A Registered Gas Installer (RGI) has a duty of care where a hazard is identified to issue a Notification of Hazard (NOHZ) to the owner/occupier (original white copy). The RGI may decide in the interest of safety to isolate the gas supply to the installation at the gas meter (NOHZ - type C) or part thereof or to any appliance (NOHZ - type B)  if deemed appropriate any isolation shall be as such as to require the use of tools to restore supply.

If isolating the gas at the meter the RGI needs to inform the network operator i.e.Gas Networks Ireland.