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Roland_S.9 Aug 2016 20:52Good evening everyone,
could someone please explain the function of an F90 shaft in connection with a condensing boiler in a new building? Specifically, the exhaust gas discharge, intake air, etc.
Thank you very much and best regards
Roland
could someone please explain the function of an F90 shaft in connection with a condensing boiler in a new building? Specifically, the exhaust gas discharge, intake air, etc.
Thank you very much and best regards
Roland
Hello Roland,
A gas condensing boiler is connected using a LAS (air-flue chimney) for both fresh air supply and exhaust gases.
Simply put, the LAS provides the fresh combustion air on one side, while the exhaust gases (which are not very hot, around 40°C (104°F), and therefore must be conveyed to the roof via a fan inside the gas condensing boiler) are vented separately. Of course, these run in separate circuits. The LAS is usually made of plastic.
The FW90 shaft (FW = fire resistance rating) may be required depending on the state and, as I often say, also depending on the mood of the local chimney sweep inspector.
This shaft is a fire-resistant box around the LAS, typically running from the ceiling of the ground floor (or the basement, depending on where the gas condensing boiler is located) up to under the roof.
You don’t really need to understand all the details. I didn’t fully understand it myself at the time and, due to time constraints, had prefabricated parts installed (see below: money, expensive).
There are many ways to create an FW90 shaft on site, including prefabricated components, such as Skuberne. In any case, it involves effort and costs money. An unfavorable exhaust routing can cause wall protrusions, so please pay attention to this and, if necessary, have the exhaust routing changed. Having such a bulky unit in the middle of a bathroom or bedroom is undesirable.
In your case—if I understand your question correctly—it is required. Discuss the options on site to choose the most cost-effective method of installation.
Best regards
Thorsten
A gas condensing boiler is connected using a LAS (air-flue chimney) for both fresh air supply and exhaust gases.
Simply put, the LAS provides the fresh combustion air on one side, while the exhaust gases (which are not very hot, around 40°C (104°F), and therefore must be conveyed to the roof via a fan inside the gas condensing boiler) are vented separately. Of course, these run in separate circuits. The LAS is usually made of plastic.
The FW90 shaft (FW = fire resistance rating) may be required depending on the state and, as I often say, also depending on the mood of the local chimney sweep inspector.
This shaft is a fire-resistant box around the LAS, typically running from the ceiling of the ground floor (or the basement, depending on where the gas condensing boiler is located) up to under the roof.
You don’t really need to understand all the details. I didn’t fully understand it myself at the time and, due to time constraints, had prefabricated parts installed (see below: money, expensive).
There are many ways to create an FW90 shaft on site, including prefabricated components, such as Skuberne. In any case, it involves effort and costs money. An unfavorable exhaust routing can cause wall protrusions, so please pay attention to this and, if necessary, have the exhaust routing changed. Having such a bulky unit in the middle of a bathroom or bedroom is undesirable.
In your case—if I understand your question correctly—it is required. Discuss the options on site to choose the most cost-effective method of installation.
Best regards
Thorsten
If it is a single-family house, a low-rise building according to the national building code, then F30 fire resistance is sufficient at most, or after consultation with the responsible district fire safety officer, installation in a gypsum board drywall construction without combustible components (metal stud profiles) is also acceptable. The planning, especially roof or wall penetrations, taking into account the fire protection requirements and the fire regulations (FeuerVO) of the respective federal state, is the responsibility of your architect.
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Roland_S.9 Aug 2016 22:23Hello Thorsten, hello wpic,
thank you for your detailed and clear answers.
The way it works now makes more sense to me.
For exactly the reason you mentioned with the wall projections, we had this shaft installed inside a drywall partition, of course after consulting with our architect.
This shaft is quite large, and when I look inside, what do I see? A small milky mini pipe, maybe about 50mm (2 inches) in diameter, and I wondered whether this pipe is for supply air or exhaust air, or what purpose a single small pipe serves in such a large shaft?
Best regards
Roland
thank you for your detailed and clear answers.
The way it works now makes more sense to me.
For exactly the reason you mentioned with the wall projections, we had this shaft installed inside a drywall partition, of course after consulting with our architect.
This shaft is quite large, and when I look inside, what do I see? A small milky mini pipe, maybe about 50mm (2 inches) in diameter, and I wondered whether this pipe is for supply air or exhaust air, or what purpose a single small pipe serves in such a large shaft?
Best regards
Roland
R
Roland_S.10 Aug 2016 19:23Hello Thorsten, I could certainly do that. I just didn’t want to be left clueless like the proverbial “deer in headlights” again...
I thought there might be a standard for how fresh air supply and exhaust air are routed, specifically whether the exhaust or supply air goes through the small pipe, or if the exhaust or supply air passes through the shaft without anything in it, similar to a chimney.
Regards
Roland
I thought there might be a standard for how fresh air supply and exhaust air are routed, specifically whether the exhaust or supply air goes through the small pipe, or if the exhaust or supply air passes through the shaft without anything in it, similar to a chimney.
Regards
Roland
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