Germany's DIN4102 also includes a significant impact test for a potential firewall, which is, however, applied from the wrong side: the cold side. Applying the impact from the cold side is more practical to do in a lab setting, however, potential impacts should come from the exposed side, not the unexposed side. Still, for the person designing, building and paying for the test, the fire resistance itself may be rather uneventful unless major problems appear. The burn itself is the long duration, up to 4 hours, but the hose stream test only lasts a few minutes, with large damage potential due to the sudden thermal and kinetic impacts, as the fire was upwards of 1,100 °C (see curves above), whereas the sudden hose-stream test is as cold as the domestic water fed to the fire hose used in the test, which might be 10-20 °C. This combined impact explains the debris that can be seen coming from test specimens during the hose stream test, as seen herein.