Hi All We currently have our new 40mm kitchen sink waste pipe going under a suspended floor and connecting directly into the main 110mm drain (that then goes to the sewer). This length of 40mm pipe is less than 1.5meters to the main waste pipe. We have been told by building approval that our 40mm kitchen sink drain needs to connect into the 110mm wastepipe at floor level (not under the floor). The suspended floor is about 50cm off the ground. We can't find anything in the Part H building regs that says this is necessary. Any advice would be much appreciated! Thanks!