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How Qualified are You to Detect and Correct Shaft Alignment?

by John Piotrowski

     Purchasing an alignment measurement system does not necessarily qualify you as an alignment 'expert'. What is the best method to measure misalignment under different circumstances? What effect does excessive 'soft foot', runout, and piping stress have on rotating machinery? What are the different levels of testing that can be performed at your plant to determine the skill level of the people responsible for alignment? What sort of training is required to become proficient in this area? The effectiveness of written or oral exams, simulated misalignment test, and actual on the job skills testing on process machinery is discussed.

Why do certification testing?

     Perhaps several true life examples will illustrate the need for certification testing in shaft alignment.

- A maintenance technician at a chemical plant was asked to align a motor and a pump with a newly purchased laser shaft alignment system. Shaft position measurements were captured with the instrument and the alignment corrections required to align the motor (assigned as the movable machine) to the pump indicated that the outboard end of the motor had to be lowered 85 mils and the inboard end of the motor had to be lowered 37 mils and there was no shim stock under any of the motor feet. After completely removing the motor, the technician began grinding the baseplate away. The motor was place back on the base and shaft position measurements were captured again. The technician then added shims under the motor since too much metal had been ground away and several side to side moves were made to bring the equipment into alignment.

- A company who manufactures gas turbines was in the process of installing several large air compressors to expand the capacity of the compressed air system used to test their jet engines. Requests for bids were sent out to several general contractors to install the 11,000 hp motors, gearboxes, and compressors. Very detailed specifications were sent to each of the general contractors including very specific instructions on installation of the foundations, sole plates, correcting 'soft foot' conditions, rough alignment procedures, final 'cold' alignment procedures, and 'hot' alignment procedures. The general contractor was told to sub-contract the alignment work to companies who specialize in machinery alignment. When the alignment specifications were sent to the 'alignment' sub-contractors, several of the contractors did not understand many of the detailed specifications for the required work but submitted bids anyway believing that no one would check their work. The contract awards were dispensed and toward the completion of the project the company discovered that the alignment work was not performed to the written specifications and withheld payment to the contractors who performed the work (or lack thereof).

- A company who was in the process of becoming ISO 9000, 9001, and 9002 compliant, requested information on who administers certification testing for their maintenance personnel for shaft alignment. Several of their people had been certified in vibration analysis and thermography and they wanted to show documentation that their personnel were adept at not only finding problems but also adept at fixing them.

- A petroleum company decided to sell one of their facilities and several of the prospective buyers were interested in retaining as many employees as possible. However they only wanted to hire the people who were adequately trained and were certified to do certain tasks. When asked to provide information on task certification of their employees, the petroleum company was unable to provide the information.

- A steel company was having some problems with a fairly complex, multiple element drive train where misalignment was found to be the root cause of the failures. No one in the plant knew how to align the drive system. An alignment service company was contacted and the technician said that they could align the drive system in less than 4 hours. When the work was actually done, the job took several days to complete.

- An electric utility company had experienced several failures on a critical pump. The in-house maintenance personnel had been using a laser shaft alignment system to measure the positions of the shafts. The pump was being driven by a variable speed hydraulic clutch and the manufacturer of the clutch stated in the instruction manual that the clutch would raise upward 15 mils once it attained normal operating conditions. The maintenance personnel henceforth set the clutch 15 mils lower than the pump shaft assuming that the pump would not move from off-line to running conditions. A survey was conducted that showed that the pump shaft raised upward far greater than the clutch did forcing the unit to run under severe misalignment conditions.

     Twenty years ago, there were so few people doing vibration analysis, IR thermography, and oil analysis compared to today that companies we delighted to have anyone taking vibration or thermography data. With a couple thousand dollars, anyone could buy a hand held vibration meter, an oscilloscope, or a swept frequency analyzer (FFT analyzers and computers weren't readily available back then). Today, the equipment available to us for vibration and thermography is far superior to the instruments of twenty years ago and the number of people working in these areas has increased substantially. With a couple thousand dollars, anyone can buy a personal computer and a vibration data collector and a good IR camera and be in business.

     Most of us are keenly aware that purchasing this equipment does mean that we know how to use it. Buying a vibration analyzer does not make one a vibration analyst, nor does and IR camera qualify someone as knowledgeable in thermography, or a scalpel magically transform someone into a surgeon. The learning curve for this equipment and the knowledge to use it properly is long and steep. Determining what buttons to push, how to operate the software program that came with the instrument as well as learn how to use a computer can consume several months of time. Once you've figured out how to operate the equipment and begin to collect data, the next task is to ascertain what the data is telling you so some sort of judgement on the condition of our machinery can be made. This part can take years to become proficient at since the equipment being monitored at your plant doesn't necessarily follow generic equipment deterioration 'patterns' and proper condition assessment can only be realized with experimentation and experience. During its infancy, many CBM programs have turned people off because one or two bad 'calls' were made assessing the condition of the machinery. People get really mad after tearing down a machine to find that nothing or very little was wrong when you made it sound like the machine was about to catastrophically fail.

