Kitchen hood systems are designed according to each individual cooking appliance arrangement. Depending on sizes and types of cooking areas will depend on how many nozzles you will need and where they should be located.
Once these fusible links reach there manufactured tempature, they will melt releasing the cables which causes the suppression system to go off. Fusible links can be manufactured to melt at 350 and 450 degrees. They should be replaced every 6 months when your hood system is inspected.