Open prefab chase in attic

[Hank Vanderbeek]

I see that the builder left the chase open in the attic in some homes he built in the 90s. Any reason I should know of. Isn't this a no no? Since 1992 these chases should have been sealed and insulated. Need info for a report am doing today.

Thanks!

[Shawn Rowe]

Hank,

I am unaware of the 1992 sealed and insulated requirement but the photo you show is a typical installation seen here all the time. There is a firestop requirement at the ceiling line. Check the manufacturer's recommendations as these usually supercede other requirements.

It really looks like that flue is way too close to combustibles.

[Hank Vanderbeek]

Thanks for the reply. The 1992 reference is Dr Smith's Avoiding Litigation article on chimneys on NACHI's website.

[Keith Swift, PhD.]

It's actually "Swift," not "Smith," but I'll check the source of my statements in my "Chimneys" article that appeared in The Mall. However, bear this in mind, there are many "authorities." For instance, do we want to cite the manufacturer's specs, the National Fire Protection Association (NFPA) standards, the Chimney Safety Institute of America (CSIA), or should we just use palin old common sense. This is what I can tell you, in the rich oxygen atmosphere of an attic, I would prefere to see a prefabriocated fireplace flue enclosed within a chase sheather with drywall. Regardless, i'll check my sources and keep you informed. Meanwhile, my advice is that you ere on the side of caution and safety.

[Keith Swift, PhD.]

PS Forgive the typos. I typed furiously, and did not proofread before posting.

[Keith Swift, PhD.]

As a follow up on my last post, what I referred to as a "chase" is actually called a "vertical fire-block" that has the same function as the "horizontal fire-block that surrounds the flues of prefabricated chimineys on attic floors. I believe that this went into effect in 1992 with UBC 702.8. However, it is rarely enforced by the authorities having jurisdiction (AHJ), because it would require a third site visit after the "rough-framing" inspection, at which time the inspector would have to climb into the attic. Therefore, in keeping with my "generalist" label, I'm not going to cite code but merely recommend a vertical fire-block surround any factory-built chimney flue that passes through an attic, in any residence built after 1992. Don't forget, it's all abou safety, serving our clients, and avoiding litigation. Take care.