They are covered by the Pressure Equipment Directive.
Reason:
Portable extinguishers are specifically mentioned in Article 4 paragraph 1 (a)(i) second indent and Annex II, Table 2 of the Pressure Equipment Directive.
All fire extinguishers according UN 1044 are specifically mentioned in special provision 594 of ADR as an exclusion when appropriately packed for transport.
Thus, these fire extinguishers are not covered by the exclusion in Article 1 paragraph 2 (s) of the PED.