense, aerospace, telecommunications, nuclear and high technology markets. Through its worldwide network of resources, the company provides full product life-cycle support, including design engineering, compliance, testing, certification, quality registration and program management.)

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6:00 am
May 1, 2007
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Justify Your Equipment Reliability Enhancements

Bearing applications are ideal places to look for process and cost improvements around your plant. As illustrated by the following examples, cost-justifying these enhancements often is very easy—in many cases, much easier than you might have imagined.

To cool or not to cool pump bearing housings Many refinery applications deal with flammable fluids. Safety and reliability are crucial in these services—that is why the API Standard 610 was developed. Although not legally binding, this well-known industry standard covers the basic requirements that impart reliability to process pumps. It is of the utmost importance in severe pump applications.

“Hot oil” (300 F/149 C to 850 F/399 C) is one of the most severe pump services there is, in that it creates high thermal expansion of pump components. The pump supports, in turn, must maintain shaft alignment at these elevated temperatures. Casing centerline support, without a separate support for the bearing housing, is normally used to address this problem. On the overall subject of safeguarding acceptable pump component temperatures, however, there is the (often incorrect) notion that all types of pump bearings require cooling. They dont.

Cooling water IS NOT desirable for rolling element bearings…
Decades of solid experience with literally thousands of pumps have shown that cooling water is not needed for the majority of centrifugal pumps in process plants worldwide. Regardless of convention and tradition, there is no net advantage to the use of cooling water in pump bearing housings equipped with rolling element bearings. Five statements explain these long-term findings:


  1. Rolling element bearings do not require cooling if a lubricant of sufficiently high viscosity is chosen. [Ref.1]
  2. Well-formulated synthetic lubricants are ideally suited for high-temperature pump bearings.
  3. Since the early 1970s, thousands of high-temperature pumps have been in successful high-MTBF service after all cooling water was removed from their oil sumps and/ or from their respective cooling water jackets.
  4. Cooling water jackets that surround or are in close proximity to bearing outer rings primarily cool the bearing outer ring, while the bearing inner ring remains at a higher temperature. As this causes bearing-internal clearances to vanish, the bearing will experience excessive preload. Close-clearance bearings surrounded by cooling water jackets are almost certain to fail prematurely.
  5. Cooling water coils in the oil sump tend to promote condensation of the water vapor contained in the air floating above the oil. Lube oil degradation is the inevitable result.

In any case, for rolling element bearings that are properly installed and loaded per the manufacturer’s allowable guidelines, cooling the oil is neither necessary nor is it advantageous. It may only be necessary to choose a higher viscosity oil, if indeed warranted.

Cooling water IS desirable for sleeve bearings…
The correct oil viscosity is needed for reliable oil application and long bearing life. In other words, an oil ring will not function the same way in lubricants with substantially different viscosities. Furthermore, the oil film thickness developed in the bearing will differ for different oil viscosities.

It is intuitively evident that some heat is being conducted to pump bearings. Moreover, oil shear in bearings produces heat. In many applications involving sleeve bearings, though, the oil may indeed have to be kept cool through the use of cooling water jackets that surround the bearings or by cooling water coils immersed in the oil. Cooling thus tends to ensure that the correct lube oil viscosity is being maintained. Nevertheless, there are many sleeve bearings that will simply not require cooling water. As explained in Ref. 1, they can be identified by temporarily shutting off cooling water in a controlled test, during which the steadystate oil temperature of a premium ISO Grade 32 synthetic is observed to remain below approximately 170 F (77 C).

To restate, while cooling may still be needed for sleeve bearings lubricated by oil rings, using cooling water jackets can prove disastrous to bearing life. Cooling water jackets that only partially surround bearing outer rings have often restricted the uniform thermal expansion of operating bearings and have been known to force bearings into an oval shape. There have been many instances where, as a result, bearing operating temperatures were higher with “cooling,” and lower after the cooling water supply was disconnected and the jackets left open to the surrounding atmosphere. [Ref.1]

Similarly, cooling water flowing through a coil immersed in the lube oil also has been known to cause problems. Adherence to this “traditional” cooling method very often invites vapor condensation in bearing housings. Unless the bearing housings are hermetically sealed [Ref. 2], moist air fills much of the bearing housing volume. When it is cooled, the air sheds much of its water vapor in the form of liquid droplets. Since this condensate causes the lube oil to degrade, cooling the bearing environment can be indirectly responsible for reduced bearing life in pumps.

Regrettably, some pump manufacturers and installation contractors have been painfully slow in endorsing the deletion of cooling water. Others have been equally slow advocating superior synthetic lubricants and certain highly advantageous application methods. Where cost-justified, advantageous application could refer to pure oil mist (“dry sump”) for both effective lubrication of operating pumps and, especially, the protection of non-running pumps against harmful environments [Ref. 3].

