Referencing information is a method of accessing data that may be located elsewhere. On websites we use Hyperlinks to inform that there is more information elsewhere. On site, we can use bar & QR codes. These tools can link us to other data that may be relevant to the job in hand. This is not particularly sexy, but very practical.
All mobile smartphones and tablets can download free bar code and QR code readers, so the tool is readily available.
Bar codes are linear in nature. I have a preference for the Bar code and text beneath the bar code (in case these is wear or partially obscured code, then you can type the code in). Its also a check that the correct bar code has been put in the right place.
QR codes, due to their Area or 2D nature, can hold a lot more data. So you have the option of having a hyperlink to data on the internet, in which case you need to ensure that the device has access to the internet, or you embed a lot more data into the QR code so that all the data is readily available on site (this then has an updating issue if things change) or you could have a dual method that has data on site and a cross check on the web.
Note, the QR codes may take you to another older website with the same information
Room Data Sheets. Link
Map index. Link
To Panorama. Link
QR codes can be placed in the property, say in door frames, so people visiting the property can scan the QR code to be taken to page relevant to specific information. You could put reference to Map of site with buildings with links or to all the information of the building or specific Room Data Sheet download or Photo Panorama of Room.