Class II - Moderate
When one of these valves is closed, it could open up slightly. If the gas supply is on, gas will leak from the inlet port through the ball/seat and travel through the outlet port. If the valve is not connected to an appliance, and is not capped or plugged, as required by the National Fuel Gas Code Section 6.7.2.1, leaking gas will escape into the air. However, subsequent testing confirms that this potential for a gas leak is eliminated as gas flows through the valve. As a result, there is no risk with installed valves.