Another Untrained Mechanic Is Almost Killed While "Testing" A Hydraulic Cylinder

An untrained mechanic and a hydraulic flow meter - a lethal combination!

Most maintenance people’s hydraulic diagnostic skills are acquired at the college of trial and error. Ironically, even the companies who design and manufacture flow meters don’t fully understand how, and where, to use their products to test hydraulic components safely and effectively.

The proper and safe use of a flow meter can only be achieved if a person is thoroughly trained in three disciplines:

1. Hydraulic safety.

2. Basic hydraulic laws and principles.

3. How to test hydraulic systems and components.

1. Hydraulic Safety - Hydraulic systems present a wide variety of unique safety hazards. An awareness of these safety hazards can only be garnered through training that focuses on all aspects of hydraulic safety.

2. Basic Hydraulic Principles and Laws - Every element of hydraulic component and system function is, in one way or another, tethered to a basic hydraulic principle or law. These principles and laws CANNOT be learned through on-the-job training - or more appropriately; trial-and-error.

3. How To Test Hydraulic Systems and Components - Once a person has a thorough understanding of hydraulic safety; principles and laws that govern hydraulics; the purpose of the primary components in a hydraulic system; and finally, the theory-of-operation of each of the primary components, they are ready to advance to learning and understanding how to execute safe and meaningful diagnostic procedures.

One of the challenging aspects of testing the volumetric performance of hydraulic components is knowing what the normal leakage rates of hydraulic components are. The question is: "how is it possible to determine what abnormal leakage rates are, if you don't know what normal leakage rates are, to begin with?"

This is again, where the hydraulic industry fails dismally. The few technicians that have instruments to test leakage, usually have no idea what they are looking for because they may not know what particular pump's volumetric efficiency is. Accordingly, if they don't know what normal is, they will have difficulty figuring out when a particular pump's leakage becomes marginal, and then unacceptable. It's safe to say that 99% of the time hydraulic components manufacturers leave the decision as to when to retire a hydraulic component at the discretion of the end user - very confusing to say the least!

In my book, "Performance Testing Hydraulic Components Using Leakage Path Analysis Methods," I provide normal, marginal, and unacceptable leakage rates for ALL hydraulic components.

Ironically, while the “health” of hydraulic components is determined by analyzing leakage rates, there is little or no comparative data available to support a technician’s findings.

In fact, while the industry marches out of step with regard to safety, it appears to march in-step with regard to component testing. For example, the entire industry embraces the case flow test for hydraulic pumps and motors. Yet, the so-called “case flow test” has a 95% margin of error. This proves that the vast majority of so-called “test procedures” floating around the industry are “plagiarized.” It is blatantly apparent that no-one has paused to question the merits of the many component test procedures.

Case In Point

A mechanic, with no formal training in hydraulics, was asked by his supervisor to determine why the bucket on the company’s front-end loader was drifting down when the directional control valve was in neutral. Although he had never personally used a flow meter, he had, during the course of his career, watched a person use a flow meter to test a pump. He found an inline, analog type, flow meter lying on a shelf, so he cleaned it off, installed the adaptors he needed to install the flow meter in the transmission line at the most accessible point, which in this case was the rod-end of the cylinder. He had no idea that the flow meter was designed to permit flow in one direction only. This was not shown anywhere on the flow meter, which is, in and of itself, a "failure to warn" issue.

Note: A flow meter is not the correct instrument for testing hydraulic cylinders. A MicroLeak test makes it possible to test cylinders with the power safely isolated. The test takes only 15-minutes.

Caution: Flow meter manufacturers (in-line analog type) generally do a very poor job of indicating whether a flow meter is a uni-directional type or a bi-directional type.

After the mechanic installed the flow meter, he asked the operator to start the machine, and cycle the cylinder so he could observe the flow meter. When the cylinder rod was retracting, all seemed well. As soon as the operator extended the cylinder rod, there was a thunderous explosion. Oil spewed from the cylinder at extreme velocity and pummeled his body. The force of the oil literally “blew” his hard-hat and safety glasses off, and filled his eye sockets with hydraulic oil.

