ESFR Sprinkler employs the use of an Early Suppression Fast Response Sprinkler and is predominately used for the protection of High Piled Storage. Storage arrangements man include palletized, solid pile, shelf, bin box, or rack storage of materials. The primary advantage associated with ESFR Sprinklers is a protection scheme that does not require the use of in-rack sprinklers in a rack storage configuration. Using ESFR sprinklers may eliminate the use of in-rack sprinklers and can help avert the discharge of water caused by the rupture of a sprinkler or pipe accidentally struck by a piece of material handling equipment or pallet load. Another advantage with an ESFR system will allow the rearrangement of storage racks without the costly reconfiguration of the in-rack sprinkler piping when such systems are installed in racks.
The ESFR sprinkler relies on three important factors: the sprinkler response (response time index), the Actual Delivered Density (ADD), and the Required Delivered Density (RDD). ADD is defined as the water flux delivered to the top surface of a burning rack-storage array after penetrating the fire plume. RDD is defined as the water flux required to be delivered at the top of the burning storage array to achieve suppression.
The ESFR sprinkler is based on the concept of early suppression, whereby the activation of the sprinkler occurs during the early stages of a fire while the RDD is minimal. During the early stages of the fire, the ADD will exceed the RDD and thus provide an adequate density to suppress the fire.
ESFR ceiling-mounted sprinklers can be used in warehouses in place of in-rack fire sprinkler systems, providing protection that exceeds that on in-rack systems. ESFR high output, high volume systems are located in ceiling spaces as the conventional fire sprinkler systems. It incorporates very large high volume, high pressure heads to provide the necessary protection without the need for in-rack sprinklers.
ESFR sprinkler systems can protect a variety of commodities from non-combustible to normal combustible products to high hazard commodities such as plastics without the use of additional in-rack sprinkler protection in rack storage structures. ESFR sprinklers are intended to operate differently than most other types of sprinklers. While most other sprinklers are intended to control the growth of a fire, an ESFR sprinkler system is designed to suppress a fire. To suppress a fire does not necessarily mean it will extinguish the fire, but rather it is meant to ‘knock’ the fire back down to its original point of origin. ESFR sprinklers accomplish this task by using large volumes of water, nearly 380 liters per minute per sprinkler. Obviously, these systems require large water supplies and often require the installation of fire pumps.
However, ESFR cannot protect all types of rack storage, they cannot be applied to open-top containers. Since the concern with open-top containers relates to these containers retaining the water (like a reservoir) and therefore not allowing the water to flow down into the lowest levels of the rack.
While ESFR systems may solve many of the more challenging problems in warehouse protection against fires, ensuring that the correct type of ESFR is used involves a full understanding of the commodity and methods of storage in the warehouse. Careful consideration must also be given on the long-term use and range of flexibility expected by the owner of the building.