What is a natural gas tightness test

A natural gas tightness test is a technical inspection used to verify whether a specific section of an installation holds gas without leaks under defined test conditions. It covers piping, joints, valves, and any components included in the examined section. The precise scope of the inspection must be recorded so that it is clear what was tested and what was excluded.

An installation may appear to operate normally and yet show a minor leak at a connection or component. The absence of an odor does not certify safety, and a visual inspection alone does not prove tightness.

A distinction must also be made between a strength test, which examines the mechanical behavior of the piping, and a tightness test, which checks for potential losses. These are not identical procedures. A new installation may require different tests than a periodic re-inspection of an existing network.

The inspection must be assigned to a licensed professional with the appropriate authorization. This is not a task for a user to perform with a simple pressure gauge or a household gas detector.

When it is required and how often it is repeated

Tightness is tested before the initial commissioning of an installation, according to the prescribed procedure. A new test is also required after any interventions that affect tightness, such as replacing a pipe section, changing a valve, or modifying the network.

For standard internal natural gas installations subject to the Greek technical regulation of up to 500 mbar, a periodic tightness test is required every four years. The application of this interval and the required documentation must be confirmed by the competent licensed professional based on the current regulation, the category of the installation, and the requirements of the network operator. Special or industrial installations should not be automatically treated like a residential property.

The four-year interval does not mean that one should ignore signs of a problem until the next scheduled inspection. An additional check is needed when there is a suspicion of a leak, damage, corrosion, or external stress. After long periods of inactivity or supply disruption, the technician must evaluate the requirements for a safe restart.

  • Keep the date of the last inspection available.
  • Do not confuse boiler maintenance with a test of the entire piping network.
  • Do not wait for the four-year period if an intervention has occurred or if a suspicious odor appears.

How the licensed technician performs the inspection

The process begins with identifying the installation and checking available drawings and previous documents. The technician examines the routing of the pipes, accessible connections, supports, any corrosion, and signs of unauthorized modifications. Simultaneously, they determine which section will be tested and which components require isolation.

Next, safe shutdown and isolation of the section under examination are organized. Appliances, regulators, and other sensitive components are not indiscriminately subjected to test pressure. Work on the meter, seals, or equipment under the jurisdiction of the operator is not performed without the required authorization.

Depending on the type of inspection, the prescribed method is applied using suitable test media and measuring instruments of sufficient accuracy. For scheduled tests, air or inert gas is used; never oxygen. The pressure, stabilization time, and monitoring duration are determined by the applicable regulation and network characteristics, not by general guidelines for all installations.

Before evaluating the readings, thermal stabilization is taken into account. Temperature changes can affect pressure, so a simple reading without proper preparation does not yield a reliable conclusion.

If a problem is detected, an investigation follows using a suitable detector or approved leak detection fluid on accessible points. These tools help in locating the leak but do not automatically replace the required test. After repairs, the necessary inspection is repeated, and the installation is returned to service only if safety requirements are met.

What the documentation must include

A verbal assurance that "everything is fine" is not enough. Request the required inspection document, which should reflect the installation, date, tested section, method, and result, along with the details and signature of the competent professional.

Depending on the procedure, the test medium and pressure, its duration, the measuring instruments, and any observations or corrective works are also recorded. If any section was excluded, this must be clearly stated, and the inspection should not be presented as a certification of the entire installation.

Keep the document along with the study, drawings, previous protocols, and maintenance records. In an apartment building, a clear distinction between the common network and individual supply lines is necessary so that no sections are left without scheduled inspections.

The combustion analysis report does not replace the tightness document. Boiler maintenance addresses a different subject, such as appliance operation, combustion, and related safety devices. Both tasks can be coordinated but must be requested and documented separately.

What to do if you smell natural gas

A characteristic gas odor should be treated as a potential leak. Do not attempt to confirm the problem with a flame, by loosening connections, or via improvised testing. Do not activate or deactivate electrical switches, exhaust fans, or other appliances, and do not use a phone within the suspected area.

  • Evacuate people from the area without delay and without using the elevator.
  • If possible to do so immediately and safely, manually open doors and windows for natural ventilation.
  • Close the accessible valve only if you can do so safely, without approaching the suspected leak.
  • From a safe outdoor location, contact the network operator's emergency service. In case of immediate danger, call 112.

In the event of a strong odor, hissing noise, or feeling unwell, immediate evacuation is the priority. Do not return to ventilate or close valves. The supply should not be restored simply because the smell is no longer perceived, but only after the proper inspection is completed and authorization for safe operation is granted.

Frequently Asked Questions

Does the annual boiler maintenance cover tightness?

Not automatically. It may include specific checks on the appliance, but it does not prove that the entire internal installation was tested. Confirm the scope of work and request the corresponding documentation.

How long does the tightness test take?

There is no single duration for all cases. It depends on the volume and layout of the network, the method, stabilization, and accessibility. If leak detection and repair are needed, additional time is required.

Is a household natural gas detector enough?

No. The detector can provide additional warning if correctly selected and installed. It does not certify the tightness of the piping nor does it replace the periodic professional inspection.

Is an inspection needed when I change a gas appliance?

The connections and parts affected by the replacement must be tested before operation. The licensed technician determines the required extent of the inspection and any additional procedures based on the modification.