0507_equipmentreliability_img2For rolling element bearings that are properly installed and loaded per manufacturer’s allowable guidelines, cooling the oil is neither necessary nor helpful. Instead of following misguided tradition, and for bearing housings from which cooling liquid has been removed, reliability-focused users choose the right synthetic base stock (generally diester or diester/PAO blend formulations, [Refs. 2 and 3]). Reliability- focused users also select the correct viscosity and, as discussed previously, avoid the use of oil rings because of their serious limitations at today’s higher operating speeds.

The cost benefits can be considerable. For example, by no longer using cooling water on hundreds of pumps with rolling element bearings, one petrochemical plant estimated that it could save $120,000 in water consumption, piping maintenance and water treatment cost annually. Deleting cooling water also was expected to prevent at least three pump failures per year (at $6700 each). The annual savings were estimated to exceed $140,000 at this facility. This, again, is just one instance where the implementation of a cost-saving measure has shown positive reliability impact and instantaneous payback. All it takes is for reliability professionals to familiarize themselves with 30-years-worth of well-documented prior experience and the scientific principles behind it—which are very easy to explain to plant personnel. If necessary, a simple wellinstrumented test will convince even the most traditional doubters of the laws of physics.

Double-row angular contact bearings with two inner rings
Pump bearings can fail for a number of different reasons. Two of these are bearing overload and bearings being too lightly loaded. What at first seems like a paradox— failure due to loads being too light—can be explained by the analogy of an aircraft landing. The tires skid until their peripheral velocity matches the forward velocity of the aircraft. Skidmarks on the runway and smoke and noise coming from the tires attest to this fact.

0507_equipmentreliability_img3Until the late 1990s, failure avoidance through upgrading was pursued by some pump users, while others were content with frequent bearing replacements. Thus, upgrading the double-row angular contact ball bearings (DRACBBs) in pre-sixth edition API-610 standards, or in ANSI and ISO-style pumps to meet “ANSI-Plus” standards generally meant one of two things:

  • The equipment owner could purchase sets of single-row angular contact ball bearings (SRACBBs) complete with a specially designed shaft and housing, at a premium price.
  • Parties interested in upgrading could purchase sets of SRACBBs and then modify the existing shafts and housings in-house to accommodate them.

When it became evident that conventional, 30° contact angle, double-row angular contact ball bearings often represented the limiting factor in achieving extended pump life, the need to devise a retrofit bearing with characteristics approaching those of the API 610-recommended 40° contact angle back-to-back orientation arose. This prompted a multinational bearing manufacturer to develop DRACBBs with two inner rings and 40° contact angles. [Refs.1 and 4]

Using a specially designed DRACBB with two inner rings (Fig. 1) requires no labor-intensive retrofit work and represents an ideal upgrade for many API and ANSI/ISO pumps (Fig. 2). The DRACBB bearing employs a closely controlled axial clearance. This optimized clearance promotes load sharing between the two rows of balls— a design that reduces the possibility of skidding in the inactive ball set without the use of a preload. Skidding produces heat and often causes the oil film to be wiped off. Either way, metal-to-metal contact will result and bearing failure risk increases exponentially.

Preloading a bearing can help prevent skidding, but may also have the undesired effects of generating excessive heat or contributing to poor bearing performance. While one ball set is supporting the axial load, the backup set becomes inactive, supporting only a portion of the radial load. Without sufficient loading, the motion of the balls in the inactive set leads to skidding and heat generation.

The new separable inner ring DRACBBs’ shaft and housing fits are identical to those for standard SRACBB and DRACBB with comparable sizes. ISO k5 is the recommended shaft tolerance for this bearing in most pump applications. This tolerance produces an interference fit between the bearing inner ring and the shaft. Interference fits are necessary for bearings supporting any radial load. A lighter fit using modified tolerances may be necessary for bearings mounted on shafts made of stainless steel, or for the occasional bearings that have a large temperature differential between the inner and outer rings.

The mounting recommendations for DRACBBs with two inner rings differ slightly from those applicable to the conventional double-row configuration. But, the benefits of selective upgrading to these retrofit bearings will more than make up for the inconvenience of looking up a different instruction sheet.

Assume that an incremental outlay of $40 per bearing plus $120 in conversion cost were to lead to an $8,000 repair avoidance on a large ANSI/ISO pump every four years (or $2000 annually). In that case, $160/4 years = $40/year has returned $2000/year. That’s a rather attractive benefit-to-cost ratio of $2000/40, or 50:1. Or, project an ultra-conservative scenario of spending $200 on conversion and extending a previous 1.5-year MTBR to a post-conversion MTBR of three years. In that case, avoiding even a $6000 repair will still yield a solid 10:1 payback.

