Why am I feeling good about blogging these days?

The reason has everything to do with cost effective, quite reliable forensic investigation. I’m realizing, more and more, how easy this can be.

People still get hurt and things break and fall down during a pandemic and someone wants to know why – like injured parties, lawyers and insurers. At least well enough to resolve a dispute or claim in some fashion.

Well enough doesn’t mean exhaustively, at least in the beginning, nor necessarily at all.

This acceptance of well enough has coincided with my interest lately in how much forensic investigation is enough. It also suits the requirement these days to stay home/in-the-office and minimize social and work contact.

My interest developed on realizing experts often know the cause of an accident or failure with considerable certainty very early in an investigation. (Ref. 1) And well enough to resolve a dispute or claim.

Experts know this based on their experience and the well known causes of so many problems in the natural and built environments. (Ref. 2) And also knowing the many parameters that could be investigated in slip, trip and fall accidents, and going about this efficiently. (Ref. 3) The parties to a dispute see where an expert’s findings might go and decide to resolve rather than spend more money.

I’ve been blogging on these aspects of forensic investigation for some time in the interest of more cost-effective work. This also suits pandemic times just fine.

My interest was kick-started

  • When I realized the value of drone photography in recent years, (Ref. 4)
  • Moved along when I researched the different ways structures can fail and these classified and used in forensic investigation, (Ref. 5)
  • Went faster in the last year or so on recognizing the need and value of virtual visual site assessments during COVID-19, (Ref. 6)
  • And faster still when I realized the reliability of virtual assessments could be subjectively and usefully quantified, (Ref. 7)
  • Jumped forward on assessing the cause of a retaining wall failure in Ottawa based on a virtual visual site assessment, (Ref. 8)
  • Took off during that retaining wall assessment on seeing the contribution of Google Earth Pro photography to my assessment of the wall, (Refs 9 and 10)
  • Was reinforced when I got word back on how my virtual visual site assessment of the retaining wall contributed, along with input by others, to reducing the re-construction costs of the wall by almost half, and
  • My interest finalized on realizing how forensic investigation of the dozens of parameters that need to be considered in slip, trip and fall accidents can be dealt with efficiently and cost effectively with a simple initial task and many parameters eliminated, (Ref. 11)
  • But, just to be sure, add in 3D plotting of the results of a slip and fall investigation using an app and Google Earth Pro. (Ref. 9)
  • If that’s not enough, my interest was driven home on realizing how Zoom meetings will add further to cost-effective forensic engineering investigation.

This is the reason I’m blogging these days. It’s hard not to. It’s exciting and very satisfying to see quite reliable, cost effective forensic investigation in dispute resolution.

At the end of the day, this reason reflects the purpose of my blog: To explain the nature and methods of forensic engineering and expert services in jargon-free writing to non-technical people like civil litigation lawyers, litigants, injured parties, insurers and property owners.


You might also take a look at the blogs posted on August 15, 2019, July 13, 2018, June 30, 2017 July 22, 2016 and August 7, 2014 about my reasons for blogging, particularly the first in this list: August 15, 2019; a good read.


  1. You could be excused for thinking that everything is falling down. Posted July 23, 2020
  2. What’s in “…the built environment” and how many ways can it fail? Posted July 8, 2020
  3. Experts, Litigants, Insurers: Beware! There are dozens of parameters that could be investigated at slip, trip and fall sites. Posted February 18, 2021
  4. Drone photography continues to soar to new uses in forensic investigation. Posted March 30, 2020
  5. What’s in “…the built environment” and how many ways can it fail? July 8, 2020
  6. A Bundle of Blogs: On using visual site assessment in forensic investigation. Posted January 25, 2021
  7. The reliability of an educated guess on the cause of a failure or accident. Posted October 22, 2020
  8. What can you get from a virtual visual site assessment about the cause of a leaning retaining wall? Posted November 13, 2020
  9. Using Google Earth photographs in forensic engineering investigation. Posted December 5, 2020
  10. A Bundle of Blogs: Aerial video of insurance and forensic sites taken with cameras mounted on drones. Posted October 31, 2019
  11. What does an engineering expert do at the scene of slip, trip and fall accidents? Posted February 5, 2021


(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada February 26, 2021 ejorden@eastlink.ca)      

Experts, Litigants, Insurers: Beware! There are dozens of parameters that could be investigated at slip, trip and fall sites

I was prompted in a recent blog to recommend assessing the physical setting of a site first then go to more detailed investigation later, if necessary. (Ref. 1) This cost effective, staged approach works in other fields of engineering investigation, why not for slip, trip and fall accidents?

