Forensic Engineers and Consultants

Archive: Workplace Injuries

HEY…Cover Up Please!

Machine guards can be compared to the clothes we wear every day.  Indeed, they serve a very important purpose.  Imagine someone leaving their home on a fine, sunny morning wearing nothing but a smile.  Wonder how far they will get through the day before things start going poorly for this individual?

 

 

 

 

 

There will be more than a few raised eyebrows and blushes when he stops into the local Starbucks for his usual morning double-dipped and whipped, chocolaty chip with a touch of pumpkin spice cappuccino fix.  Good luck with that!  Probably going to leave disappointed, empty-handed, and likely wearing handcuffs.  This will be the beginning of a very long, very bad day for that individual.  Had he recognized the risks associated with this type of behavior, and then put forth a little effort to cover up, he would have prevented many unfavorable and possibly life-changing personal and legal problems from ever occurring!

And so it is with properly guarding a machine.  Machine safeguarding helps to protect workers from preventable injuries. Read More

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One Small Step…

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Ladders…not a particularly exciting topic I’ll admit.  But hey, we need ladders to help us accomplish all kinds of tasks.  Most people have used at least one of the many types of ladders that are available today.  And the odds are probably pretty good that many of those users strayed outside the limits of safety a time or two while on a ladder.  It is amazing the risks some people will take to save some time or avoid the inconvenience of getting down to move the ladder into a safer position.  I wonder how many of those risks would be taken on a ladder if the users knew they were on camera.

Think about astronaut Neil Armstrong.  He travelled by rocket almost 239,000 miles through space and has just successfully landed the lunar module on the surface of the moon.  Quite an accomplishment!  Now, with the eyes of the world on him, he is going to come down a ladder and become the first person to set foot on the moon.  I wonder how many times Neil Armstrong practiced coming down that ladder.  Now imagine him saying during that historic moment: “That’s one small step for a man… one giant leeee….aaaaaahhhhhhh!” And then the world watches as he falls back off the ladder and comes to rest lying on his back….on the surface of the moon….with a broken leg, a sprained wrist, and a bruised back, and clutching a ladder rung in one of his hands!  And 239,000 miles from the nearest Urgent Care!

Image Credit: NASA Archives

That would have drastically changed everything about the overall mission of the astronauts!  The investigation into this ladder accident would be an interesting and important one for sure, and the fact that such strong evidence was caught on video would be a luxury not usually available to the investigator.  Well, fortunately that accident did not happen!  Neil Armstrong finished his famous quote, he successfully stepped off the lunar module ladder, and the overall mission of the Apollo 11 flight was incredibly successful.

Obviously, the everyday use of ladders at factories and homes across the U.S. lacks the drama and suspense of a moon mission ladder descent, but there are some similarities that we can look at.  Using a ladder always involves a level of risk.  That risk level is dependent on things such as the type of ladder, the height climbed, the attention of the user to follow all ladder safety rules, as well as the design and stability of the ladder used.  Ladders that are available these days are typically safe with respect to their design and the materials they are constructed of.  However, statistics show that in the US, on average, work-related ladder falls result in one death and more than 180 nonfatal injuries every two days.  In some of these cases, questions are raised about what actually caused or contributed to the accident.  When this happens, it is common for a forensic engineer to be hired to investigate the accident to determine if there was a defect in the ladder’s design or the materials it was manufactured from, or if the user of the ladder was possibly at fault.

The things a forensic engineer will consider in the investigation are dependent on the specific circumstances of each accident as well as the scope of the accident request.  Typically, the type of ladder and whether it adhered to the design standards that were in place when it was manufactured will be a part of the investigation.  A quick internet search will show whether there are or have been recalls for that particular ladder model.  A thorough study of the ladder, whether through quality photos or having the actual ladder involved in the accident, can reveal evidence that will show whether a defect was present in the ladder at the time of the accident.  The specific members that were damaged can sometimes show how the ladder was loaded when it failed, and whether that failure may have been due to either a defect or the user’s bad judgment.  The goal of the investigation will be to find the truth as to what happened and to give a concise explanation of the expert’s findings along with his /her opinions in the final report.

If you need an investigation of an accident involving any type of ladder, please call our experienced mechanical engineering experts at Warren.