As this four-part series has shown time and again, many reliability improvements are readily available and easy to justify from an economic standpoint. As an example and dealing only with compressors and pumps, advances in high-performance polymer materials and synthetic lubricant technology can lead to significant extensions in equipment run times, or mean times between repairs. If a reliability professional must wrestle with a population of centrifugal pumps, he or she might do well to consider several of the easily cost-justified enhancements described in this series of articles. For instance, it would seem appropriate to look into:

  • Hermetically sealing bearing housings with dual-faced magnetic bearing housing seals
  • Using a high-film-strength synthesized hydrocarbon lubricant of appropriate viscosity, i.e. ISO Grade 32 for pumps
  • Applying diester-base synthesized hydrocarbon lubes on reciprocating compressor cylinders
  • Upgrading ANSI/ISO pumps to double-row angular contact bearings with dual inner rings
  • Installing pre-grouted (pre-filled with epoxy) pump baseplates
  • Selective upgrading of certain medium-size pump lube application methods to an inductive pump jet-oil application

Removal of cooling water from bearing housings equipped with rolling element bearings Other upgrade opportunities were described years ago in this magazine (formerly known as Lubrication & Fluid Power). They include the merits of:

  • Using only balanced constant level lubricators
  • Replacing vulnerable oil rings with flexible flinger discs
  • Using proprietary PTA, high-temperature capability, ultra-lowthermal- expansion-performance polymers as a wear ring and throat bushing material

There surely are other “things” that can be done to decrease pump and compressor failures—this series just highlighted several of the simplest and most cost-effective. Needless to say, reliability-focused plants and users will follow up with the speedy implementation of these and other cost-justified upgrade and enhancement measures.


  1. Bloch, Heinz P. and Alan Budris; Pump User’s Handbook: Life Extension, (2nd Edition, 2006) The Fairmont Press, Inc., Lilburn, GA 30047, ISBN 0-88173-517-5
  2. Case Studies published by Royal Purple, Ltd., Porter, TX 77365
  3. Bloch, Heinz P., Practical Lubrication for Industrial Facilities, (2000) The Fairmont Press, Inc., Lilburn, GA 30047, ISBN 0-88173-296-6
  4. SKF Interactive Engineering Catalogue, CD-ROM, Version 1.2, 1998 Contributing editor Heinz Bloch is the author of 17 comprehensive textbooks and over 340 other publications on machinery reliability and lubrication. He can be contacted directly at:


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6:00 am
May 1, 2007
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Introduction To Synthetic Lubricants & Their Applications

These days, equipment is running faster and hotter than ever to meet productivity demands—and higher performance lubricants are required to meet these demands. Synthetics offer that level of performance.

Synthetics aren’t new; they’ve been around for 70 years. Esters were used in WWII by both Germany and the U.S. to keep equipment running under harsh conditions. Only in the last 20 years, however, have end users throughout industry really recognized the cost benefits of synthetics. Now, more and more uses are being found for these formulations and they are experiencing significantly high growth rates.

Synthetics are formulated by combining low molecular-weight materials in a chemical reaction to produce higher molecular-weight materials. These reactions are controlled to produce products with uniform consistency and targeted performance properties. Mineral-based lubricants don’t exhibit the consistency and uniformity that synthetics exhibit, nor do they have the performance properties.

Synthetic classifications There are many types of synthetic fluids. Within the scope of this particular article, we will deal with the most common.

Synthetics are classified into the following major groups:

  • Synthetic Hydrocarbons
    • Polyalphaolefins (PAO)
    • Alkylated Aromatics
    • Polybutenes
  • Esters
    • Diesters
    • Polyol Esters
    • Phosphate Esters
  • Others
    • Polyglycols
    • Silicones

PAOs are the largest synthetic group, followed by esters and PAGs. Most of the discussion will focus on these three synthetic types.


Fig. 1 details the overall advantages of synthetics as a class. Not all synthetics have all these advantages—and some have more than others. Fig. 2 describes some of the disadvantages. Note that this is a composite of all the major synthetic types. The only disadvantage common to all synthetics is cost. For the most common synthetics (PAO, Esters and PAGs) the cost is 3-5 times the cost of a high-quality mineral oil.

The advantages offered by synthetics allow these formulations to be real lubrication problem solvers. The three major categories for synthetic use are:

Temperature extremes—Synthetics are wax-free, so they can be used at very low temperatures. High temperatures (over 200 F) call for the use of synthetics. They should be considered when mineral bulk temperatures reach 180 F. The high- and low-temperature capability of the most common synthetic types is illustrated in Table I. These numbers indicate the highest and lowest levels of operation and are not common operating conditions.

Wear reduction—Synthetics are custom manufactured and the molecular sizes are more uniform than mineralbased products, thereby providing greater film strength and lubricity than mineral oils. Diesters and polyol esters, because of their polarity, have excellent lubricity and film strength, followed by polyalkylene glycols. PAOs, which are non-polar, have the lowest level of lubricity and film strength of this group. The film strength, coupled with additives, helps minimize wear under boundary lubrication conditions.


