For the record ADR requirements (ADR 2007 Part 7 Annex B Chapter
are:
One portable fire ext with minimum capacity for A,B & C type fires in the cab. i.e. 2Kg ABC Dry Powder;
Vehicles with permissable mass of more than 7.5 tonnes- a minimum of 12Kg ABC- including cab provision, one of which must be a 6Kg size;
Vehicles wit total capacity of 3.5 to maximum of 7.5 tonnes is 8Kg ABC - including cab provision - one of which must be a 6Kg size;
Ditto the above max 3.5 tonnes is 4Kg ABC type extinguisher.
Must meet EN3 Parts 1 to 6. So it is not the BS (British Standard) part of the UK's BSEN3 that is the ADR recognised compliance requirement i.e. European Area, although obviously any kit bought in this country must be compliant with BSEN3, whereas our European brothers will have EN3.
As for servicing of these many on these pages will have experience of the wonderful quality of some of the extinguisher boxes out there i.e. seals and fitting. If they are not completely watertight, box seals replaced regularly and boxes fitted very, very well, the extinguishers will be condemned in a very short period of time regardless of manufacturer. The continuous vibrating also damages the extinguishers if they are not fitted correctly within the box.
So as for parts falling of the extinguisher, that really is nothing new. Some very strange things are also stored in these boxes!