How Separate Are Duplexes, Triplexes, and Quads Really?

[Daniel Milde]

Hi Folks! I am new to the real estate investing game and have settled on house-hacking/ live in land-lording. Many of the properties I am considering in my area are older homes that have been converted to multifamily at some point in time (i.e. old victorians that are now up-down duplexes).  My question is slightly unusual in the multi-family realm, but concerns how well separated the units are.  From my research it seems that homes built after 1980 or so are supposed to adhere to stricter guidelines for fumes, fireproofing, noise-proofing, etc. when separating small multifamily units. Homes older than this are supposedly grandfathered in, but may not be as separate as newer homes. 

I have pet parrots who are incredibly sensitive to the toxic fumes given off from cooking teflon pans, and am concerned that the ventilation in certain homes may bring my tenants fumes into my own living space. Is this a legitimate concern when considering older small multi-family investments or am I worrying for nothing? I have lived in apartment complexes before and have had no issues with fumes, but I am wondering if duplexes/triplexes/quads are held to different building standards than apartment complexes. 

 If anyone could provide some insight into what it's been like sharing walls/ceilings with your tenants I would greatly appreciate it!