Three major producers of brake hose are asking the National Highway Traffic Safety Administration to rewrite the new federal safety standard for that product.
Petitions by Cooper Standard Automotive Inc., Degussa Corp. and Parker Hannifin Corp. all involve NHTSA's rules on plastic brake tubing, though for different reasons.
Parker Hannifin objected to the rule's retention of generic terminology on air-brake tubing. By using generic terms, Parker Hannifin said, NHTSA failed to meet one of its stated goals, which was to block the sale of tubing incompatible with the end fittings most commonly used in the United States.
``Many of the air-brake fittings in use today rely on the hardness and compressive strength provided by [nylon] in order to effectively hold on to the tubing,'' Parker Hannifin said.
The old rule controlled the properties of tubing enough to give fittings manufacturers confidence that their products would work with all types of tubing, the company said. But design controls in the new standard are insufficient and place the entire burden of compatibility on fittings makers, according to Cleveland-based Parker Hannifin.
Degussa said NHTSA chose the generic language largely because of 22 performance tests that, NHTSA believed, would ensure safe service for air-brake systems. The Parsippany, N.J.-based company, however, disagreed, saying that none of the 22 tests cover long-term field use.
``Many of the performance tests are specific to the currently used nylon materials and do not cover potential deficiencies of new materials without a proven track record,'' Degussa said. The company recommended additional language stating that material suppliers, tubing manufacturers and end users must agree on additional tests to measure performance of new materials.
Novi, Mich.-based Cooper Standard said the final rule's provisions on allowable in-use deformation of vacuum brake hose effectively outlaw the use of plastic vacuum brake tubing.
The tolerances in the standard are based on the performance of reinforced rubber hose for vacuum brakes, which is the product of choice for North American vehicle manufacturers, Cooper Standard said. ``However, the majority of European automakers that import their product to the U.S. use plastic tubing for vacuum brake,'' the company added, urging NHTSA to add language to the final rule stating that plastic tubing need not meet the deformation requirement.
NHTSA issued the final rule Dec. 20, to go into effect Dec. 20, 2006. The rewrite was based on 1998 petitions from Parker Hannifin, Elf Atochem North America Inc. and Mark IV Industrial/Dayco Eastman for a consolidation of NHTSA and Federal Motor Carrier Safety Administration brake-hose safety rules.
The agency gave interested parties until Feb. 3 to ask for reconsideration of the rule. It has not answered the three petitions yet.
