Hydraulic sprinkler systems are the most efficient when properly designed, because their design makes the most efficient use of the available water supply.  Four things determine the ability of any piping system to pass water through...
distance that the water has to travel, amount of flow through the piping, type of material used, and
the age of the piping network, in many cases. The advent of the computer has enhanced the design of sprinkler systems in the past forty years.  prior to the computer, almost all systems were installed as pipe schedule systems.  These types of systems were based on the number of sprinklers loaded onto a specific diameter pipe.  There wasn't too much thought given to the water supply, as long as the supply met some rudimentary requirements for flow and pressure.

Hydraulically designed systems can use a variety of design methods, based on the requirements of the occupancy and the desire of the designer.  The most common type of hydraulic system is the density/area method, which can be used in alomost every occupancy.  However, as the hazard of the space increases, designs that use more appropriate methods, such as ESFR for high challenge occupancies, are necessary in many cases.

NOTE: This is an unformatted excerpt from our online fire protection training library.