Union Carbide Corporation - Comments

March 19, 2001 RE: Docket No. NHTSA 00-8633 Methods Update Comment Clerk (W-99-21) US Environmental Protection Agency Water Docket MC-4101 Ariel Rios Building 1200 Pennsylvania Ave. NW Washington, DC 20460 Dear Methods Update Comment Clerk (W-99-21), The purpose of this letter is to comment on the proposed rulemaking Docket No. NHTSA 00-8633 concerning technical modifications in two of the tests included in the brake fluid standard. Corrosion Test: We support the proposed modifications. Evaporation Test: As members of the SAE Motor Vehicle Brake Fluids Standards Committee and brake fluid technologists for a company that has been formulating/producing/selling brake fluid for 50 years, we believe this test to be outdated. Brake fluid evaporation leading to vapor lock is not a danger in modern braking systems. It has been our experience, and has been supported by data generated by the SAE Brake Fluid Standards Committee, that even with the proposed test improvements, results are unacceptable in repeatability and reproducibility. Furthermore, we consider the evaporation test redundant with respect to both the boiling point and wet boiling point requirements. Therefore we do not support the test change proposals and recommend the evaporation test be omitted from the DOT Brake Fluid standards. If the DOT cannot fully support this change as proposed by the SAE, we suggest a possible alternative: DOT Brake Fluid must have a minimum ERBP (equilibrium reflux boiling point) of 235°C or pass the evaporation test. Note that most modern brake fluids have ERBP significantly more than 235°C, whereas when the evaporation test was instituted, they were typically much lower. Sincerely, Tammy T. Shannon, Ph.D. Gregory A. Carpenter Brake Fluid Technologists & Members of the SAE Motor Vehicle Brake Fluids Standards Committee Union Carbide Corporation A Subsidiary of The DOW Chemical Company