Technical Inspection of Vehicles Equipped with LPG and CNG Systems — What You Need to Know

In recent years, the number of vehicles equipped with liquefied petroleum gas (LPG) and compressed natural gas (CNG) systems in Georgia has increased significantly. Some vehicles are factory-equipped with gas systems, while in most cases, an LPG or CNG system is installed later as an additional fuel system.

The presence of a gas-fuel system also involves certain additional requirements during The periodic technical inspection. In practice, most questions arise around these requirements: What documents are required? When is it mandatory to present a gas-fuel system inspection certificate? How should the fuel type be indicated on the vehicle registration certificate? What is checked during the inspection, and in which cases may a vehicle fail to receive a positive inspection result?

In this article, we will discuss in detail all the key requirements related to the periodic technical inspection of vehicles equipped with LPG and CNG systems. You will also find practical recommendations to help you properly prepare your vehicle for inspection and avoid the most common deficiencies.

What You Need to Know Before the Technical Inspection — Required Documents and Requirements
Before presenting a vehicle equipped with an LPG or CNG system for periodic technical inspection, it is important to check several things in advance. To ensure that the inspection process goes smoothly, make sure that both the documentation related to the gas system and the vehicle's registration details are in order.

Gas-Cylinder System Certificate
Let us start with the document that vehicle owners most frequently have questions about - the gas-cylinder system inspection certificate.
To obtain the certificate, the gas system installed in the vehicle must be inspected at an accredited inspection center, where its technical condition, safety, and compliance with the applicable requirements are assessed. If the inspection is successfully completed, a gas-cylinder system inspection certificate is issued, confirming that the system is safe for use and meets the established requirements.
The certificate and the blue identification plate attached to it must be presented by the vehicle owner at the inspection center during the periodic technical inspection.
Please note that the certificate is issued for a specific period of validity. Therefore, before bringing the vehicle for technical inspection, it is recommended to check the certificate's expiry date and make sure that the document is still valid.

Indicating the Fuel Type on the Vehicle Registration Certificate

You should also pay attention to the vehicle's registration certificate (vehicle registration document). The fuel type must be correctly indicated - for example, "Petrol/Gas." If this information is not included in the registration records, you will need to update it through the Service Agency.

What Happens If I Cannot Present the Gas-Cylinder System Certificate?

If a gas-cylinder system is installed on the vehicle, but the relevant certificate cannot be presented during the inspection, the vehicle can still undergo periodic technical inspection. However, in this case, the non-compliance will be recorded in the inspection report, and the vehicle will be assigned a failed status. After correcting the deficiency and getting the required documentation in order, the vehicle must be presented for re-inspection, where it will receive a positive inspection result upon confirmation of compliance with the requirements.

If the Gas-Cylinder System Is Removed from the Vehicle, Is It Necessary to Update the Registration Certificate (Vehicle Registration Document)?
Yes. After the complete removal of the gas-cylinder system from the vehicle, the registration details must be brought into compliance, and the information related to the fuel type must be updated through the Service Agency. During the inspection, the information indicated on the vehicle's registration certificate must fully correspond to its actual technical condition.

How do vehicles equipped with LPG and CNG systems undergo inspection?
Periodic technical inspection of vehicles equipped with LPG and CNG systems is carried out in accordance with the same basic requirements that apply to other motor vehicles. The only difference is that, due to the presence of a gas-cylinder system, the relevant documentation and the safety of the system itself are additionally checked.
The inspector checks the validity of the Gas-Cylinder System Inspection Certificate and compares the information provided in the certificate with the vehicle and the installed gas cylinder. A special gas detector is also used to check whether there is any gas leakage from the system.

If a vehicle runs on both petrol and gas, which fuel type is used to test exhaust emissions (CO)?
For a vehicle that was originally manufactured to run on petrol and was later equipped with an LPG or CNG system, the exhaust emissions are tested based on the fuel type specified by the vehicle manufacturer and the applicable standards.
This means that regardless of whether the vehicle owner primarily uses the additionally installed gas system for everyday driving, during the periodic technical inspection, the CO (carbon monoxide) level is checked in accordance with the requirements applicable to the engine and fuel type specified by the vehicle manufacturer.

Specific Features of the Technical Inspection of Factory-Fitted Gas-Powered Vehicles:

If a vehicle is factory-fitted with a system designed to operate entirely on gas, a common question arises: Is an inspection certificate for the gas-cylinder system required in such cases as well?
The answer is yes - the certificate must be presented. During the technical inspection, a valid inspection certificate, issued in accordance with the procedure established by law for the gas cylinders and gas-cylinder system installed on vehicles powered by compressed natural gas (CNG) and liquefied petroleum gas (LPG), is checked. The certificate confirms that the gas system is technically sound, safe for operation, and compliant with the established requirements.

As for emissions testing, an exhaust gas analyzer is used for vehicles powered by compressed natural gas (CNG) and liquefied petroleum gas (LPG).

During the inspection, the CO (carbon monoxide) content is measured both at engine idle and at high engine speed (not less than 2,000 rpm). Visible smoke emissions are also checked for compliance with the established requirements.

As with vehicles equipped with petrol engines, the permissible CO level for vehicles powered by compressed natural gas (CNG) and liquefied petroleum gas (LPG) is no more than 0.5% at engine idle and no more than 0.3% at high engine speed.

For factory-fitted gas-powered vehicles, the lambda coefficient (air-to-fuel ratio) is not measured, and compliance with a specific lambda value is not required.