A drop tight PRV has specific internals that ensure that the valve holds and maintains the set pressure during both static and dynamic operation.
'Standard' PRV's only regulate during 'dynamic' flow operation and can sometimes suffer creep during no flow 'static' operation, this can be more prevalent where the unregulated mains is significantly higher. Therefore when the flow starts there can be a pressure spike until the valve catches up and regulates the pressure. It can be seen when a standard PRV has a downstream gauge and it sometimes shows higher than set pressure when the system is static.
It's all about protecting downstream connected equipment and outlets, valves etc can be damaged by pressure spikes just like electrical equipment can be damaged by voltage spikes.
'Standard' PRV's only regulate during 'dynamic' flow operation and can sometimes suffer creep during no flow 'static' operation, this can be more prevalent where the unregulated mains is significantly higher. Therefore when the flow starts there can be a pressure spike until the valve catches up and regulates the pressure. It can be seen when a standard PRV has a downstream gauge and it sometimes shows higher than set pressure when the system is static.
It's all about protecting downstream connected equipment and outlets, valves etc can be damaged by pressure spikes just like electrical equipment can be damaged by voltage spikes.