     So it became apparent that these CBM/Predictive Maintenance programs only worked effectively after the people have received adequate training. Consequentially the people went to the training courses. Some people learned a lot, some learned a little, and some had their minds occupied elsewhere during the training courses. Those who worked hard and learned a lot started wondering how they could prove that they knew more than those who didn't.

     Henceforth came the 'certification' testing along with the arguments and disagreements on who had the authority to dispense 'certification' in the first place. Over the past five years, there has been a lot of effort put into determining the skill level of people working in vibration analysis and infrared thermography through qualification/certification testing by several companies and/or institutions. Some people may disagree with the need for testing, but it has become a way of life and many companies are requiring their employees to become certified in these areas. In fact, this made people begin thinking about certification for several other kinds of 'tasks' performed in the industrial work place. If certification is desirable for methods to detect problems with rotating machinery, then certification should also be desirable for correcting problems with rotating machinery such as balancing, shaft alignment, and tribology for example.

     How qualified are people in finding and correcting shaft misalignment however? As more companies are turning to 'Task Based Training' and 'Task Based Testing', what is the best way to determine if people are suitably qualified to do shaft alignment? Another facet that should be addressed is ... how qualified in shaft alignment are the contractors who are installing new rotating machinery?

     Before qualification testing begins, you should have a fairly good idea of how knowledgeable you and your coworkers (or the contractors you hire) are in the field of shaft alignment already so unnecessary training isn't done. Assessing what you and your coworkers know about shaft alignment can be done by soliciting the employees through an Experience Evaluation Form that queries their knowledge and experience on specific types of machinery and specific types of tasks performed on this machinery. The next step is to test each individual on the tasks that they said they were adept at to determine if they are truly capable of performing that task and if not, what supplementary training would be required to elevate their level of proficiency. In summary, what do you think you know, what do you actually know, and what do you need training in?

Who needs to needs to be trained and/or qualified in shaft alignment?

     Many organizations feel that the full responsibility for shaft alignment rests solely in the hands of the trades people (e.g. mechanics, millwrights, pipefitters, electricians). Ask yourself these questions. Is it the responsibility of a trades person to: - Pick training courses they feel they need and send themselves to the course(s)? - Research all of the available types of shaft alignment measurement systems and purchase a system that best fits the needs of their organization? - Tell a contractor that they are not installing new rotating machinery correctly? - Hire some new people or a contractor to help with the work overload? - Rebuild a piece of rotating machinery due to excessive runout conditions? - Determine that a rotating machinery foundation or baseplate has be removed and reinstalled if it has deteriorated excessively or been installed improperly? - Redesign and rework improperly installed piping that is putting and excessive strain on the rotating machinery itÕs attached to? - Purchase and install piping supports or design a custom piping anchor on a CAD system, purchase the materials, and install the anchor? - Select a new flexible coupling design to replace one that doesn't work well or fails often? - Pick a pump to be the 'moveable' machine and leave the motor as the 'stationary' machine? - Issue work orders to check the alignment of all the rotating machinery every year? - Shut a machine down based on vibration and temperature data that indicates a misalignment or 'soft foot' condition? - Determine which machinery might need to have the 'hot' alignment checked, select an off-line to running machinery movement measurement technique, install the equipment on the machinery, measure and analyze the data, and alter the 'cold' alignment position based on the data collected? - Maintain records of the alignment work that was performed and save it in the equipment files or computer data base? - Install X-Y proximity probes on a machine supported in sliding type bearings to analyze the Lissajous orbit for signs of running misalignment?

      I wouldn't be surprised if a lot of managers, engineers, front line supervisors, and trades people felt that some, if not several of the above items are not their responsibility (let alone what some of them mean). Well then, if the trades people aren't responsible for some of the above items, then who is?

     Shaft alignment training should be for managers (who can't understand why alignment takes longer than 45 minutes), engineers (who were never taught this in school and are rarely allowed to do 'hands-on' work), technicians (who are asked to identify it through CBM programs but don't know how to correct it), front line supervisors (who need to help the trades people if they get stuck or need a special tool for the work), and trades people (who are the ones ultimately responsible for the final outcome) to give them the minimum working knowledge to achieve accurate alignment and to let them know what's involved in the overall alignment process. Since it is apparent that trades personnel should not be accountable for every facet of shaft alignment, several people need to be trained and qualified in whatever tasks they are responsible for. Engineering and maintenance managers, rotating equipment and maintenance engineers, maintenance technicians, vibration specialists, foremen and front line supervisors, as well as the trades personnel all should be trained and qualified to do their respective tasks. 

Assessing a persons knowledge and experience level in shaft alignment

     Field Experience Evaluation forms (shown at the end of this article) which could be used for your in-house personnel or for contractors working at your plant site. Part 1 identifies the person and what their job titles are (or have been). Part 2 gives you an indication of what type of rotating machinery a person has worked on in the past. Part 3 gives you some idea of the training a person has received in different shaft alignment measurement tools and techniques. Part 4 lists the amount of actual filed experience a person has in measuring shaft alignment when the equipment is off-line. Part 5 lists the amount of actual filed experience a person has in measuring off-line to running machinery movement (aka thermal movement or 'hot' and 'cold' alignment). 

