Tampatundra wrote:The horizontal 1x4 furring strip on the 1st floor (CMU wall) is attached on top of the RMAX foam insulating board. Is this acceptable for fire blocking or draft stopping.
First is it "fire blocking or draft stopping"? It is "fireblocking", 2014 FBC-Residential: (underlining is mine)
- R302.11
Fireblocking.
- -
In combustible construction,
fireblocking shall be provided to cut off all concealed draft openings (
both vertical and horizontal) and to form an effective fire barrier between stories, and between a top story and the roof space.
- - Fireblocking shall be provided in
wood-frame construction in the following locations:
- - - 1. In concealed spaces of stud walls and partitions,
including furred spaces and parallel rows of studs or staggered studs, as follows:
- - - -
(Jerry's comment: In "wood-frame" construction, and wood furring strips adds wood framing to the inside surface of the CMU walls; additionally, R302.11 Item 1. specifies "including furred spaces", and the wood furring makes those spaces "furred spaces". This is an AHJ decision as some AHJ can't get past "wood-frame" to the "including furred spaces", while other AHJ do get to the "including furred spaces". This makes those "furred spaces" on the inside the CMU walls as "combustible construction ... concealed draft openings" which require "fireblocking".) - - - - 1.1. Vertically at the ceiling and floor levels.
- - - - 1.2. Horizontally at intervals not exceeding 10 feet (3048 mm).
- - - 2. At all interconnections between concealed vertical and horizontal spaces such as occur at soffits, drop ceilings and cove ceilings.
- - - 3. In concealed spaces between stair stringers at the top and bottom of the run. Enclosed spaces under stairs shall comply with Section R302.7.
- - - 4. At openings around vents, pipes, ducts, cables and wires at ceiling and floor level, with an approved material to resist the free passage of flame and products of combustion. The material filling this annular space shall not be required to meet the ASTM E 136 requirements.
- - - 5. For the fireblocking of chimneys and fireplaces, see Section R1003.19.
- - - 6. Fireblocking of cornices of a two-family dwelling is required at the line of dwelling unit separation.
Now that the above identifies those "furred spaces" as requiring fireblocking, we go to permitted fireblocking materials.
Also from the 2014 FBC-Residential: (underlining is mine)
- R302.11.1
Fireblocking materials.
- - Except as provided in Section R302.11, Item 4,
fireblocking shall consist of the following materials.
- - - 1. Two-inch (51 mm) nominal lumber.
- - - 2. Two thicknesses of 1-inch (25.4 mm) nominal lumber with broken lap joints.
- - - 3. One thickness of 23/32-inch (18.3 mm) wood structural panels with joints backed by 23/32-inch (18.3 mm) wood structural panels.
- - - 4. One thickness of 3/4-inch (19.1 mm) particleboard with joints backed by 3/4-inch (19.1 mm) particleboard.
- - - 5. One-half-inch (12.7 mm) gypsum board.
- - - 6. One-quarter-inch (6.4 mm) cement-based millboard.
- - - 7. Batts or blankets of mineral wool or glass fiber or other approved materials installed in such a manner as to be securely retained in place.
- - - 8. Cellulose insulation installed as tested for the specific application.
- - R302.11.1.1 Batts or blankets of mineral or glass fiber.
- - - Batts or blankets of mineral or glass fiber or other approved nonrigid materials shall be permitted for compliance with the 10-foot (3048 mm) horizontal fireblocking in walls constructed using parallel rows of studs or staggered studs.
- - R302.11.1.2 Unfaced fiberglass.
- - - Unfaced fiberglass batt insulation used as fireblocking shall fill the entire cross section of the wall cavity to a minimum height of 16 inches (406 mm) measured vertically. When piping, conduit or similar obstructions are encountered, the insulation shall be packed tightly around the obstruction.
- - R302.11.1.3 Loose-fill insulation material.
- - - Loose-fill insulation material shall not be used as a fireblock unless specifically tested in the form and manner intended for use to demonstrate its ability to remain in place and to retard the spread of fire and hot gases.
- R302.11.2 Fireblocking integrity.
- - The integrity of all fireblocks shall be maintained.
-
(Jerry's comment: I could not find "foam plastic" in the above, nor could I find "foam plastic insulation" within the sections addressing insulation. Foam plastic is required to meet specific surface burning and smoke developed limitations, and all thermal insulation is required to be basically in substantial contact with the backside of the interior surface.)The horizontal 2x4 furring strip on the 2nd floor (Frame Construction) is attached directly to the studs and the RMAX is under the furring with additional furring running vertical.
Both of the above conditions with the foam plastic insulation under the furring creates an additional "furred space", while at the same time not being an approved fireblocking material for dividing the spaces up into areas which are fireblocked 'at the ceiling', 'at the floor', and 'horizontally at maximum spacing of 10 feet- see above R311 item "1.2. Horizontally at intervals not exceeding 10 feet (3048 mm)." This includes measuring around corners – all furred spaces have a 10 maximum horizontal spacing between vertical furring strips which need to be fully block off each 10 foot maximum space from floor to ceiling.
Here is an additional item I noticed:
- The first photo and the hanger with what appears to be the bottom chord (and end) of a floor truss – is that a spacer behind the back of the floor truss? If so, the truss is too short for the span (the span may have been widened - accidentally or intentionally - without reconfiguring the truss which spans it) and is not sufficiently bearing in the hanger, the hanger is not attached to the floor truss - the hanger is only attached to the shim/blocking behind the truss.