Minimizing Liability Risk in Engineering Product Design

The threat of product liability lawsuits looms large for manufacturers. December 9, 2014


Every year in the U.S., consumers claiming harm from a product, file thousands of product liability cases in the court system.

As product designers, engineers shoulder much of the responsibility for creating goods that are as safe as possible. Doing so requires a blend of identifying hazards and minimizing the risk of defects while facing pressures such as cost reduction and time-to-market.

Although design engineers do not need to become product liability experts, they should have at least “a rudimentary understanding and appreciation of the legal concepts and consequences,” says Robert Scheibe, principal of GT Engineering and an affiliate associate professor at the University of Washington.

Three types of product defects can result in liability: design defects, manufacturing defects and marketing defects. Design defects mean that the product has an inherent design flaw that makes it unsafe to use. Manufacturing defects indicate that the error occurred during the product’s construction. Marketing defects occur as a result of improper warning labels or instructions, or over-promising a product’s capabilities.

When a product is involved in an incident, attorneys first look to see if the hazard could have been designed away by some reasonably economical and available technology. This is weighed against the foreseeability, likelihood and severity of the risk, says Phil Van Herle, a forensic engineer with 4X Forensic Engineering Laboratories.

If a consensus of lawyers, forensic engineers and other experts determine that the risk cannot have been designed or guarded against, lawyers will examine whether manufacturers have sufficiently alerted end-users about a potential hazard and how to avoid it.

To help deflect product liability claims, manufacturers have to make a fundamental shift in mindset because “engineers don’t treat safety as an equal partner in the design process,” says Richard Ziernicki, president and CEO of forensic engineering firm Knott Laboratory.

This is because, from the outset of the design process, engineers must design not only for reasonable use but also foreseeable misuse. For the latter, that means more than simply trusting that the end-user will read the product manual.

According to Ziernicki, companies typically take the position that the user was injured because he or she was not careful enough. “People should not die or suffer a serious injury just because they did not read instructions,” Ziernicki says. “Manufacturers have a duty to design the safest practical equipment.”

That is where risk mitigation comes into play.

Mitigating Product Design Risk

Although they cannot eliminate all of a product’s hazards, engineers can implement a variety of tactics to mitigate risk and keep product liability claims at bay.

Design engineers first must attempt to understand the true needs of the product’s customer, says Paul Mainprize, operational quality risk manager and consultant with IHS. It may sound oversimplified, he says, but doing so is “an elaborate task because if you only try as a designer to comply with the written list of requirements, you will most likely miss the mark.”

Of the product-related quality and reliability issues, Mainprize has been involved over the past 40 years, many of the incidents were the result of engineers not envisioning and/or fully understanding the customer’s unspoken requirements.

To keep engineers from introducing design-related weaknesses into the products they design, he suggests integrating quality function deployment (QFD). Not only does this methodology correlate the customer’s needs and expectations to downstream design work and process development, it ultimately helps to ensure smoother production with higher yields and low to nil field failures.

One of the most important tools in minimizing product defects is hazard analysis in order to consider all the possible ways that a product may fail or be misused. Product liability experts recommend a team approach to undertake such a hazard analysis. Early input could come from sources such as focus groups, surveys with customers and even psychologists, GT Engineering’s Scheibe says.

In addition to the design engineers themselves, the group performing the hazard analysis could include sales staff, field employees, personnel responsible for writing safety warning labels and customer-use instructions, a product liability attorney and third-party design professionals.

At this stage, and throughout the design process, third-party engineers bring a new perspective to the design table. They can provide insights often overlooked by some engineers who may favor using product design thinking that worked well in the past but miss out on opportunities for improving the products they are designing, Mainprize says.

Once the hazard analysis concludes, engineers should have a complete list of the ways in which the product might fail or potentially hurt somebody. These factors are prioritized by severity and likelihood. Product designers then are tasked with designing away the hazard, guarding against the hazard if possible, and/or providing applicable warnings and instructions on how to avoid potential hazards while using the product.

“If you as a company show that you designed out hazards as best you could, it will go a long way toward showing a jury that you took reasonable efforts to prevent defects,” says Scheibe.

IHS’s Mainprize emphasizes the importance of performing failure modes and effects analysis (FMEA). Companies that take this approach typically fall into two categories: those that are looking for ways to improve their products on a continuous basis, and those that do so in order to “check off the box to prove to third-party auditors that they did risk management,” he says.

He cites several detrimental outcomes in the latter approach to FMEA. In addition to the lack of truly seeking out potential failures in the product that manufacturers design, engineers may underestimate the probability of potential failures, and in some cases significantly overestimate “the level of control they think they have in preventing failures and/or mitigating the failure-related effects they have identified in their analysis,” he says.

In his work as a forensic engineer, Van Herle often uses computer simulation for stress, heat transfer, fluid flow and fire modeling to demonstrate why a product failed. He recommends that engineers use similar methods in the design stage to determine a design’s weakness and improve upon it.

To identify product matters relating to metal fatigue, corrosion and polymer issues, Van Herle uses materials examination and testing techniques such as scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR).

Role of Safety Standards

Manufacturers encounter many mandatory and voluntary safety standards they must meet on both the national and international levels. These standards go a long way toward minimizing product liability risk, though many manufacturers assume that their product is safe if it complies with standards, according to Knott Laboratory’s Ziernicki. However, injury and death can still occur.

This is because many standards are considered the minimum bar and may lag as they await updates. “If you really care about human life and welfare, you should go beyond the standards and make the product as safe as practical,” he says.

In some situations, the design approach diverges in a way that renders a standard incorrect. For example, a warning label on a baseboard heater might read, “Caution. Keep away from furniture.” Although the wording technically heeds an established standard, it is vague and leaves it to the user to decide what “away” means, says Charles Seyboldt, a lawyer and engineer with technical consulting firm Weinstein Associates.

“Warning labels must give information about the magnitude of downside risk if the reader fails to follow the warning,” he says.

A design engineer’s objective is to minimize the rate of injury in the real world, but if the standard does not do that, “then, by all means, deviate from it,” Seyboldt says. “Just be prepared to defend whatever it is you produced.”

He also has seen warnings that he knows the public will not follow because the labeling is difficult to understand, awkwardly worded or has too much information. That is why engineers must know their audience. He shares the example of an electrical connector manufacturer whose warnings delved into subjects such as too much current in the circuits.

The recipient of this message, however, was a harness fabricator “who didn’t have a clue about how much electric current is supposed to be going to the wires,” Seyboldt says. His advice? “Focus their attention on where they can screw up.”

No single method or standard eliminates product defects and failures. However, design engineers can implement a series of risk mitigation techniques not only to protect their companies from lawsuits but, ultimately, end users from harm.

This article was originally published July 23, 2015, by Winn Hardin on the IEEE GlobalSpec Engineering360 website.