Space problem fitting a sink trap

[Rogercranstoun]

I've a 'space' problem fitting a trap to a 2 bowl sink.

I want to run the waste into a stack pipe situated in my garage, the floor of which is some 15 inches higher than the kitchen floor. As a result, I only have a gap of some 6 inches from the underside of the sink waste/overflow fitting to the base of the 7 foot pipe run at the sink end if I work to a 1-in-80 drop.

I had planned to fit Wirquin's espace extra flat bottle trap which accommodates an also necessary appliance plug as well as both bowls, but have now discovered regulations require the trap to be 75mm when fed into the soil stack.

Does anyone know of a piece of kit or another solution to my problem?

 

[TicklyT]

The depth of the water seal in a trap makes no difference to the height of the trap outlet. All that changes is the size of the trap bottle, or the depth of the 'U' bend linking the trap inlet and outlet. The trap inlet and outlet remain in the same relative positions.

 

[Rogercranstoun]

Thanks Ticky T: however, I'm confused.

My understanding of the regs is that the 75mm trap depth is specified to prevent the water being drawn out by wc flushing within the stack, and that the very flat bottle trap is only permitted where there is an air break prior to entering the soil pipe.

 

[TicklyT]

A trap is just a simple 'U' tube full of water, so the outlet has to be as near the top as the designer thinks he can put it. If he moved it down the side in proportion to the depth of the trap, the deeper water seal he is trying to create would just drain away through the lowered outlet.