Energy savings—Many times, the use of synthetics has been justified on energy savings alone. This is particularly true in the case of gearboxes (something that will be discussed in the an upcoming article in this series.) Efficiency is related to lubricity and film strength. Traction coefficient is an important factor with synthetics during elastohydrodynamic lubrication (EHL), which occurs with rolling motion, such as that in bearings and pitch point in gears. EHL lubrication results in a thin film under high pressure that increases the viscosity of the film. The internal resistance of the fluid film to sliding, known as traction coefficient, can affect energy savings in rolling element bearings. PAOs and PAGs have low traction coefficients compared to mineral oils and, as such, can lead to energy savings.

Synthetic types
PAOs are produced by the following reaction:


Decene is reacted with itself to produce high molecular weight hydrocarbons that are linked in groups of 10 carbon atoms; thus, we can produce any molecular weight in groups of 10. The initial reaction involves a reaction of a linear alpha olefin to produce molecular weights in groups of 10 carbon atoms. The final reaction saturates the double bond to produce a PAO.

It is also possible to react dodecene (which has 12 carbon atoms) to produce increasing molecular weights in groups of 12 carbon atoms. For the purposes of this article, however, our discussion will focus on carbon atoms in groups of 10.

PAOs are classified in terms of viscosity at 100 C. Table II illustrates some of their viscosity grades.

By blending different viscosities, there is a great deal of flexibility in creating different viscosity grades with PAOs.

Key properties:

  • Excellent low-temperature fluidity
  • Good high-temperature properties
  • High viscosity index
  • Low volatility
  • Hydrolytic stability
  • Highly compatible with mineral oils
  • Low biodegradability
  • Slight elastomeric seal shrinkage
  • Low additive solvency
  • Low lubricity

PAOs are formulated with 5-20% ester—which is typically a diester—to overcome the seal shrinkage and non-polarity, resulting in good additive solubility and increased lubricity. PAOs have the widest application of any of the synthetics. This will be discussed in the next article

Esters… Two major groups of esters to be discussed are diesters and polyol esters. Diesters are produced by the following reaction:


This reaction is reversible so, in the presence of heat and water, a diester can decompose back to an acid and an alcohol. The conditions need to be severe to cause this reaction to reverse, but it will occur under high-temperature and high-moisture conditions.

Depending on the alcohol and acid selected, a large number of diester types can be produced and tailored to a particular application.


Key properties:

  • Low pour point
  • Low volatility
  • Good thermal and oxidative stability
  • Excellent solvency and cleanliness
  • Good metal-wetting properties, resulting in good lubricity
  • Good biodegradability
  • Poor compatibility with some elastomers, plastics and paints
  • Hydrolyze under high-temperature, high-moisture conditions

Polyol esters… 
These synthetics are produced by reacting a highly branched di-functional alcohol with a mono-basic acid as follows:


This ester is highly branched, which results in the following key properties:

Key properties:

  • Low pour point
  • Low volatility
  • Good viscosity index
  • Excellent thermal and oxidative stability
  • Excellent solvency and cleanliness
  • Very good lubricity
  • Highly biodegradable
  • Slight tendency to hydrolyze under severe conditions
  • Nearly 50% more expensive than diesters

Polyalkylene glycol…
PAGs are quite versatile. Many different types can be created, which allows for a wide variance in properties. PAGs are produced as follows:


Either 100% ethylene oxide, 100% propylene oxide or a combination of the two are used to create many different types of PAGs with unique properties— and with many different molecular weights.

PAGs can be made either water soluble or insoluble. Increasing the ethylene oxide (EO) ratio increases the water solubility and decreases the oil solubility. Water soluble PAGs are inversely soluble, meaning that the solubility decreases with increasing temperature.

Table III illustrates the various ratios of ethylene and propylene oxide and their properties.

Key properties:

  • Versatile with both water-soluble and water-insoluble grades
  • High viscosity indexes
  • Hydrolytic stability
  • Excellent lubricity
  • Low volatility
  • High oxidative and thermal stability
  • Can be formulated to have limited gas solubility
  • Resistant to sludge formation
  • Compatible with most elastomeric seals but may cause slight shrinkage
  • Incompatible with many paints and polycarbonate and polyurethane
  • Incompatible with mineral oil and other non-ester synthetics

Table IV summarizes the strengths and weaknesses associated with each of the major synthetics that have been discussed in this article.

Synthetic fluids are real problem solvers—and very important in improving equipment reliability. Their usage is growing as equipment conditions require higher performing lubricants. In the next installment of this series, selecting the optimal synthetic based on the equipment and conditions will be discussed.

The author wishes to thank Dr. Ken Hope, of Chevron Phillips, and Dr. Martin Greaves, of Dow Chemical, for their assistance in the preparation of this article.

Contributing editor Ray Thibault is based in Cypress (Houston), TX. An STLECertified Lubrication Specialist and Oil Monitoring Analyst, he conducts extensive training in a number of industries. E-mail:; or telephone: (281) 257-1526.

