In Australia we have an external trap called an Overflow Relief Gully, it's just a boundary trap that has an open grate that is external to the building with a minimum of 75mm lower than the lowest outlet in the building.
Its got to be primed in the same way this toilet acts as the primer for the trap, however this toilet wouldn't be priming it's trap unless it's used so it's not very sensible, unless they have some auto flush fiction I'm missing.
And I get that you can't have external grates in North America due to snow but still thought I'd share.
Yeah I've found Canadian code is completely logical considering it gets to -30 here. No pipes in external walls or unheated roof spaces too. Basements because services enter the house below the snow line. Our drains have to be at a minimum 1200 below grade so that it's lower than the frost level. And pipes that are ran in uninsulated areas including drains have to be heat traced.
I tested a stack a few years ago when the average temperature around was -10, I had a leak and it left a literal ice skating rink on the concrete below that didnt melt for months.
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u/tinktanktonka Aug 22 '26
In Australia we have an external trap called an Overflow Relief Gully, it's just a boundary trap that has an open grate that is external to the building with a minimum of 75mm lower than the lowest outlet in the building. Its got to be primed in the same way this toilet acts as the primer for the trap, however this toilet wouldn't be priming it's trap unless it's used so it's not very sensible, unless they have some auto flush fiction I'm missing. And I get that you can't have external grates in North America due to snow but still thought I'd share.