Good evening ladies and gentlemen and greetings to you all.
Let's start from the beginning - I am a laundry manager in a hotel and recently have had new laundry equipment installed - 2x 45kg Washers and Driers. Along with the washers, I wanted my drain to be replaced, but it caused some delays with the project approval and additions to it.
While it is absolutely not my cup of tea, I am interested in calculating the drainage requirements for my laundry to be able get a clear picture and future proof it and not be ripped off at the same time.
So, currently I have a 7 meter long runoff/troth open top glass fiber lined square shaped drain that leads to the main drain point. The main drain is a 4inch drain in the floor that is connected to the main hot water drain point, that leads to the pumping station. Currently it is leaking and it needs to be a sealed unit.
My understanding is, that the troth has been designed as a holding tank/sump type device to hold the overspill from the machines because the 4inch drain cannot handle the waste water output from the washers.
Currently, the new machines drain at a rate of 160l/minute each, which makes it 320l/minute combined. I have another small washer of 10kg capacity and a water softener that drain in to the troth, for which I need to account for.
My understanding is that a 4inch diameter bottom drain can handle a maximum of 272l/minute (taken the info from a fishing pond forum, as a pump assisted bottom drain). This is where the issue kicks in as even with simple maths, this will cause a problem.
The current suggestion is to install a 6 inch cast iron pipe that will lead to the 4inch drain. When calculating the internal volume of a 6 inch diameter 7 meter long cylinder, it comes to 123.7L;
My understanding is, that the pipe cannot be full to the brim either, that will cause drain errors on my machines, so, if I do quick calculation that the pipe can be 50% full, which is 61,85L, it leads me to believe, that there is not much playing space.
I do not know the Velocity of the output water, which is another issue in the calculations.
Can somebody enlighten me on my issue, please? If i need to go to a physicists/mathematicians forum, please direct me that way.
To avoid questions - I cannot use PVC due to two factors:
1) midway of the 7m the 10kg washer joins in that dumps 90degC water fairly often during the day;
2) The large washers are disinfecting with O3, hence the sealed unit and O3 will corrode the pvc (?) hence teflon/cast iron has to be used;
Thanks,
Netbeast
Let's start from the beginning - I am a laundry manager in a hotel and recently have had new laundry equipment installed - 2x 45kg Washers and Driers. Along with the washers, I wanted my drain to be replaced, but it caused some delays with the project approval and additions to it.
While it is absolutely not my cup of tea, I am interested in calculating the drainage requirements for my laundry to be able get a clear picture and future proof it and not be ripped off at the same time.
So, currently I have a 7 meter long runoff/troth open top glass fiber lined square shaped drain that leads to the main drain point. The main drain is a 4inch drain in the floor that is connected to the main hot water drain point, that leads to the pumping station. Currently it is leaking and it needs to be a sealed unit.
My understanding is, that the troth has been designed as a holding tank/sump type device to hold the overspill from the machines because the 4inch drain cannot handle the waste water output from the washers.
Currently, the new machines drain at a rate of 160l/minute each, which makes it 320l/minute combined. I have another small washer of 10kg capacity and a water softener that drain in to the troth, for which I need to account for.
My understanding is that a 4inch diameter bottom drain can handle a maximum of 272l/minute (taken the info from a fishing pond forum, as a pump assisted bottom drain). This is where the issue kicks in as even with simple maths, this will cause a problem.
The current suggestion is to install a 6 inch cast iron pipe that will lead to the 4inch drain. When calculating the internal volume of a 6 inch diameter 7 meter long cylinder, it comes to 123.7L;
My understanding is, that the pipe cannot be full to the brim either, that will cause drain errors on my machines, so, if I do quick calculation that the pipe can be 50% full, which is 61,85L, it leads me to believe, that there is not much playing space.
I do not know the Velocity of the output water, which is another issue in the calculations.
Can somebody enlighten me on my issue, please? If i need to go to a physicists/mathematicians forum, please direct me that way.
To avoid questions - I cannot use PVC due to two factors:
1) midway of the 7m the 10kg washer joins in that dumps 90degC water fairly often during the day;
2) The large washers are disinfecting with O3, hence the sealed unit and O3 will corrode the pvc (?) hence teflon/cast iron has to be used;
Thanks,
Netbeast
Last edited:
