Trap in slab

Is it permissable, or just a good/bad idea, to have the trap roughed in at an elevation higher than below the slab? In other words the trap would be encased in concrete. My reason for exploring this is to save some elevation.
Thanks,
Gary

trap

To quote Dirty Harry Callahan, "A man's gotta do what he's gotta do." If that is where conditions require that it go, then it goes there, although an inspector might have a problem with it and wonder why it had not been planned so it did not occur there. And if the pipe to the trap is also in the concrete, which it should be under these conditions, then the concrete will probably crack above it.

Good point about the concrete cracking, hadn't thought about that. I'll try to keep it as thick as possible. I'll take it then that it's not entirely rare that pipes run encased for a distance in concrete as opposed to stubbing right through?

pipe

It is rare, because inspectors usually reject it. IF you had to do it, most require that it be enclosed/covered so it is not in direct contact with the concrete.

Thanks for your help hj.