Discharging Oil Under Pressure To The Atmosphere Can Kill You - Just Kidding!

Need expert witnesses for your injection injury lawsuit? Look no further than the hydraulic system's design engineer and the person that composes the warnings and cautions in the respective manufacturer's service manuals.

Recently, I was conducting a hydraulic safety workshop at a mine. OSHA's and safety personnel's lack of understanding of fluid power and the lockout standard makes lockout and tagout one of the most controversial topics I teach.

Often I wish I was as ignorant about hydraulic systems and stored energy as most safety supervisors and managers. That way, I too could fool workers into believing that when they sign the LOTO training attendance roster and return to work, they are safe.

It is my duty of care to teach students LOTO as it applies to hydraulic systems. However, LOTO is the topic I enjoy teaching the least because it ignites controversy. It's challenging to explain the LOTO standard to students, and then do an about-turn and tell them its all hogwash. Once I let the proverbial cat out of the bag I have to waste time explaining to students why hydraulic system design engineers ignore the standard and also why OSHA looks the other way while design engineers ignore the standard.

The next day one of the students brought a service manual for a Caterpillar 824H dozer to the class. He handed it to me and asked me to read the section titled "System Pressure - Release."

Here is the manufacturers warning about releasing stored hydraulic energy to the atmosphere:

Here is the same manufacturer's about face with respect to the warning:

By the way "cracking the hydraulic lines" provides a "pinhole size leak that can penetrate body tissue and cause serious injury and possible death."

He explained that despite the fact he followed the recommendations to the letter he faced two of the most serious hazards he believed OSHA's lockout standard protected him from - the uncontrolled release of stored energy and the unexpected movement or startup of machinery. He said it was one of the scariest and most dangerous tasks he had ever undertaken. He also said that he would never do it again and warned his colleagues not to do it. 

Let me explain why when the power source driving a hydraulic pump is locked out, the system can retain/store sufficient energy to cause a worker (s) to suffer severe injury or death.

When a hydraulic cylinder is supporting a heavy load/weight, the weight transforms the cylinder into a weight-loaded accumulator. An accumulator is an "energy storage device." The amount of energy stored in the accumulator is determined by the following factors: pressure, which is determined by the weight of the load; the surface area of the piston; and, the volume (GPM), which is determined by the weight of the load and the size of the opening. 

Example:

Regrettably, since over 99% of the people that work on and around hydraulic systems have never received hydraulic safety training, which would cover accumulator safety, not only are they oblivious to the severe hazards accumulators pose, but they have no problem following recommendations that can cause them to suffer severe injury or death.

Loosening a connector on an accumulator port exposes a worker to two significant hazards: one, the worker will release sufficient hydraulic energy to cause him or her to suffer severe injury or death. And two, releasing the oil could cause the load it's supporting to move unexpectedly and very rapidly.

According to the student, he was slowly loosening the connector to allow the stored energy to bleed out of the cylinder slowly. What he did not know that it's virtually impossible to bleed stored hydraulic energy from a split-flange type connector slowly.

Here is a photo of "split-flange" type connector. The two halves retain the connector. There is an O-ring seal between the connector and the oil port in the component. If the connector is loosened while it is under pressure the pressure will cause the O-ring seal to burst.

Here is a video I captured of a mechanic executing the identical procedure as recommended by Caterpillar: (https://www.youtube.com/watch?v=1VYqoTpv5EU)

Here is a photo of a mechanic "slowly" loosening a split-flange type connector:

He loosened the four retaining bolts a few turns and then there was an explosion. He explained that the force of the oil discharging at extreme velocity from the fitting might have been an advantage. It drove him out of the way as the massive blade moved unexpectedly and rapidly.  

WARNING: ANY AND ALL PROCEDURES AND OR PRODUCTS THAT PERMIT HYDRAULIC OIL UNDER PRESSURE TO DISCHARGE TO THE ATMOSPHERE ARE INHERENTLY HAZARDOUS. WORKERS HAVE BEEN SEVERELY INJURED AND KILLED WHEN THEY RELEASED STORED HYDRAULIC ENERGY TO THE ATMOSPHERE. 

Now let me shift your attention from a procedure that tells workers to release stored hydraulic energy to the atmosphere by loosening connectors to a product that is exponentially more hazardous - an air-bleed valve aka a jet-injector device.

Photo of air-bleed device AKA "jet-injector" device (small valve at top center of photo):

The fact that design engineers are permitted to use this product is powerful evidence that OSHA and safety personnel have no clue about safety as it relates to hydraulic systems. 

Here is further evidence that the people that develop a company's warnings and cautions are out of touch with what the way their engineers design hydraulic systems.  

Here is the manufacturer's warning:

Here is a photo of a product on the same manufacturer's machine that contradicts the warning. This device, when loosened will release a jet of oil to the atmosphere with sufficient energy to cause a person to suffer a debilitating "jet-injection" injury. 

Several years ago, an identical device allegedly killed a machine operator in a plant in Anoka, Minnesota.

Conclusion:

State and federal safety agencies, hydraulic system design engineers, and safety managers and supervisors aren't going to fix the problem any time soon. Accordingly, I strongly urge people that work on and around hydraulic systems to "stand down." DO NOT follow any manufacturer's recommendations that advise you to release stored hydraulic energy to the atmosphere. Moreover, DO NOT open any valve that discharges hydraulic oil to the atmosphere. 

Here is the evidence you need to hand to your supervisor and or your company's safety supervisor if he or she tries to "force" you to make a bad decision:

Finally, here are a few words of advice from an expert in hydraulic safety:

1. If you are tasked to perform invasive work on a hydraulic system and you have not received training in hydraulic safety DO NOT perform the task.
2. If you are tasked to perform invasive work on a hydraulic system and the hydraulic system is not equipped with devices that makes it possible for you to detect if the hydraulic system contains stored energy, or to control the release of that energy, DO NOT make an attempt to remove the energy by discharging the stored energy to the atmosphere. Don't get injured or killed because and design engineer ignored his or her responsible to design a safe hydraulic system.
3. If you are "forced" to remove stored hydraulic energy by loosening a connector, and you get sprayed with hydraulic oil YOU MUST file a lawsuit against the respective manufacturer. If you need help my services are free of charge. The only reason why your life is on the line is that the manufacturer saved a few dollars by designing a hydraulic system, which is inherently unsafe.

It's time for maintenance personnel to stand down and refuse to work on hydraulic systems that are unsafe by design. It's obvious that the fluid power industry and machinery and equipment manufacturers have a powerful lobby in Washington - enough to get state and federal agencies to look the other way when it comes to hydraulic systems. The technology that can be incorporated in to hydraulic systems to protect you is more than two decades old.

I have taken my cause to OSHA, MSHA, many technical schools and colleges, the American Society for Safety Engineers, the Fluid Power Society, the British Fluid Power Association, machinery and equipment manufacturers, and many others. They have no interest in changing the status quo because most either have an insatiable lust for profit, or are sponsored buy the very corporations that have no interest in investing in safety.

Never forget this - 100% of workers that have been injured or killed while working on and around hydraulic systems never received training in hydraulic safety. in 1966 eight men died three days before Christmas because they allegedly could not detect if the system they were working on contained stored energy. In the year 2019 nothing has changed. It's obvious that state and federal agencies and hydraulic system design engineers don't care.