All certificates under this division shall be in effect until December 31 of even-numbered
years and may thereafter be renewed biennially by payment to the building official
of a renewal fee shown in section 8-172.1(a) and submission of 12 clock hours of continuing education of a type satisfactory
to the building official. All certificates, which are nontransferable, must be registered
with the building official not later than January 10 of the year following expiration
or they will become void, and it is hereby made the duty of each mechanical contractor
to see that each master, journeyman and apprentice working for him has been registered.