How is the baffle board of this stove able to heat up without combusting?

Question

I'm not sure if this question is right for this site, but since it is home improvement-related I thought I'd ask.

I recently helped my family acquire this stove from a local distributor, and whilst putting it together, I noticed a big flat board covering almost the entire top of the stove where the two cooking burners are. The material in it feels like styrofoam, which feels like it might instantly burst into flames if exposed to the heat of the fire. From what I read, this is called a baffle board or baffle plate, which is supposed to aid in secondary combustion to ensure that as much heat is generated and not being lost through the flue pipe.

Additionally, I noticed that the flue collar has a hole where I assume the licenced NFI professional would put in a damper or another baffle plate that you would twist by hand. I'm not sure what the purpose of this would be, except that I also read that older fireplaces have dampers, which need to be open to ensure that no smoke backs up into the room.

Can anyone help clarify this? If y'all need any pictures, I'd be happy to include them. Thanks!

Answer 1

Ceramic (and "non-ceramic" or silica-free - less hazardous to handle) wool is a common refractory material that's flexible/soft. The product sequece generically would be from Asbestos (whoops - not safe) to ceramic (whoops, not safe) to the current era of "non-ceramic" products - though I don't know that the ceramic versions have actually been banned.

Vermiculite board is a grayish product sold for stove use. You should see a coarse grain in the material, and perhaps reflections from the mica on close examination (vermiculite is steam-expanded mica)

Perlite is a "more styrofoam-like" (or whiter, anyway) volcanic material, but it crushes more than being "spongy." it's typically available as loose-fill or as boards. You should see a coarse grain in the material.

Rigid ceramic-fiber boards are also common. And indeed. while poking around, I find "universal ceramic fiber baffle board, 2300°F rated" as a product. It's probably ceramic fiber board, lacking a picture.

Modern stoves use refactory/insulating baffles to attain higher temperatures (compared to uninsulated steel or cast-iron baffles) that help burn more of the wood products, creating less creosote and delivering more efficiency and a cleaner burn.

Answer 2

As Solar Mike says, the baffle plate is normally metal and the purpose is to reflect the heat back in the chamber.

WHAT DOES A BAFFLE PLATE DO? The simplest way to describe a baffle plate, which is placed at the top of the fire chamber, is a deflector shield which reflects heat back into the combustion chamber. This ensures that as much heat as possible is retained in the stove and emitted into the room in a controlled manner. If there was no baffle plate, which is simply a curved part made of cast iron, heavy steel, stainless steel or vermiculite, then heat would be lost through the flue system and not circulated around the room.

Stove Baffle Plate

It is probably vermiculite

Vermiculite is a hydrous phyllosilicate mineral which undergoes significant expansion when heated

Wikipedia

The damper allows you to control the rate of combustion. Once the fire is lit, you can turn it to reduce the rate of combustion and hence the heat output from the beast. We used to top up the stove with firewood (different model, different country) before going to bed and then turn the damper fully. It would keep producing heat all night.

A damper is a valve or plate that stops or regulates the flow of air inside a duct, chimney, VAV box, air handler, or other air-handling equipment. A damper may be used to cut off central air conditioning (heating or cooling) to an unused room, or to regulate it for room-by-room temperature and climate control

Wikipedia