Combustible Concealed Spaces Created by Eaves

[Haldorson]

I have a simple two level rectangular building (combustible construction) with an attic space under a pitched roof. The exterior walls of the building run up through the attic to the roof assembly. The eaves run around the perimeter of the building creating a "wedged" combustible concealed space between the edge of the eave and the wall of the building that connects up to the roof assembly. These eaves are 2' wide and at the wall assembly are 1' high with no building space below them. The attic will be protected with a dry system.

Do we need to protect the combustible concealed space within the eaves? If so, any recommendations on a practical way to do so?

 

[cdafd]

What edition of 13 are you using


Exterior more than likely not

Are they open to the attic area inside?

And I take it the attic is wood construction

 

[skdesigner]

NFPA 13-2010 8.15.1.2.8 Sprinklers shall be permitted to be omitted from within combustible soffits, eaves, overhangs, and decorative frame elements that are constructed in accordance with 8.15.1.2.18.1 through 8.15.1.2.18.4.

Looks like the only issue you may have is sentence (2). Combustible soffits, eaves, overhangs, and decorative frame elements shall be draftstopped, with a material equivalent to that of a soffit, into volumes not exceeding 160 cu. ft.

 

[Haldorson]

I am required to comply with 13-1999.

The eaves are not open to the attic however following up on skdesigner's comment the separating wall is combustible construction. So I am cannot satisfy 8.15.1.2.18.3. Unfortunately it seems to me I will need to protect this area. I really appreciate both of your comments.

 

[cdafd]

Do not sprinkle them

Need to look at 1999 edition for a section

 

[cdafd]

Hald

do not have access to nfpa 1999 electric version
so this is from 2010 edition, just look for similar language in the 1999


Your eaves are not over four feet::::

8.15.7* Exterior Projections.

8.15.7.1 Unless the requirements of 8.15.7.2, 8.15.7.3, or 8.15.7.4 are met, sprinklers shall be installed under exterior projections exceeding 4 ft (1.2 m) in width.



8.15.7.2* Sprinklers shall be permitted to be omitted where the exterior projections are constructed with materials that are noncombustible, limited-combustible, or fire retardant–treated wood as defined in NFPA 703.



8.15.7.3 Sprinklers shall be permitted to be omitted from below the exterior projections of combustible construction, provided the exposed finish material on the exterior projections are noncombustible, limited-combustible, or fire retardant–treated wood as defined in NFPA 703, and the exterior projections contain only sprinklered concealed spaces or any of the following unsprinklered combustible concealed spaces:


(1)
Combustible concealed spaces filled entirely with noncombustible insulation


(2)
Light or ordinary hazard occupancies where noncombustible or limited-combustible ceilings are directly attached to the bottom of solid wood joists so as to create enclosed joist spaces 160 ft3 (4.5 m3) or less in volume, including space below insulation that is laid directly on top or within the ceiling joists in an otherwise sprinklered attic [see 11.2.3.1.4(4)(d)]


(3)
Concealed spaces over isolated small exterior projections not exceeding 55 ft2 (5.1 m2) in area



ALSO::::


You are not over four feet:::




8.15.1.2.18 Soffits, Eaves, Overhangs, and Decorative Frame Elements.

8.15.1.2.18.1 Combustible soffits, eaves, overhangs, and decorative frame elements shall not exceed 4 ft 0 in. (1.2 m) in width.



8.15.1.2.18.2 Combustible soffits, eaves, overhangs, and decorative frame elements shall be draftstopped, with a material equivalent to that of the soffit, into volumes not exceeding 160 ft3 (4.5 m3).



8.15.1.2.18.3 Combustible soffits, eaves, overhangs, and decorative frame elements shall be separated from the interior of the building by walls or roofs of noncombustible or limited-combustible construction.



8.15.1.2.18.4 Combustible soffits, eaves, overhangs, and decorative frame elements shall have no openings or unprotected penetrations directly into the building.




and if they did exceed four feet thatn look at the combustible space rules to see if any apply, so you did not have toe sprinkle:::



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.



8.15.1.2* Concealed Spaces Not Requiring Sprinkler Protection.

8.15.1.2.1* Concealed spaces of noncombustible and limited-combustible construction with minimal combustible loading having no access shall not require sprinkler protection.


8.15.1.2.1.1 The space shall be considered a concealed space even with small openings such as those used as return air for a plenum.




8.15.1.2.2 Concealed spaces of noncombustible and limited-combustible construction with limited access and not permitting occupancy or storage of combustibles shall not require sprinkler protection.


8.15.1.2.2.1 The space shall be considered a concealed space even with small openings such as those used as return air for a plenum.




