What Do Forensic Engineers Do?

What do forensic engineers do? They apply engineering knowledge with detective work to problem-solve why something fails.

The word “forensics” comes from the Latin word forensis, which means:

“Of a forum, place of assembly.”

In ancient Rome, the forum was a marketplace where people gathered. A lot of the time, the gatherings were to address public affairs. In the forum, the accused and accuser would give speeches before a public assembly.

Now, think of forensic engineers as scientific versions of Sherlock Holmes. There’s detective work involved in gathering clues and evidence. But also, you need to use engineering skills to deeply analyze evidence to form conclusions.

More often than not, forensic engineers investigate the following types of incidents:

  • Structural collapses
  • Safety system failures
  • Fires and explosions
  • Equipment failures
  • Accidents

These investigations are critical parts of legal decision-making. Even more so, they’re integral for continued public safety by holding professionals accountable.

To highlight the importance of forensic engineers, I’m going to go over what they do in detail.

The 6-step workflow of a forensic engineer

The workflow of a forensic engineer remains the same in all fields of work. But, the background knowledge of the engineer will vary depending on the type of incident.

For example, each incident type will need an engineer with a different background. You can’t have an expert automobile engineer investigate building structural failures.

In every case though, the forensic engineer follows the 6-step workflow. Not surprisingly, this workflow resembles the scientific method.

#1 Identify the failure

Identify the exact failure.

With some incidents, the failure is more than obvious. For example, with an exploded transformer, the failure is the exploded transformer.

But other times, the failure is less than obvious. For example, investigating the cause of a forest fire is often nebulous.

#2 Gather evidence

Collect evidence from the failure scene. This can be physical evidence or eye-witness testimonies.

This includes interviewing the professionals who have ties to the failure. This can be executives, designers, and builders.

For example in the interviews, you may look to see if a critical design procedural step is missing. Your goal is to gather enough evidence to reconstruct the event failure step by step.

#3 Develop a hypothesis

Using your gathered evidence, draw up a hypothesis. In other words, an explanation for what you think caused the failure.

You do this by studying the failure site and learning about the damages. To do this work effectively, you need a strong background in math and the laws of physics.

#4 Perform tests

Test your hypotheses. You want to assess the plausibility of your hypothesis.

You may need to develop models to recreate how the failure unfolded. Then, compare the test data you gather to the data you collected at the failure scene.

#5 Form a conclusion

Draw up a conclusion through your analysis. Your conclusion may not be definite, but you can always offer probable causes.

In the end, you want to have a good idea of who is liable. This way you’ll know who needs to pay for the costs of repair and other damages. Also, to prevent future failures.

#6 Testify

Provide expert testimony in a courtroom over the cause of the failure. The goal is to provide enough evidence to jurors, so they can confidently make a verdict.

Methods used in forensic engineering investigations to form conclusions

the workflow of a forensic engineer

In forensic engineering, the investigation is sometimes called the “root cause failure analysis.”

In this analysis, the forensic engineer uses some of the following tactics:

  • Reverse engineering the accident
  • Testing exemplar parts
  • Examining and analyzing the failed parts using various instruments
  • A deep review of the evidence with comparisons made to similar accidents

Mastering these tactics is critical. Because every investigative case has slight differences.

Each time a given material or part fails, the cause of failure may be different. Thus, you need to deeply understand the investigative process to form accurate conclusions. Otherwise, you’ll go down the wrong road by following a cookie-cutter investigative approach.

At the same time, first principles thinking is critical in efficiently solving cases.

Important Note: sometimes certain evidence is inaccessible. Sometimes, you can’t take apart a component without destroying what’s inside. 

When the destructive examination isn’t acceptable, engineers use Non-Destructive Examination (NDE) techniques. For example, one NDE technique is to use a multimeter for electrical measurements. Another NDE technique is to use radiography equipment to inspect the inside of parts.

Like a crime scene, forensic engineering requires detailed and careful work. Because in the end, a single piece of wire may be the smoking gun.

Example forensic engineering case analysis

building electrical fire

Did you know the leading cause of fires is electricity? According to ESFi in 2015, there are 51,000 electrical fires every year. This equates to nearly 500 deaths, 1,400 injuries, and $1.3 billion in property damage!

With our dependency on electricity growing every year, these figures aren’t too surprising. Electrical fires typically start because of the following reasons:

  • Design and manufacturing defects of electrical products
  • Poor power system designs by licensed engineers
  • Misuse and poor maintenance of electrical products by end-users

To better understand fires, it’s important to know the ingredients needed for a fire. These ingredients include oxygen, a heat source, and a combustible fuel. If one ingredient is missing, a fire can’t start. In electrical fires, electricity is the heat source.

With the stage set, imagine a building fire. A forensic engineer would walk onto the scene and do the following:

  • Investigate the cause of the building fire
  • Figure out if the fire was avoidable
  • Investigate if the manufacturer, engineer, construction team, or end-user is at fault
  • Determine how to prevent future fires

Take note how I didn’t say “electrical fire.” The forensic engineer doesn’t yet know if an electrical problem started the fire. BUT, the forensic engineer will answer the following questions in the investigation:

  • Which part of the building first caught on fire?
  • What are all the electrical wire sizes? Were any wires undersized?
  • What’s the maximum available fault current in the building? What’s the maximum interrupting rating of the protective devices?
  • Were there any damaged switches or breakers in the electrical panels?

Many times, the forensic engineer will find the fire started from a bad wire connection. It’s why you shouldn’t ever overlook flickering lights inside your home.

I go over the causes of flickering lights to help you troubleshoot the issue.

The ideal expert witness

the ideal forensic engineer expert witness

After an investigation is complete, a forensic engineer may testify in court. They’d be a neutral expert witness.

Thus, it’s important a forensic engineer has experience in litigation matters. This means you know how to treat evidence, present in court, and record investigations.

Again, these forensic investigations are critical parts of legal decision-making. They can completely swing a decision in one direction or the other.

On that note, the most effective expert witnesses aren’t highly credentialed. Rather, they’re people who have a deep understanding of a subject who also use simple words.

Because in the end, you want jurors to completely understand what you’re saying. This way they can make the right decision over a case.

I find the most effective expert witnesses have the following qualities:

#1) Storytellers who help jurors visualize messages and ideas.

#2) Not pompous, but rather down to Earth. Someone who the jurors can relate to.

#3) Ability to speak English in an easy-to-understand way. Not throw around big words from their profession that jurors won’t understand.

#4) Creative with producing and then discussing visuals such as schematics and charts. Jurors can more easily soak in the facts through visuals.

#5) Strong presentation skills.

#6) Enjoyment for the presentation of investigative work. Joy in your work is contagious and will draw eyes to you.

“What do forensic engineers do?” wrap up

Forensic engineers play a critical role in the safety of the public. They figure out the cause for accidents and whose at fault.

In return, courts may revoke practice permits and press criminal charges.

I find this creates a culture of diligent engineers. Engineers who will closely follow the engineering code of ethics.

As a result, forensic engineers actively prevent future accidents. Because accountability is a real and strong force to keep professionals in line. In fact, the best engineers I know use the following motto when they do any design work:

“Prepare all your records for court.”

What are your thoughts on forensic engineers? Do you find the role of forensic engineers is important? 


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