Replacing a bidet with a "pedestal" sink

[Phil Parsons]

I'm looking at replacing a bidet with a "pedestal" sink, quoted because the base is large enough to surround all plumbing and is a stand-alone unit. The bidet was never actually installed, but all plumbing is through the floor. A correct bidet plumbing would have the p-trap below the floor, but I've seen suggestions that the maximum allowed drop from the sink to a p-trap is 24", although I've seen other jurisdictions modify code to permit this type of retrofit. It's not possible (easily) to relocate the existing plumbing.

 

[Terry]

It seems that Canada still uses S-traps for some fixtures. I guess if it fits, it's an option.

 

[Sponsor]

 

[Phil Parsons]

It seems that Canada still uses S-traps for some fixtures. I guess if it fits, it's an option.

An S-trap was my first thought to slow the velocity until I started investigating any side affects of double trapping. A pure S-trap I would not use, too risky, but I might go for an additional P-trap vented which would end up being a vented S-trap.

 

[hj]

A 'thru the roof" vent would do that, but NOT an AAV at the trap.

 

[Terry]

Wait..........is there a p-trap below the floor already?

 

[Phil Parsons]

Wait..........is there a p-trap below the floor already?

Yes, I guess my OP wasn't clear on that. My concern is the vertical drop from the sink to the p-trap below floor would be over 24", and potentially create enough force to flush the trap

 

[Reach4]

Canada allows traps below the floor. The allowed drop before the trap is bigger than US codes. I remember a scan of Canadian code that allowed more than a meter drop to the trap for a kitchen island.

 

[Phil Parsons]

It seems that Canada still uses S-traps for some fixtures. I guess if it fits, it's an option.

Unfortunately not, S-trap is not allowed anywhere except for an "S-trap standard". It took a lot of digging to find out that "trap standard" refers to "the trap for a fixture that is integral with the support for the fixture", such as a toilet.

 

[Phil Parsons]

I found the answer. Section A-2.4.9.3.(2) of the Canadian Plumbing Code (2015) illustrates:

The current installation does not have a CleanOut as indicated on the underfloor part, but adding one to the vertical would be a piece of cake. 1.2 metres from the base of the sink to the trap weir is just over 47", plenty of space for a pedestal sink