Forensic Engineers and Consultants

Archive: Workplace Injuries

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. The force testing machine violated applicable safety standards including ASME B15.1-2000 Safety Standard for Mechanical Power Transmission Apparatus sections 1.3 and 3.1.

Unguarded Shear point 1 white

The force tester. 

It was technologically and economically feasible for the manufacturer to have guarded the hazardous shear point at the time they designed and built the force testing machine by installing a fixed guard to prevent a worker from getting too close to the hazard. The hazardous, unguarded shear point on the force testing machine was capable of producing serious injury, including amputating fingers.

The risk of injury associated with the hazardous shear point was high because the hazard was unguarded, workers were exposed to the hazard every time the force testing machine cycled, and serious injury would occur every time a worker’s body part became trapped in the rapidly closing shear point. The high risk of injury associated with the hazardous, unguarded shear point was not tolerable because it was feasible to control the hazard using a fixed guard with no effect on the utility of the force tester.

It was or should have been foreseeable to the manufacturer at the time they designed and manufactured the force testing machine that the hazardous, unguarded pinch point would cause serious harm any time an operator got too close to the hazard.

Unguarded Shear Point Img 2

A shear point was created between the fixed frame and the movable mounting plate when the pneumatic cylinder lowered the mounting plate.

The force testing machine was unreasonably dangerous and defective.  It contained an uncontrolled hazard with a high, foreseeable and intolerable risk of serious injury with a certain probability of occurrence any time a worker’s body part is caught in the shear point.  There were technologically and economically feasible means that existed to control the hazard at the time of the machine’s design and manufacture. The unreasonably dangerous and defective condition of the force tester was a cause of the worker’s injury.

Unguarded Shear Point IMG 3 whiteA simple Lexan guard was all that was required to protect a worker from the hazardous shear point.

If you have a case involving personal injury involving a worker injured on a machine in an industrial setting, please give us a call. We are happy to consult with you.

box bailer

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.

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An example of a process flow diagram

OSHA’s Process Safety Management – Is This Process Covered?

In February of 1992, the OSHA Process Safety Management (PSM) standard was issued. The official title is: ‘Process Safety Management of Highly Hazardous Chemicals.’ As its title implies, not every facility is covered by this rigorous standard. A process must contain highly hazardous, as defined by OSHA, chemicals above a certain weight threshold, again defined by OSHA. Notice that this is a process by process determination, so there could be certain processes at a manufacturing facility that are not covered by this standard situated beside other processes that are.
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A corroded boiler tube

Boiler Blowdown – It’s Not a Dance Move

When thinking about the safe operation of boilers (and don’t we all?), several systems can readily be named; flame control, fuel/air ratio; steam pressure control, levels in the vessel, etc. What about the water? It seems so passive, as long as there is enough for level control, what’s the big deal? Well, it turns out, that as the steam produced by a boiler is used in the process, the condensate from that steam is returned to the boiler as feedwater. However, since 100% of the condensate is not returned, whatever solids had been in that water before it evaporated to form steam are left in the remaining water.  Fresh feedwater is added to maintain levels, but even fresh water contains some dissolved solids. So over time, the water in the boiler system gets saturated with all sorts of dissolved minerals.
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Cooker - Figure 2

Commercial Gas-Fired Cookers Can Do More Than Burn

The first hazard that comes to mind when thinking about large scale ovens and steam kettles is burning or scalding injury. Carbon monoxide poisoning is just as dangerous but less understood, so oftentimes proper prevention methods are not followed. In the United States, this results in over 20,000 emergency room visits and over 400 deaths a year. Before we get to the case study and poisoning prevention methods, we need to know what CO is, where it comes from, and why it is poisonous. Read More

stock-picker-forklift

Evolution of Narrow-Aisle Stock Picker Forklifts

Author

As the cost of warehousing has increased over time, material handling equipment has evolved to allow higher density storage capacities. Narrow aisle and order picker forklifts are among the innovations that have evolved over the past 50 years to accommodate this trend. Read More

Figure 2: A view of some of the undersize anchors used to secure the capstan winch. The anchors at the upper right failed by pulling out of the concrete slab. The one at the lower left failed by bending and pulling out.

Injury Involving a Capstan Winch

Co-Authored with Jeff Warren, PE   

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

Figure 2.  A view looking into the mixer. The grate and ribbon are visible. The grate openings are large enough to admit a worker's leg.

Case Study of an Injury Involving a Soil Mixer

Co-Authored with Aron Olson, P.E.

In May, 2014, a plant farm worker was seriously injured when he fell into the hopper of an electrically powered soil mixer.  The mixer in question used a rotating steel ribbon powered by a 7-1/2 hp electric motor to mix batches of materials such as sand, mulch, wood shavings, fertilizers and other landscaping materials to create potting soil. At the top of the hopper sidewalls, within 6 inches of the ribbon, was a steel grate. Read More

Warren engineers,   John Holecek and Aron Olson working with new fall protection equipment.

Not Falling for Your Job?

Periodically, Warren Engineers and Consultants are asked to perform inspections that require work at raised elevations. Typical jobs and tasks include climbing on commercial and residential roofs with steep pitches, working on scaffolding, climbing from one level to the next at a fire or industrial loss scene, riding in the buckets of lift equipment, and inspecting exterior structural elements such as windows and masonry.  Read More

steel-decking

Metal Decking Provides for Building Stability and Worker Safety

Author

It’s simple, right?!  Buildings being constructed must maintain a structural stability at all times during the steel erection process. That’s according to OSHA Federal Register Subpart R 1926. OSHA also reminds us that “Since structural collapse is second only to falls as a cause of fatalities in the construction industry, stability is essential to the successful erection of any steel structure, including single- story, multi-story, bridges, etc.” Let’s further examine what goes into the erection and installation practice for roof or floor metal decking as a safe working platform. Read More

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