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Spells Safety
BEFORE ANY PRODUCT REACHES THE MAR- KET, it must go through a gauntlet of testing. Within each industry, there is a set of regulatory agencies that set the standards for this testing, and sometimes changes to the procedures can require companies to alter how their products are certified. Te 2008 NHTSA final rule on school bus seating has done just that, requiring seating manufacturers to begin quasi-static testing, a term that sounds complicated but is actually just the combination of two different tests that com- panies have already performed in the past.
Quasi-What? To simplify the term “quasi-static testing,” you
must define each part separately: quasi, meaning “almost,” and static meaning “gradually.” Te new testing, which will be mandated on school bus seats in November 2011, is a very slow load applica- tion. NHTSA developed the quasi-static test to en- sure that manufacturers of uni-frame constructed seatbacks did not compromise FMVSS 222. “I think what the feds were really after, and
they talk about this in their final rule, was to make sure if lap/shoulder belts are on school bus seats, that it either compliments or enhances compart- mentalization of the seat,” said James Chinni, the director of the Center for Advanced Product Evaluation (CAPE), IMMI’s seat testing facility for SafeGuard, one of the company’s business divi- sions. “Tey wanted to make sure that the seats weren’t so flimsy that the seat belts would fold the seat over and reduce compartmentalization protection for any unbelted passengers.” Te new quasi-static test requirement applies
existing test capabilities in a new, sequential way. First, force is applied and held to the rear of the seat using a lower load bar to simulate unrestrained oc- cupants’ knees striking the rear of the seat. Next, force is applied to the torso belt of each seat belt system using semi-circular body blocks. Finally, to simulate unrestrained occupants’ bodies striking the rear of the seat, an upper load is applied to the seat back. Te amount of force applied during the test depends on the seat width, capacity and the size of bus in which it will be installed. During the test, the forward movement of the seat back and upper torso belt anchorages are measured.
Working Ahead of the Due Date Even before NHTSA finalized its 2008 ruling
on school bus seats, manufacturers were get- ting ready for what they knew to be inevitable. CE White started eight years earlier, applying both FMVSS 210 and 222 to its Student Safety Seat, and, according to Executive Vice Presi- dent Bob Knapp, NHTSA “put their envelope pretty close to the way our seat performed” when it defined the quasi-static test. “Back in 1999, the talk of the industry was
the fact that someday there would be a need for three-point belts in school buses, so we acted on that thought and went ahead and designed the seat,” said Knapp. “At that time, NHTSA had no rules for which that seat was to be built under, so we built it under the rules that we thought would apply, taking into con- sideration some of the existing rules that NHT- SA has for school buses and applying some of the rules the automotive companies have for their three-point belts.” Other companies worked in the virtual
world before performing any actual tests. Syn- tec Seating Solutions, the manufacturer of the M2K seat, relied on its automotive develop- ment tools, such as computer-aided engineer- ing, to develop a seat that would survive the rigors of a school bus. “Using the lessons learned from our virtual
development, we progressed into physical test- ing shortly before the final rule was published last October,” said Brandon Marriott, general manager of Syntec. “We have run hundreds of actual tests to ensure that our customers, and children, are riding in seats that meet NHTSA performance criteria.” Unlike IMMI and its CAPE facility, Syntec has
performed testing through a third-party com- pany, MGA Research, that is also one of NHTSA’s contract labs for FMVSS 222 testing. Develop- ment testing, on the other hand, was done in- ternally at the company’s manufacturing plant in High Point, N.C. “We wanted an independent, accredited lab to
validate our designs without any bias, and we’ve done as much up-front virtual development as possible to keep costs down,” said Marriott.
FMVSS 222 load application cylinders aligned with the rear of a SafeGuard seat installed in a school bus section.
Load application to the seat belts in an FMVSS 210 test of a SafeGuard seat in a bus section.
M2K seat going through the quasi-
static test. 53
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