Hybrid system “Preaction-system"

OK, here we go from the previous post,

A combination of previous types , 2 subcategories of Hybrid system do exist

• Single interlock that act like dry system except these systems require that a “preceding” fire detection event, typically the activation of a heat or smoke detector, takes place prior to the “action” of water introduction into the system’s piping by opening the pre-action valve.
• Double interlock similar to deluge systems except that automatic sprinklers are used. Activation of either the fire detectors alone, or sprinklers alone, without the concurrent operation of the other, will not allow water to enter the piping