I am about to install a new bath and sink in new positions in my bathroom. The sink waste will run through a box and meet at a T junction with the bath waste. The pipe will then run off to a waste stack. I didn't think about siphonage until I read the forums on here. Am I likely to get siphon problems? Do I need to fit some kind of anti-siphon device? If so, what are they and where do I fit them?
Also, I am assuming I fit 40mm waste from the bath and 32mm waste from the sink. Is this correct?