Shutdowns and turnarounds the halls have posted ahead of time, plus outages and projects from public regulator reports (each says where it's from and when it was read). Dates move; the hall's call is what counts.
These post work publicly, but aren't copied here. Tap through to each one.
Each hall's public list, read once in the evening. If a hall's page can't be read, its last good list stays up and says how old it is.