Bob Hickman is a Licensed Professional Engineer and Certified Machinery Safety Expert.  He has over 30 years of manufacturing and machine design experience in production and quality-driven environments.  Bob holds a Bachelor of Science in Mechanical Engineering from Clemson University.  Over his 30-year engineering career, Bob has designed many custom manufacturing machines and processes that improved quality, productivity, reliability, and safety.  He designed several machines to automate manual processes, replacing inefficient/unreliable manual equipment and has assisted with plant layout/production line planning.  He has significant experience with pneumatic systems and components, as well as hydraulics.  Bob regularly investigates personal injury, wrongful death, and product liability claims, as well as property damage claims involving machinery and equipment in a variety of environments for both insurance adjusters and attorneys.  Bob has an in-depth knowledge of many standards with emphasis on ANSI B11 standards for machine tool safety.

The Concepts of Hazard, Risk, and Harm in Machine Safeguarding

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Hazard, risk, and harm are terms that are used in the world of machine safeguarding.   How do these words shape the concept of machine safeguarding? Let’s look a little deeper….

Hazard, which Merriam-Webster defines as a noun, lists its first meaning as a source of danger.

1: a source of danger

2athe effect of unpredictable and unanalyzable forces in determining events CHANCERISK

  b:  a chance event ACCIDENT  Read More

Conveyor Backstops: Sometimes One Isn’t Enough, Part 2

This is the second in a two-part blog series about conveying equipment that severely injured a worker at a mine. In case you missed it, click here to read Part 1 where I describe the incident and the mining equipment. In this part, I will discuss my engineering analysis of the incident and the machinery involved and share the conclusions I reached.

The injured miner was a front-end loader operator. He was not a maintenance worker. He simply responded to a radio request for help with the conveyor. Power to the electric conveyor motors was locked out, but none of the maintenance workers did anything to lock out or block the hazardous gravitational potential energy in the heavy load of stone on the belt. Read More

What’s Behind That CE Mark Part Three, Machine Guard Requirements

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In the first blog in this series, we discussed the story behind the CE mark, the Machinery Directive, and the associated requirements regarding the design, production, and sale of machinery bearing the mark. The second blog discussed a cornerstone of safer machine design, the risk assessment. This installment will discuss another crucial piece of the safety puzzle, machine guard design. Read More

Ammonia

Ammonia – The Good, The Bad, The Smelly… Part One

Ammonia is a compound consisting of one nitrogen atom and three hydrogen atoms and is denoted by the formula NH3. Its boiling point is -28°F at atmospheric pressure, so unless it is under pressure, it is gaseous at room temperatures. Therefore, pure ammonia is typically stored under pressure in a liquid form. Household ammonia is only 5-10% NH3, the remaining 90-95% is water. Ammonia is extremely soluble in water. It is often depicted  like this: Read More

Unguarded Shear Point on Force Tester Amputates Worker’s Finger

A worker was injured while testing gas springs similar to the type that hold the hatchback of an SUV open. The hazard that injured the worker was an unguarded shear point. The tester contained a mounting plate that was raised and lowered by a pneumatic cylinder.

The pneumatic cylinder lowered the mounting plate while the worker’s fingers were in the hazardous, unguarded shear point. Read More

Defective Vertical Baler Causes Serious Crush Injury to Operator’s Arm

I recently worked on an interesting case involving a box baler. An employee of a butcher shop put some empty cardboard boxes in a vertical box baler and pushed the control switch to compact the boxes. After the 30 by 60 inch platen weighing 851 pounds returned to its raised position, the employee reached into the open space above the bottom door on the baler and began to clear cardboard from the bale tie slots in the bottom of the raised platen. Suddenly, and without warning, the steel pin attaching the platen to the raised hydraulic cylinder rod failed. The heavy steel platen fell and crushed his arm which was outstretched over the baler door into the compaction space.

Read More

Injury Involving a Capstan Winch

A capstan winch uses a mechanically powered rotating cylinder, called a capstan, to apply pulling force through a rope. When the rope is looped around the rotating capstan and tightened, friction between the rope and capstan allows the winch to apply force to pull a load. A typical capstan winch is shown in Figure 1 below. Read More

Timber – Falling Beam Strikes Worker

As an experienced safety consultant, I have investigated many serious injuries and deaths at construction sites over the past 39 years. The United States Department of Labor reports that the fatal injury rate for the construction industry is highest of all industries in the nation. Out of 4,386 worker fatalities in private industry in calendar year 2014, 899 or 20.5% were in construction i.e., one in five worker deaths were in construction. Read More

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