Cylinders discharge gas when upright. When connected to the feed system, the cylinder must be secured to prevent movement or falling. The use of load cells or scales is recommended to monitor the contents of the container when feeding chlorine. The container outlet valve is supplied with a valve outlet cap. When the valve outlet cap is removed, plant personnel should inspect the outlet for any nicks that may prevent a good seal and remove any foreign material before placing it in service. A yoke and adaptor for use with CGA Connection 820 or 820C (either open or closed yoke) is the standard connection to the cylinder valve outlet (See Figure 6.1). A gasket on the face of the valve is part of the connection, and a new gasket must be used each time a connection is made. The CGA Connection 660, which utilizes a threaded union that threads to the valve outlet, is not recommended for connecting to the cylinder valve. Valve outlet threads are not standard tapered pipe threads and, therefore, are not suitable for use with standard pipe fittings.