210.52 (H) ststes "in dwelling units" etc. It does not specify single family, nor multi-family.
The commentary within the Handbook states "This req. does NOT apply to common hallways of hotels, motels, apartment buildings, condominiums and so on".
Now, if your multi-family is an 'apartment building' you have a reference.
As always, the best idea is to speak to your local AHJ! He/she is the 'man' that has to approve your job.
John
