Section 3R. At least one of the doors of the main common entryway into every apartment house having more than three apartments shall be so designed or equipped as to close and lock automatically with a lock, including a lock with an electrically-operated striker mechanism, a self-closing door and associated equipment, and such lock, door or equipment shall be of a type approved by the state board of building regulations and standards. Every door of the main common entryway and every exterior door into every such apartment house, other than the door of such main common entryway which is equipped as provided in the preceding sentence, shall be equipped with a lock of a type approved by said state board of building regulations and standards; provided, however, that the said board may, in writing, waive any of the requirements of this section in appropriate cases in which, in its opinion, other security measures are in force which adequately protect the residents of such apartment house. Whoever, being in control of such premises, willfully and knowingly violates the provisions of this section shall be punished by a fine of not more than five hundred dollars.
This section shall not apply to lodging houses, as defined in section twenty-two of chapter one hundred and forty, dormitories of charitable, educational or philanthropic institutions, or projects of housing authorities, as defined in chapter one hundred and twenty-one B.