^^^^What he said. If the (new) CMU is in a public space, bury the box and pipe. In a mechanical or electrical space it's usually on the surface. However, specs and plans über alles, code permitting. If the engineer really did his job, there should be a detail sheet or two with mounting details for all the devices in their various configurations.We ususally find that info in the spec. Last job we did required recessed conduit and boxes in any areas accessible to the public within the building. So called back of house areas were surface mounted.