Exceptions have been added which allow an increase in the height of storage along walls in sprinklered and nonsprinklered buildings.
315.3.1 Ceiling clearance. Storage shall be maintained 2 feet or more below the ceiling in nonsprinklered areas of buildings or not less than 18 inches below sprinkler head deflectors in sprinklered areas of buildings.Exceptions:
- The 2-foot ceiling clearance is not required for storage along walls in nonsprinklered areas of buildings.
- The 18-inch ceiling clearance is not required for storage along walls in areas of buildings equipped with an automatic sprinkler system in accordance with Section 903.3.1.1, 903.3.1.2, or 903.3.1.3.
The limitation of storage heights in buildings addresses two conditions; a sprinklered space and a nonsprinklered space. In the sprinklered space, the top of storage is limited to 18 inches below the sprinkler deflector, while in the nonsprinklered space storage is limited to 24 inches below the ceiling.
In a nonsprinklered space, the height limit provides the ability for fire fighters to direct hose streams over stored materials to extinguish fires deeper within the room. However, the storage of materials along the wall does not impede this ability. The hose streams do not need to go over the top of the storage if the storage is along the wall.
Additionally, the installation of wall-mounted cabinets is not prohibited by the section, and could extend to the ceiling. This change recognizes that the arrangement of the storage along the wall should not be regulated differently whether it is in a cabinet or on a shelf.
In a sprinklered building, NFPA 13 Section 18.104.22.168.1 allows the top of storage on shelving on a wall to extend above the plane at 18 inches below the deflector. NFPA 13, Section 22.214.171.124 indicates that shelving, by definition, is 30 inches or less in depth. Based on these two sections, NFPA 13 stipulates that storage along the wall on shelves with a depth of 30 inches is not limited to the storage height of 18 inches below the deflector. The new exception in the IFC correlates with this allowance.
It is important to note that this allowance is located in Chapter 3 and is a general requirement applicable to general storage arrangements. These exceptions are not located in Chapter 32 for high-piled combustible storage, nor is this section reference by Chapter 32. As indicated in Section 102.10 of the IFC, when there is a difference between a general requirement and specific requirement, the specific requirement will apply. Applying this concept, Section 315.3.1 will apply to general storage, but not to high-piled storage arrangements.