Fire extinguishing installations and equipment on premises - Commissioning and maintenance of portable fire extinguishers. Code of practice BS 5306-3 details best practices in how to install and maintain portable fire extinguishers. BS 5306-3 puts the responsibility on businesses to use a competent person to perform the annual inspections, install, commission (skilled checks made to the extinguisher on-site), service, and test discharge fire extinguishers. They should also replace extinguishers that are no longer usable with serviceable extinguishers.