Why Manufacturers Like to Beat Up Their Products

THERE'S A REASON IT'S CALLED "durable" medical equipment.

Before the products you sell - wheelchairs, lift chairs, walkers, concentrators or beds - ever make it out the manufacturer's door, they have likely been dropped, frozen, pounded, jerked, steamed, poked, needled, slammed, jarred and almost everything else just short of deep-frying.

But as persecuted as the equipment might sound, manufacturer durability tests are nothing more than attempts to simulate the abuse that beneficiaries and/or their caregivers dole out. That's why major DME manufacturers put their products through such rigorous tests - to see not only how but if equipment will hold up under a variety of real-life conditions.

To the Limits - and Beyond

"The main reason for testing is to find a weakness that affects the use of the product," says Lee Sheffield, senior lead technician at Invacare's test lab in Elyria, Ohio. "[If any flaw is found,] it then goes back to the design engineers, and they make the changes to the design to correct it.

"Not only do we do a test, get a product to break and then figure out what happened and why," he says, "but we want the test to be repeatable and to quantify the loads or stresses in that test so that we can understand what the results of the test mean to the [product's] actual life event. The fundamental question we ask ourselves is, `Is this test we're performing a real-life correlation or am I twice the acceleration or some other factor?' It's really understanding what that failure mode is that you're going after."

Pushing a product to its limits, he says, and forcing it to fail is the name of the game in this line of business.

Sometimes, however, there's no better test than real life, and many manufacturers examine returned items for design or production flaws.

"When we get back anything we warranty, we always look at the equipment to see where it failed," says Foster Davis, national sales manager for Simi Valley, Calif.-based Freedom Designs. "What we've found over the years is that you can do stress and strength tests, but until that equipment has been in the school, on the bus, in the home and in the trunk a few times, you really don't know how it will hold up."

Not Just a Gorilla with Suitcase

Although it is their job to break products, testing professionals aren't handed a sledgehammer and simply told to go get ornery with a product. Most in the industry adhere to American National Standards Institute-Rehabilitation Engineering and Assistive Technology Society of North America, International Organization for Standards and, sometimes, their own internal testing standards.

"We adopted the ISO 7176 International Standards for North America, so we do all the ANSI-RESNA tests as prescribed," says Mark Greig, global products director for power products at Sunrise Medical's Longmont office. "Most are `test-and-report' tests."

Each product has a prescribed set of minimum standards that must be adhered to in order to receive ISO or ANSI-RESNA certification. "Each product would have what we call a reliability test plan," Sheffield says, "and in that test plan is where we would identify the standard that applies to that particular product, if there is such a beast."

In some instances, he adds, Invacare sets more stringent internal standards. "There's a fatigue test called the double-drum test where the prescribed ANSI-RESNA test is 200,000 cycles, or 107 miles," Sheffield says. "We take that all the way to 250,000 cycles or 150 miles, just to be sure that we have a safe and reliable product."

An Electric and Light Parade Fatigue or "accelerated life tests" are easy enough to perform on wheelchairs and other DME. But what about products such as concentrators that are made of plastic or composite materials and can be damaged by environmental conditions?

"When you get into composites, you need to look at the effects of temperature and ultraviolet light," says Sheffield. "But you do still have to deal with impact resistance as well because users might drop that product when setting it up or taking it out of the trunk of a car. You have to take into account loading conditions that you wouldn't necessarily have to test when you're dealing with steel or aluminum products."

A number of electronic tests, such as the radio frequency interference test, are also performed on concentrators and other electronic equipment, including power wheelchairs. In an RFI test, products might be hit with up to 15,000 volts of static electricity. There are multiple sources of RFI in the home environment, include such things as blenders. The RFI test has also become more important in recent years because of cellular phones.

"This test is critical for power chairs because if a user was, say, crossing the street and somebody was using their cell phone and it interfered with the operation of the chair, that could be potentially deadly," says Sheffield.

Ho-hum? Not Hardly

One thing product testing isn't is boring. After all, these professionals get to destroy things for a living.

"We don't get bored very often because we're always trying to improve the way we do our tests by making them repeatable, which improves our products," Sheffield says.

Sometimes, he also admits, he and his colleagues "have grins on our faces when we take an engineer's pride and joy back to him in pieces."

Adds Greig: "Sometimes we do see some disappointment [from design engineers], but it's all a learning experience," he says.

"After every test, there's always something to be learned - and it's amazing the solutions that come. It seems there's always a solution to a problem, and the tests are what make us aware of those problems."

That, says Davis, is the point of all this destructive activity: to make sure any product that hits the street lives up to expectations. "You almost have to make everything bulletproof," he says.

Perhaps the name of the industry's products should be changed to BME ... bulletproof medical equipment.