GMNA GM9508P PDF

This standard describes the test procedures to evaluate the chip resistance of coatings. Method A is the contained method where the gravelometer is contained in a constant temperature freezer and Method B is the transfer method where test panels are transferred from a freezer to gravelometer at room temperature. 

Method A must be used for qualification of exterior body coatings applied to zones A, B or C as specified in GM4348M. Method B may be used for qualifications and approvals of all other coatings and painted parts.