Fluid Power Journal

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Safety in Fluid Power Systems

kent-darnellAs an employee at Womack for 26 years, I have had several jobs. I spent almost 10 years as an outside salesman in West Texas, working around oil field equipment and mobile units. From there, I moved to Dallas, and for three years I supervised the Publication Department and trained inside and new outside salesmen. After driving a desk for those three years, I asked the company to put me back into outside sales, and in 2001, I moved to East Texas and became an outside salesman. My customer base was steel and wood mills, foundries, and other manufacturing, which means I was selling industrial hydraulics components and systems to my customers. In 2010, after a short-term medical leave, I became the department leader for the hands-on training unit. I was given the task to expand the company’s product offering, and one of the things I did was develop a one-day safety seminar for fluid power. Working on that safety seminar reminded me of my first car—a 1965 Ford Mustang.

My dad purchased the brand-new Ford Mustang in August 1964. I was only three years old at the time, but that car has been part of my family, and I still own it. When Dad purchased that car, it didn’t have seat belts in the rear seat (my dad had those installed by the dealer).

Are you wondering why I’m talking about seat belts? Well, in 1964, seat belts (also called “safety belts”) were not required by national law, but some state laws required them. And seat belts were not required in the rear seat. In fact, seat belts were not called “safety belts” because the automotive industry thought the name would put off the American public. Pre-1964, there was an average of 44 fatalities per 100,000 registered cars, and that number dropped after 1967 to 1972 because more states required seat belts in the cars. In 2011, that number dropped even more to 10.39 per 100,000 registered cars. Seat belts were invented in the early 19th century and have made cars and drivers safer, but the belts were not really used until 1955.

I know how it was in the early 1970s when the automotive industry started talking about air bags. My parents, like so many other people, were against them because of the extra expense and how they were viewed as dangerous. Seat belts were not any different back in the 1950s and 1960s, and the public had a hard time accepting them.

People are reluctant to change, and people also don’t like to be told what to do. Today, if you go into an automotive shop, you will mostly likely see a sign that says “Safety Glasses are Required.” In 1970, the Occupational Safety and Health Act was signed into law, which established the Occupational Safety and Health Administration (OSHA). OSHA sets and enforces protective workplace safety and health standards, and one of those safety and health standards is to wear “Personal Protective Equipment” (PPE). OSHA tells us that PPE should be worn or used “wherever it is necessary by reason of hazards of processes or environment, chemical hazards, radiological hazards, or mechanical irritants encountered in a manner capable of causing injury or impairment in the function of any part of the body through absorption, inhalation, or physical contact.” In 1985, I wish that the shop I worked for had required PPE, especially safety glasses, because my wife once had to take me to the emergency room at four a.m. to have a piece of metal removed from my eye. But even today, people are reluctant, or forget, to use safety glasses.

There were 3-million work-related injuries in 2011, and according to the Bureau of Labor Statics, there were 4,693 fatal work-related accidents. The sad part of that number is that there were 4,693 workers who didn’t go home to their families. The good thing about that number is it keeps falling year after year. In fact, in the last 20 years, that number has dropped by 1,500. In 1992, there were 6,217 fatal work-related injuries. One of the reasons that number has dropped is because the work force is using safer work practices and there is more regulation by organizations like OSHA.

When I began working on the safety seminar for Womack, I found there wasn’t a lot of information on safety in fluid power. There are international standards ISO 4413 and ISO 4414, the titles to which are General Rules and Safety Requirements for Hydraulic and Pneumatic Systems. But even though we have these safety standards on fluid power, do we use them?

Sometimes the reason that we don’t use these standards is because we don’t know about them. We never stop learning, and every day I realize how much I don’t know. When I started working with fluid power, I had heard about oil injection injuries. It was always a friend’s uncle who knew someone’s dad who had a finger cut off by a hydraulic leak on an airplane’s hydraulic system. I figured oil injection injuries were an urban legend. As I researched information for the safety seminar, I confirmed that oil injection injuries do occur. Based on the size of the orifice or the leak size and how high the system’s pressure, oil could come out of the pinhole leak up to and surpassing 600 feet per second. That is the velocity of a 38 special bullet. Oil injection injuries do occur, and while they may not be very common, it is common for workers to use their hands to check for hydraulic or pneumatic leaks.

