License is authority granted by the City and County of Denver to a person, agency or political entity to perform the work authorized by the license. Licenses shall be required for all types of work described in Chapter 1 of the Denver Building Code Amendment Book. Plumbing contractors shall be licensed by the Building Department and shall have a master plumber license issued by the State of Colorado as the licensee or in the full-time employ of the contractor. Electrical contractors registered by the State of Colorado shall also register with the Building Department. Electrical registrants are required to comply with all requirements of this code. Each licensee shall be required to have in his employ a supervisor who holds a Supervisor Certificate of Qualification for that particular license. Licenses are renewed annually.