The operator shut the machine down and rushed to his aid. The mechanic was fortunate in that he did not (this time) suffer a lost time injury. The mechanic initially thought the hydraulic hose had burst. Upon inspection, he found there was a gaping hole in the flow meter. Of course, he had no understanding why.

His supervisor, who was as equally ignorant about hydraulics as the mechanic, simply wrote the failure off as a being caused by a "defective flow meter." The company never conducted a formal investigation to determine the root cause of the failure. Moreover, even though the company had a near-miss reporting program, the accident was never recorded as a near-miss.

There is no doubt that training would have prevented this accident.

A course in basic hydraulics would have taught the mechanic about force, pressure, and area as it applies to a hydraulic cylinder. He would have learned that a double-acting, single rod hydraulic cylinder is, in addition to being a device which converts fluid energy into linear mechanical energy, is also a device, which can amplify flow and pressure.

Incidentally, less than 1% of America's technical colleges teach students how to use electronic flow meters. Ironically, over 99% of college's automotive departments teach students how to use state of the art tools and equipment like electronic wheel alignment, digital analyzers, etc.

Hydraulic system design engineers totally ignore the fact that hydraulic systems must be to incorporate ways that make it possible for technicians to safely perform routine component performance testing. Moreover, there is only one way to determine the volumetric efficiency of a hydraulic pump scientifically; and safely, and that's with a flow meter, which is equipped with a load cell.

Let me explain how a double-acting single rod cylinder amplifies pressure.

Let's say that a given cylinder has a rod-to-bore ratio of 2:1. This means that the major area of the cylinder piston is 10 square inches (25.4 cm) and the minor area is 5 square inches (12.7 cm). Let's also say that the system's pressure relief valve is set at 3000 PSI (207 bar).

The formula for cylinder force is: FORCE = PRESSURE x AREA, then 3000-PSI (207 bar) X 10 square inches (25.4 cm) = 30,000 pounds (1360.7 kg).

Now, let's focus on pressure. If the formula for pressure in a cylinder is: PRESSURE = FORCE ÷ AREA, and there are 30,000 pounds (1360.7 kg) pushing on the confined liquid in the rod end of the cylinder, if the piston's minor area is 5 square inches (12.7 cm), then the pressure is 6,000 PSI (414 bar).

Untrained people have no clue what they get themselves into when they "test" hydraulic components without the proper training. In this case, the maximum pressure rating of the flow meter was 3000 PSI (207 bar), and the untrained mechanic unknowingly subjected it to 6000-PSI (414 bar). Bear in mind, test equipment is always within an arm's length from a mechanic's face.

Here Is What Happened -

The type of flow meter the victim used was equipped with an internal check valve, which permitted flow in one direction only (see schematic below). When the operator was instructed to cycle the cylinder – retract and extend the rod – the check valve blocked the flow causing the pressure in the rod end of the cylinder to amplify to twice it's maximum rated pressure.

The photographs below show how the extreme pressure literally “blew” a gaping hole in the flow meter.

CONCLUSION:

Over 99% of America’s maintenance workforce that work on and around hydraulic systems have never received training in hydraulic safety. Over 80% have never received formal training in fundamental hydraulic.

Warning - Despite what the so-called "experts tell you, NEVER "test" hydraulic components by discharging hydraulic oil to atmosphere - it could severely injure or kill you. I have many more articles coming up that will make that abundantly clear.

If the college you are attending teaches you to "test" hydraulic components by discharging hydraulic oil into a "bucket," the instructor is literally teaching you how to injure or kill yourself.

If your supervisor refuses to purchase a flow meter because the irresponsible machine supplier recommends testing hydraulic components into a bucket, ask the supervisor if he/she is going to take volt meters away from the electricians. Moreover, if your supervisor tells you to "test" any hydraulic component, knowing full well you are not properly trained to perform the task, hand write a note to the effect, and have the supervisor sign it. If a supervisor is willing to sacrifice you to the production God's, you might just as well make it official.

