Does anybody know what, if any, clearance requirements are necessary around buss ducts. We have one that runs along a walkway and I want to mark the flooring for aisle space and safety.

It depends somewhat on the voltage of the busduct. For systems that operate at 600v or less use NEC article 110 section II, for greater than 600v use NEC 110 sectin III. Hope this helps.

So it does fall under the same requirements as all other electrical. My next question is can the required working space be in an aisle or do they need to be seperate from eachother. If I were to come three feet from the front of the bus duct to "gaurd" the area it will not leave enough walking space in the hallway where it is running through.

We have always based it on the same principles as other electrical equipment. The working space can in combination with the aisleways. You might want to, however, check with the local AHJ, (electrical inspector), to get his approval.