Open fireplace?

[Jonas Westbom]

In the Norwegian Lom, there is a fjellsenter with a fantastic fireplace. Are there any engineering or legal issues with building one like that in a private home? (I understand one might think it might smoke in or be inefficient heat, etc. That is not my question)

 

[Claes Sörmland]

We can start with the hearth area. Since the fireplace has no walls, you must have a hearth area around the entire construction. According to general recommendations, it should be at least 1 m, and since the fireplace is elevated, you should add half the elevation that exceeds 40 cm. In practice, it's probably best if the entire floor in the room functions as a hearth area, just like in the picture. It can likely shoot burning wood much further than 1 m...

Then there's the matter of smoke gas management...

 

[Jonas Westbom]

So, as you see it, there are no problems then?

We can start with the hearth pad. Since the hearth has no walls, you need a hearth pad around the entire construction. According to general advice, it should be at least 1 m, and since the hearth is elevated, you should add half the elevation that exceeds 40 cm. In practice, it might be best if the entire floor in the room functions as a hearth pad, just like in the picture. It could likely shoot burning wood clearly longer than 1 m...

Then there's the issue of flue gas management...

 

[Claes Sörmland]

So as you see it, there are no problems then?

I think it's more of a technical challenge, fireplaces are not covered by the emission requirements for room heaters. But check what the municipality allows where you live regarding fireplaces. If the area has air quality issues, they might prohibit the installation of fireplaces. I believe they have the ability to do that.

 

[Bjober]

I think that a lot of ventilation air is required to draw the smoke into the hood/chimney. Among other things, so that people can move around the fireplace without the smoke spreading into the room.
In the large hall that the picture shows, that ventilation flow can be part of the total necessary ventilation.
But in a villa, it becomes a total draft.
I see it as completely impractical except possibly during the part of the year when the front door and windows can be wide open.

 

[ArneTW]

It's probably the ventilation that becomes tricky in a modern villa.

But I guess it's solvable like everything else.

The one in the picture is a "fancy" version of a fireplace in an eldpallkoja.

/ATW

 

[Avemo]

Grillkåtor often have a similar fireplace sometimes. They lack the challenge present in a modern house where the ventilation seeks to create a negative pressure in the house. Despite this, it tends to be quite smoky inside the grillkåta. Especially if not everyone is sitting completely still.

Similar fireplaces are sometimes found in restaurants and the like. I think it will be a challenge not to blacken the house with smoke when you have a fire. But it's certainly not impossible.

 

[Jonas Westbom]

That may very well be the case. Of course, you need a damper to prevent warm air from escaping when the fire is not burning. I would still guess it's not too hard to get the smoke to rise up and out when the fire is burning; a draft enhancer can be used if there are issues. The smoke hood is substantially sized in relation to the fireplace. But it's hard to know; it's really unfortunate to have a cubic-meter block in the middle of the room that's unusable.

I think that a lot of ventilation air is needed to pull the smoke into the hood/chimney. Among other things, to allow people to move around the fireplace without smoke getting into the room. In the large hall shown in the picture, that ventilation flow could be part of the total necessary ventilation. But in a villa, it causes total drafts. I see it as completely unfeasible, except possibly during the part of the year when the front door and windows can stand wide open.

 

[Jonas Westbom]

Yes, I really like the grillkåta feeling. It becomes airy yet maintains good contact with the fire. An alternative that doesn't feel as cool is a stove with visibility. For example: https://nordpeis.se/Produkter/Murspis/Fristaaende/Tokyo

Grillkåtas sometimes have a similar fireplace. There, you miss the challenge present in a modern house where the ventilation strives for a negative pressure. Despite this, it tends to be quite smoky inside the grillkåta. Especially if not everyone stays completely still.

Similar fireplaces are sometimes found in restaurants and the like. I think it will be a challenge not to blacken the house with smoke when burning. But it's certainly not impossible.

 

[Jonas Westbom]

Yes, of course, but I don't want to install an electric fan. I think you can always hear them a little, and it obviously affects the mood.

It's probably the ventilation that becomes tricky in a modern villa.

But I assume it's solvable like everything else.

What's in the picture is a "fancy" version of a fireplace in a firewood hut.

/ATW

 

[ArneTW]

Yes, it's possible of course, but I don't want to install an electric fan. I think you can always hear them a little and it affects the atmosphere of course.

Some fantasies...

Could one imagine a round stove without a bottom that covers the fireplace and can be hoisted up into the chimney once the draft is going...

I suppose it would get sooty.

/ATW

 

[Bjober]

That could very well be the case. Of course, you need a damper to prevent releasing warm air when not burning. I would still guess that it is not too difficult to get the smoke to rise and out when burning, you can use a draft enhancer if there are issues. The smoke hood is considerably sized in relation to the hearth. But it's hard to know, it would be really unfortunate to have a cubic meter block in the middle of the room that is unusable.

I don't mean that it would be difficult to get a draft. I mean more that it requires so much air to prevent smoke and soot indoors that it becomes unreasonable ventilation for a normal household. The heat that is ventilated out must also be replaced. I think it's much more than what a normal home boiler or heat pump provides. I believe it requires much more air than a regular open fireplace, which is usually covered on at least two sides. Therefore, I think it quickly gets cold inside when burning in that hearth.

I compare a bit to when I'm welding in the garage. There I have 315mm spiro and 650w fan. It becomes smoke-free but not a setting you'd want in a home. And indeed, the temperature drops after venting for a few hours.

 

[Jonas Westbom]

Yes, it is indeed a risk. Good input!

I'm not really implying that it would be difficult to get draft. I'm more concerned that it requires so much air to avoid smoke and soot indoors that it becomes impractical ventilation for a normal household. The heat that is ventilated out must also be replaced. I believe it involves much more than what a normal residential boiler or heat pump provides. I think it requires much more air than a typical open fireplace, which is usually covered on at least two sides.
Therefore, I believe it quickly becomes cold indoors when you burn in that fireplace.

I compare it a bit to when I weld in the garage.
There I have 315mm spiro and a 650w fan. It becomes smoke-free but not in a way you'd want that environment in your home. And sure, the temperature drops when you've been using the fan for a few hours.