sink compartment size?

Check these two links. They are pretty typical of different plumbing codes I have seen. Usually the plumbing code will be pretty much what the health officials require.

http://www.cityofsanrafael.org/Asse...+$!26+Grease+Trap+Installation+Guidelines.pdf

http://www.lincoln.ne.gov/city/health/environ/consumer/food/guide/3sinks.pdf

When we started building our trailer the inspector told me there really wasn't a set size that they required. He said be real and put in decent sized sink, but he has approved some very small set ups.
Do yourself a favor and call your health dept and make friends with your inspector. They will help you out in the long run and save on some headaches as well.

General rule is the largest pan/utensil you have in the kitchen must be able to be submerged...some of the best setups I've seen have "small" sinks, but they use disposable pans. Like was said above, check with your inspector.