Hello everyone,
this is my first post here.
First of all: Yes, I know that according to the DIN standard, a mechanical backflow preventer for wastewater containing fecal matter is not allowed.
However, I want to understand why. I have done some research, and interestingly, in the USA, Canada, and also Switzerland, it seems quite common and accepted (both legally and by insurers) to use mechanical backflow preventers for wastewater containing fecal matter. These are used either as a single or double flap, sometimes with additional manual operation.
For our new build without a basement, on a slight slope, the prefab house manufacturer considers the next higher manhole cover as the backflow level. Normally, wastewater does not flow uphill, of course.
Rainwater is directed into a separate drainage system. So this only concerns wastewater, and here only from the ground floor.
I have the option to have the prefab house manufacturer prepare the installation of a backflow preventer for the ground floor of the single-family house (there is also a toilet on the upper floor/attic) and then carry out the actual installation myself or have it done externally.
I am not only reluctant because of the high cost of a potentially unnecessary electrically operated and electronically controlled backflow flap but also because of the required maintenance twice a year by a specialist company. Over the financing period of the house, this will cost several times more than the backflow preventer itself, including installation.
Therefore, my question is: If a mechanical flap is sufficient in other developed countries, why shouldn’t it work here as well? I would be willing to disregard the DIN standard if the practical risk involved is negligible.
I look forward to your expert opinions.
Best regards
Stefan
this is my first post here.
First of all: Yes, I know that according to the DIN standard, a mechanical backflow preventer for wastewater containing fecal matter is not allowed.
However, I want to understand why. I have done some research, and interestingly, in the USA, Canada, and also Switzerland, it seems quite common and accepted (both legally and by insurers) to use mechanical backflow preventers for wastewater containing fecal matter. These are used either as a single or double flap, sometimes with additional manual operation.
For our new build without a basement, on a slight slope, the prefab house manufacturer considers the next higher manhole cover as the backflow level. Normally, wastewater does not flow uphill, of course.
Rainwater is directed into a separate drainage system. So this only concerns wastewater, and here only from the ground floor.
I have the option to have the prefab house manufacturer prepare the installation of a backflow preventer for the ground floor of the single-family house (there is also a toilet on the upper floor/attic) and then carry out the actual installation myself or have it done externally.
I am not only reluctant because of the high cost of a potentially unnecessary electrically operated and electronically controlled backflow flap but also because of the required maintenance twice a year by a specialist company. Over the financing period of the house, this will cost several times more than the backflow preventer itself, including installation.
Therefore, my question is: If a mechanical flap is sufficient in other developed countries, why shouldn’t it work here as well? I would be willing to disregard the DIN standard if the practical risk involved is negligible.
I look forward to your expert opinions.
Best regards
Stefan
T
Traumfaenger25 Jul 2019 23:02aviator schrieb:
A purely mechanical flap that is normally open and therefore supposed to be suitable for sewage. (even though it is not allowed according to DIN standards in Germany....)Nice patent, but it doesn’t help. In case of damage, insurance won’t pay because it’s not compliant with DIN standards. We also tried to buy a mechanical flap, but it was not available on the market. Here in Germany, only electronically controlled flaps are sold. Additionally, at least in our area, during heavy rain the water company distributes the water volume throughout the entire sewer system. This can lead to full sewers even in residential areas without flood risk. Considering the unusual weather patterns in recent years, I find having a safety margin quite reasonable. We installed it voluntarily; according to the expert assessor, it wasn’t strictly required. But of course, you can also do it like the railway:Quote from WDR today: "When acquiring air conditioning systems for the ICE trains, the railway made mistakes in the past.
“The former railway CEO Mehdorn believed that temperatures in Germany would not fall below minus 7 degrees Celsius (19°F) and not exceed 26 degrees Celsius (79°F) — with a maximum of only about 30 degrees Celsius (86°F).” The railway has recognized the problem and is in the process of upgrading — but the transition is taking time."
I imagine retrofitting an electronic backflow valve with a maintenance shaft and piping, etc., is much more complicated than installing it during new construction from the start.
Hello Dreamcatcher,
thank you for your post.
My concern is explicitly not about insurance. If the backwater valve works as it should, I will not have an insurance claim. I am willing to accept the minimal residual risk and don’t have an all-inclusive coverage mentality.
By the way: I just found out that even the company Kessel states in their English brochure (of course not in the German one) that the mechanical flap Staufix SWA is also suitable for sewage (with the note to check the regulations in the respective country).
I get the impression that here in Germany or the EU, something unnecessarily complicated and expensive is being imposed on us. And fear of sewage backing up into the house is obviously a good way to make money. The manufacturers must have done good amateur work in creating the applicable DIN standards...
Regarding the weather: rainwater is completely separated here, and there is no risk of backflow into the house. My concern is only about wastewater from the ground floor.
Regards
Stefan
thank you for your post.
My concern is explicitly not about insurance. If the backwater valve works as it should, I will not have an insurance claim. I am willing to accept the minimal residual risk and don’t have an all-inclusive coverage mentality.
By the way: I just found out that even the company Kessel states in their English brochure (of course not in the German one) that the mechanical flap Staufix SWA is also suitable for sewage (with the note to check the regulations in the respective country).
I get the impression that here in Germany or the EU, something unnecessarily complicated and expensive is being imposed on us. And fear of sewage backing up into the house is obviously a good way to make money. The manufacturers must have done good amateur work in creating the applicable DIN standards...
Regarding the weather: rainwater is completely separated here, and there is no risk of backflow into the house. My concern is only about wastewater from the ground floor.
Regards
Stefan
Bookstar schrieb:
You can question that throughout the entire house construction. Even the energy saving regulations prescribe many things, and so on. Pressure switches for stoves that don’t really help, and so on.
Either you follow the regulations or you don’t.That’s probably true. At least I agree with your first paragraph. However, when it comes to backflow prevention, I find it really hard to just accept the expensive solution simply because the DIN standard requires it, especially when boilers in other markets specify something different…
Stefan
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