UNE EN 1793-2 defines the laboratory method to measure the behaviour of airborne sound insulation of anti noise panels on the roads. This standard is used to evaluate the intrinsic behaviour of anti noise panels that can be assembled inside the testing facilities described in EN ISO 140-3 standards.
The results provide a table and a graph reflecting the levels of acoustic insulation Ri for all tested frequencies.
The evaluation index of airborne sound insulation, DLR, is obtained by rounding to the nearest integer.
If, in addition to the index, the behaviour of absorption is meant to be classified, the standard provides the following table:
| Absorption behaviour categories | |
| Category | DLα dB |
| B0 | Undeterminated |
| B1 | < 15 |
| B2 | 15 a 24 |
| B3 | > 24 |
The evaluation index DLR is best suited to characterize the airborne sound insulation in situations where the incident sound received by the panel comes from road traffic and without undergoing reflections on other surfaces. Only in the case of more complex situations in which multiple reflections occur, or when sound waves are diffracted, it is advisable to evaluate the behaviour of the absorbent materials according to the frequency.