ᐅ Controlled residential ventilation / DIBt-certified stove / pressure monitor
Created on: 16 Jul 2013 09:23
P
PhoenixDH
Hello everyone,
we are planning to build a prefabricated house meeting the KfW 70 standard.
The house will be heated primarily with a gas/solar (water) system, partly with underfloor heating and partly with conventional radiators.
In addition, a controlled residential ventilation system with heat recovery will be integrated.
We also want to install a stove, since the heat from a stove has a different character.
I am familiar with the technical requirements from my chimney sweep.
This means the stove must be room-air independent and ideally certified by DIBt.
However, as is often the case, the stove we have chosen is room-air independent but does not have DIBt certification.
According to my information, a pressure monitor must then be installed, which shuts off the controlled ventilation system if the negative pressure becomes too high.
My question now is: what does such a pressure monitor look like and how is it installed?
Where does it measure? I assume in the room where the stove is located, but where else?
Does it measure outside? If so, how can I route the sensor outside?
Retrofitting a penetration to the outside later would be problematic due to airtightness concerns.
Can someone bring me up to date on this?
By the way: the range hood will be recirculating and can be disregarded.
Thank you very much!
we are planning to build a prefabricated house meeting the KfW 70 standard.
The house will be heated primarily with a gas/solar (water) system, partly with underfloor heating and partly with conventional radiators.
In addition, a controlled residential ventilation system with heat recovery will be integrated.
We also want to install a stove, since the heat from a stove has a different character.
I am familiar with the technical requirements from my chimney sweep.
This means the stove must be room-air independent and ideally certified by DIBt.
However, as is often the case, the stove we have chosen is room-air independent but does not have DIBt certification.
According to my information, a pressure monitor must then be installed, which shuts off the controlled ventilation system if the negative pressure becomes too high.
My question now is: what does such a pressure monitor look like and how is it installed?
Where does it measure? I assume in the room where the stove is located, but where else?
Does it measure outside? If so, how can I route the sensor outside?
Retrofitting a penetration to the outside later would be problematic due to airtightness concerns.
Can someone bring me up to date on this?
By the way: the range hood will be recirculating and can be disregarded.
Thank you very much!
Hello,
I’d like to share how things turned out for us.
As I mentioned on August 29th, I have a single-family house of 53m² (570ft²) with controlled residential ventilation and a room-air-independent wood stove. The chimney sweep insisted on a pressure monitor or proof that the house does not generate more than 8Pa (0.03 inches water column) negative pressure.
Neither the manufacturer, planner, nor installer could provide this proof. They also recommended a pressure monitor. The chimney sweep then reported the construction defect to the building authority.
In the end, we agreed with the chimney sweep to perform a pressure comparison measurement during regular operation. The pressure difference between outdoor air and the air in the stove installation room was measured. It was quite windy that day, causing the pressure to fluctuate by about 4Pa (0.016 inches water column). No difference was observed whether the ventilation system was off, running at normal speed, or full fan speed. This satisfied the chimney sweep’s requirements.
Additionally, I wanted to have a measurement with the supply air blocked at full fan speed (the worst case). Here, the negative pressure in the room increased by about 2Pa (0.008 inches water column), reaching a maximum of 5Pa (0.02 inches water column). Of course, it should be noted that although my house was extensively modernized, it does not have the airtightness of a passive house.
Conclusion:
My wood stove with controlled ventilation was approved without a pressure monitor.
The pressure test cost 250 euros.
For my safety, I installed a CO alarm. It costs 50 euros, runs on batteries, and must be completely replaced every 6 years. I argue that it is safer and more reliable than a pressure monitor.
Regards,
Michael
I’d like to share how things turned out for us.
As I mentioned on August 29th, I have a single-family house of 53m² (570ft²) with controlled residential ventilation and a room-air-independent wood stove. The chimney sweep insisted on a pressure monitor or proof that the house does not generate more than 8Pa (0.03 inches water column) negative pressure.
Neither the manufacturer, planner, nor installer could provide this proof. They also recommended a pressure monitor. The chimney sweep then reported the construction defect to the building authority.
In the end, we agreed with the chimney sweep to perform a pressure comparison measurement during regular operation. The pressure difference between outdoor air and the air in the stove installation room was measured. It was quite windy that day, causing the pressure to fluctuate by about 4Pa (0.016 inches water column). No difference was observed whether the ventilation system was off, running at normal speed, or full fan speed. This satisfied the chimney sweep’s requirements.
