Forensic Engineers and Consultants

Archive: Liability Claims

Improper Design Leads to Fatigue Failure In Blower Shaft

A blower used to exhaust air from an industrial process stopped functioning when the blower wheel drive shaft fractured.  The process, and thereby most of the plant, had to operate at a reduced volume until the blower wheel could be replaced.  The blower wheel had been installed during a shutdown a week before the incident.  The blower wheel was a spare installed when the existing blower wheel was sent for scheduled remanufacturing. 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


Painting of Handicap Ramps

As an experienced safety consultant, I’m called on to investigate a wide range of premises liability incidents. One common premises liability incident that often results in serious injury is a fall on a handicap ramp. There are at least four types of handicap ramps – flare side, parallel, returned curb and built-up.

Handicap ramps were originally designed and incorporated into buildings as a means of egress to accommodate individuals with disabilities, particularly those in wheel chairs. Navigating a standard 6-inch curb can be a significant barrier for someone with a mobility disability and a proper ramp eliminates that barrier. This post will focus on painting on and around handicap ramps.


The International Code Council/American National Standards Institute ICC/ANSI) A117.1 Accessible and Usable Buildings and Facilities and ADA Standards for Accessible Design provide standards and guidelines for the proper construction and placement of handicap ramps, however, it often surprises people when they find out that no Codes or Standards have provided any specifics on painting of ramps, that is up until the 2009 ICC/ANSI A117.1 which became effective in 2011.  Even then the painting requirement only applies to one specific part of a curb ramp.

The 2009 ICC A117.1 states: 406.3.2 Marking. If curbs adjacent to the ramp flares are painted, the painted surface shall extend along the flared portion of the curb. The purpose of this new requirement is to provide a visual cue to pedestrians approaching the flared side of the curb.

Although there are limited painting requirements, it is the practice of many to paint ramp structures and I have seen ramps painted in many different ways with no real consistency.  So why do people paint ramps? The reason is to bring attention to various aspects of a ramp such as slope, and changes in elevation, which can be a pedestrian fall hazard in some constructed ramps. Proper painting of ramps is a good practice when proper paint materials are used and it effectively highlights or alerts pedestrians to a feature of the ramp. On the other hand, improper painting can create hazards.


Walking surfaces should have adequate color contrast at change in elevation points.  For example, many ramps have black asphalt abutting the white concrete of sections of the curb ramp. The color difference serves to highlight transition points and bring attention to them. Where no color contrast exists, proper painting can improve the visibility of elevations points. In the ASTM F1637 Standard for Safe Walking Surfaces, warnings and color contrast are stated to be helpful preventative measures. Painting of the top side of the entire flare or flare is discouraged by many safety professionals. One potential problem with painting the entire top side of the ramp slopes is that the paint can make the inclined surface less slip resistant. The type of paint used is a factor in slip resistance. Many paint types can make walking surfaces extremely slippery when wet. If painting is done on or around a ramp the paint used should be checked to see if it is of a formulation approved for use on exterior walking surfaces.

ASTM F1637 Standard Practice for Safe Walking Surfaces states: 5.1.3 Painted walkways shall contain an abrasive additive, crosscut grooving, texturizing or other appropriate means to render the surface slip resistant where wet conditions maybe reasonably forseeable.

On some ramps painting may camouflages areas where a change in elevation exists such as the start of a sloped section or where a curb and the walking surface meet. I often see curbs and curbs on ramps painted not only on the side face and top face but also on the walking surface just in front of the curb. In some cases, when walking on the top side this can hide the curb edge from sight and increase the fall potential.


Painting of handicap ramps is a serious consideration that should be carefully planned and performed to insure the safety of all pedestrians who interact with the walkway surface.

J. Steven Hunt, CPCU, ARM, is president and senior safety consultant at Warren. Steve specializes in premises liability incidents, construction falls and safety management programs, has achieved the designation of Associate Risk Management and Chartered Property and Liability Underwriter from Insurance Institute of America, Chicago, IL. Steve has investigated more than 1,000 accidents in his more than 39-year career, including 33 cases involving fatalities. He holds a Bachelor of Science in Administrative Management with a Minor in Occupational Safety and Health from Clemson University.

Figure 1: An illustration of a properly constructed flared side curb ramp.

A Steep Price: Improperly sloped curb ramps increase the potential of serious pedestrian injury

As an experienced safety consultant, I’m called to investigate a wide range of premises liability incidents. One common premises incident that often results in serious injury is a fall on a curb ramp. There are at least four types of curb ramps: flare side, parallel, returned curb and built-up. This post will focus primarily on flare side curb ramps which are the most common type constructed today. Read More

A closer view of the hole through which the worker fell.

Why did he fall off the edge? – Part 2 of series on Fall Through Openings

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

Roof drain with membrane installed in opening.

Water Intrusion/Moisture Issues – Finding the Source and Location


What you see is not always what you get.  This commonality exists in the numerous cases I have investigated for water intrusion and moisture issues in buildings.  The source that appears most obvious and straightforward may not, in fact, be the root of the problem at all. Read More

Foundation issues

Identifying Foundation Issues for Adjusters


As a structural engineer, I am often called upon to determine the cause of commercial and residential building problems. Common problems I investigate include doors or windows that don’t open properly, cracks in interior and exterior walls, gaps in the trim, leaking roofs when the exterior covering is otherwise in good condition, sloped and out-of-level floors and leaning walls. Many of these problems are a direct result of foundation cracks, settlements and/or failures. Read More

Building Envelope Components

What is a Building Envelope?


By definition, the building envelope (or building enclosure) is the physical separation between the interior conditioned areas and the exterior environment space of a building. The envelope serves as the outer covering (shell or skin) to help maintain the indoor environment together with the mechanical conditioning systems and to facilitate its climate control. The building envelope must be carefully designed with regard to site specific climate, ventilation, and energy consumption within the structure. The design is a specialized area of architectural and engineering practice that draws from all areas of building science and indoor climate control. Read More


Metal Decking Provides for Building Stability and Worker Safety


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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