If a machine or equipment manufacturer provides warnings about discharging oil to atmosphere stating that it can "cause severe injury, death, and/or severe property damage, and then tells you to "test" a hydraulic component by discharging oil to atmosphere, if, while you are executing the test, you get blasted in the face with hydraulic oil, take the warning, along with the procedure, to an attorney. I believe you have a good "ignored duty of care" case.

If you are not trained in hydraulics DO NOT work on hydraulic systems. It's only a matter of time before I will be writing a similar article about you.

Respectfully

Are America's Technical College’s Teaching Students How to Injure or Kill Themselves?

I am going to ask you to answer the question. According to global giants Caterpillar©, John Deere©, and others, discharging oil to atmosphere, under any circumstances, is extremely hazardous. Here’s a warning from a John Deere© service manual:

“Escaping fluid under pressure can penetrate the skin causing serious injury. Avoid the hazard by relieving pressure before disconnecting hydraulic or other lines. Tighten all connections before applying pressure. Search for leaks with a piece of cardboard. Protect hands and body from high-pressure fluids. If an accident occurs see a doctor immediately. Any fluid injected into the skin must be surgically removed within a few hours or gangrene may result. Doctors unfamiliar with this type of injury should reference a knowledgeable medical source.”

Here’s a similar warning from a Caterpillar service manual:

 "Escaping fluid under pressure, even a pinhole size leak, can penetrate body tissue, causing serious injury, and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury.” 

 Now let’s turn to a training document that was given to me by a student that attended my hydraulic safety workshop. The document titled “Troubleshooting” was allegedly taken from a textbook published by Womack Educational Publications. The document contains test procedures for finding internal leaks in numerous hydraulic components. Incidentally, Womack Educational Publications is not alone when it comes to recommending hazardous hydraulic component test procedures. You will find similar test procedures in 99% of college textbooks. Regrettably, over 95% of college instructors teach their students these procedures.

WARNING – DO NOT ATTEMPT TO TEST ANY HYDRAULIC COMPONENT USING THE TECHNIQUES RECOMMENDED BY WOMACK EDUCATIONAL PUBLICATIONS, OR OTHER AUTHORS. DISCHARGING HIGH-PRESSURE OIL TO ATMOSPHERE, UNDER ANY CIRCUMSTANCES, CAN CAUSE SEVERE INJURY, DEATH AND/OR SUBSTANTIAL PROPERTY DAMAGE.” 

Pressure relief valve test procedure: “Disconnect the transmission line from the relief valve’s discharge port, and attach a hose to it. Hold the hose over the filler opening in the tank then run the pump while observing whether or not a full stream of oil is being discharged from the relief valve. While making this test run the relief valve setting up and down. If a flow meter is available the flow should be measured and compared with the pump rating. Sometimes the discharge can be run into a bucket and the volume measure while timing the flow.”

Cylinder test procedure: “The cylinder should be tested under pressure. A satisfactory test which is not too difficult is shown an illustration. To make the test run the cylinder piston to one end of its stroke and stall it. Disconnect the line on the opposite side of the piston. If the system is hydraulic, the disconnected line must be capped to prevent back pressure from spilling oil during the test. Start the power supply and observe for leakage coming out of the opened end of the cylinder. Make a similar test by running the cylinder to the other end of its stroke.”

Test directional control valve: “A sure test for a directional control valve is to disconnect the cylinder lines and plug the cylinder connections to the valve. Operate the valve under pressure, shifting it to various positions, while observing any leakage coming out of the exhaust.” The illustration shows the discharge port open to atmosphere."

A message to instructors: Your most important job is to teach your students how the think safety and work safely. It is your duty of care to censor the textbooks you recommend for your students. I am willing to help. You can attend my safety-based workshops free of charge (tax-payer funded colleges). Moreover, I am prepared to send you a free copy of my book (Continental USA), which from cover-to-cover shows technicians how to test every hydraulic component safely, effectively and efficiently. I am also prepared to help you develop a “safety-based” curriculum. That too is free.

I share because I care.

