The original post makes no mention of whether these are in a staircase or in the accommodation.
In a staircase
I think kurnal et al have wrapped it up pretty well. I agree about the gas meter and electrical intake but I would add that an assessment is necessary for the electrical installation. A small consumer unit probably doesn't warrant protection but you often see old distribution boards that don't immediately fill you with a sense of trust. These, I would have enclosed.
On the matter of enclosure, note that the cupbpoards created have to be fire resisting from the inside out, not necessarily the other way round. That is, the important thing is to have them completely internally lined and sealed with fire resisting materials. A timber framework with f.r. on the outside is a waste of time.
Having done all that, do you put a detector in the new cupboard? You would if it was a single staircase building and you may for other reasons, that's another issue.
In the accommodation
If the riser cupboard is not in the staircase but in the accommodation then, for some buildings, the minimum required protection to them is nothing at all. If the riser passes from floor to floor in an office building, for example, there is no requirement for compartmentation between floors and, therefore, there is no requirement for risers between floors to be fire resisting. Having said that, it would not be terribly good for property protection or business continuity to allow fire to spread vertically freely within a building and so enclosure is a good idea.
Most buildings other than offices will have compartmentation between floors (and, indeed, most offices have it also (but they don't have to)) and will need the f.r. enclosure around the duct.
The duct does not need enclosure at all if the duct is fire stopped at each compartment floor that it passes through. The problem with this, though, is that the fire stopping often becomes breached over the years by contractors fitting new services and these breaches are easy to ignore and forget about (hidden as they are in cupboards). It is better to have the enclosure round the entire shaft and accept that there may be holes between floors within it.
There have been cases in the past, one being the cause of a large fire in my neck of the woods, where the duct is nicely enclosed at every level but then not continued through the loft space to the roof or not properly capped. Watch out for that or you might have a nice roof fire to explain away.
On the whole, my answer would be that they usually need f.r. enclosures but not always. A good fire safety answer. Yes and no.
Stu