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6:00 am
May 1, 2007
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Connecting With Centralized Lubrication Technology

Every moving part on a machine benefits from timely and effective lubrication to help reduce wear, minimize lubricant consumption and maximize efficiency. These benefits can be more fully realized by introducing centralized lubrication technology to deliver the right lubricant at the right time in the right quantity to the right point of use.

All types of standard and specialized machines can run with centralized lubrication systems. Applications encompass equipment used in a wide range of industries, including automotive, machine tool, metals, printing, paper, food and beverage, mining, chemical, plastics, hydrocarbon processing, refinery and wind energy, among many others. (Commercial vehicles, off-road equipment and rail systems represent viable candidates, too.)

0507_lubesystems_img1In all cases, centralized lubrication feeds lubricant from a central source to the points on a machine or machining system where friction occurs. The goal is to reduce friction and dissipate some of the heat generated by friction. With centralized lubrication, every bearing receives the proper lubricant in an exact amount to minimize wear and promote longer service life. The problems associated with excessive lubrication can vanish, lubricant consumption can fall over time (in some applications by as much as 50% compared with inexact manual methods) and maintenance time, energy and costs can diminish. The only requirements: Refill the lubrication reservoir and occasionally inspect the connected lubrication points.

The potentially staggering number of on-site (and sometimes hard-to-access) lubrication points makes perhaps the most compelling case for implementing centralized (vs. manual) lubrication technology. A customer census, for example, has identified 7500 individual lubrication points for a paper mill; 5500 for an automotive assembly plant; 4000 for a steel mill; 3500 for a refinery; 2000 for a cement mill; 1500 for a plastics plant; and 1000 for a frozen foods facility. Regardless of the number, centralized lubrication systems foster opportunities to improve productivity and profitability by increasing machinery uptime and keeping maintenance issues in check.

System profiles
0507_lubesystems_img2Centralized lubrication technology generally falls under two broad “umbrella” categories: total-loss and circulating-oil systems.

In total-loss systems friction points are always supplied with fresh lubricant (oil, fluid grease or grease) at specific intervals (time or machine-cycle dependent) during the lubricating cycle (such as pump run time). The lubricant is furnished in the proper quantity at friction points to allow for buildup of an adequate film of lubricant during the subsequent idle period. Over time, the forces of aging, evaporation, bleeding and leaks will contribute to partial depletion of the lubricant at the friction point.

Circulating-oil lubrication systems provide for the lubricant to flow back into the lubricant reservoir for reuse after passing through the friction points. In this way, the lubricant carries even more benefits as it transfers forces and damps vibrations; removes abrasion particles from friction points; stabilizes the temperature (cooling or heating) of friction points; prevents corrosion; and removes condensate and process water.

Within the total-loss and circulating-oil categories, primary types of installations include single-line, dual-line, progressive feeder and minimal-quantity lubrication systems. Their profiles are as follows:


0507_lubesystems_img3Single-line. . .
These total-loss lubrication systems supply machinery lubrication points with relatively small amounts of lubricant (oil or fluid grease up to NLGI grade 2) to cover precisely the amount consumed. As such, they operate intermittently as required. Lubricant can be delivered by manually, mechanically, hydraulically or pneumatically operated piston pumps or by electrically driven gear pumps. In single-line systems, lubricant is metered out by piston distributors installed in the tubing system. Exchangeable metering nipples on the distributors make it possible to supply every lube point with the requisite amount of lubricant per stroke or pump work cycle. Metered quantities can range from .01 to 1.5 ccm per lubrication pulse and lube point. The amount of lubricant to be fed to the lube points can also be influenced by the number of lubrication pulses.

The standard layout of a single-line total-loss lubrication system incorporates a pump and spring-loaded piston distributor; main line (connecting to pump and distributor) and secondary line (connecting to distributor and lube point). Performing as a total-loss lubrication system, an oil return line from the lube point to the oil reservoir is unnecessary.

Dual-line. . . 
These systems can deliver oil or grease (up to NLGI grade 2) to as many as 1000 lube points (and distribution points can be easily added or removed). They can be configured to run either as total-loss or circulating-oil versions.

Dual-line layouts consist of two main lines with their respective secondary lines and fittings; an electrically driven pump with reservoir; dual-line feeders; reversing valve and control unit.

All the distributors of a dual-line system are pressurized at the same time— resulting in low pressure losses—and the “reset” of the delivery piston is simultaneously the second delivery stroke, which takes place at full pump pressure. This is what makes dual-line versions especially suitable for extended systems and more viscous types of grease. Assemblies with or without compressive seals can be specified to accommodate light and heavy-duty operating conditions.

Progressive feeder… 
0507_lubesystems_img5Whether functioning as a total-loss or circulating-oil system, progressive feeder systems are intended for intermittent delivery of lubricant (grease up to NLGI grade 2) and are capable of handling up to several hundred lube points. They also offer the ability to provide central monitoring of all feeder outlets, if desired, at relatively low cost.

