sprinklernotes
Sprinkler Protection in Decorative Cupolas
You have asked the following question: “Is there a section in NFPA 13 that will
allow a sprinkler to be omitted from a cupola which is built on top of a roof
as a decorative feature? There is no penetration between the roof and the
cupola. Inside the cupola, there will be a window and light at the top. The
exterior dimension of the base is approximately 8 ft. by 8 ft. but narrows to 4
ft. by 4 ft. before the top and is approximately 11 ft. tall. The cupola will
be subject to freezing temperature, requiring a dry system to be installed for
a single sprinkler if sprinkler protection is required.” In response to your
question, we have reviewed NFPA 13, 2016 edition as the applicable standard.
Our informal interpretation is sprinkler protection is required.
In this situation, it is important to keep in mind the purpose of installing
sprinklers per NFPA 13. The purpose is stated in Section 1.2.1:
The purpose of this standard shall be to provide a reasonable degree of
protection for life and property from fire through standardization of design,
installation, and testing requirements for sprinkler systems, including private
fire service mains, based on sound engineering principles, test data, and field
experience.
With this purpose in mind, the requirements for protecting the cupola can be
reviewed.
The first section to review for this situation is Section 8.15.1.2.18.1, which
states:
Sprinklers shall be permitted to be omitted from within combustible soffits,
eaves, overhangs, and decorative frame elements that are constructed in
accordance with 8.15.1.2.18.2 through 8.15.1.2.18.5.
Since Section 8.15.1.2.18.1 states “8.15.1.2.18.2 through 8.15.1.2.18.5” all
four conditions listed have to be met. With the cupola being on top of the roof
structure Section 8.15.1.2.18.2 does not apply because the 4-ft maximum width
in Section 8.15.1.2.18.2 is directed at limiting the impact of combustibles
beneath overhang type features. With that being said, this allowance is not
limited to just features on the exterior wall such as overhangs. It also
applies to features on the roof, as indicated by Section 8.15.1.2.18.4
dictating separation by walls or roofs of noncombustible construction. Next,
Section 8.15.1.2.18.3 is requiring the cupola to be less than 160 cu. ft.,
which it is not. Since the cupola does not meet Section 8.15.1.2.18.3, this
alone removes the possibility of applying Section 8.15.1.2.18.1 to omit
sprinkler protection. Continuing on to Section 8.15.1.2.18.4, the cupola is
required to be separated from the main building interior by walls or roofs of
noncombustible or limited-combustible construction. To be considered
noncombustible or limited-combustible the structural members have to be
noncombustible along with the exposed finish material. If the any portion of
the roof structure is combustible then Section 8.15.1.2.18.4 also removes the
possibility of applying Section 8.15.1.2.18.1 (to omit sprinkler protection).
Finally, Section 8.15.1.2.18.4 requires no openings or unprotected penetrations
directly into the building, which there are none. As stated, all of the
conditions listed in Section 8.15.1.2.18.1must be met to omit sprinkler
protection and not all of the four are not met in this situation, thus
sprinkler protection is required in the structures.
However, the purpose of “to provide a reasonable degree of protection for life
and property from fire” “based on sound engineering principles, test data, and
field experience” can be achieved through other means. NFPA 13 states this in
Section 1.5:
Nothing in this standard is intended to prevent the use of systems, methods, or
devices of equivalent or superior quality, strength, fire resistance,
effectiveness, durability, and safety over those prescribed by this standard.
This allows the designer and AHJ the flexibility to use other protection
methods than those prescribed by NFPA 13 as long as the protection methods
proposed do not decrease the level of safety required by NFPA 13. This supports
the overall purpose of NFPA 13. In this situation, it could be argued
installing a heat and/or smoke detector within the cupola would provide a
similar level of life safety since the cupola is only for decorative purposes.
If a fire were to start within the cupola and activate the detector it would
allow for the occupants to evacuate and the fire department to respond before
progressing into the main structure. This protection method would have to be
discussed with the local AHJ and a written agreement with this protection
method shall be obtained before proceeding further with the project per Section
1.5.2, which states:
The system, method, or device shall be approved for the intended purpose by the
authority having jurisdiction.
This protection method would allow for omission of the sprinkler within the
cupola while still meeting the level of life safety required by NFPA 13.
