Editor’s Note: In our January automotive access supplement, we discussed the WC-19 testing standard for wheelchairs that transport users in motor vehicles. PaceSaver/Leisure-Lift President DuWayne Kramer points out that safely transporting bariatric clients, however, presents a whole new set of challenges. “For example, a lot of bariatric chairs would be too wide to even sit on the (testing) sled,” he says. “Theoretically, the standard goes up to 450 lbs. (user weight) as the maximum that they can test with the lap belts. Primarily, the limiting factor right now, I believe, is the seat belts. The other thing to worry about is the hold-down points when you’re trying to hold the person — so the chair doesn’t just rip the floor of the van out. That was one of the first things we saw years ago in testing: Things start coming apart from all the forces involved. You can imagine just a thin sheet of metal trying to hold… that’s a lot of weight there.”
From recent discussions and watching automotive shows on TV, I believe there is a great misunderstanding about transporting a person in a wheelchair in vehicles. In particular, there are major issues in transporting bariatric persons.
The chair and rider are the equivalent of a Peterbilt tractor. |
Let’s start by discussing the enormous forces involved. In a 30-mph crash, you can see forces of 20 G’s (20 times the pull of gravity). A 350-lb. chair with a 650-lb. rider equals 1,000 lbs. at 1 G and 20,000 lbs. or 10 tons at 20 G’s. To put that into perspective, a Peterbuilt semi-tractor with crew cab option only weighs 18,000 lbs., or 9 tons.
So if a van hits a wall at only 30 mph, the chair and rider are the equivalent of a Peterbilt tractor plus 2,000 lbs. flying into the back of someone’s seat and out the front of the van. If a van stops quickly just by braking from 60 mph, the forces involved are .5 to .75 G.
We rate our 650-lb. Boss power wheelchair for a 7-degree incline. For safety, each 650-lb. Boss brake is tested to the equivalent of a 15-degree incline fully loaded. But the braking forces involved in holding a Boss with a 650-lb. person when a van stops quickly can reach the equivalent of a 30-degree ramp or 4.2 times the incline-rated holding power of the brake. There is no scooter or power wheelchair brake I am aware of that can hold at this force level repeatedly. Even if the brake did hold at .75 G, we still are not talking about what would happen in a simple 5- or 10-mph parking lot impact.
Conclusion: We need to secure the chair and the rider separately.
Understanding Current Testing Limitations
Currently, the standard automotive seat belts used in the RESNA standard are rated for a 9,000-lb. capacity, 5,000-lb. lap belt and 4,000-lb. upper-torso belt. So the maximum rider weight is 450 lbs. (20 x 450 = 9,000 lbs.). Currently, there is no RESNA testing standard for persons weighing more than 450 lbs. The standard states wheelchairs and users with total mass greater than 275 lbs. should be transported in a vehicle with a gross vehicle weight of 8,800 lbs. — a Ford E-250 van or bigger.
Wheelchairs with a mass greater than 275 lbs. may use four-point rear securement points and two front securement points.
Making Transport Safer for Bariatric Clients
So how can you help to make transport safer? First, you must have the bariatric client transfer to seating provided by the van manufacturer, since there is no testing standard for a person weighing more than 450 lbs. The person in the van seat will be several times safer than he would be in the wheelchair, if for no other reason than the securement points are not designed to handle the “Peterbilt” combination of a 350-lb. chair and a 650-lb. rider. Even with four rear hold-down points, by splitting up the total mass of the rider and chair, we give the user a much better chance of survival.
Next, secure the chair separately. There must be two sets of rear floor-attachment straps to secure the chair to the floor. In testing we conducted in 1989 with standard-size chairs and riders, the first components to fail were the rear floor strap-attachment points.
These comments are only suggestions. You must follow the requirements of each of the component manufacturers in the chair, seating system and van restraint system.
