What is the smallest orifice size for a head in a rack storage system?

The smallest orifice size for a head in a rack storage system is represented by the 5.6 K factor. The K factor is a measure used to characterize the flow characteristics of sprinkler heads—the higher the K factor, the larger the orifice size and the greater the flow rate.

In rack storage systems, where high-density storage is common, the use of sprinklers with a K factor of 5.6 allows for sufficient coverage and effective distribution of water to suppress fires without overwhelming the area with excessive water flow. This K factor strikes a balance, providing adequate protection for overhead storage while also being mindful of potential water damage to the stored items.

The other K factors represent larger orifice sizes capable of delivering greater water flow rates, which may be suitable for different applications but do not meet the specific requirements for density and efficiency necessary in a rack storage system. Therefore, for optimal function in such environments, the 5.6 K factor is the appropriate choice.