Keep the whole roll fire hose in a dry state and place it at -30 ℃ for 10h. The hose should be wound tightly, and there is no leakage under the working pressure.
This clause is just for dry hose on the fire truck. In practical applications, the polyurethane lining of fire hose can withstand is -55 ℃. Therefore, from the perspective of low temperature resistance and test data, this test condition is of little significance for pu-lined hoses.
In practical applications, the fire hose is often wet on the outer surface. And the surface will become harden and not flexible under low temperature conditions. In this case , after bending, the fire hose is greatly damaged and may cause leakage.
Therefore, in a low temperature freezing environment, pay attention to keeping the fire hose dry.
China has a vast territory. The climate difference between north and south is obvious. Under extreme conditions in winter, the min temp in the three northeastern provinces reaches -30 ℃. In the south area there are few extreme conditions in winter. And the minimum temperature is generally around -10 ℃.