Jotul Stove - NFPA 211 protection clarification

[Nanstine]

I’m planning on installing the Jotul F500 V3 in an alcove. The installation manual is fairly clear on the clearances and dimensions however I'm a little confused on exactly what material to use for the protection to make it a "protective alcove" per the manual and NFPA 211. So a few specific questions, number 2 being the most important question for me to get some insight:

1. The floor protection has to have an R value of 1.6. I have determined 1/2 durock R value is .39 from their website documentation. Micore 300 is 1.08. So if I use 1" of durock and 1/2 micore that would suffice for an R value of about 1.8 for the floor protection as long as my dimensions are correct. Does that sound about right? Does the floor have to have a 1" air gap off of the wood framing underneath or just the walls/ceiling because I haven't read anything about that?

2. The manual states to make a protective alcove "the walls and ceiling must be protected per NFPA 211. The wall protection must be elevated from the floor and from the combustable material 1". I understand the 1" air gap all the way around the walls and ceiling however what material will suffice for "wall protection"? So as I go in and read NFPA 211 Section 13, I see where they begin to say what protection is required to reduce clearances and in table 13.6.2.1 it lists several options, specifically in letter (f) it states 1" air gap with 1/2 thick non-combustable insulation board with the air space. And further down in section 13.6.2.7 it gives sort of a definition of what type of insulation board is required stating insulation material used as part of the clearance reduction system must have a thermal conductivity of less than 1.0 BTU-in/hr-ft squared- Fahrenheit. But what does all of that mean? What non-combustable insulation board do they mean?

What I'm gathering is so as long as the material on the wall/ceiling has a K factor of less than 1.0 and has the 1" air gap I am good? My plan was 1/2 micore (K factor of .48) of with 1/2 durock over top and then finish with 1/2 thin brick.

I just wanted to make sure I am interpreting the Jotul manual correctly and mainly the NFPA 211 Section 13 correctly when it defines what material to use for protection. Attached is a screenshot from the part of the NFPA 211 I was referring to. Thanks!

 

[begreen]

Alcove design can be fussy and in some cases prohibitive. The devil is in the details.
Can you post a sketch of the alcove design including dimensions? A picture of the location will help too.

 

[Nanstine]

Alcove design can be fussy and in some cases prohibitive. The devil is in the details.
Can you post a sketch of the alcove design including dimensions? A picture of the location will help too.

This attachment is directly from the jotul manual showing the clearances required. This will be going into a new home build planned for next year so right now I just want to make sure I have all my planning in order so I know what it will cost and to make sure it passes inspection. I will pretty much adhere directly to these dimensions unless I make the alcove larger for more clearance just to be safe. My main questions are about exactly what protective material is required per the NFPA 211. My original post pretty much spells out what I plan on using for protective material, but want to make sure that adheres to the NFPA 211 and is the proper Floor wall and ceiling material?

 

[begreen]

Yes, I have the manual. As long as all requirements are met, or exceeded, then it will be ok. Follow section 4.4 of the manual. This included locking the left side door and meeting or exceeding ceiling height requirements.

 

[Nanstine]

Yes, I have the manual. As long as all requirements are met, or exceeded, then it will be ok. Follow section 4.4 of the manual. This included locking the left side door and meeting or exceeding ceiling height requirements.

Thanks. Do you think what I have planned for the wall protection is up to the requirements as far as using the Micore then durock with the air gap? In 4.4 #2 it says refer to the NFPA 211 for wall protection so I wanted to make sure what I had planned for the wall protection as I said in my first post meet those requirements. The NFPA wording is a little confusing to me

 

[stoveliker]

Regarding the heart,

1. The floor protection has to have an R value of 1.6. I have determined 1/2 durock R value is .39 from their website documentation. Micore 300 is 1.08. So if I use 1" of durock and 1/2 micore that would suffice for an R value of about 1.8 for the floor protection as long as my dimensions are correct. Does that sound about right? Does the floor have to have a 1" air gap off of the wood framing underneath or just the walls/ceiling because I haven't read anything about that?

Your numbers are correct and you don't need an air gap on the floor.
Air gaps are for reducing clearances to walls (if allowed, see the manual).

 

[Nanstine]

Regarding the heart,

Your numbers are correct and you don't need an air gap on the floor.
Air gaps are for reducing clearances to walls (if allowed, see the manual).

Thanks I appreciate it. NFPA 211 wording is a little confusing Since I have no experience in this.

 

[begreen]

The air gap is for the walls and ceiling. The protective material on 1" spacers must be non-combustible. This could be sheet metal, cement board, brick, etc. It must be open top and bottom to permit the free flow of air behind it. No need for it on the floor.

 

[begreen]

Thanks. Do you think what I have planned for the wall protection is up to the requirements as far as using the Micore then durock with the air gap? In 4.4 #2 it says refer to the NFPA 211 for wall protection so I wanted to make sure what I had planned for the wall protection as I said in my first post meet those requirements. The NFPA wording is a little confusing to me

All that is required for the wall is the air gap as long as the clearances are met. The micore is just for the hearth floor insulation.

 

[Nanstine]

All that is required for the wall is the air gap as long as the clearances are met. The micore is just for the hearth floor insulation.

So the 1/2 insulation board with the certain k factor as the NFPA 211 section 13 states isn’t required? I could just use cement board with air gap and that would be up to code for walls and ceiling?

 

[begreen]

Correct. NFPA 211 lists several options for proper wall shielding. The insulated wall is just one of them. The main thing needed is free airflow behind the non-combustible shield. Section e) and f) list the alternative of just sheet metal or 1/2" cement board.

Wood Stoves and Fireplaces Thread 'WOOD STOVE WALL CLEARANCES - PRIMER'

Oct 18, 2015

Written by Ken Rajesky, Hearth Industry Expert.

After the difficult decision of what stove to buy has been made, you’ll need to install the stove safely. However good the stove is, it’s still not safe unless installed to manufacturers specifications.

First, review the owners guide that came with the stove. Discuss the installation with your retailer. If you have further questions, contact the technical service department of the manufacturer. The Hearth.com Forums (on this site) can also help you get answers about stove clearances.

Firebrands and test booth wall...

• webfish
• wood stove
• Replies: 0
• Forum: Articles

• 

NFPA Wall Clearance Reductions

The following table sets forth some of the reductions in wall clearances possible with certain wall construction details. For some further discussion on wall clearances, see: http://www.hearth.com/econtent/index.php/articles/stove_wall_clear

www.hearth.com

 

[begreen]

Have to go.

 

[Nanstine]

Have to go.

Thanks!

 

[Todd]

If this is new construction why build an alcove for the stove? I would try and install the stove dead center of the home.

 

[stoveliker]

So the 1/2 insulation board with the certain k factor as the NFPA 211 section 13 states isn’t required? I could just use cement board with air gap and that would be up to code for walls and ceiling?

Yes for walls and ceiling, no for hearth.

 

[xman23]

I to wonder with a new house why this stove location.