Turbine vents on a poured concrete roof?

2 story condo - Maintenance insists that there is metal I-beam rafter construction with poured concrete for the roof deck. It is covered w/ tar & gravel roof covering & what is standing out to me is the turbine vents over each unit…

Have you seen turbine vents on this type of construction?

Thank you!

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Yes, often. When you comment on concrete deck it is likely in this scenario it is lightweight concrete deck, very pourous. I look for sleepers under roof top equipment as supporting members etc.