"Fire resistance-rated assemblies, such as fire doors, fire walls and dampers, must undergo rigorous performance testing before they are recognized in model codes and standards. In addition to being exposed to heat and flames, assemblies must survive a hose stream test. The hose stream test is intended to provide a standardized way of evaluating the assemblies' ability to remain intact after a fire exposure test lasting up to one hour. The test assesses hose stream impact, erosion and cooling effects in a consistent manner. It is not intended to replicate conditions that firefighters might create when attacking a fire."
Coffee Break Training - Fire Protection Series No. FP-2013-35
United States Fire Administration: http://www.usfa.fema.gov/