Nevertheless, sprinklers with different thermosensitive elements have been designed to activate the system at different temperatures, whether they are based on the fusion of an eutectic alloy or on the expansion of a liquid until the quartz glass bulb is broken, in both cases to allow water flow from the dispenser.
The operation of a sprinkler system is a delicate compromise between the operating temperature and the flow rate of the water supplied depending on the number of dispensers that are activated. Another variable concerns the way the water flow is delivered.
The research has gone on to develop different forms of deflectors both to orient and shape the jet and to determine the size of the drops, thus acting on the penetration capacity of the hot fumes. With the development of storage systems that allow large quantities of material to be stacked, the challenge for installers and manufacturers is to develop systems that allow them to hold the correct quantity of water to tackle fires, the so-called "height challenge".
These sprinklers, the so-called large drops, are sized to attack the fire and to reduce it as well as control it; the "coarse" or "heavy" drop technology was later joined by the CMSA Control Mode Specific Application systems.
The substantial difference between these two types lies in the design of the system that not only considers the discharge density and the area to be protected but which adheres to specific parameters for the application for which it is intended. Designed for an actual suppression action, the ESFR (Early Suppression Fast Response) sprinklers are designed to require only a minimum intervention to complete the emergency team. Compared to large-drop sprinklers, these systems protect complex areas, in terms of fire safety, such as large warehouses with vertical storage of more than 10 meters, exclusively with ceiling systems without regulators at the intermediate levels of the shelves.
However, this is a type of system that must be used according to stringent technical specifications that concern both the plant aspects and the characteristics of the structures to be protected. For intensive storage areas, so-called ELO Extra Large Orifice sprinkles are also available.