I nsertar a twin in the water supply network in a dry, could be a bad idea because the twin acts as a rigid bar exerting force on the joint areas between the end parts of the dry network and can damage Storz connections and fittings.
There are also dry building where the network is poorly installed, for example, the threads of the fitting does not provide sufficient returns to ensure a secure connection. It has happened that in dry test network, the terminal part of it has moved out and with it our twin and can injure firefighters and / or people leaving the building on fire.
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To prevent this incident, it is recommended not to connect the twin input directly on the network dry, but place it on the floor, connecting to the network via a hose dry relatively short 70 mm (about 6 m in length).
The twin can be most useful in terms of supply that invested and check valve.
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Why put a twin line network that supplies dry? The idea is to have an alternative if dry network to fail. This line of support is known as "Sub-Base" and corresponds to a hose of 52 mm supply line and twin correspond to the "Naval Base" of 70 mm.
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A hose too tight, less than 4 meters is not recommended, since the movements produced by cutting and opening of the twin, can greatly strain of the network gateway. 
This practice is not recommended especially if dry we know that each network has a check valve in the water column that prevents water from flowing back to the pump. .
dry network can save much time and firefighters. The inappropriate use of our material may accentuate the flaws in the fire protection system of the building. .
risky Note the proximity of the dry network to access the building. .
