In this particular case, the Chapter 4 FBC-Building requirements should take precedent over the plumbing code. Aside from being (slightly) more stringent, Chapter 4 is also more specific since it explicitly addresses public food service establishments, whereas the plumbing code merely refers to "structures or tenant spaces." The Dept. of Agriculture regulates food establishments (i.e. food processing, packing, preparing, etc.) and DBPR regulates public food service establishments where food is actually served to the public. Please see the attached commentary to understand how this conclusion is reached.