One of the main critical aspects for the injection of gases (including biomethane) into the grid is the odourisation process.
For domestic use and transportation purposes, gases must possess specific olfactory characteristics to ensure user safety.
Determining the correct level of odourisation is therefore of primary importance. This verification is carried out by LOD using rhinanalysis.
Our laboratory is accredited to perform sensory tests in accordance with UNI 7133-3:2023 -“Odorisation of gas for domestic and similar uses - Part 3: Procedures for defining the olfactory characteristics of odorous fluids.”
Rhinanalysis is the only recognised technique for verifying the odorisability of biomethane, as established by UNI 7133-2:2023 - “Odorisation of gas for domestic and similar uses – Part 2: Requirements, control, and management.”
The analyses are carried out inside a specialised testing chamber known as the rhinanalytic chamber.
Within this chamber, an osmogene atmosphere is recreated in accordance with the technical standard, consisting of a controlled mixture of air, sample gas, and odorising compounds.
Trained and selected assessors (rhinanalysts) enter the chamber and describe the type and intensity of the perceived odour, using the DecaSales scale (the unit of measurement).
The results are then compared against the reference requirements for gas odourisation.
In the case of biomethane, a sample is considered suitable for introduction into the network if:
•The smell intensity is greater than or equal to 4 olfactory degrees of the DecaSales scale;
•The conformity of the type of odor is recognized by at least 85% of the examiners taking part to the test (minimum of six).
LOD is the only private laboratory in Italy equipped with both an olfactometric chamber, according to UNI EN 13725: 2022, and a rhino-analytic chamber, according to the UNI 7133-3: 2023 Standard. It is therefore the only one in a condition to perform analyses in parallel and correlate the collected data according to both methods.
LOD also has the necessary skills to perform specific studies on elements potentially interfering with a proper odorization of biomethane (such as limonene, pinene and butanone).
