nuuvox000
Mechanical
- Sep 17, 2019
- 344
I have a project for a commercial office building where they want to add a bunch of flush valve toilets and other plumbing fixtures without upsizing the pipe outside of the building. I have concluded that the 2" size will have issues with the added fixtures due to high velocities. Due to the circumstances, upsizing the service line to the building would be very cost-prohibitive.
My plan is to add a "drawdown" hydropneumatic expansion tank that will serve as a pressure and volume reservoir that can fill up slowly with the small building pipe and then provide volume and pressure to run the new flush valve toilets with a larger outlet pipe.
Just some numbers for context:
2" line serves the building
Adding 12 flush valve water closets (1.1 gpf)
Adding 12 lavatories (0.5 gpm)
Adding 4 kitchen sinks (1.5 gpm)
Planned expansion tank is 211 gallons in the penthouse of the 5-story building. I've confirmed that there will be about 55 psi of pressure at the tank. I've sized it so that we can get 60 gallons out of it before the pressure drops to 35 psi (code minimum).
Does anyone have any other thoughts or tips about this? I've wondered about adding a pressure independent control valve to make sure it doesn't pull too much water from the main building pipe but I know that those are typically made for hydronic applications and I'm unsure if it would actually be needed. Let me know what you think; thanks!
Edit: I'm having a hard time finding the right forum for plumbing questions so let me know if there's a better place for this.
My plan is to add a "drawdown" hydropneumatic expansion tank that will serve as a pressure and volume reservoir that can fill up slowly with the small building pipe and then provide volume and pressure to run the new flush valve toilets with a larger outlet pipe.
Just some numbers for context:
2" line serves the building
Adding 12 flush valve water closets (1.1 gpf)
Adding 12 lavatories (0.5 gpm)
Adding 4 kitchen sinks (1.5 gpm)
Planned expansion tank is 211 gallons in the penthouse of the 5-story building. I've confirmed that there will be about 55 psi of pressure at the tank. I've sized it so that we can get 60 gallons out of it before the pressure drops to 35 psi (code minimum).
Does anyone have any other thoughts or tips about this? I've wondered about adding a pressure independent control valve to make sure it doesn't pull too much water from the main building pipe but I know that those are typically made for hydronic applications and I'm unsure if it would actually be needed. Let me know what you think; thanks!
Edit: I'm having a hard time finding the right forum for plumbing questions so let me know if there's a better place for this.