Designing for Safe Use

100 Principles for Making Products Safer

Michael Wiklund, Jonathan Kendler, Jon Tilliss, Cory Costantino, Kimmy Ansems, Valerie Ng, Ruben Post, Brenda van Geel, Rachel Aronchick, Alix Dorfman

• Publisher: CRC Press
• Year: 2019
• Print ISBN: 9780367188313
• eBook ISBN: 9781351579155
• Topic: Business
• Subtopic: Marketing
• Index: Business

How do you prevent a critical care nurse from accidentally delivering a morphine overdose to an ill patient? Or ensure that people don't insert their arm into a hydraulic mulcher? And what about enabling trapped airline passengers to escape safely in an emergency?

Product designers and engineers face myriad such questions every day. Failure to answer them correctly can result in product designs that lead to injury or even death due to use error. Historically, designers and engineers have searched for answers by sifting through complicated safety standards or obscure industry guidance documents.

Designing for Safe Use is the first comprehensive source of safety-focused design principles for product developers working in any industry.

Inside you'll find 100 principles that help ensure safe interactions with products as varied as baby strollers, stepladders, chainsaws, automobiles, apps, medication packaging, and even airliners. You'll discover how protective features such as blade guards, roll bars, confirmation screens, antimicrobial coatings, and functional groupings can protect against a wide range of dangerous hazards, including sharp edges that can lacerate, top-heavy items that can roll over and crush, fumes that can poison, and small parts that can pose a choking hazard.

Special book features include:

• Concise, illustrated descriptions of design principles
• Sample product designs that illustrate the book's guidelines and exemplify best practices
• Literature references for readers interested in learning more about specific hazards and protective measures
• Statistics on the number of injuries that have arisen in the past due to causes that might be eliminated by applying the principles in the book

Despite its serious subject matter, the book's friendly tone, surprising anecdotes, bold visuals, and occasional attempts at dry humor will keep you interested in the art and science of making products safer. Whether you read the book cover-to-cover or jump around, the book's relatable and practical approach will help you learn a lot about making products safe.

Designing for Safe Use is a primer that will spark in readers a strong appreciation for the need to design safety into products. This reference is for designers, engineers, and students who seek a broad knowledge of safe design solutions.

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PRINICIPLE 1

Provide stabilization

Principle

Prevent products from tipping over or falling on someone by adding stabilizing features or securing them to their surroundings.

Know your center of gravity

Toppling objects can cause injury as well as property damage. Consider the consequences of a parked motorcycle falling onto a bystander, a ladder falling sideways with a house painter aboard, and a chest of drawers pitching forward onto a toddler who is climbing it to fetch a toy (see Principle 63 - Childproof hazardous items). An object is naturally stable when its center of gravity is within its footprint rather than outside of it. Move the center of gravity beyond the footprint (i.e., beyond the area of support) and the result is instability plus the potential to tip over. It also helps to keep the center of gravity low so that applied forces, such as the centrifugal force acting on a riding lawnmower turning sharply, do not overcome the stabilizing forces.

The motorcycle is stable because the center of gravity is within the motorcycle’s footprint.

Tip-overs are no joke

Between 2000 and 2013, the US Consumer Product Safety Commission reported that product tip-overs and/or instability led to 430 deaths. They also reported that tip-overs caused an average of 38,000 injuries requiring emergency department visits per year during the period of 2011 to 2013. Most of those injuries (56%) were caused by furniture tip-overs. The most common injuries were contusions, abrasions, and internal organ damage. The most commonly injured body part was the head, followed by the legs, feet, and toes. Children between the ages of 1 month and 10 years accounted for 84% of the reported deaths.¹

The motorcycle is unstable and prone to tipping over because the center of gravity is outside the motorcycle’s footprint.

Never go beyond your footprint

When you add a person into the mix—such as one standing on a stepladder—the key is to keep the person reasonably centered within the footprint, rather than extending past it. In the case of stepladders, railings (see Principle 32 - Provide a handrail) help to do this as does making the steps narrower as the height increases. A crossbar-type of hand hold also encourages safe positioning.

Training wheels increase a bicycle’s footprint, which helps children keep their balance.

Stability improves as you enlarge an object’s footprint without changing other physical variables (e.g., height, weight). That is why an office chair with a five-leg base is inherently more stable than one with a four-leg base.

To prevent tip-overs and still handle heavy loads, lift trucks and cranes have outriggers that extend to increase their footprints so that they remain under the entire apparatus’s center of gravity. Outriggers of a sort are also used to stabilize the top of some roofing ladders.

Cranes use extensions (outriggers) to increase the crane’s overall footprint and create added stability.

If you cannot keep an item’s center of gravity within its footprint, or if forces might overturn the object, then some kind of retention or hold-down device might help. Common examples are brackets and tethers used to keep ovens and chests of drawers/bookshelves from toppling forward.

PRINICIPLE 2

Make things easy to clean

Principle

Reusable products should be designed to facilitate easy and effective cleaning, sterilization, and/or disinfection.

Clean up nicely

Perhaps the biggest risk associated with things becoming dirty is exposure to chemical and/or biological agents. That’s why the food and medical industries have standards for cleanliness and even sterility.

Aside from causing contamination, filth can make labels and warnings illegible, make surfaces slippery when wet, and interfere with mechanical motion. For example, consider the following scenarios:

• A poorly located warning label could be obscured over time by soot from a machine’s exhaust pipe or by clippings from a mower’s discharge chute.

• A greasy handle could lead someone to lose his or her grip while lifting a heavy object.

• Gears contaminated by dirt could fail to mesh properly, possibly leading to a dramatic mechanical failure or perhaps a motor overheating.

Accordingly, manufacturers of reusable devices should ensure that devices facilitate easy and effective cleaning, as well as any necessary disinfection or sterilization.

Toppings no one ordered

Easy cleaning should also be a priority in the food industry. Restaurants and establishments serving a high volume of customers typically use several devices to help expedite food prep in the kitchen. Unfortunately, some of these devices can have nooks and crannies that harbor guck and unwanted bacteria.

In July 2017, a McDonald’s employee was fired after he tweeted pictures of an ice cream machine drip tray filled with mold (see image on left).¹

FDA and reprocessing

Sobering to those who have undergone or will undergo a related examination, the US Food and Dru...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• An introduction to safety
• About the book chapters
• About the exemplars
• About the endnotes
• In conclusion
• Acknowledgments
• Principle 1: Provide stabilization
• Principle 2: Make things easy to clean
• Principle 3: Eliminate small parts from kids’ products
• Principle 4: Limit sound volume
• Principle 5: Include pads
• Principle 6: Make it buoyant
• Principle 7: Temper the glass
• Principle 8: Provide tactile feedback
• Principle 9: Make it fire resistant
• Principle 10: Use non-toxic materials
• Exemplar 1: Car seat
• Exemplar 2: Diabetes management software
• Exemplar 3: Tractor
• Exemplar 4: Stepladder
• Exemplar 5: Anesthesia machine
• Exemplar 6: Chainsaw
• Exemplar 7: Medication blister pack
• Exemplar 8: Steam iron
• Exemplar 9: Automated external defibrillator
• Exemplar 10: Stretcher