BS 5306-3:2017 Fire extinguishing installations and equipment on premises Commissioning and maintenance of portable fire extinguishers. Code of practice

Fire safety in buildings
Portable
Fire extinguishers
Halogenated hydrocarbons
Inspection
Labels
Training
Air pollution
Personnel
Marking
Maintenance
Defects
Firefighting equipment
Fire extinguishers (built-in)
Commissioning
Visual inspection (testing)

Link: BS 5306-3:2017 Fire extinguishing installations and equipment on premises Commissioning and maintenance of portable fire extinguishers. Code of practice
Source: BSI Standards