Section 237. As used in this section and sections 237 to 251, inclusive, the following words shall have the following meanings unless the context requires otherwise:

''Apprentice'' or ''apprentice sheet metal worker'', a person at least 16 years of age who is learning or working at the business of sheet metal work under the direct supervision of a master sheet metal worker or a journeyperson sheet metal worker in the employ of a master.

''Board'', the board of examiners of sheet metal workers, established in section 101 of chapter 13.

''Certificate of a sheet metal corporation, partnership, LLP, LLC or other entity'', a certificate of registration issued by the board to a master sheet metal worker authorizing him to conduct a sheet metal business as a corporation, partnership, LLP, LLC or other such entity, as the case may be.

''Inspector'', the inspector of buildings, building commissioner or other local inspector charged with enforcing the state building code under section 3 of chapter 143.

''Journeyperson'' or ''journeyperson sheet metal worker'', a person who performs sheet metal work or who, through an apprentice in the employ of a master, employs the journeyperson and who has passed an examination and been issued a license as provided in this chapter.

''Master'' or ''master sheet metal worker'', a person having a regular place of business and who, by himself or through journeypersons in his employ, performs sheet metal work, subject to inspection and in compliance with any law, rule or regulation pertaining to sheet metal work. The master sheet metal worker may be in the employ of another master sheet metal worker, but shall not be in the employ of a journeyperson or apprentice.

''Sheet metal work'', the manufacturing, fabrication, assembling, handling, erection, installation, dismantling, alteration and repairing of all commercial duct or air exhaust systems, except for refrigeration and combustion units; installation of commercial fans, sheaves, belt guards, dampers, louvers, screens, registers, grilles, diffusers, sound traps, attenuators, mixing boxes and access doors in connection with duct or air exhaust systems, commercial and industrial architectural sheet metal watershed roof systems, except for roof coverings and associated metal flashing; the testing, adjusting and air-balancing of all air-handling equipment and ductwork installed during new or remodeling construction, the installation of commercial and industrial kitchen hoods, kitchen vents, bathroom exhaust vents and fans; provided, however, that sheet metal work shall not include the work conducted by a licensed pipe fitter, oil burning technician, refrigeration technician, plumber or gasfitter as determined by the laws and regulations relating to those professions; and provided further, that nothing in this section shall be construed to supercede chapters 142 and 146.

''Veteran'', as that term is defined in clause Forty-third of section 7 of chapter 4.