Progressive feeder installations use pneumatically or manually operated or electrically driven piston pumps. Metered quantities of lubricant are fed progressively in predetermined ratios from master feeders to the lube points, either directly or via a secondary downstream feeder. The lubricant does not leave the respective feeder until the preceding one has discharged its volume. If a lube point does not accept any lubricant, regardless of the reason, or if a secondary feeder is blocked, the entire lubrication cycle is interrupted, which can be used to emit a signal to alert operators to the problem.

These specialized types of total-loss metering systems have been variously engineered for the lubrication of tools and chains, oiling of joined parts and converting from “wet” to “dry” machining operations, where only a minimal amount of lubricant (10ml to 50ml per hour) is required to prevent premature tool wear and/or a poor work piece surface finish.

Minimal-quantity lubrication (MQL) replaces traditional “flood” coolant lubrication by enabling lubricant to be fed to the exact friction point between the tools and work piece externally or from the inside through the tool. Combined systems have been developed to accomplish both.

In an external volumetric MQL system, both lubricant and air are supplied to a spray nozzle or mixing point via coaxial feed lines. The lubricant is then atomized using compressed air and applied to the work piece or tool. In an external, continually dispensing system, oil mist is generated in the supply unit and a feed line supplies the aerosol to the tool or work piece. Using internal MQL, the tool applies the aerosol directly to the lubrication point.

By converting from conventional “flood” lubrication to minimal-quantity lubrication for some equipment, shorter production times can be achieved. Cost savings from this method can result from, among other things, cooling lubricants becoming redundant and elimination of entire machine tool components (such as lubricant filters and conditioning installations) and the expense associated with the disposal of chippings and cooling lubricants.

Installation notes 
Decision-making for the most appropriate system will depend, in general, on the application and, in particular, on a range of other parameters, such as the operating conditions (variations in the operating temperature and lubricant viscosity); accuracy requirements for lubricant quantities system geometry (size, dimensions, and symmetry); and monitoring demands, among others. When planning and subsequently installing a centralized lubrication system the following guidelines can help advance the process:

  • Determine the number of lube points.
  • Factor in the amounts of oil required per lube point and the total amount of oil required per stroke (with piston pumps) or work cycle (with gear pumps).
  • Select the distributors in accordance with the metering range and available space. A distinction must be made between oil-only distributors and those that are also suitable for fluid grease.
  • Choose pumps consistent with the type of actuation and capacity of the system.
  • Determine the type of control for the automatic system (timeor load-dependent) and any monitoring system that may be required.
  • When installing a system, lay out all the main lines and distributors to enable air in the system to escape on its own via the lube points.
  • Check the resistance in the main line, particularly regarding the relief process, when especially large and widely branched systems are involved and when high-viscosity oils are used.

When centralized lubrication systems are properly designed and implemented, advantages will flow. Users can expect reliable lubricant coverage (especially important for machines with dozens or more lubrication points); optimal lubrication intervals and dynamic lubrication; enhanced oversight (supported by available integrated control units and fill-level monitoring); and lubricant consumption-specific setup and adjustment of maintenance intervals via different sizes of pumps and lubricant reservoirs.

It is important to take care during the installation, startup and maintenance of any centralized lubrication system. The designated system should receive the same attention as all other sophisticated equipment on a machine. Partnering early in the process with an experienced, knowledgeable expert can help fulfill the promise these systems can deliver.

Jerry McLain is business development manager, Lubrication, for SKF USA Inc. His experience includes assisting in the development and implementation of customized machinery and equipment lubrication programs for industry. Telephone: (513) 248-4335; e-mail:

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6:00 am
May 1, 2007
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Education and Training

Training has changed radically over the past decade. Nowhere are these changes more evident than in the maturation of training that is based on or utilizes electronic media, including numerous additions to the training lexicon.

Here are just a few of the most important terms maintenance professionals need to know as they make their way through the new education mazes.

Asynchronous training/learning…
Any training program that does not require the student and instructor to participate at the same time. Common examples are self-paced, online tutorials.

Blended learning…
A training curriculum that combines multiple types of media. Blended learning usually refers to a combination of classroom-based training with self-paced e-learning.

Classroom training…
Any training that takes place with the students and facilitator interacting in a real, physical classroom. A form of “instructor-led training (ILT)” which, although there is an instructor, could still take place over an Internet connection.

Collaborative learning…
Learning through the exchange and sharing of information and opinions among a group. Computers and the Internet have enabled collaborative learning for geographically dispersed groups.

Computer-based training/learning/education (CBT, CBL or CBE)…
Any computer program used by a learner to acquire knowledge or skills.

Software used to support educational activities.

Distance learning… 
Education and training activities in which the instructor and students are separated by time, location, or both. Distance learning may be synchronous or asynchronous.

Broad defi nition of the fi eld of using electronic technology to deliver learning and training programs. e-Learning applications and processes include Web-based learning, computer-based learning, virtual classrooms, and digital collaboration. Content is delivered via the Internet, intranet/extranet, audio or video tape, satellite TV, and CD/DVD.

