Solution | Posted 10/15/19

Being told I need two fire dampers to serve a single fire wall. The fire wall is made of a "double wall", essentially two masonry walls next to each other with a very small (less than 2-inch) air gap in-between. The engineer on the project is stating that this "double wall" requires a fire damper in each.

I've never come across this as a requirement before. Do I need two fire dampers?

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Are calculated stair widths based on occupant loads based only on a single level that the stair is serving, or a cumulative (total) occupant load for all floors the stair serves? 

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Our project has a proposed layout includes convenience stairs next to a corridor that serves restrooms, utility spaces, and doors to large open office areas. It's a B-occupancy subject to NFPA 101 requirements.

As a side note, the International Building Code (2018) makes it clear that two-story openings are permitted in occupancies other than I-2 and I-3 when they meet certain limitations, per section 712.1.9. One of the limitations it that is it not open to a corridor, but that's in Group I or R occupancies only. Group I and R occupancies require special treatment for corridors.

NFPA 101 has similar provisions for Convenience Openings (Section 8.6.9). One of the requirements is that "such openings shall be separated from corridors", per section 8.6.9.1(3). If corridors in a building are not required to be separated (such as for an open-office B occupancy), does this requirement still apply, or is this section saying that we have to have rated corridors whenever we have convenience stair openings?

   8.6.9 Convenience Openings.
  8.6.9.1 Where permitted by Chapters 11 through 43, unenclosed vertical openings not concealed within the building construction shall be permitted as follows:
   (1) Such openings shall connect not more than two adjacent stories (one floor pierced only).
   (2) Such openings shall be separated from unprotected vertical openings serving other floors by a barrier complying
with 8.6.5.
   (3)* Such openings shall be separated from corridors.
   (4)* In other than approved, existing convenience openings, such openings shall be separated from other fire or smoke compartments on the same floor.
   (5) In new construction, the convenience opening shall be separated from the corridor referenced in 8.6.9.1(3) by a smoke partition, unless Chapters 11 through 43 require the corridor to have a fire resistance rating.
   (6)* Such openings shall not serve as a required means of egress.

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The International Building Code requires identification of fire partitions, barriers, or fire walls with 3" letters identifying the wall itself.

I've seen (especially in hospitals) labels for each through-penetration with a UL Listing sticker right below each penetration. Is this a requirement by code, or just a hospital standard?

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Considering all potential components in a building, which of the following occupancies has the most restrictive requirements for material flame spread and smoke development?
a. new day-care centers
b. existing duplex home
c. existing Class B department store
d. new large warehouse

Solution | Posted 07/22/19

A new healthcare building is being designed with a suite with no sleeping areas and full smoke detection. What is the required construction for the corridor walls?
a. smoke partition only
b. smoke barrier only
c. 1-hour fire resistance and smoke barrier
d. none of the above

Solution | Posted 07/11/19

Solution | Posted 06/26/19

Up through the 2015 Edition of NFPA 101, membrane penetrations in 1-hour or more rated walls/partitions allows any "steel electrical box not exceeding 0.1 sqft" to be addressed by several options. 

The IBC has a similar provision, although it talks about 16-square-inch boxes instead of 0.1 sqft.

NFPA 101 2012
8.3.5.6.3 Where walls or partitions are required to have a minimum 1-hour fire resistance rating, recessed fixtures shall be installed in the wall or partition in such a manner that the required fire resistance is not reduced, unless one of the following is met:
(1) Any steel electrical box not exceeding 0.1 ft2 (0.01 m2) shall be permitted where the aggregate area of the openings
provided for the boxes does not exceed 0.7 ft2 (0.06 m2) in any 100 ft2 (9.3 m2) of wall area, and, where outlet boxes are installed on opposite sides of the wall, the boxes shall be separated by one of the following:
(a) Horizontal distance of not less than 24 in. (610 mm)
(b) Horizontal distance of not less than the depth of the wall cavity, where the wall cavity is filled with cellulose loose-fill, rock wool, or slag wool insulation
(c)*Solid fireblocking
(d) Other listed materials and methods

The 0.1 sqft threshold seems overly vague - a 4-inch x 4-inch electrical backbox, for instance, is 16 square inches while 0.1 sqft = 14.4 square inches.

Has anyone come across this part of NFPA 101 before and addressed this issue with anything other than a listed box or puddy pad? My understanding is that the only way to address these 4x4 boxes, since they don't qualify as being 0.1 sqft or less, is to have a listed electrical outlet box or to use a listed assembly around the box (like a puddy pad).

After looking into this question a little more, it looks like the 2018 Edition of NFPA 101 even clarified this section to change 0.1 sqft to 16 square inches, but we're not under the 2018 Edition for this project.

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​A building addition is to connect two existing buildings of different construction types. Which of the following construction type arrangements is always permissible?
a. Provide the least fire-resistive construction type of the connected portions with no fire barrier separation
b. Provide 1-hour vertically aligned fire barrier wall is installed between them to create separate buildings
c. Provide any construction type for the connection portion with 2-hour fire barrier between buildings
d. none of the above

Solution | Posted 06/19/19

A hospital's patient tower has an an exit access corridor with 1/2 hour partition fire resistance rating on the first level. If the interior architect would like to provide side transoms (narrow windows) along the side of the doors that lead to the exit access corridor, what fire resistance rating must the transoms have?
a. 1/3 hour
b. 1/2 hour
c. 3/4 hour
d. 1-hour

Solution | Posted 06/8/19

Does anyone have experience with a mamava (mobile lactation room/pod) being placed in a commercial business occupancy?

The square footage is approximately 50 sqft. It is composed of only Class A rated materials (flame spread index).

From a practical perspective it does not make sense to me to drop a sprinkler in. However, I'm hard-pressed finding an exemption from code (NFPA 13 or 101) to not sprinkler the space since it's inhabitable and not a bathroom or closet (which I know they are exceptions for sprinklering based on size). 

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