It is unlawful for any person, corporation, partnership or firm to engage in the work of repairing or erecting steam boilers, steam kettles, pressure tanks, or steam generators in this state without a valid license as provided under this part. Any violation of this part is a Class C misdemeanor. Each day of such violation constitutes a separate offense. This does not apply to any person repairing such equipment whenever a licensed repair worker cannot be readily obtained, and an emergency exists.