display area. The statue has an overall figure dimension (L x W x H) of 24.77 ft x 8.67 ft x 5.06 ft and will be suspended from the ceiling with wires. The existing ceiling height of the area is 27 ft above finished floor and the statue is to be hung from 16 to 19 ft above finished floor. Section 8.5.5.3.1 states, “Sprinklers shall be installed under fixed obstructions over 4 ft wide.” Section 8.5.5.3.2 also states, “Sprinklers shall not be required under obstructions that are not fixed in place, such as conference tables.” Is the suspended statue considered a fixed obstruction that will require the installation of sprinklers below it?”
ANSWER: In response to your question we have reviewed NFPA 13, 2013 edition as the applicable standard. Our informal interpretation is that omitting protection under the obstruction would require approval by the AHJ. The standard is explicit that sprinklers are required under obstructions greater than 4 ft wide as indicated in the question above. It would seem to be hard to argue that this obstruction is not fixed in place. As such, this will be a decision of the AHJ to omit sprinklers under the obstruction. With that said, displays at museums typically do not have sprinklers under them although they are greater than 4 ft wide. There are displays where a sprinkler under them would ruin the visual effect of the piece. A good example is aircraft suspended from the ceilings. These types of displays typically do not have sprinklers under them. Display areas of most museums have light hazard fuel loading and are not considered high challenge fires. The floor beneath such exhibits is often kept clear presenting little chance for a fire that is obstructed. Thus, the only option is to discuss omission of sprinklers under the obstruction with the AHJ. If they still have concerns, consider providing as a compensating feature an increase to the size of the remote area.
SUBJECT: Elevator Shaft With Wood Studs
SUBJECT: "Our local AHJ is requiring a sprinkler at the top of an elevator hoistway that is constructed with a two-hour rated enclosure (2 layers of 5 /8-in. drywall on either side of 2 x 6 wood studs). The studs
are not fire treated. Does the drywall make the hoistway limited-combustible as required per Section 8.15.5.6?"
ANSWER: In response to your question we have reviewed NFPA 13, 2013 edition as the applicable standard. Our informal interpretation is that sprinkler protection should not be required. This issue is not particularly well addressed by NFPA 13. For starters, section 8.15.5 states that the sprinkler protection is not required at the bottom for noncombustible shafts or at the top for noncombustible hoistways. We have to assume hoistway is synonymous with shaft. Though not explicitly stated, a noncombustible shaft means the entire shaft construction is of noncombustible materials, not just the surface materials. Although a literal application of the term shaft would include all portions including enclosure, the building code treats this portion differently. In the IBC for Section 713.4, Fire-resistance rating, the shaft enclosures shall have a fire-resistance rating of not less than two hours where connecting four stories or more, and not less than one hour where connecting less than four stories. Shaft enclosures shall have a fire resistance rating not less than the floor assembly penetrated, but need not exceed two hours. The IBC provides the requirement for the partition rating and does not limit the construction type to attain that rating. Historically, elevator shafts were constructed of noncombustible materials. There appears to be a shift for buildings of wood construction to use wood as the studs for elevator shafts. The IBC in Section 713.3, Materials indicates that the shaft enclosure shall be of materials permitted by the building type of construction. As such, wood can be used. The 2010 edition of NFPA 13 included a limited-combustible wall surface material to be allowed in the shaft to omit sprinklers. This change did not address the combustibility of the studs within the construction of the shaft. At times, the NFPA 13 standard lags behind the building code requirements. The question is will a fire progress into the two-hour rated shaft. That is not likely. We can point to Section 8.15.3.1 for combustible stair shafts that sprinklers will be required. This is a different application than an elevator shaft since the combustible stairway could include combustibles inside the shaft/
stairway such as stringers, landings, treads and kick plates. It is also worth pointing out that section 8.15.5.3 allows omission of sprinklers in elevator related spaces such as the machine room, control rooms, or hoistways when separated with fire-rated construction without the additional requirement for noncombustible construction. Unfortunately, NFPA 13 does not address this issue explicitly so concurrence by the AHJ is necessary.
EDITOR’S NOTE: These interpretations were prepared by AFSA’s Technical Services Department in answer to specific questions from contractors and/or AHJs. These opinions are provided for the benefit of the requesting party, and are provided with the understanding that AFSA assumes no liability for the opinions or actions taken on them. AFSA members can access over 4,000 informal interpretations online. Visit firesprinkler.org, click on “Tech Services” and then “Informal Interps.” (Member user name and password required to gain entry.)
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