In the event of a smoking area or room not having an external wall with an openable window, fresh air may be introduced from an existing, if any, air supply system. Such existing system must not be used to extract from such area or room (i.e. return air inlets blanked off). An independent extract system must be installed. Building and Ventilation plans must be submitted to the Environmental Health Section for approval – such plans must be endorsed by a registered person as contemplated in terms of the National Building Regulations and Building Standards Act before any work commences).