Additionally, I wanted to have a measurement with the supply air blocked at full fan speed (the worst case). Here, the negative pressure in the room increased by about 2Pa (0.008 inches water column), reaching a maximum of 5Pa (0.02 inches water column). Of course, it should be noted that although my house was extensively modernized, it does not have the airtightness of a passive house.
Conclusion:
My wood stove with controlled ventilation was approved without a pressure monitor.
The pressure test cost 250 euros.
For my safety, I installed a CO alarm. It costs 50 euros, runs on batteries, and must be completely replaced every 6 years. I argue that it is safer and more reliable than a pressure monitor.
Regards,
Michael
motte2 schrieb:
Hello,
I would like to share how things turned out for us.
...
We finally agreed with the chimney sweep to perform a pressure comparison test during regular operation.
...
Conclusion:
My RLU stove was approved without a pressure monitor.
The pressure test cost 250 euros.
For my own safety, I installed a CO detector. It costs 50 euros, runs on batteries, and must be completely replaced every 6 years. I believe it is safer and more reliable than a pressure monitor.
Regards,
Michael Hello Michael,
I am interested in a few details about the pressure comparison test.
Who carries out this test?
Was the measurement done before installing the stove?
Was there an agreement with the chimney sweep regarding the maximum value up to which he would accept the installation without a pressure monitor? I am thinking of a safety draft limit.
Best regards,
Ulf
Hello Ulf,
the pressure comparison test was carried out by a structural engineer specializing in blower door tests. Local companies for this can be easily found online.
The measurement was done after the installation of the stove. The chimney sweep insisted that the stove be lit during the test. We performed measurements both before and after lighting it and found no difference. This makes sense since the stove is room-air-independent, and we measured the pressure difference between indoor and outdoor air.
The chimney sweep accepted a value up to 8 Pa (0.03 inches water column), which is the test pressure for room-air-independent stoves. There was no mention of a safety draft; we didn’t even have to check failure scenarios like fan failure or clogged filter. Similarly, a stove door not properly closed or a defective seal is not considered.
With a properly functioning controlled ventilation system, supply and exhaust air are balanced, so no pressure difference occurs. Only when the supply air fails does negative pressure build up. We simulated this, and the negative pressure only increased slightly. I think in passive houses, the 8 Pa (0.03 inches water column) will be exceeded.
On the other hand, 8 Pa (0.03 inches water column) can also be reached without a ventilation system, just due to wind.
Regards,
Michael
the pressure comparison test was carried out by a structural engineer specializing in blower door tests. Local companies for this can be easily found online.
The measurement was done after the installation of the stove. The chimney sweep insisted that the stove be lit during the test. We performed measurements both before and after lighting it and found no difference. This makes sense since the stove is room-air-independent, and we measured the pressure difference between indoor and outdoor air.
The chimney sweep accepted a value up to 8 Pa (0.03 inches water column), which is the test pressure for room-air-independent stoves. There was no mention of a safety draft; we didn’t even have to check failure scenarios like fan failure or clogged filter. Similarly, a stove door not properly closed or a defective seal is not considered.
With a properly functioning controlled ventilation system, supply and exhaust air are balanced, so no pressure difference occurs. Only when the supply air fails does negative pressure build up. We simulated this, and the negative pressure only increased slightly. I think in passive houses, the 8 Pa (0.03 inches water column) will be exceeded.
On the other hand, 8 Pa (0.03 inches water column) can also be reached without a ventilation system, just due to wind.
Regards,
Michael
Thanks for the information.
Our situation is a bit different since we live in a newly built house (KfW70 standard). The mechanical ventilation system operates with decentralized supply air (meaning vents in the walls) and a central exhaust fan. Because of this setup, a slight negative pressure is created by design. However, the supply air vents cannot be sealed airtight, so air can always flow in.
I’ll discuss this with the chimney sweep...
Best regards,
Ulf
Our situation is a bit different since we live in a newly built house (KfW70 standard). The mechanical ventilation system operates with decentralized supply air (meaning vents in the walls) and a central exhaust fan. Because of this setup, a slight negative pressure is created by design. However, the supply air vents cannot be sealed airtight, so air can always flow in.
I’ll discuss this with the chimney sweep...
Best regards,
Ulf
ypg schrieb:
Yes, I have news – the chimney installation is about to happen. The local chimney inspector "does not require" a pressure monitor because the stove is certified.
However, the electrical cable has already been installed and is now just dangling around the chimney. Hello Yvonne, did you install a mechanical ventilation system with heat recovery?
micric3 schrieb:
Hello Yvonne, did you have a mechanical ventilation system installed?Yes, definitelySimilar topics