Behind the wall there's an air duct roughly 30x30 cm that goes through the whole building starting from the ground floor up to the roof.
It's a passive solution, meaning that it mostly works only when there's some wind outside creating some negative pressure and sucking air out of the apartments. When there's strong wind outside, it's actually very effective, you can even feel the air moving but it's also loud (not that it matters and can't do anything about the noise).
Every apartment below me including mine connects to this air duct with a roughly 15-20 cm wide, 40 cm high and 20-30 cm long rectangular pipe. We are renovating the bathroom and the toilet and in the process we're replacing the wall on which there's the air hole, creating a new, 12x12 hole for the fan.
According to Noctua something similar was already done:
Cabins for simultaneous interpretation often run hot due to small size and acoustic dampening. However, quietness is vital for the interpreters work. One of our clients solved this problem by using our ULN type S12 series fans that produce over 70m³/h of airflow while being almost inaudible at only 8.6dB(A)
The reason I'm picking the Noctua industrial fan is because it would be used in a wet environment and also for longetivity. Sadly an IP67 rated fan is only available with a PWM connector and that's what giving me some trouble.
Just checked the 3-pin industrial fan and it has IP52 rating so that might also work just fine.
So, my options:
NF-F12 iPPC-2000 IP67 PWM
NF-F12 iPPC-2000 3-pin - still might only work with voltage regulation, not with resistance/potentiometer
NF-F12 PWM on 12 V with L.N.A adaptor
all 3 fans above would run ~1500 RPM, 70 CFM/119 m3, 1.6 mmH20 @ 18.8 dB(A)
NF-A12 3-pin 2000 RPM, with L.N.A. adaptor resulting 1700 RPM, 50 CFM/85 m3, 1.65 mmH2O @ 18.8 dB(A)
I would still prefer the iPPC fans as if needed they can be cranked up to max. The easiest solution would be to use a regular fan with a potentiometer/L.N.A adaptor but these fans don't have an IP rating or the performance if needed.
So, my questions:
Did anyone test the iPPC fans with a potentiometer/resistor?
Do I need an IP67 for the bathroom, or IP52/none would be just fine?