So, how are we safe around a fluid power system? Following the standards and regulations established by others is one way, but so is having the knowledge of how a system works and taking the time to make safety a number-one priority. Today’s ongoing demand to get things done faster should not exclude the most important part of the job: Safety First! I urge you and your employees to be safe around fluid power equipment.

About the Author: Kent Darnell, CFPAI, CFPHS, is Hands-On Training Business Unit leader for Womack Machine Supply Co. and an Accredited Instructor for the International Fluid Power Society. This article is based on his presentation at the Fluid Power Systems Conference in November 2013. He can be reached at k.darnell@womack-machine.com.

Perfect Reliability

steve-skinnerIs it possible, in the 21st century, to build a hydraulic system that doesn’t break down? Mechanical devices will eventually wear out, of course, so by “break down” we really mean fail unexpectedly. To help us achieve this aim of perfect reliability, we now have systematic tools available, such as proactive maintenance procedures and Design For Six Sigma (DFSS).

The objective of DFSS is to design systems that have a target reliability level of at least 99.99966%, which equates to no more than 3.4 failures in every million opportunities. Proactive maintenance combines many of the techniques of preventive and predictive maintenance into a process also designed to achieve similar levels of reliability. The essence of both tools is to attempt to think of all possible failure mechanisms and then to prevent them from happening, either by design or maintenance.

However, safety experts tell us that between 80% and 85% of industrial accidents are caused by human error, so is perfect reliability already a lost cause? Fortunately, human beings are very predictable animals, so it’s a fair bet that at some time during the life of a hydraulic system, someone will try to start it up with no oil in it. There’s a 50:50 chance that when the electricians first wire up the electric motor, the motor (and pump) will run backwards. If there’s a shut-off valve on the inlet or drain line of the pump, someone’s inevitably going to start the pump up with one or both of the valves closed. If something is adjustable, then as sure as eggs is eggs, at some time or another, someone will adjust it. If there is an accumulator on the system, sooner or later someone will forget to drain it down before starting maintenance work on the system. And one thing that’s 100% certain is that if there’s a pressure-compensated pump on the system with a relief valve to protect it, one day the compensator will be wound up higher than the relief and the oil’s going to boil.
Anyone who’s worked with hydraulics for any length of time could probably come up with a whole page full of such instances. It’s not that maintenance people are fools; it’s just that sometimes we get tired and lose concentration, sometimes our mind is elsewhere, and sometimes we forget things. Sometimes we don’t really know enough about the job we’re doing, so we shouldn’t really be doing it … but someone has to. So there are all sorts of reasons why people sometimes do stupid things; I’ve done enough myself to know.

Engineers therefore need to think about all these things that might (or rather, will) go wrong and try to design them out. Automatic drain valves for accumulators, interlock switches on shut-off valves, float switches in tanks, thermal cut-off switches, lockable adjusters, etc. I know, it all sounds very expensive, but probably not as expensive as the first breakdown, if anyone ever stops to reckon up its true cost. Not only are we talking about lost production, consequential repairs, premium labor rates and shipping costs, clear-up costs, etc., but we may also be talking about people’s well being and even their lives.

To illustrate the point, in 1886 it was decided that a new bridge was required across the River Thames in London, but being downstream of what was then the biggest port in the world, it had to allow tall-masted ships to pass freely beneath it. The result was Tower Bridge, one of the best-known landmarks of the City of London with its two opening sections or “bascules”. The problem was, each 162-foot long bascule weighed around 1,500 tons, and for the bridge to open, each had to tilt through almost 90 degrees in just over a minute then close again once the ship had passed through. To begin with, this would happen more than 20 times a day. The solution was eight 20-gal/rev hydraulic motors (with built-in brakes) operating via a curved rack and pinion arrangement. But being aware of the consequences of a failure of the bridge, the Victorian engineers built in numerous parallel systems and devices, and no doubt when the bridge opened in June 1894, they were confident that they had covered every eventuality.

Unfortunately they were wrong, and one sunny afternoon in July, the bridge suffered a mechanical failure and failed to close. However, this was in July 1968 and in the interim 74-year period, the bridge had hydraulically opened and closed its 1,500-ton bascules 352,713 times.

So is it possible, in the 21st century, to build a hydraulic system that doesn’t break down? Maybe not, but we should be able to get pretty close if they could achieve 99.99972% reliability in the 19th century.

Steve Skinner’s 46 years of experience with hydraulics was gained mainly with Vickers and subsequently Eaton in the UK. Although having roles in applications, sales, and product management, for most of his time there he was employed as European training manager. Now a freelance lecturer but still actively involved in BFPA and CETOP fluid power certifications, he will shortly be publishing a book on the history of hydraulic fluid power. Visit www.steveskinnerpresentations.co.uk.

“What a Long, Strange, Trip it’s been.”

tom-blansettIn the words of one of my favorite bands, “What a Long, Strange, Trip it’s been.” Having been elected to serve as the 2014 president of the International Fluid Power Society (IFPS), I can pause and reflect on just how I arrived at this point. Never in my wildest dreams did I imagine this day when I first heard of the organization so many years ago. This is truly an honor, and I am humbled.

There have been a lot of very smart people in this industry with whom I have had the pleasure of becoming acquainted with over the course of my career, and many of them have served a number of roles to help get me where I am today. Some of those roles were as mentors, teachers, peers, co-workers, and students. Yes, I have learned a great deal from my teaching experiences over the years, and I have had the privilege of knowing some of the legendary teachers in the industry, such as George Altland of Vickers. In fact, that is really what I want to focus my comments on—education in our industry.

I’m sure I am preaching to the choir when I say that education is extremely important in any professional field, but in some aspects, it is uniquely so in the fluid power industry because there is not a widely accepted and consistent set of standards that exist for educating students in the technologies of fluid power. Unlike ABET, which is the accreditation body for engineering and technology degree programs, there are no specific standards that are universally adopted and accepted to ensure that those working within the industry at various levels have consistent core knowledge and skill levels. The closest the fluid power industry has are the various certifications offered through the IFPS.

What is lacking is a consistent and agreed-upon set of teaching standards to ensure that everyone attains at least the same foundational levels of knowledge. A lot of different sources offer hydraulic training with a wide and varied level of instruction. There are programs that propose to teach basic hydraulics in as little as a day to well-structured associate degree programs lasting for two years. A disturbing trend over the past few years is that many of the individuals who say they are seeking knowledge aren’t as concerned about the quality of the instruction and the depth as they are about the length of time they have to lose from “work” and corresponding cost to obtain a “certificate.” As a result, those individuals who take the shortcuts don’t possess enough knowledge to perform optimally.

Because of this, I am a firm believer in IFPS certifications. They offer the best tool currently available to evaluate and substantiate an existing knowledge and skill set. It is a shame that companies within the industry don’t as a whole actively embrace and seek certification for their employees. Certification provides a mechanism of validating that those responsible for the operation, maintenance, and selection of fluid power components and systems have met at least some minimum established standard of knowledge. I encourage all professionals in the industry to take a positive step forward and attain certification at whatever level is appropriate for their job functions. This would go a long way to help improve safety, reduce energy waste, enhance productivity, and promote the professionalism of those within our industry.

By Tom Blansett, CFPAI, CFPS, CFPIHT, CFPCC, Manager of Hydraulics Training Services at Eaton Corp. and 2014 IFPS President

Fluid Power Journal is the official publication of the International Fluid Power Society

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