Alignment qualification / certification testing

     The Experience Evaluation Form can be used to determine what training is required for personnel installing, maintaining, or aligning rotating machinery. However anyone could fill out the form and say they were proficient and experienced working with every type of rotating machine and alignment method listed but how can they verify what they say they know? Written or oral examinations are one mechanism to verify a persons knowledge level for each item in the Experience Evaluation Form. There could be one comprehensive test administered that encompasses every facet of shaft alignment or there could be a series of tests given for discrete blocks of information. By breaking down the overall body of information into separate blocks, the people with little or no experience could be tested incrementally as their level of knowledge grew. 

     A Basic or Level 1 examination would test the individuals knowledge on the following blocks of information :

     ¥ the detrimental consequences of poor alignment on rotating machinery - detecting misalignment on running rotating machinery (i.e. vibration, IR methods) - use and care of measuring tools and instruments (feeler gauges, dial indicators, optical encoders, laser/detector system, proximity probes, etc.) - finding and correcting excessive runout conditions - finding and correcting 'soft foot' problems - finding and correcting excessive piping strain - foundation and baseplate design, installation, and care - concrete and grouting installation - alignment tolerances - rigid and flexible coupling design, installation, and care - how to perform the Reverse Indicator method - basic mathematical or graphical/modeling principles for re-alignment - how to determine effective alignment corrections using the Reverse Indicator technique - keeping records of alignment work

     An Intermediate or Level 2 examination would test the individuals knowledge on the following blocks of information :

- how to perform the Face & Rim method - how to determine effective alignment corrections using the Face & Rim technique - how to perform the Shaft to Coupling Spool method - how to determine effective alignment corrections using the Shaft to Coupling Spool technique - how to perform the Double Radial method - how to determine effective alignment corrections using the Double Radial technique - how to perform the Face-Face method - how to determine effective alignment corrections using the Face-Face technique - mathematical or graphical/modeling principles for all of the above methods 

     An Advanced or Level 3 examination would test the individuals knowledge on the following blocks of information :

- how to align multiple element drive trains - how to align right angle drives - the four general categories for measuring off-line to running (OL2R) machinery movement (aka 'hot' and 'cold' alignment) - calculating machine case thermal expansion - inside micrometer-tooling ball-angle measurement methods - proximity probes with water cooled stands technique - using optical alignment tooling for OL2R machinery movement - alignment bars with proximity probes OL2R method - using laser-detector systems to measure OL2R machinery movement - using the Ball-Rod-Tubing Connector system to measure OL2R machinery movement - using the Vernier-Strobe system to measure OL2R machinery movement - mathematical or graphical/modeling principles for all of the above methods - how to align rotating machinery to compensate for OL2R machinery movement

 

     Written or oral exams can test a persons knowledge on a subject but is somewhat inadequate in determining a persons skill level in performing specific tasks. Shaft alignment is a 'hands on' task. Someone can understand how the Reverse Indicator alignment method works but not be able to perform the method correctly.

 

     Perhaps the most effective means of verify a persons knowledge and skill level is to have the person perform the task on a simulation machine or directly on a operating rotating equipment drive system at the plant site. However using process machinery as a test platform may not be possible. What if the equipment canÕt be shut down for a schedule test time, or what if the person being tested misaligns the machine and no one checks to see that itÕs not correct? By having simulation equipment available, testing can occur at virtually any time without impacting on production or maintenance schedules. For accurate skills assessment, it is important to insure that the test equipment simulate 'real life' circumstances.

Conclusions

      In todays society, specialized jobs in many different areas require some sort of certification to verify that an individual is proficient in that task. In the health, education, and finance industries for example, doctors, nurses, teachers, and accountants must show that they are certified in those areas before they are even considered for employment. In industry, welders must be certified before they can work on pressure vessels and HVAC technicians must be certified to work with freon refrigerants. You can't even drive a car or fly a plane without a license! The need for qualification / certification testing in specialized tasks such as vibration analysis, thermography, and shaft alignment is justifiable. Establishing the requirements for qualification or certification can be accomplished by appraising the experience level of personnel through an evaluation form that addresses all of the aspects of the task. Skill requirements for each individual can then be assessed and appropriate training can be administered. Written/oral exams and/or task simulation tests can then be conducted to determine the true proficiency of the individual. Although most of us don't like to be tested on what we know (or think we know), appraising our skill level is beneficial to the companies or customers we all work for. Certification / qualification / licensing examinations can be used as an effective tool in verifying an individuals level of proficiency in any specific task and a viable mechanism to let someone know where they need additional training.

References

Guidebook for Maintenance Proficiency Testing, Electric Power Research Institute, December 1989, EPRI NP-6679.

Handbook for Evaluating the Proficiency of Maintenance Personnel, Electric Power Research Institute, March 1988, EPRI NP-5710. 

Experience Evaluation forms

This article is provided courtesy of Turvac Incorporated.

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