Historically in rack sprinkler systems were designed using K5 6 K80 gpm psi1 2 or K8 0 K115 sprinklers The K5 6 K80 sprinkler dates back to the early days of sprinkler protection By comparison ceiling sprinklers have evolved over the years and now have values as high as K25 2 K360 By utilizing sprinklers that were origi nally designed to suppress fires from ceiling level FM Global was able to dramatically alter its in rack Data Sheet 8 9 guidance Fewer sprinklers better protection When protecting commodity hazards cur rent FM Global and National Fire Protec tion Association guidelines NFPA 13 as well as other codes from around the world require in rack sprinklers to be installed on vertical increments ranging from 10 to 15 feet 3 to 4 6 meters The guidelines also limit the maximum storage area above the top level of in rack sprinklers to 10 ft 3 m Data Sheet 8 9 now allows for in rack sprin klers to be installed on vertical increments ranging from 30 ft 9 1 m to as high as 40 ft 12 2 m depending on the commodity In addition storage heights above the top level of in rack sprinklers can be as high as 40 ft 12 2 m depending on the commodity being protected and the ceiling level sprinkler being installed All the sprinkler research and innova tion over the past 30 years has been focused on ceiling sprinklers In rack sprinklers have been pretty much ignored explains FM Global s Weston Baker Jr assistant vice president senior engineering technical spe cialist Baker works in engineering standards and oversees developments in this particular area We decided to leverage the relatively new ceiling level sprinkler technology and apply it to the in rack segment and what we found was better performance at lower costs Baker said most of the research cov ering current in rack system designs was conducted in the 1960s and 70s FM Global itself did nearly 50 large scale in rack sprinkler tests from 1969 to 1976 which helped form the basis for today s in rack sprinkler installation and design guidelines Nearly all of those tests were conducted using small K5 6 K80 sprinklers protect ing short storage heights 25 to 30 ft 7 7 to 9 1 m compared to today s standards goals FM researchers needed to develop a new level of understanding of in rack sprin klers and their role in fire suppression The biggest questions we answered were what is the critical amount of water needed to suppress a fire and what is the optimal flow rate and coverage area for in The new protection guidelines greatly reduce the number of in rack sprinklers needed maximize their vertical spacing and reduce installation costs by more than 40 percent when compared to today s in rack sprinkler design guidelines According to Baker FM Global began looking into the idea of applying new larger sprinklers to in rack solutions in the late 2000s FM Global he said began to ques tion if the knowledge base of in rack sys tems was sufficient The data was more than 40 years old and a lot had changed since those tests were conducted Warehouses had gotten taller the commodities being stored are quite different and even the fire char acteristics of cardboard and other storage materials have changed So three years ago FM Global launched a research project to optimize in rack sprinkler design We knew there had to be a better sim pler way to protect commodities in storage racks using in rack sprinklers Baker said So we committed three years a lot of man power materials and time It made sense to move forward because we knew the invest ment would really benefit our clients Ambitious goals The goals of the project were to maximize vertical increments of the sprinklers increase storage heights above the in rack systems allow for independent in rack and ceiling design and reduce the likelihood of sprinkler damage All of which would greatly reduce the cost of in rack systems To reach those rack sprinklers Jamison said Those were unknown phenomena Existing in rack pro tection had never been optimized So this really was a new approach It had never been done before With those two pieces of information obtained from extensive testing and model ing FM Global was able to more than dou ble the vertical increments of the sprinklers At heights of 30 to 40 ft 9 1 to 12 2 m the higher K factor in rack sprinklers are able to suppress any fire that starts beneath them This creates a virtual floor because the test ing confirmed the ceiling sprinklers won t activate for any fire that starts below the top level of in rack sprinklers The amount of storage space above the top level of in rack sprinklers is now solely based on the capacity of the ceiling sprin klers If the ceiling sprinklers can protect 40 ft 12 2 m of rack storage for example then a warehouse could have 40 ft 12 2 m of storage above the top tier level of in rack sprinklers And because modeling showed and testing proved that the in rack system and ceiling sprinklers would not be needed at the same time they can now be independent of each other The in rack sprinkler system designs offered in NFPA 13 and other fire ISSUE 2 2015 REASON 15

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