ᐅ Door gap Controlled mechanical ventilation Ventilation gap for air exchange
Created on: 21 Dec 2014 16:24
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PhoenixDH
Hello everyone,
I understand that controlled residential ventilation systems require ventilation gaps for air exchange, which makes sense. We have two glass doors, and it is clear that maintaining the required gap height is not possible; the door will be as tall as possible.
We have a list with the specified dimensions outlining the requirements.
What are your thoughts on the assumption that a gap is present but does not always meet the required height? For some doors, a gap of 1.4 cm (0.55 inches) is required, which is quite a significant height.
I understand that controlled residential ventilation systems require ventilation gaps for air exchange, which makes sense. We have two glass doors, and it is clear that maintaining the required gap height is not possible; the door will be as tall as possible.
We have a list with the specified dimensions outlining the requirements.
What are your thoughts on the assumption that a gap is present but does not always meet the required height? For some doors, a gap of 1.4 cm (0.55 inches) is required, which is quite a significant height.
P
PhoenixDH22 Dec 2014 06:26Hello, thanks!
Well, we actually don’t want to recess anything into the wall because it doesn’t really look good, but the same goes for the gap under the doors. Modifying the frames afterward is also out of the question.
So I think we will leave a bit more space under the doors; it’s not like there’s no room at all.
But the question I still have is:
What happens if the calculated values are not met?
Sure, the air exchange takes longer, but it still happens. There are also people who don’t run their mechanical ventilation systems regularly. In that case, it ends up being the same. And if the doors are open, the calculated system is basically irrelevant anyway.
It’s just the two of us and we’re not home most of the day, so in my view, it doesn’t really matter.
One could argue here that the values were calculated and should be adhered to, but maybe it’s a case of using a sledgehammer to crack a nut.
Well, we actually don’t want to recess anything into the wall because it doesn’t really look good, but the same goes for the gap under the doors. Modifying the frames afterward is also out of the question.
So I think we will leave a bit more space under the doors; it’s not like there’s no room at all.
But the question I still have is:
What happens if the calculated values are not met?
Sure, the air exchange takes longer, but it still happens. There are also people who don’t run their mechanical ventilation systems regularly. In that case, it ends up being the same. And if the doors are open, the calculated system is basically irrelevant anyway.
It’s just the two of us and we’re not home most of the day, so in my view, it doesn’t really matter.
One could argue here that the values were calculated and should be adhered to, but maybe it’s a case of using a sledgehammer to crack a nut.
PhoenixDH schrieb:
There are also people who don’t run their mechanical ventilation with heat recovery regularly. In that case, it’s basically the same result.
Or if the doors are open, the designed system becomes irrelevant anyway.
There are only two of us, and we’re not home most of the day, so in my opinion, it doesn’t really matter.
You could argue that the values are calculated and should be followed, but maybe this is a case of using a sledgehammer to crack a nut. I’m wondering why you install a ventilation system and then want to “limit” the air exchange? Maybe a decentralized system — or even no system at all — would have been better for you.
You might as well have just given the money to me.
Well, it’s not as if the function is completely impaired when the gap falls slightly below the target dimension. The pressure difference increases somewhat due to higher flow resistance. At best, this causes a slight draft at the narrow point (which hardly anyone will notice, since hardly anyone stands constantly in front of the door). Audible noise might occur, but for that to happen, quite a lot of air would have to whistle through. My biggest concern would be that, due to the pressure difference, air flows uncontrollably through tiny cracks in the masonry, around the windows, etc., instead of passing through the door gap.
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miraculum28 Dec 2014 01:28Hello PhoenixDH,
Quote: "One could argue that the values here are calculated and should be adhered to, but maybe it’s an overreaction."
Why should that be the case? The mechanical ventilation system for residential buildings is designed according to DIN 1946-6. A ventilation volume plan is created for this purpose. However, the air volumes are not determined arbitrarily or based on personal judgment; they are calculated. These calculated air volumes must be ensured at the specified pressure loss across the transfer opening or door gap. Accordingly, this pressure loss must also be calculated.
If the gap is smaller, the system cannot operate as intended. This could mean, for example:
- the planned air volumes are not achieved
- the pressure loss increases, which leads to higher electricity consumption
- the infiltration airflow increases, resulting in higher heating energy consumption
- the allowable pressure loss is exceeded, which can interfere with the safe operation of a chimney
and so on.
Best regards
miraculum
Quote: "One could argue that the values here are calculated and should be adhered to, but maybe it’s an overreaction."
Why should that be the case? The mechanical ventilation system for residential buildings is designed according to DIN 1946-6. A ventilation volume plan is created for this purpose. However, the air volumes are not determined arbitrarily or based on personal judgment; they are calculated. These calculated air volumes must be ensured at the specified pressure loss across the transfer opening or door gap. Accordingly, this pressure loss must also be calculated.
If the gap is smaller, the system cannot operate as intended. This could mean, for example:
- the planned air volumes are not achieved
- the pressure loss increases, which leads to higher electricity consumption
- the infiltration airflow increases, resulting in higher heating energy consumption
- the allowable pressure loss is exceeded, which can interfere with the safe operation of a chimney
and so on.
Best regards
miraculum
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