Forensic Engineers and Consultants

Archive: Workplace Injuries

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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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

A close-up view of the steel column.

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

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

Figure 2: A self-propelled roof bolter similar to the one described in this post. The canopy is on the extreme left of the image.

A Case Study in a Coal Mine: What are a Machine Rebuilder’s Responsibilities?

Co-Authored with Aron Olson, P.E.

In November of 2010, a miner was injured by a roof bolting machine (roof bolter) in an Alabama underground coal mine. The roof bolter in question had undergone a complete rebuild intended to return the machine to the original equipment manufacturer’s (OEM’s) specifications. Warren was hired to analyze both the design of the roof bolter and the actions of the rebuilder to determine if either contributed to the unfortunate coal miner’s serious injury. Background information on coal mining and roof bolters, as well as an analysis of the roof bolter and the actions of the rebuilder are included. Read More

openings-graphic

Who is Responsible for a “Booby Trap” Opening on a Roof Top? Part 3

As an experienced safety consultant, I have investigated many incidents in my career in which a worker “falls through an opening.”  The majority of these incidents have occurred at construction sites and most resulted in serious injury or death. 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

Don't let your building become a disaster?

Major Causes of Wood Truss Failures

Author

It’s a fact! Many roof structures fail during the construction process while others have taken years for an incident to occur. Buildings with proper design and construction of bracing systems are essential in reducing and/or eliminating wooden roof truss failures.
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