8.15.1.2.3 Concealed spaces formed by studs or joists with less than 6 in. (152 mm) between the inside or near edges of the studs or joists shall not require sprinkler protection. (See Figure 8.6.4.1.5.1.)



8.15.1.2.4 Concealed spaces formed by bar joists with less than 6 in. (152 mm) between the roof or floor deck and ceiling shall not require sprinkler protection.



8.15.1.2.5* Concealed spaces formed by ceilings attached directly to or within 6 in. (152 mm) of wood joist or similar solid member construction shall not require sprinkler protection.



8.15.1.2.6* Concealed spaces formed by ceilings attached to composite wood joist construction either directly or onto metal channels not exceeding 1 in. (25.4 mm) in depth, provided the joist channels are firestopped into volumes each not exceeding 160 ft3 (4.53 m3) using materials equivalent to the web construction and at least 3 1/2 in. (90 mm) of batt insulation is installed at the bottom of the joist channels when the ceiling is attached utilizing metal channels, shall not require sprinkler protection.



8.15.1.2.7 Concealed spaces filled with noncombustible insulation shall not require sprinkler protection.


8.15.1.2.7.1 A maximum 2 in. (50 mm) air gap at the top of the space shall be permitted.




8.15.1.2.8 Concealed spaces within wood joist construction and composite wood joist construction having noncombustible insulation filling the space from the ceiling up to the bottom edge of the joist of the roof or floor deck, provided that in composite wood joist construction the joist channels are firestopped into volumes each not exceeding 160 ft3 (4.53 m3) to the full depth of the joist with material equivalent to the web construction, shall not require sprinkler protection.



8.15.1.2.9 Concealed spaces over isolated small rooms not exceeding 55 ft2 (5.1 m2) in area shall not require sprinkler protection.



8.15.1.2.10 Concealed spaces where rigid materials are used and the exposed surfaces have a flame spread index of 25 or less, and the materials have been demonstrated not to propagate fire more than 10.5 ft (3.2 m) when tested in accordance with ASTM E 84, Standard Test Method of Surface Burning Characteristics of Building Materials, or ANSI/UL 723, Standard for Test for Surface Burning Characteristics of Building Materials, extended for an additional 20 minutes in the form in which they are installed, shall not require sprinkler protection.



8.15.1.2.11* Concealed spaces in which the exposed materials are constructed entirely of fire retardant–treated wood as defined by NFPA 703 shall not require sprinkler protection.



8.15.1.2.12 Noncombustible concealed spaces having exposed combustible insulation where the heat content of the facing and substrate of the insulation material does not exceed 1000 Btu/ft2 (11,356 kJ/m2) shall not require sprinkler protection.



8.15.1.2.13 Concealed spaces below insulation that is laid directly on top of or within wood joists or composite wood joists used as ceiling joists in an otherwise sprinklered concealed space, with the ceiling attached directly to the bottom of the joists, shall not require sprinkler protection.



8.15.1.2.14 Vertical pipe chases under 10 ft2 (0.93 m2), where provided in multifloor buildings where the chases are firestopped at each floor using materials equivalent to the floor construction, and where such pipe chases shall contain no sources of ignition, piping shall be water-filled or noncombustible and pipe penetrations at each floor shall be properly sealed and shall not require sprinkler protection.



8.15.1.2.15 Exterior columns under 10 ft2 (0.93 m2) in area, formed by studs or wood joist supporting exterior canopies that are fully protected with a sprinkler system, shall not require sprinkler protection.



8.15.1.2.16* Concealed spaces formed by noncombustible or limited-combustible ceilings suspended from the bottom of wood joists, composite wood joists, wood bar joists, or wood trusses that have insulation filling all of the gaps between the bottom of the trusses or joists, and where sprinklers are present in the space above the insulation within the trusses or joists, shall not require sprinkler protection.


8.15.1.2.16.1 The heat content of the facing, substrate, and support of the insulation material shall not exceed 1000 Btu/ft2 (11,356 kJ/m2).




8.15.1.2.17* Concealed spaces formed by noncombustible or limited-combustible ceilings suspended from the bottom of wood joists and composite wood joists with a maximum nominal chord width of 2 in. (50.8 mm), where joist spaces are full of noncombustible batt insulation with a maximum 2 in. (50.8 m) air space between the roof decking material and the top of the batt insulation shall not require sprinklers.


8.15.1.2.17.1 Facing that meets the requirements for noncombustible or limited-combustible material covering the surface of the bottom chord of each joist and secured in place per the manufacturer's recommendations shall not require sprinklers.