Two different issues?
If you're referring to the 'Alternative C' (sleeving) method in the 2019 AD-B then you just follow the diagram and use a (normally steel) pipe as the sleeve.
If someone is using a Rockwool penetration sealing product, then the installation details should be as in the evidence of fire performance (classification, assessment, test or whatever) and the manufacturer's installation instructions.
uPVC pipes typically need (unless they're <40mm dia) the intumescent collars / sleeves to crush them closed - I've not seen any evidence that a sleeve alone can maintain fire resistance. That doesn't mean it doesn't exist of course - just that I've not seen it!
Fishy - Yes, 'Alternative C' is the one. You could just follow the diagram but we know where following the 'guidance' gets us; combustible cladding?
Seems counter intuitive that we can allow a 160 mm diameter 'hole' through a compartment wall in a building with progressive horizontal evacuation for example.
I must admit it's not a detail one sees very often, doesn't fill me with warm fuzzy feelings, especially when there is no detail for independent support of the sleeve.
The Rockwool sleeve detail is an interesting one. I have questioned them for further supporting information on the fire barrier system (this the chicken wire reinforced mineral wool curtain). I have been given a fire assessment from Warrington fire referencing previous tests, the only mention of penetrations is a test with steel pipes ? and yet there detail says you simply wrap your plastic pipe with a rockwool sleeve for 1 meter either side of the curtain (bearing in mind that this isn't just a cavity barrier but it quoted as being suitable for extending fire resistant construction above ceilings). When I asked about how the sleeved pipe should be supported I was told 'that's up to the builder'