Use the data gained to identify in a second stage the most important components of the accident and how they relate. Then in a third stage focus the investigation on the parameters characterizing these components, rather than on the many dozens. This approach is reliable and cost effective.


I was struck again on leafing through the literature on the many factors that could be investigated. I thought, I must make sure readers understand the cost effectiveness of this approach.

One exhaustive European study of the slip resistance of footwear has also been accepted by American firms that design, manufacturer and sell skid testing equipment. (Ref. 2) The study counted the following approximate numbers of parameters/factors for the four main components of an accident that would need to be investigated:

  1. Floor covering component: … 34 parameters
  2. Lubricant: …………………………….. 28
  3. Shoe: ……………………………………… 23
  4. Ambient parameters: …………. 22

Other researchers identified more components and fewer parameters but this gives you an idea of the possible magnitude of forensic investigations of slip, trip and fall accidents.

For example, take the shoe component from the above list. The 23 factors can be grouped under:

  1. Type of shoe
  2. Properties of the shoe material, and,
  3. Design of the tread

An investigation of the Type of shoe would determine if the accident victim was wearing a leisure shoe or a work shoe/boot, or if the victim was barefoot.

Investigation of the Properties of the shoe material might look at the type of material, the additives present, the hardness, density, elasticity and strength of the shoe material, whether it was a single or dual layer sole and it’s chemical composition.

Investigating Design of the tread would determine the size and width of the shoe, the geometry and depth of the tread, it’s texture, it’s roughness, the edge finish, the amount of wear and if there were cleats.

This involves a lot of forensic engineering investigation – just of the 23 parameters in the shoe component.

Then add in all the factors associated with the Floor covering – as many as 34 depending on how you count them. And any Lubricants present, about 28 – like rain water in a foyer and cooking oil in a kitchen. And the 22 Ambient parameters, including weather and temperature, the many human factors, the floor gradient and lighting, and the existence or absence of handrails.

This could add up to an exhaustive engineering investigation – if its not done right – and a red light for both experts, litigants and insurers; Beware!

This has come out of one widely accepted study in Europe that is accepted in the U.S. And no question in Canada. I’ve read and seen how other American studies tweak the European work and add a little more to a forensic investigation.


For sure, some of the many factors I’ve noted above would be covered off quickly after the physical setting of the accident site has been surveyed.

For example, was the victim wearing a recreational shoe or a work boot? Was it raining that day just outside the foyer? Was the victim walking or running? Were there handrails on the stairs, and did the ratio of step width to riser conform to the standard of practice for stair design?


I believe, considering the dozens of factors involved, (Ref. 2) – and hopefully you have a better understanding of this from the above – that slip, trip and fall accidents are prime candidates for peer review of the expert’s forensic investigation. (Refs 3, 4 and 5) Particularly if the investigation involves additional stages after initially assessing the physical setting of the accident site. (Ref. 1) Peer review is cast-in-stone in science and should be in applied science, like the investigation of slip, trip and fall accidents.


  1. What does an engineering expert do at the scene of slip, trip and fall accidents? Posted February 5, 2021
  2. Sebald, Jens, System oriented concept for testing and assessment of the slip resistance of safety, protective and occupational footwear, Pro Business Gmbh, Berlin 2009
  3. Is there an argument for a peer review of a peer review? Posted January 11, 2020. A good read.
  4. Ridding peer review of potential bias. Posted December 30, 2019. Another good read.
  5. A Bundle of Blogs: On the need for peer review in forensic engineering and expert services. Posted November 29, 2019

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada February 18, 2021 ejorden@eastlink.ca)   

What does an engineering expert do at the scene of slip, trip and fall accidents?

