Is the chimney dependent on room air or independent?

Hello everyone,

we have a Kfw 70 house with a fireplace.
Do we absolutely need a room air-independent chimney, or is a (normal) one also possible? The architect thinks a room air-dependent one would also work, but the chimney builder says otherwise.
Furthermore, I would like to know if the chimney also requires a condensate drain.

Best regards mrdabado

Hello,

...we are building a KfW 70 house with a fireplace.
Do we absolutely need an room-air-independent chimney, or is a (normal) one also possible? The architect says a room-air-dependent one would also work, but the chimney installer says otherwise.

The chimney installer is right! An architect is not an HVAC planner, as is clearly shown here once again!
However, neither opinion ultimately counts, because the deciding factor is the chimney sweep. Room-air-dependent only works if the room connection is sufficient and no exhaust air from the kitchen or controlled residential ventilation system is present or active! Moreover, it should be considered that room-air-dependency means additional energy losses and cold outside air with room-air-independency enables better draft (thermal lift)!
The best option is always a separate combustion air supply through the basement or beneath the finished floor level!

...Furthermore, I want to know whether the chimney also needs a condensate drain.

The surcharge for glazed (condensate suitable) flues costs about €11/m. So not a cost factor.
A drain is always advisable and easy to implement! In addition to condensate, precipitation of various forms can enter the chimney. A condensate drain therefore always means higher safety!

Best regards

Hello Euro, we want to build a house on a slab foundation. Furthermore, it is a fairly open design, i.e., open kitchen, hallway, dining and living area, stairs to the upper floor and gallery connected without doors, totaling about 80m2. That is why the architect thinks that an air-independent system is not necessary. What is your opinion on this? How is room-independent air supply installed under the slab foundation? What properties must this pipe have? Is there something special about it? What does such a condensate drain look like? Simply a pipe connected to the chimney and the wastewater system? Regards

....That is why the architect thinks that no air-independent system is needed. What do you say about that?

See previous post!

....How is air-independent ventilation laid under the floor slab? What properties must this pipe have? Is there anything special about it?

I cannot provide planning services free of charge without an assignment, only point in a direction!

....What does such a condensate drain look like? Simply a pipe connected to the chimney and the sewage?

There must be a responsible MEP planner for this construction project—right? Best regards

What is a TGA?
You meant with enough space an air-dependent one would also work, right or did I misunderstand something?

regards

Hello everyone,

so we have a fireplace that we could have installed either dependent on the room air or independent. We chose the room-air dependent option because at that time we already had the floor slab, etc. in place. Just as an example. Our living/dining room is open to the kitchen. In total, the living room + dining room + kitchen are just under 50 sqm. In the kitchen, we have a range hood with exhaust. Because you are not allowed to operate that together with the fireplace like that, we bought a wireless switch on the internet. That means the range hood only turns on if a window in the kitchen is tilted open. That’s no problem, those things don’t cost much and it was also approved by the "Halbgott in schwarz".
Our chimney flue also has a condensate drain. Until recently, unfortunately, this was not yet finally connected. So the condensate water flowed nicely directly under the screed. Therefore, a condensate drain is definitely recommended.

Best regards
Nina