Automatic fire sprinklers were developed in the 19th century as a response to the Industrial Revolution. Some of the first factories and mills built in the early 19th century were also first to burn to the ground. Early attempts at providing fire protection involved bucket brigades and perforated pipe.
In 1876, Henry Parmelee, the owner of a Connecticut piano factory, developed what has been recognized as the first automatic fire sprinkler. The Parmelee sprinkler used a low-temperature melting metal (solder) to activate the sprinkler. The solder would melt at a temperature of about 165 F/74 C when exposed to the heat released from a fire and allow water to discharge from the sprinkler to address the fire.
Over the next 100-plus years, significant improvements were made to the automatic fire sprinkler to increase its effectiveness in fighting fires. In addition to solder thermal elements, triggering devices made of glass bulbs were developed. Sprinklers were made to respond faster and discharge more water to address higher hazards.
The industry is now to the point where ceiling-only fire protection exists up to a 55-foot ceiling in warehouse applications using automatic sprinklers.
Until recently, the operation of an individual automatic sprinkler occurred when its thermal element reached its specific set temperature. The use of electrical devices to activate sprinklers has been primarily used in pre-action systems, whereby electric detectors and electric solenoids are used to open a valve to allow water to flow into the sprinkler piping network.
In pre-action systems, closed or open sprinklers can be used. With closed sprinklers, once the valve is opened, water discharge from a sprinkler will be predicated on the release of its thermal element, whereas with open sprinklers, water will discharge from all of them.
The storage industry continues to evolve and presents unique fire hazards that require customized detection and suppression solutions. For example, modern lift technology allows for higher storage heights, increasing the need for fire protection systems that can monitor and help protect these increasingly larger and denser areas.
In addition, the storage of exposed expanded group-A plastic (EEP) materials creates a particular challenge since they produce fires that grow much faster than similar products stored in cardboard containers. EEP materials do not absorb water as readily as cardboard, making fires difficult to contain.
Typically, fire protection schemes used to protect EEP rack storage arrangements have required the use of intermediate-level, in-rack automatic fire sprinklers. Fire testing conducted by the Fire Protection Research Foundation led to the incorporation into NFPA-13 of a ceiling-only protection scheme using early suppression fast response (ESFR) automatic fire sprinklers to protect EEP in single-, double- and multi-row rack storage arrangements up to a 40-foot ceiling height and 35-foot storage height.
The protection scheme requires the use of ESFR sprinklers with a nominal K-factor of 25.2 at a minimum pressure of 60 psi flowing through 12 sprinklers. In addition, the scheme requires the use of solid, vertical barriers for the full storage height and limits the aisle width to 8 feet.
Electronically Activated Fire Sprinklers
To address the need for better ceiling-only fire protection for EEP storage applications, Johnson Controls developed and launched the first UL-listed, electronically activated sprinkler, the EAS-1; the 16.8 K-factor sprinkler offers earlier fire detection. It requires less water and reduces smoke damage compared to a traditional storage-space fire protection plan — using only 52 psi flowing through nine sprinklers.
The EAS-1 technology is designed to avoid sprinkler “skipping” and react more efficiently to a fire. It is suited for high-rack storage applications containing more complex group-A EEP, which requires more water per square foot than other commodity classes. The ceiling-only sprinkler system allows more flexibility with storage racking arrangements and helps meet the height requirements for protecting group-A EEP. And it makes retrofits easier as the sprinklers use the same thread size compatible with piping infrastructure found in older storage facilities.
The sprinkler system uses an intelligent operation of an array of sprinklers around a point of origin. This is accomplished through various system components, including a sprinkler with metron activator, heat sensor and a suppression-releasing panel wired to all heat sensors. A number of full-scale fire tests were conducted at UL to validate the effectiveness of the EAS-1 system.
It detects the fire location faster than traditional protection systems through the sensors that gather data on the rate of rise in the surrounding air temperature. This temperature spike allows the system to select the most accurate sprinklers to activate.
Based on the grid pattern design, between six and nine sprinklers activate simultaneously to address the fire location. This design targets the fire with a “surround-and-drown” approach, which activates only the required sprinklers earlier in the development of the fire. This is a critical part of combatting fires quickly in high-rack storage while ensuring other areas of the facility remain unharmed.
This type of sprinkler system allows for a significant update in fire protection without upgrading the fire pump and installing vertical or horizontal barriers. It provides the minimum upgrade cost while maximizing operational flexibility.
Johnson Controls also launched a 25.2 K-factor, UL-listed EAS-1 to protect automated storage and retrieval system (ASRS) arrangements. The controls manufacturer partnered with an ASRS manufacturer to develop a ceiling-only protection scheme. It uses the 25.2 K-factor sprinkler and a customized algorithm; the ceiling-only fire protection scheme not only provides effective fire control but extinguishment as well.
The EAS-1 sprinkler system is designed for the ever-changing world of warehousing and logistics. With two-day, overnight and same-day delivery now commonplace, e-commerce has dramatically changed the way warehouses operate. This new paradigm makes fire protection paramount to keep business moving.
The increased plastic content in packaging used to transport and store products creates new, higher-risk challenges. Companies must adapt to meet customer expectations — and electronically activated sprinkler systems are ready to meet that demand.
You really can mix water and electricity.
With more than 32 years of engineering experience, Manuel Silva is the chief engineer for Johnson Control’s fire suppression products business. For 21 years, he has developed numerous products for use in fire sprinklers systems and is named on 37 U.S. patents related to fire suppression devices. In his current role, Silva is involved with the research and development of new fire protection products and is a member of the NFPA 13, 30B and 1910 technical committees.