California Code, Health and Safety Code - HSC § 13175.1

The provisions of this article shall not apply to any person servicing, charging, or testing any portable fire extinguisher owned by such person when the portable fire extinguisher is not required by any statute, regulation, or ordinance, to be provided or installed.

The provisions of this section shall not prohibit the servicing, charging, or testing of portable fire extinguishers by new employees of a licensed person for a period not to exceed 90 days provided such servicing, charging or testing is conducted in the presence of and under the direct supervision of a natural person holding a valid certificate of registration.