Thread: Fireplace insert questions

I’m trying to better understand the requirements for a fireplace insert.

As I currently understand it:



1) An insert can be installed:

1a) In the firebox without a vent (not desirable)

1b) In the fireplace, with a vent connector to the bottom of the chimney flue (better)

2b.1) Must this be a connector listed by the manufacturer?

2b.2) Does this require a cap/termination listed by the insert’s manufacturer?

2b.3 If not, what if anything must typically be changed at the chimney top when an insert is installed in this manner.

1c) In the firebox, vented to the top of the chimney (best). Entire system (insert, vent, and cap/termination) must be listed.

2) What happens to the original damper when an insert is installed?



Thanks as always.

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There are pellet stove inserts, gas inserts and wood inserts.... and maybe even others. The ones I've installed or had installed have always had very detailed instructions about what materials to use and how to use them.

There countless different things depending on your fuel and other factors. From the ones I've done the venting fits past the damper with it just being opened all the way. I imagine on some older fireplaces the damper may have to be removed and on some, certain equipment may not fit at all. The venting for my pellet stove and wood stove are each 3" and the venting for a gas insert I had was 3".

I'm no pro with this stuff, I've just had several different types of inserts. The manual is probably your best bet. I'm sure if it's addressed in the code anywhere someone will point it out shortly....

What I'm most likely to see are WB fireplace inserts, and I've been reading the manuals for some; clearly, if the manual is on-hand at the inspection. it will quickly answer a lot of my questions.

Often however the manual is not available, and what I'm trying to do is understand what features/methods/requirements of installation are universal.

Most of the inserts have to be dismantled to some degree to check this stuff. I personally don't open them up. My state SoP's don't require it and it's addressed in my contract.

I'm quick to recommended an evaluation and/or cleaning from a pro. All of the manufacturers I've seen recommended annual cleanings/service. That is virtually never done so you're totally justified in telling them to look into it further. Fireplace inserts are a huge liability issue and I'm not into blessing them in any way.

In general, the old style of hooking up an insert was to just put it in the fireplace and let it vent right out the top, below the damper. The problem with that is if it doesn't get cleaned regularly, creosote builds up in the dead space behind the insert. In extreme cases the creosote becomes explosive. I read a story once about an insert blowing out of a fireplace and through a bedroom wall. It sounds pretty extreme but I suppose anything is possible. There may be additional reasons not to hook them up this way.

The next idea was to seal off the firebox from the chimney (usually with sheetmetal) and run the vent past that point so it's into the flue. I believe that is still an acceptable way to do it (again, it depends on manufacturer instructions). The latest installs I've seen have the chimney fully lined to a cap at the top. A lot of this also has to do with environmental concerns too. The newer insert that came with the house I just bought has a catalytic convertor of sorts that re-circulates some of the exhaust and puts off less pollution.

In the end, there's a lot of variables and if you're going to bite this off and claim to be an expert on it, you should take some classes or something. There are just too many different types of units out there.

I'd be curious to see what the others say but I really don't see many inserts. Maybe one in 50 houses.

Michael - that is some numbering scheme. 1a- 2a - 2b -1c – you have been reading too many code books!

There are some minimum requirements (unless otherwise listed by the manufacturer). NPFA 211 chapter 12 outlines these minimums. The connector from the insert must extend to the flue liner, the installation must allow the connector and chimney to be inspected and cleaned, and it also restricts dilution air from the habitable space from entering into the chimney.

Since the connector must extend into the flue the damper would have to be removed or secured in an open position to gain access.

Connectors must be stainless steel or “an equivalent material that resists corrosion” and withstand temps up to 1800 degrees F, and again the AHJ is the final approval for use.

IRC and NFPA address flues and sizes and the break point (size, condition) at which a flue must be relined.

As to listing, current NFPA standards require ALL solid-fuel-burning appliances to be listed or approved by the AHJ.

Thanks for those responses.

Recently ran across this, interesting discussion of fireplace draft problems:

http://us.exhausto.com/files/pdf/Brochures/3911002.pdf

Hello Folks; I want to get in on the fireplace insert debate from our perspective in the great white north...ha ha (it's 84 degrees today). Anyway It is required here to have a continuous listed connector (liner) from the appliance to the top of the chimney. A flashing then goes over the tile flue liner and a rain cap attached to this whole apparatus. In those cases where a wood insert is to be used and the chimney and house clearance to combutibles are not to code ( 2" inside- 1/2 " outside) an Insulated liner must be used.
The damper must rendered inoperable and open. We are permitted small enlargements of the throat/damper area to facilitate the metal liner, but are not permitted changes to the firebox area to accomodate the appliance.
We are not permitted vent free or short "past the damper type" installs. Of course it goes without saying that all installs should have the chimney, firebox and there components cleaned, checked and corrected prior to that install.
My name is Barrie and I work and live in British Columbia Canada. I'm WETT certified and have also been working in the fireplace install and retail business for the past 14 years. Many years back I was a Masonry contractor. At our store we also have a full sweeping service.
There thanks for listening......

Barrie,

Welcome to IN!

Like a lot of inspectors, I'm constantly trying to improve my fireplace and chimney inspection knowledge and skill, and really appreciate the time that members of industry have spent answering questions here.

I've been trying to post questions and pictures as they come up in my inspections, please feel free to comment on any of them, including any comments or advice that suggests itself irrespective of whether it's exactly "on-topic" as regrades my specific questions.