Hi there , if you are going to follow the rules cisco would tell you 100 Meters is the limit.
I have in the past gone to 150-200M but you can’t expect to get the full throughput. watch out for the florescent lighting and A/C equipment as this will cause interference. I would suggest that if you need to break the 100M length you could use a small linksys Soho router as a repeater thus theoretically expanding you network by another 100M. I think the max nesting on this 2 -3 devices. you really should be looking at fibre if your going over 200M
thats my 10 cents worth