In the beginning, to ensure a reliable, cost effective investigation, s/he should do no more than capture the physical scene where the accident happened – and do this quickly before conditions change.

An expert does this by carrying out as many as 13 different tasks at or near the specific location of the accident indoors or outdoors.

For example, if the accident occurred indoors:

  1. Video and photograph the site as seen by the victim and as seen from a drone,
  2. Measure the slope of floors and ramps, and the width and rise of stairs
  3. Record the nature and surface condition of the materials forming these features,
  4. Measure the location and construction of handrails and guardrails,
  5. Record the presence of debris, liquids or dust at the location of the slip, trip or fall accident, and,
  6. If the shoe or boot is available, examine and record it’s construction

Carrying out these tasks and others is basically an elaborate visual site assessment. Nor is it unlike a topographic survey outdoors that might be done by a provincial land surveyor.

Use the data from this work to show the scene in accurate drawings and photographs. Make, what we call in engineering, as-built or as-constructed drawings. These can also be rendered today with the software that is available in very impressive 2D and 3D formats.

Components of accidents

The expert should refrain initially doing more because these types of accidents have several components. The relevance of each of these to one another and to the accident can’t be evaluated – and the significant one(s) focused on – till the physical setting is nailed down. Trying to do otherwise is expensive – a waste of time and money.

A list of the components of the slipping- or tripping-while-walking hazard looks like the following: (Refs 1, 2 and 3)

  1. Person
  2. Activity
  3. Floor covering (walking or working surface)
  4. Lubricant
  5. Footwear (slider)
  6. Ambient and environment parameters

Each component contains a lot of parameters that are far too numerous to list here. A few are noted in the following:

The condition of the person involved can be crucial. For instance, gender, age, experience and personal situation help determine how much caution a person uses.

Some activities require more foot traction than others. For instance, walking normally in a straight line is least demanding. Walking fast, turning or stopping is more risky.

The floor covering is likely to be different for walking surfaces compared to working. The properties of the floor are important in traction. These are determined by no less than two and half dozen parameters.

A lubricant can be any substance between the walkway and the footwear that reduces slip resistance. Water is just one. And it can get on the floor in different ways both inside and out. For instance, at drinking fountains and sinks indoors and by lawn sprinklers outdoors.

An accident occurs when there’s insufficient traction between footwear and the walking or working surface. A couple of dozen properties characterize the contact between the footwear and the floor in determining traction. Material properties and tread are of paramount importance.

(Ice cleats on boots won’t necessarily save you. I found this out this morning while cleaning wet snow from the timber stairs up to my deck. I slipped on the stairs but can run on ice with these cleated boots. So why the slip? February 2, 2021)

For sure, the environment influences the slipping-while-walking-hazard. Parameters like weather in general – sunshine, rain, snow, wind and humidity. But also lighting, surface slope, handrails, and room equipment and furniture.


The engineering and scientific literature has identified numerous factors in the slip, trip and fall hazard. (Refs 1, 2 and 3) Legal and claim settlement practice manuals have identified others relevant to resolving disputes arising from these accidents. (Ref. 4)

The engineering expert must focus on the big picture initially – the setting of the accident – and do this quickly. And in the process identify the relevant components and parameters for more detailed investigation. This is the only way forward in reliably and cost-effectively determining the cause of slip, trip and fall accidents.


  1. Sebald, Jens, System oriented concept for testing and assessment of the slip resistance of safety, protective and occupational footwear, Pro Business Gmbh, Berlin 2009
  2. Sotter, George, P.E., Ph.D., Stop Slip and Fall Accidents!, Sotter Engineering Corporation, California, 2014
  3. Di Pilla, Steven, Slip, Trip and Fall Prevention, A Practical Handbook, 2nd edition 2010 ESIS, Inc. CRC Press, Boca Raton
  4. Turnbow E, Charles, Slip and Fall Practice 2nd edition, Revision 17 2012 James Publishing, Inc.

(Posted by Eric E. Jorden, M.Sc., P.Eng. Consulting Professional Engineer, Forensic Engineer, Geotechnology Ltd., Halifax, Nova Scotia, Canada February 5, 2021 ejorden@eastlink.ca)