Is there any IFC class for swimming pool filter?
IfcFilter with predefined type of WATERFILTER.
If you are on IFC2X3, this is a great example you can use to persuade your team to upgrade 
but if that’s not happening, use IfcFlowTreatmentDevice.
Thank you very much, @Moult. What about the pool bottom drain, skimmer, return device, suction device, and whirlpool device. Are there any specific classe for them?
I don’t know much about pools, but the bottom drain would probably be an IfcWasteTerminal. The skimmer also sounds like an IfcFilter. Can you explain what a return device, suction device and whirlpool device is? At an uneducated guess from the names, suction device might be some form of IfcPump (there are some predefined types for submersible / suction things)? The whirlpool might also be a pump?