Worker was not trained to perform the task; no training was required to perform the task, but he died nonetheless

Another worker killed, and his colleagues injured, due to, what appears to be, a combination of an inherently unsafe hydraulic system, and the lack of training. What surprises me is, how many more deaths and injuries will need to occur before state and federal agencies wake up to the fact that less that over 95% of the people that work on and around hydraulic systems are properly trained, and that more than 99% of the hydraulic systems operating in mills and factories throughout the US are inherently unsafe by design, from the point of view of stored energy.

I suggest you read the newspaper article below so you can understand why I am frustrated.

http://www.oregonlive.com/washingtoncounty/index.ssf/2011/10/stimson_lumber_fined_5000_for.html

The regrettable, and completely avoidable, accident that occurred at the Stimson Lumber Mill is just another example of just how out of touch State and Federal safety agencies are when it comes to matters relating to hydraulic safety. From all accounts the victim and his colleagues were working on a hydraulic system that was equipped with one, or more, hydro-pneumatic accumulators (energy storage devices).

Hydro-pneumatic accumulators are known to trained mechanics as energy storage devices. However, in the hands of untrained personnel, they are nothing more and nothing less than “bombs.”

From all accounts, the victim and his colleagues could not determine if the hydraulic system contained stored energy, which seems to be what caused the accident. 

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The fact is, over 99% of the hydraulic system operating in mills throughout Oregon, and every other state in the nation, are inherently unsafe from the point of view of stored hydraulic energy. The hydraulic system that the victim and his colleagues were working on was, in my opinion, unsafe from its inception.  It was only a matter of time before it either killed, or seriously injured, one or more people.

OSHA mandates that companies have an energy control program, and that companies train their people on energy control procedures. However, OSHA, hydraulic system designers, and corporate safety managers, ignore the fact that hydraulic systems DO NOT comply with OSHA’s standards with regard to the controlled release of stored hydraulic energy.

The standard requires workers to isolate a machine’s power source (lockout and tagout) before performing work on the machine. However, hydraulic systems have the inherent ability to store energy after the power source is locked out and tagged. What workers cannot do is determine if a hydraulic system contains stored energy, and even they could, it is not possible for them to safely remove it. What they are forced to do, as it seems they did in this case, is fly by the seat of their pants, and hope and pray they live to see another day.

The fact that both state and federal agencies, and companies like Stimson Lumber permit people that have little or no training in hydraulics to perform service and repair work on hydraulic systems, doesn’t help the matter. Telling an untrained mechanic to work on hydraulic systems is irresponsible enough. Giving an untrained worker an order to work on a hydraulic system, which is unsafe by design, is ludicrous. 

From all accounts, it was only a matter of time before a Stimson worker was either killed, or seriously injured while working on the company's hydraulic systems. Working on and around a hydro-pneumatic accumulators without proper training is akin to diffusing a bomb. Things can get very ugly very quickly.

From all accounts the hydraulic system Mr. Allen and his colleagues were working on was inherently unsafe by design (like the other 99% of the hydraulic systems operating in the US). It is also evident that Mr. Allen, and his colleagues did not have the critical training needed to identify the potential hazard, or perform the task safely. Ironically, companies, like Stimson, are not bound by law to insure workers are trained in hydraulic safety, or fundamental hydraulics. 

Most companies will only spend money on worker safety if it’s required by law, which means that over 98% of the millworkers working in Oregon have never received hydraulic safety training, and only about 20%, if that, can pass a hydraulic competency test. Accordingly, there will be more accidents, and there is no doubt, there will be more injuries and deaths. Sadly, the conclusions will remain the same: "worker was not trained to perform the task; no training was required to perform the task."

I sincerely hope that Mr. Allen’s family was able to sue the company that designed the hydraulic system. I would be interested to know if the Oregon Occupational and Health Safety Administration cited the machine manufacturer for delivering to Stimson a machine that I am alleging was inherently unsafe by design.

I was astounded by the comments made by Ms. Debra Muchow, Stimson’s Vice-President, regarding Mr. Allen: “We'll never know from the employee's perspective if he was not trained properly or whether it was just a matter of a mistake at that time.” How disgraceful!

