For a simple upgrade add top and bottom covers, a rear panel, and a few gaskets to ensure good electrical and mechanical contact between adjacent surfaces. These components are readily available from stock and Rittal have a 20 strong sales team who can assist customers with the selection.
Of course if you want to ensure full protection from the beginning, the Ripac Vario EMC subracks are also available on short lead times, along with EMC front and rear panels and a wide range of useful accessories.