I guess the policy for IRROPS is 8 hours, based on a very recent experience.

I was on DEL-HKG with some ~15-20 colleagues, all in business class...most of us with final destination HKG while maybe 3 TPE, 1-2 PEK, 2 NRT etc. original schedule had the flight arriving at some 6 am so decent connections for all of them. but because of technical problem, the flight was delayed 20 hours and hence we all arrived like 2 am the next day, already completely exhausted. they were then told on arrival in HKG there's no hotel provided for <8 hours for IRROPS and even when it's overnight and CX has no lounges open (all of us were in business class and at least 3-4 of the 6-7 having connections are long time DM).

this was especially bad when they were told in India by some managers that CX would certainly provide hotels in HK in such situation, and they in fact have their assistants in TPE called CX TPE etc as well and was confirmed the same message. but on arrival in HKG, I didn't see this myself but my colleague said, basically one said, "only for 8 hours or above"...then the other echoed, yes, now you "only" have 6 hours...literally just asking these DM flying business class to find a bench in the airport themselves to sleep.

Eventually of course they did fight for it and got it...but was also initially asked to share rooms...