Then you will also know that most commercial roofs are “flat roofs” to hold and sustain the weight of water so it would be no difference in this case ... also look at the three 7-ton a/c units I have above me on my restaurant roof that may say otherwise too. When they built the building they didn’t know where a/c’s were going ... but they know the multiple steel I beams that create the structure of the building can hold the roof all in the proper load bearing places.
here where i live we just had a super market roof colapse in with 5 inches of snow so i dont think they would just let people put them up on buildings period