Exposed flexible duct passing through floor (SpacePak)

[Michael Thomas]

1) Is there a code requirements that this duct in a closet be protected from physical damage?

2) It is there a code requirements for fire stopping at the passage through the floor?

Thanks.

[Jerry Peck]

1) Is there a code requirements that this duct in a closet be protected from physical damage?

From the IRC. (underlining and bold are mine)
- M1601.2 Factory-made ducts. Factory-made air ducts or duct material shall be approved for the use intended, and shall be installed in accordance with the manufacturer’s installation instructions. Each portion of a factory-made air duct system shall bear a listing and label indicating compliance with UL 181 and UL 181A or UL 181B.

I cannot find it right now, but I recall that I had an e-mail or a letter from the ADC (Air Diffusion Council) stating that flexible duct had to be protected from physical damage where exposed from physical damage.

Additionally, those duct are not sunlight resistant sufficiently to be left exposed where sunlight can get to them, however, that closet would be (to some) a debatable location and may need protection over the flexible duct to protect/hide it from sunlight when the door is opened (the more often the door is opened, the shorter the life expectancy of that duct is).

Those manufacturer's installation instructions also include supporting vertically installed duct at maximum 6 foot intervals.


2) It is there a code requirements for fire stopping at the passage through the floor?

- M1601.3.3 Fireblocking. Duct installations shall be fireblocked in accordance with Section R602.8.

- R602.8 Fireblocking required. 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:

- - - 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 R311.2.2.
- - 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.
- - 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.

Plus, if under that floor is space which is outside the thermal envelope, then all the openings need to also be sealed against air infiltration and exfiltration.

[H.G. Watson, Sr.]

Ditto JP

Subfloor compromised blocking likely necessary for structural integrity.

Spun Fiberglass insulation exposed to occupiable (note not habital as closet) space (damage in R tube in one photo).

Windy City & some burbs would also have issue with "rodent (pest) proofing".

Not certain that type of flexible insulated duct is even permitted to be in (occupied space or not) in the big city or cook county (the land of steel & emt electrical) I'd have to check. Looks to be 6-8" ID duct, is it?

City & most burbs would require at a minimum it be supported, and enclosed in a chase minimum framing & drywall 20 mins in addiiton to fire/draft blocking at floor & ceiling of each penetration. If invasion of a rated assembly futher protection would be required.

Location (big city or burb) and what is below the floor & behind the closet wall (multi-family or single family or commercial - basement, crawl, occupied space, occupied & habital space, & if conditioned space.

[Jerry Peck]

Windy City & some burbs would also have issue with "rodent (pest) proofing".


If it is crawlspace below, every city with a code would require rodent proofing, but the, that duct in and of itself is not "rodent proof", so that would be a problem any if coming from a crawlspace. When I mentioned outside the thermal envelope I was thinking basement, not crawlspace - I probably should have specifically stated basement.

[Michael Thomas]

Thanks to you both - exactly what I needed!

[Michael Thomas]

Thanks to you both - exactly what I needed!

(The UV issue was completely new to me. BTW)

[Markus Keller]

The silver foil ones like that are allowed in the City. The gray plastic ones aren't. Depending on occupancy class. there are length limitations. As JP and HG mentioned fireblocking and support are needed.
Protecting those in a closet is hard to get people to do, because once the area is framed and rocked it pretty much kills the closet. People don't like that, just commenting of course.

[A.D. Miller]

The bottom of page 7 applies: