Fire Stop Question

[JSoko]

removed the old pre-fab fireplace and installed a High Valley 2500 in a ZC cabinet
the new pipe is triple wall
is it ok for me to seal the gap between the pipe and the metal fire stop ?
the gap is about 1/4" all round the pipe

 

[bholler]

removed the old pre-fab fireplace and installed a High Valley 2500 in a ZC cabinet
the new pipe is triple wall
is it ok for me to seal the gap between the pipe and the metal fire stop ?
the gap is about 1/4" all round the pipe

That depends on how you are planning on sealing it. And when in doubt call the manufacturer and ask

 

[webby3650]

Yes. With high temp silicone.

 

[JSoko]

I plan on using 'Fire Caulk' or '3M Fire Block Foam'

the inside of the chase has spray foam insulation between the studs as do all the exterior walls

my thought is to seal out the cold/hot air that would come down from above the fire stop

but as the pipe is triple wall, the outer section is open to the outside on top/cap and open to the inside by the starter piece set on top of the ZC cabinet

the installer is no help, one says seal it the other says a gap is recommended
and the 'High Valley' folks don't seem to know much about anything

 

[webby3650]

You definitely want to prevent hot air from collecting in that chase. Spray foamed chases are very problematic, they have constant condensation problems. Every one I've seen has had mold at or near the top, new construction and existing homes alike.
On some, the foam was saturated with condensation in places. Is the chase open to the attic so you can inspect it periodically?

 

[JSoko]

the chase extends out from the house 3 feet and is 6 feet wide
two back to back pre-fab fireplaces the remaining one is for the outside deck
the house is 7 years old and the chase is only accessible by removing siding or drywall
the existing pipes were a tight fit through the metal fire stop but not sealed ; NO mold found

installer told me to disconnect the outside air flex pipe and seal the opening to the outside because the outside fire place will get enough air without the vent

if I seal the metal stop tight, I will still have air travel through the outer wall of the triple wall pipe

 

[bholler]

Do not use fire stop foam it is very flammable. i would check the tem rating on the fire stop caulk also It should be atleast 400

 

[bholler]

if I seal the metal stop tight, I will still have air travel through the outer wall of the triple wall pipe

Yeah that is the problem with triple wall and the reason i avoid it if at all possible.

 

[JSoko]

Do not use fire stop foam it is very flammable. i would check the tem rating on the fire stop caulk also It should be atleast 400

thanks for the heads up on the fire Foam
I have HILTI red fire caulk, son uses it to seal pipe penetrations through fire walls

 

[bholler]

I have HILTI red fire caulk, son uses it to seal pipe penetrations through fire walls

Yes but that does not mean it is high heat caulk fire stop caulk and foam is meant to stop air movement and in doing so it slows fire movement greatly but neither are fire proof at all. Fire walls are not fire proof either they just slow the spread of fire so check the temp ratings

 

[JSoko]

on the FIRE FOAM the first words are "Extremely Flammable. foam will support combustion" rated to 240F

 

[Lake Girl]

Hilti CP606 Flexible Firestop Sealant Temp resistance to 176F

Chemical basisWater-based acrylic dispersion
Approx. Density99.9 lb/ft³
ColorRed, White, Grey
Application temperature range40 - 104 °F
Approx. cure time3 mm/3 days 1
Movement±12.5% (ISO 11600)
Temperature resistance range-22 - 176 °F
Mold and mildew performanceClass 0 (ASTM G21-96) and Class 0 (EN ISO 846)
Mold and mildew resistantYes
Surface burning characteristics UL 723 (ASTM E84)Flame spread: 10
Smoke development: 0

 

[bholler]

With a temp capacity of 176 i would not use it get some high temp silicone