Kirkpatrick Evaluation Model… 
The four-step training evaluation methodology developed by Donald Kirkpatrick in 1975. Level 1 refers to the students’ reaction to the training. Level 2 refers to the measurement of actual learning (i.e., knowledge transfer). Level 3 measures behavior change. Level 4 measures business results.

Learning management system… 
A program that manages the administration of training. Typically includes functionality for course catalogs, launching courses, registering students, tracking student progress, and assessments.

Stands for “mobile learning” and refers to the usage of training programs on wireless devices like cell phones, PDAs, or other such devices.

Synchronous training/learning… 
Any training program in which the student and instructor participate at the same time. Traditional classroom training and an instructor-led chat session are forms of synchronous training.

Technology-based training (TBT)…
Term encompassing all uses of a computer in support of learning, including but not limited to tutorials, simulations, collaborative learning environments, and performance support tools. Synonyms include CBL (computer-based learning), TBL (technology-based learning), CBE (computer-based education), CBT (computer-based training), e-learning, and many other variations.




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6:00 am
May 1, 2007
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Lubricant Analysis Supports Predictive Maintenance


Today’s most successful lubrication programs—those that boast high percentages of equipment availability and enviable machine longevity—depend heavily on identifying contaminants in lube oils and other factors that can cause mechanical damage. Identification of the root causes of internal damage is definitely part of effective lubrication management. Information on the type and extent of contamination then can be utilized for predictive maintenance to avert breakdowns and extend equipment life.

Too often, however, a “lubrication program” is limited to selecting the correct lubricant for each type of machine and following recommended oil change schedules.

The most effective lubrication programs seek to identify the presence of contaminants and apply that information as a guide to future maintenance. Such programs seem to reflect the following commonalities:

  • A motivated manager who is passionate about protecting plant assets and takes the initiative in establishing contamination controls;
  • Periodic on-site analysis of oil samples taken from operating machinery; and
  • Corrective maintenance based on predicting trouble ahead.

Periodic monitoring for metal fragments, dirt and debris, water and other contamination in a lubricant leads to the early recognition that internal damage may be occurring. Maintenance or repairs in response to such knowledge make it possible for these machines to run longer than ever imagined—which can lead to substantial economic benefits for a facility.

An effective program
An effective lubrication and oil analysis program at the General Motors Truck and Bus Assembly Plant in New Jersey recorded an ROI of 738% on the expenditure of $100,810, after a critical gearbox failure caused a very costly 27-hour shutdown. On-site oil analysis yielded reliable information regarding the condition of lubricating oils, and timely oil replacement plus some necessary repairs allowed Maintenance personnel to quickly bring the problems under control. Simply eliminating damage to machinery resulted in documented savings of $1.6 million over the next 28 months, not including the savings achieved in avoiding unexpected downtime.

Predictive maintenance 
Predictive maintenance (PdM) has been shown to be less costly than either reactive maintenance (i.e. fixing something after it breaks) or preventive maintenance, which requires significant staffing to perform the numerous tasks recommended by machine manufacturers. PdM programs are built on field-generated information that is evaluated by managers and supervisors in determining just when to perform maintenance in order to maximize productivity without endangering a machine or chancing downtime. Information on the condition of each machine is matched against its importance in the overall production process. Machines that are critical to maintaining production—key turbines, compressors, pumps, etc.—are watched carefully so as to predict future performance. When lubricant samples reveal signs of degradation in such a machine, managers have to quickly determine whether immediate repairs are necessary to prevent a catastrophic failure or whether they can wait for a regularly scheduled shutdown to make repairs.

Oil analysis enabled a large pulp and paper mill in the southeastern U.S. to avert the failure of a wood chipper that could have cost the company as much as $100,000 in repairs and lost production time. Fragile babbitt bearings guiding the chipper shaft were fragmenting, possibly due to a slight misalignment or imbalance, and the wood yard supervisor was not aware of the condition. Fortunately, the source of the fragments was identified through analysis of oil samples from the chipper and repairs were performed in time to prevent an unplanned shutdown.

The chipper had been receiving what was considered adequate lubrication—a quarterly oil change along with filtration. However, calendar-based lubrication often is not satisfactory, especially in dirty, dusty areas where oil quickly can become contaminated.

In less critical cases, predicting the runtime of a machine based on its lubricant may result in slating that machine for repair during the next scheduled maintenance period. If the oil is in good condition when tested, it even may be possible to extend the time before an oil change. Lubrication is always most effective and cost-efficient when oil changes are based on the condition of the lubricant, not a predetermined schedule.

The analytical program 
The condition of operating machinery may be determined best through a well-structured program of lubricant sampling and oil analysis—but not all oil analysis programs are equal. Just because your plant engages in some form of oil analysis, you can’t assume that your machinery is well protected.

