This is FAA stds, look at the tables to see what effect and/or NOTAM language is req'd per system degradation or lighting failure.
FAA Instrument Landing System and Ancillary Electronic Component Configuration
and Performance Requirements
This is interesting:
https://www.brainscape.com/flashcard.../packs/6250776
Another checklist:
http://www.airportsindia.org.in/aai_...chapter_11.pdf
I'm sure that previously there was a table or statement referring to the amount of runway lighting available and then a subsequent increase in required RVR. For example, an aerodrome reports a failure to circuit 1 of 2 and 50% of lights are failed, is this classed as failed or operational?
The difference in RVR or notification of degraded equipment with reason/effect would be in the NOTAM.