What plumbing traps meet code?

P-traps meet code, but S-traps, crown-vented traps, bell traps, and drum traps don’t because they more easily clog or can siphon out the water barrier that prevents sewer gasses from entering your building. See here for images of the olden-days traps, once commonly installed, that fail to work properly over time. Grease interceptors are required for commercial kitchens. --Michael Ermann, Amber Book creator