The purpose of oil analysis is to identify lubricant components that indicate wear caused by abrasion, adhesion and corrosion. Careful sampling, reliable testing and knowledgeable analysis of the test results are the basic elements of a solid program to determine whether lube oils are contaminated or changed in character. This information can be crucial in predicting when maintenance should be performed.

Samples should be collected and tested often enough to detect contamination and chemistry problems and to establish trends. It’s important to be sure sampling is frequent enough to give maintenance personnel time to respond. For example, if contamination due to a bad seal could lead to damage within three months, samples should be taken from that machine at least monthly to identify a problem early enough to replace any faulty seals. In other cases, experience may show that periodic sampling can be extended.

How many samples should be collected? Every plant is different, but most can realize excellent cost savings based on knowledge gained by collecting, testing and analyzing about 100 lube oil samples each month. Some intensive programs actually test more than 1000 samples per month.

Rule of Thumb: If there are 3000 vibration points in the oil lubricated pumps, motors, compressors, turbines, gearboxes, air handlers and other rotating machinery in your plant, at least 100 oil samples should be tested monthly to complement vibration monitoring.

Quality and reliability are the most important objectives of sample testing that can be performed offsite by a lube oil supplier or an independent laboratory. A well equipped in-house lab also is capable of doing all the essential tests, including quantitative and qualitative particle counting, particle size distribution and wear debris analysis.

Lubricant suppliers should remain just that—suppliers— and should not be involved in testing for a variety of reasons. Since they have a vested interest in retaining your business, suppliers may tend to overstate the condition of tested samples, which can result in unnecessary and costly oil replacement. Beware the supplier who offers free oil analysis as a value-added service. Such programs are generally worth about what you pay for them.

Many independent testing laboratories produce excellent results, but the going price for oil analysis by an independent lab today is about $35 per sample, or $3,500 per month for a 100-sample program. Well-equipped on-site labs operated by trained analysts can be equally effective at a lower per-sample cost.

On-site labs make good sense for plants with more than 100 oil systems in that the site can maintain better control over the samples, and testing can be done as often as necessary. Since results are available immediately, if any of them are questionable, retesting can be done very quickly.

The key to success with an on-site program is having a well-trained, in-house champion with a vision for improvement. Such was the case at the previously-referenced Southeastern paper mill, where testing equipment, similar to that shown in the accompanying photo, was installed for oil analysis. Enthusiasm for the mill’s program grew as it received credit for more and more savings.

One individual should be responsible for taking the lead in oil sampling and on-site testing. That person should be trained in testing and analysis—and should be excited about the possibility of saving money for his or her company. Formal training is essential. The Society for Tribologists and Lubrication Engineers (STLE) provides training and certifies individuals as Lubrication Specialists and Oil Monitoring Analysts. The standards for these courses are high and the exams are not easy. Training and certification also is available from many equipment vendors.

This is the real measure of effectiveness. A successful PdM program prevents costly problems and has documentation to prove it. A saving of $250,000 in the first year of an inhouse analytical program is not an unreasonable expectation in a large plant. Dedicated oil analysis will identify potentially costly problems that can be averted and oil consumption will be reduced.

Savings often are achieved by adopting a plan of “as needed” replacement rather than changing oil periodically. If analysis shows a lubricant to be free of contamination, there’s no need to replace it based on the OEM-recommended schedule. Therefore, lubricants frequently last longer than expected, especially in clean environments. Mike Lawson at the Bowater Paper Mill in Calhoun, TN, says he can do a lot of testing at $15 per sample rather than replace the 35 gallons in a gearbox at a total cost of about $480. That includes $140 for the oil, $240 for two mechanics working six hours, $50 to dispose of the used oil and another $50 to restock. As Lawson noted in another article published in this magazine, “When test results show that there is nothing wrong with the oil in a gearbox or other machinery, we don’t change it. Most times it is not degraded and is actually quite clean.” [Ref. 1]

Other elements 
Remember: Oil analysis is just one part of a comprehensive PdM program that also includes vibration monitoring and analysis, ultrasonics and thermography. Oil analysis supplements vibration monitoring and analysis by revealing two key root causes of machinery failure—changes in oil chemistry and oil contamination.

Predict, then act
Any good sized plant that is collecting and testing fewer than 50 lube oil samples per month is probably missing problems that are costing far more in labor (and other expenses) than the price of a more expansive program. It takes a person familiar with the layout about one week a month to collect and test 100 samples from critically important equipment. The payoff in both labor and cost savings is far greater than the time spent doing this work. As a certified technician at the first mill mentioned in this article said, “Our new on-site oil analysis system definitely paid for itself very quickly. We now do condition-based monitoring, oil analysis and predictive maintenance, and we’re light years ahead of where we used to be.”


  1. Garvey, Ray, and Martin, Ray, “The Bill Is Coming Due” (Lubrication & Fluid Power, November-December 2005)

Ray Garvey is the Tribology Solutions manager at Emerson’s Machinery Health Management Division in Knoxville, TN. Telephone: (865) 675-2400 ext. 3435; or

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