Section 50. For the purposes of the classification authorized by section forty-five the words laborers, workmen and mechanics shall have the same meaning as in sections thirty to thirty-six, inclusive, of chapter one hundred and forty-nine; and sections forty-five to forty-nine, inclusive, of this chapter shall not be construed as placing state employees outside the civil service laws, rules and regulations, nor shall the classification aforesaid take precedence over any rulings of the office of public safety and inspections of the division of professional licensure, of the department of fire services, of the board of boiler rules, or of the state examiners of electricians, regarding the construction, care and operation of boilers, engines and other apparatus which may be under the charge of such laborers, workmen and mechanics.