Kinder, gentler interiors: new safety rules force engineering into cosmetic plastic parts.

I'd rather look good than feel good," comedian Billy Crystal used to joke. That pretty much sums up what has been the specification for most plastic interior trim components: they had to look good and be as a low cost as possible; how they felt to unbelted passengers' heads during crashes wasn't a concern.

That's all changed now, thanks to new U.S. Dept. of Transportation head-impact standards scheduled to be phased in beginning in 1999. Announced last year, the new rules are changing the nature of many mundane interior trim parts, such as pillar covers and headliners and forcing them to evolve from mere cosmetic pieces to highly engineered components that will be scrutinized by government safety experts.

Although automakers aren't required to comply with the regulation until 1999, some new '97 models -- such as the new Toyota Camry -- already meet the standard. Numerous '98 cars are expected to comply with the mandate, which is dominating plastic interior trim development efforts.

Suppliers say the legislation will lead to significant material and design changes and force the use of slightly more plastic and energy-absorbing foam per car. But so far no one is calling it a huge windfall for the plastics industry.

Jim Best, president of Market Search, an automotive plastics consulting company, points out that almost all the components affected currently are made of plastic -- not another material -- so there likely will be only small incremental gains as urethane foam backing or reinforcing ribs are added.

Higher-cost polymers with more sophisticated engineering properties also will be used.

But the new components require extensive engineering and testing efforts -- costs that material and part suppliers may not be able to completely pass on to their automotive customers.

Many parts, such as A-, B- and C-pillar covers, now are being developed like knee bolsters, the parts on the bottom edge of the instrument panel designed to help protect unbelted passengers from injury during severe frontal impacts.

Designing knee bolsters, however, involves extensive computer crash simulations and then developing a "material system" compatible with the engineering characteristics, explains Renee Kirchner, market manager at Dow Automotive, Dow Chemical Co.'s automotive unit.

Sophisticated computer modeling enables engineers to select and optimize designs without resorting to expensive full-vehicle tests during development.

Even so, this extremely sophisticated methodology is far removed from the typical "shoot-and-ship" approach traditionally used for such simple injection-molded parts.

"We are working with our customers to avoid adding cost by minimizing development cycle time, reducing certification testing and simplifying component manufacturing and additional final assembly operations," Ms. Kirchner says.

"Basically, hard trim always has been an appearance item, never a structural item. You never had to do much of an engineering job," says one high level supplier executive. "With the new standard, these parts have to become part of the safety package. If they don't handle impacts properly, you could be looking at a recall."

Ricardo Martinez, administrator of the National Highway Traffic Safety Administration (NHTSA), estimates the requirement will increase costs by $33 for cars and $51 for light trucks.

Andy Poole, technical marketing manager for engineered foams at Bayer Corp., estimates that meeting the new head-impact requirements could add about 0.5 lbs. (0.23 kg) of energy-absorbing plastic foam per car -- and quite a bit more to larger vehicles such as minivans.

Mr. Poole says automaker demand for test parts has been so high that Bayer's prototype labs are almost starting to resemble mass-production operations.

The safety mandate, formally known as FMVSS 201, doesn't specify how automakers are to reduce the risk of head injuries, but it requires head- and shoulder- level trim in the cabin to pass the same tests as instrument panels and other components already regulated. It basically is designed to protect unbelted passengers from major injuries during severe crashes and rollovers. As currently proposed, it requires that 10% of an automaker's vehicles comply with the standard in 1999, 25% in 2000, 40% in 2001, 70% in 2002, and 100% by 2003.

Initial applications focus primarily on adding backings of energy absorbing polyurethane or other types of plastic foams to absorb energy, but automakers already are exploring other methods that may be less costly and use less material.

Ms. Kirchner says the new safety mandate requires energy-absorption capability to be an integral element of the material-selection process. The scenario is further complicated by the fact that various upper-trim components require different levels of energy absorption capability which in turn affects part design, aesthetics and cost.

In addition to energy-absorbing urethane foams, Ms. Kirchner says acrylonitrile-butadiene-styrene (ABS) and polycarbonate/ABS (PC/ABS) blends, high-impact polystyrene (HIPS), general-purpose polypropylene (GPPP) and high-crystalline polypropylene (HCPP), all are being evaluated for future parts.

Robert Eller, an Akron, OH-based consultant to the plastics and rubber industries, says the new legislation will force automakers to use tougher, more ductile plastics in place of less expensive, somewhat brittle polymers used in some interior trim areas. Plastic trim components with fabric or soft plastic "skins" also will be used more extensively, he says.

"No single material or design can be seen as the ideal solution for every interior trim application," says Dow's Ms. Kirchner, emphasizing that a `material-neutral' approach is the wisest route for most applications.

That requires suppliers to be sensitive to customer needs and understand head impact and how materials absorb energy.

"In some cases, inserting foam behind the pillar is an adequate solution, while in others an injection-molded one- or two- piece thermoplastic ribbed design has been found to be the most appropriate option, depending upon where the customer is in the design cycle," Ms. Kirchner says.

Industry insiders say the ultimate result of the legislation will be very smooth interior lines in the head and shoulder areas. Headliner grab handles and coat hanger hooks that now jut out will be recessed and retract when not in use to better prevent head injuries in a crash.

In some cases the heavy foam padding or reinforcement ribs of pillar covers and headliner parts may reduce visibility and give occupants a more "closed in" feeling by adding depth and width to A, B and C pillars and to the headliner where it meets the windshield and backlight.

That's bad news for interior designers who currently are working overtime to improve visibility and give an impression of openness to interiors, but so far no problems have surfaced that engineers find insurmountable.

Automakers have found that safety sells, and complaining about new safety regulations hurts their public image. Furthermore, supplier sources say automakers and NHTSA have been working together to keep the standards reasonable and the costs relatively low.

If the new Camry is a good example of how FMVSS 201 will change interior design, then most consumers will never notice the difference.

All upper vehicle interior components must be tested by impacting a featureless Hybrid III headform of 44.5 (10 lb.) weight that travels in a free-flight mode for not less than 25 mm at a velocity of 6.70 m/s (15 mph). This velocity corresponds to the average velocity for onset of severe injuries. The free-motion headform can be launched from any point inside the occupant compartment provided that the approach angles are within specified ranges and that the headform region contacts the target points without contacting any other part outside the specified impact zone.

The revised standard further specifies the temperatures and relative humidity at which the tests are to be conducted. The equation is used to establish a head injury criterion -- HIC (d) -- that is used to measure compliance of specific interior upper components. FMVSS 201 regulations are currently proposed to be phased in