cda said:
One example would be a raised wood platform
8.15.1 Concealed Spaces.
8.15.1.1 Concealed Spaces Requiring Sprinkler Protection. Concealed spaces of exposed combustible construction shall be protected by sprinklers except in concealed spaces where sprinklers are not required to be installed by 8.15.1.2.1 through 8.15.1.2.18 and 8.15.6.
AHJ FAQ Are sprinklers required in concealed spaces of noncombustible construction with combustible materials present within the concealed space?
ANSWER: Yes, many misinterpret 8.15.1.1 to think that sprinklers are required only in concealed spaces where of combustible construction. When in fact, Section 4.1 requires that fire sprinkler protection be provided throughout the building unless the designer can show an exception in NFPA 13 that says otherwise. If there are significant amounts of combustibles within a concealed space of noncombustible construction, typically fire sprinklers are required by Section 4.1.
Unless protected, concealed spaces can provide an unabated passage for firespread throughout a building. Subsection 8.15.1 applies to those portions of a building that have construction or finish materials of a combustible nature, are not used for the storage of combustible materials, but might contain combustibles associated with building system features, such as computer wiring or large quantities of nonmetallic piping.
Any of these scenarios could be found in a concealed space. It is important to recognize that concealed spaces are not exclusively limited to areas above ceilings but can also be found in walls and in spaces beneath the floor. For example, a raised floor in a computer room is a concealed space.
Prior to the 2010 edition, 8.15.1.1 had at times been interpreted to permit sprinklers to be omitted from concealed spaces because they were “enclosed” by drywall and concrete but contained combustible construction. This interpretation was not the intent, and the paragraph has been revised for clarification.
Where concealed spaces are provided with other protection measures, such as a CO2 system, the concealed space is considered to be protected, and sprinklers are not required.
8.15.1.2* Concealed Spaces Not Requiring Sprinkler Protection.
AHJ FAQ Are fire sprinklers required in combustible concealed spaces entirely on the outside of the building, such the spaces that may be formed at the eaves of a truss roof or at false facades on the side of the building, when there are no ignition sources?
ANSWER: Yes, unless one of the exceptions found in 8.15.1.2 can be applied. NFPA 13 is a minimum standard for the protection of property as well as for life safety. Many authorities having jurisdiction recognize the “Murphy’s Law” aspect prevalent in the experiences of the fire service, in that a lightning strike could start a fire in such a concealed space.
A.8.15.1.2 Paragraphs 8.15.1.2.3, 8.15.1.2.4, and 8.15.1.2.5 do not require sprinkler protection because it is not physically practical to install sprinklers in the types of concealed spaces discussed in these three exceptions. To reduce the possibility of uncontrolled fire spread, consideration should be given in these unsprinklered concealed space situations to using 8.15.1.2.7, 8.15.1.2.10, and 8.15.1.2.12. Omitting sprinklers from combustible concealed spaces will require further evaluation of the sprinkler system design area in accordance with 11.2.3.1.4.
The subparagraphs of 8.15.1.2 specify conditions where sprinklers are not required in concealed spaces that would normally require sprinklers. Sometimes the building is modified to meet one of these exceptions to avoid installing sprinklers in the space. Not all of these exceptions provide an equivalent level of fire safety, because some of the exceptions simply recognize that the installation of sprinklers in the space is not physically practical. This difference in level of fire safety is especially true of 8.15.1.2.3, 8.15.1.2.4, and 8.15.1.2.5, which primarily exist to cover situations where sprinklers are retrofitted into existing buildings.
It is important to note that omitting sprinklers in these spaces might require an increase in the area of operation of the sprinkler system as determined in 11.2.3.1.4. Therefore, A.8.15.1.2 provides a pointer in order to ensure a complete evaluation of the impact of omitting sprinklers.
FAQ Where NFPA 13 refers to noncombustible and limited-combustible construction, is the use of the terms in reference to building construction or to the type of combustible loading within the space?
Where NFPA 13 refers to noncombustible and limited-combustible construction, the reference is specifically applicable to the terms as defined in Chapter 3 (see 3.3.16, limited-combustible material, and 3.3.17, noncombustible material) as they relate to the construction of the space. Regardless of how a material is described, unless it is noncombustible, the material represents a level of combustible loading that may or may not be permitted by NFPA 13. For specific allowances, see 8.15.1.2.1 through 8.15.1.2.18.
