Noncomposite and composite joists have similar vibration characteristics. Attachment of the steel deck to the supporting steel joists via self-drilling screws, pneumatic driven pins, or puddle welds provides composite action between the steel joist and concrete slab when the floor is subjected to human excitation. When calculating the vibration properties for a noncomposite joist per SJI’s Technical Digest No. 5 Vibration of Steel Joist – Concrete Floor Slabs, you assume the joists act compositely.