This is in my office building, but not my office specifically, so I've done nothing about it. I have the same issue in my house; however, its the baseboard housing that is 'ticking' in that circumstance and not the piping itself. I plan to remove the screws from the metal baseboard housing, lengthen the holes that the screws go through so that the baseboard housing can expand and contract more freely, and reinstall the screws into the slotted holes.
At my house I know it is the cover because I've isolated the piping from the wall by lifting the finned piping with my hand and I continue to hear the ticking noise.
