Internal Installation Verification Process and Meters



Delivery Point: Means the Meter outlet point, and it is the dividing line between the External and Internal Installations

External Installation: Means the entire installation under the responsibility of the competent Operator, lying between the Distribution Network and the Delivery Point to the End Customer, including the metering device.

Internal Installation: Means all piping, appliances, devices, shafts, components, and other related fittings installed from and after the Delivery Point to the exhaust flue exit.

Gas Meter: Means the gas volume metering mechanism, installed by the Operator at the Delivery Point and its exit is the point of Supply and Delivery, i.e. the point where the ownership of the gas is transferred from the supplier to the consumer, indicating the end point of the internal gas installation.

The 'Technical Regulation for Internal Natural Gas Installations with an operating pressure up to 500mbar' (Ministerial Decree N. Δ3/Α/οικ.6598 OGG No 976/Series II/28.03.2012) covers the safe design, safe construction, conversion, testing, initial commissioning and the safe operation and maintenance of gas installations operated by gaseous fuel - natural gas.

As far as internal Natural Gas installations with an operating pressure between 500 mbar and 1 bar are concerned, the provisions of the Regulation published in OGG N. 963/Series II/15.07.2003 continue to apply as of the date of its publication (except for those pertaining to materials and certificates of suitability).

For installations supplied with a pressure greater than 1 bar (mainly for industrial uses), the ‘Regulation for Internal Gas Installations with Operating Pressure of more than 50mbar and up to 16 bar’, as per Ministerial Decree N. Δ3/A/ 5286 OGG 236, is applicable as of 28 March 1997.

Gas Installation File Submission Procedure - Validation of Technical Study

In case of new installations or changes (modifications or expansions) to an existing installation, consumers (or their authorized representative) shall submit to EDA THESS the respective study drawn up by a legally licensed engineer. The study shall include at least the following:

  • a technical description containing, inter alia, details on the materials to be used,

  • calculations,

  • floor plans, isometric layouts, and, if required, section and elevation drawings .

Upon submission of the installation file, EDA THESS will proceed to review and validate the gas installation study within eight working days.

EDA THESS validates design studies on works and installations regarding exclusively the internal natural gas installations.

Technical Report Submission Procedure - Internal Installation Inspection

Before the onset of the works on the gas installation, the consumer shall assign the supervision of works to a Supervising Engineer.

Forty-eight hours prior to the onset of the construction works on internal installations, the consumer must notify the competent local Town Planning Service, which will notify the respective police station (Law 4067/2012).

EDA THESS retains the right to carry out inspections during the construction phase.

All works on the internal gas installation are carried out by licensed technicians and installers in accordance with the applicable legislation.

Following completion of the construction works for the internal natural gas installation, the technical report on the installation drafted by the Supervising Engineer shall be submitted to EDA THESS, to temporarily supply the appliances to be adjusted. This report shall include:

  • A description of the installation, as built.

  • A certificate of compliance with the requirements of the Regulation indicating the works, materials used, and full data of the technical staff who executed the works of the installation.

  • Certificates of the tests and inspections carried out, which will also indicate the results thereof. The tests will also include strength and tightness tests.

  • An Operating and Maintenance Schedule for the entire gas installation.

Temporary supply with gas, is performed after it has been confirmed that the installation complies with the provisions of the technical report on the installation. If any deficiencies or construction defects are identified, temporary gas supply will not be provided until such deficiencies or construction defects are rectified.

Natural Gas File Application Completion - Issue of User License

After temporary gas supply operation, the following supplementary documents to the Technical Report shall be submitted to EDA THESS:

  • A certificate of completion of the installation and adjustment of the gas supply equipment for final gas supply.

  • Inspection sheets for boilers or other gas appliances in accordance with applicable legislation.

After the final inspection of the supplementary technical report documents and verification of the conformity of the entire technical report with applicable legislation and the provisions of the Regulation, the User License for the installation, which also approves the permanent supply of gas, will be issued.

EDA THESS may suspend the temporary provision of natural gas if it finds that the above conditions for the issue of the license are not met.  

 *In case of any matters not specifically referred to, the requirements of the Applicable Legislation and the Technical Regulation shall apply in full. 

 Natural Gas Meters

Meters are installed exclusively by the Operator in accordance with the applicable Technical Regulations. Their dimensions are proportional to the power of the installed devices and the Connection Contract.

The placement of Meters, equipment enclosures and cabinets with the respective openings, where constructed at the responsibility of the End Consumer, must have the specified dimensions indicated. Locking of the equipment enclosure or cabinet must be of the type specified by the Operator.

It is forbidden to apply paint, or to place heavy or bulky objects or corrosive substances around or above the meter, to place electrical installations or devices in the meter cabinets or enclosures, or to modify the enclosure or the cabinet itself.

The natural gas Meter remains at the property of the Operator and the End Consumer is bound to guarantee free access thereto, for as long as the meter remains on their premises, to employees and authorised representatives of the Operator who hold company identification cards, for all types of works, including reading and recording data, inspections, and various technical interventions.

The Operator may place security markings and seals on the Meter as well as on the inlet and outlet valves.