It's very difficult as there is no standard identification method - whilst several manufacturer's use pink dye, some use green or blue and I've found some that are yellow just like non FR foams.

Whilst not infallible from the different manufacturer evidence I've seen over the years if it's aerosol can type expanding foam then generally if it's being used for anything other than very small linear gaps (not penetrations to said gaps) and narrow gaps to door frames (often capped to 10mm with mastic) then there's a very good chance it is an incorrect use that will fail spectacularly early (as graphically illustrated in the ASFP video).

Gun applied cartridge single & 2 pack non aerosol 'foams' such as specialist products from Hilti, Mulcol and others generally have a much wider scope of use including service penetrations and much larger holes and visually look quite different.

My question had its roots in an ambiguous requirement for protected escape routes in BS7671A2 2022. However, a corrigendum was released by IET just this month to clarify the situation. All now reasonably clear.

The principle is simple enough

Resi care - operator acts loco parentis (I may have spelt this wrong) - eg the care home operator is directly responsible for the residents like parents are for their kids.
A such the staff should have a plan to evacuate the residents as appropriate - fire service rescue is the back up when that doesn't work

Specialised housing - people live under their own steam (kind of) and nobody is responsible for looking after them 24/7.
If they cant evacuate themselves, then they need to be rescued.

It gets a bit muddy around the edges cos people play silly beggars

A two-storey block of flats recently built (but no certain date) has 5 flats per floor. Single direction travel distance from the furthest flat entrance door is circa 36m (18m/floor). FEDs are FD30s. There is no protection to the stair and a manually openable window. A communal alarm is provided for reasons unknown.

AD B 2019 differs from the 2013 version but says (I?ve deleted non-relevant bits):

Flats with upper storeys a maximum of 4.5m above ground level
3.14 The internal arrangement of single storey flats should comply with paragraphs 3.15 to 3.17. (They all have escape windows). And: A flat accessed via the common parts of the building should also comply with the provisions for small single stair buildings in paragraph 3.28 and Diagram 3.9. A protected entrance hall may be required as a result.

Means of escape in the common parts of flats
3.25 The following paragraphs deal with means of escape from the entrance doors of flats to a final exit. They do not apply to flats with a top storey that is a maximum of 4.5m above ground level (designed in accordance with paragraphs 3.16 and 3.17).

Small single stair buildings
3.28 For some low-rise buildings, the use of a single stair, protected in accordance with Diagram 3.9, may be permitted where all of the following apply (they do).

So, paragraph 3.14 says the flats should comply with paragraph 3.28, but paragraph 3.25 says they don?t need to. (It would help if it said which paragraphs don?t apply.)

The 2013 version is worded differently but stated that the small single stair paragraph doesn?t apply in this case.

Any advice would be welcome regarding whether the block should comply with Diagram 3.9 as it clearly doesn?t.

Both Government risk assessment guides (small purpose built flats & purpose  built flats in general) indicate minimum expectations.