This standard prescribes standardized fire and hose stream test procedures that apply to fire door assemblies intended to be used to retard the spread of fire through door openings in fire-resistive walls ，The purpose of this standard is to prescribe specific fire and hose stream test procedures for fire door assemblies in order to standardize a method for determining the degree of fire protection provided by such assemblies in retarding the spread of fire (flame, heat, and hot gases) through door open- ings in fire-resistive walls The degree of fire protection measured in units of time is not an absolute value because all possible actual fire scenar ios are not represented by the standard fire exposure described herein This standard allows different fire door assemblies to be pared with each other in order to evaluate their relative performance as measured against a standard fire exposure.