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
Milo3 schrieb:
You can get a mechanical backflow flap at any hardware store or building materials supplier! You need to assess the risk for yourself. Thank you. You’re right. My main concern is to be able to assess the risk as accurately as possible. So far, I have the impression that apart from references to DIN standards and insurance requirements, there doesn’t seem to be any verifiable technical reason why a properly manufactured mechanical flap shouldn’t work reliably, provided it is checked regularly.
aviator schrieb:
...there is no verifiable technical reason why a properly designed mechanical flap should not function safely. Provided it is checked regularly.and that’s exactly where it will likely fail in case of doubt. If something is hanging under the flap, it becomes non-functional during backflow. No manufacturer in Germany wants to take on that risk..