Minimum-sized direct vent size

[ratzfatz]

Hi,
I want to install a direct vent fireplace and have tight joist spacing. What is the minimum hole size when penetrating the floor?
For a 3"/5" vent, what is the minimum size of the firestop?
For a 4" × 6⅝" vent, what is the minimum size of the firestop?

Are there reasonable (BTU/optics/flame height) gas fireplaces with 3"/5" vents?

(I haven't selected a fire place yet).
thanks!

 

[DAKSY]

The minimum size opening for a 4” DV pipe firestop is 12” x 12”. I’ve never seen “3” coaxial DV pipe. There are approved framing techniques to modify your floor joists to obtain the needed clearances.

 

[ratzfatz]

wow that is huge. Some specs say that only 1" clearance is needed, so I was hoping to get away with 6x6 inches. Hmm I cannot run such a huge soffit through my second story. Are there any alternatives? Power-vent?

 

[Burnin Since 1991]

wow that is huge. Some specs say that only 1" clearance is needed, so I was hoping to get away with 6x6 inches. Hmm I cannot run such a huge soffit through my second story. Are there any alternatives? Power-vent?

Find the pipe you want and then find their specifications and install manual. It will list the clearance to combustibles. If you're not sure, post what pipe, you're looking at and we'll help you figure out your options.