Here is a picture of the inside of a walk-in cooler. Please note that the pipe is held away from the surface (with mineralacs).

USDA, and most Health Departments, require pipes to be supported in such a manner as to not interfere with cleaning. In practice, this means leaving a pretty good space between the structure and the pipe. You don't want to make a 'pocket' to trap crud.

Also in the pic, note that the alarm guys use set-screw type fittings. This is not an area that gets hosed down, so there probably is no requirement to use compression type fittings. Also, the alarm wires are arguably 'power limited' circuits, with less exacting requirements than power circuits.

- renosteinke