Roo – There is one official “who’s responsible document” issued as a Memorandum by the Director General of NSW Land & Property Information, a couple of quasi-official versions by strata industry organisations, and many interpretations of those including the one that you’ve referenced in your post.
The problem is that the authors of most versions, interpretations, and extracts omit to read the Principles underlying the official document, and particularly the one that states that it’s “a guide to assist in determining whether a particular item in a strata scheme is part of an owner’s lot or is common property”.
Now that I’ve gotten that of my chest, it’s important to understand that the Building Codes for Class 2 Buildings, which is the Code used by Councils as the basis for their regulation of the design and construction of multi-unit developments can, whilst allowing for the degree of autonomy permitted to Councils within the Codes, empower them to require that smoke alarms be installed within individual lots as one of the elements of the building’s overall Fire Safety Schedule forming part of their Consent.
Smoke alarms then installed under that Schedule at the time of construction become part of the building’s Fire Safety Certificate, and the correct operation of those and everything else listed on that Certificate such as fire-rated entry doors, hydrants, hose reels, extinguishers, etc is subject to the annual Fire Safety Inspection and Report that Owners Corporation’s commission at their cost.
I hope that clarifies rather than confuses the position that Scotty and I posted earlier, and whilst on the subject of confusion, light fittings on ceilings can be common property is some situations.