Abstract: A valve for a gas vessel has a gas-pressure line which leads to a valve chamber and which is closed by means of a closure valve disposed in the valve chamber. The valve for a gas vessel also includes a gas-takeoff line and is configured so that the valve chamber and the gas-takeoff line as well as other gas conducting spaces at the output end of the valve can be purged in the operational ready condition of the valve. The application and removal of the purging flow occurs over different paths and the purging takes place independently of the actuation of the closure valve. For this purpose, a purging line which is equipped with a purging valve is provided. The purging line opens in the valve chamber of the closure valve.