It seems Stimson must be a very unsafe place to work. Judging from Ms. Muchow’s comments, the company doesn’t seem to know the background, qualifications and training of its employees. Her comments also reflect poorly on the company’s supervisors. Surely Mr. Allen’s supervisor must have been aware of his work skills. How would it have been possible to give him work assignments that Mr. Allen could perform with any degree of safety if his supervisor, and the company's vice president, did not know his qualifications?

The Oregon Occupational and Health Safety Administration’s response to the accident doesn't surprise me at all. It’s the usual “victim was not properly trained” scenario. Moreover, there was no mention of the fact the hydraulic system was, in my opinion, inherently unsafe by design. Regrettably, the Oregon Occupational and Health Safety Administration will probably do nothing to make it mandatory for ALL workers that perform work on and around hydraulic system receive proper training. They will also probably ignore the fact that more than 99% of the hydraulic system operating in Oregon (not just in the lumber mills) do not have the means to permit workers to determine if a hydraulic system contains stored energy, or the means to safely remove it is it does.

What we can learn from Mr. Allen’s regrettable, and avoidable, accident:

Mechanics:

1. To prevent the vice president of your company, and your supervisor, from being confused about your knowledge and training, arrange a meeting with your company’s human resources officer, and your supervisor. Have them put on record your qualifications and training. Also, make them aware of any work you do that you are not trained or qualified to do.

2. OSHA’s lockout/tagout standard clearly states: “Energy sources including electrical, mechanical, hydraulic, pneumatic, chemical, thermal or other sources in machines and equipment can be hazardous to workers. During the servicing and maintenance of machines and equipment, the unexpected startup or release of stored energy could cause injury to employees.” 

Lockout and tagout does not guarantee a hydraulic system is safe to work on. Most hydraulic systems have the inherent ability to store energy after shutdown. OSHA states, “the release of stored energy must be controlled.” Unfortunately, this is not possible to achieve on more than 99% of hydraulic systems operating in the US.

The only way for a worker to remove stored energy from a hydraulic system is to ignore both the OSHA’s standard, and the machine manufacturer’s warnings, and discharge the stored energy to atmosphere with absolutely no way to control it.

3. OSHA, US companies, and your company's safety managers do not recognize hydraulics as an occupational hazard. If they did, people that work on hydraulic systems would have the same worker rights and privileges as electricians.

In OSHA’s defense, the agency is as naive about matters related to hydraulic safety as the engineers that design hydraulic systems. It's a simple case of the blind leading the blind!

Engineers:

If you are a hydraulic system designer, even though there are no standards covering the safe release of stored hydraulic energy, make sure the systems you design are safe. Mr. Allen may have been alive today, if he had had the means at his disposal to determine if the system he was working on contained stored energy.

Safety personnel:

1. If your company does not currently provide hydraulic safety training for the people that work on and around hydraulic systems, make it your top priority to get them the training they desperately need. Bear in mind, most workers cannot recognize potential hazards because they don't have training in fundamental hydraulics to do so.

2. The fact that OSHA ignores hydraulic safety doesn't mean that hydraulic systems are safe. On the contrary, hydraulic systems are arguably more hazardous than electrical systems.

3. If you teach your employees lockout and tagout. Don’t just talk the talk, please walk the walk. See to it that the hydraulic systems in your company can be safely de-energized after LOTO is performed.

Supervisors:

1. You "borrowed" the people that report to you from their respective families. Your primary responsibility to workers and their families, is to insure that you take care of them while they are in your care, and that you return them to their respective families in the same, or better, condition than they were when you "borrowed" them. If Mr. Allen's supervisor had fulfilled his promise to his family, he would never have been killed at work. NEVER permit a person perform work on any machine/system unless you are completely satisfied they have the training to perform the work safely.

2. Like electrical, confined space, hazardous materials, etc., workers that work on and around hydraulic systems MUST receive training in hydraulic safety. 

3. Look for the best training for your workers, and don't abbreviate the training. Avoid using your suppliers’ sales personnel to train your workers unless they are competent. They may be qualified salespersons, but they are not necessarily educators. Your workers deserve the best training possible. Workers must empowered to think safety and work safely. Besides, properly trained workers will increase productivity, and decrease downtime. It's a win-win for the worker, you, and the company.

I share because I care