The minimum performance values in this recommended practice are applicable to vehicles with brake systems having typical service pressure ranges 0-1800 psi (0-12.4 MPa) hydraulic or 0-120 psi (0-0.8 MPa) air only. SAE J880 not only provides for determining maximum brake rating horsepower capability@ but also permits verification of any desired or arbitrary level such as the requirement establishment herein. The determining criteria for deciding brake rating horsepower capability are: (a) Cold brake stopping ability. (b) Fade as a result of horsepower absorption. (c) Hot brake stopping ability following horsepower absorption. (d) Brake system stability following horsepower absorption. (e) Functional and structural integrity of brake system following test. Purpose-The purpose of this recommended practice is to establish a minimum brake rating horsepower (BRHP) level for commercial vehicles tested in accordance with SAE J880.