Principles of Sprinkler Systems-Fire safety Engineering
Sprinkler systems may be installed in a building to achieve a number of different objectives. Very often the primary reason for installation is property protection. For taller, larger and more complex buildings sprinklers are often installed to help protect life. There are few sprinkler systems that are designed to fully extinguish a fire, most are designed to control and contain a fire. If they happen to put the fire out as well, as they often do, then this is a bonus. Early Suppression Fast Response (ESFR) sprinklers are used in some warehousing buildings and these are designed to extinguish the fire fully.
The sprinklers are designed to throw a sufficient quantity of water onto the items around the fire and onto the walls and ceiling of the building to stop these items from catching fire. The ceiling above a fire is subjected to very high temperatures and it is important that sprinkler heads throw sufficient water up onto the ceiling to protect it from the fire.
Sprinkler systems are often fed from their own dedicated water tanks and the supplies have to last for a specified period of time, typically 1, 1½ or 2 hours. For life safety purposes it would be expected that there are two tanks or the tank is split into two halves with each half being capable of feeding both of the supply pumps.
Where smoke control is installed in a building it is usual for there to also be sprinkler protection to the building and its contents. This is necessary because smoke control systems cannot usually cope with the smoke from very large fires and the quantity of smoke has to be restricted.
Sprinkler systems that are designed to protect life as well as property have features that make them more reliable such as by-passes at the main valve to allow the system to remain active whilst the main valve is being worked on and warning systems for alerting staff to any part of the system that might be turned off.