Field sound test (in-situ acoustic test)
A field sound test measures a built wall or floor's real sound insulation in situ (DnT,w+Ctr, LnT,w) for NCC F7V1; results run 5 to 8 dB below the lab rating.
Ask Chalkline about this →A field sound test (or in-situ acoustic test) measures the actual sound insulation of a separating wall or floor after it is built, in the finished building, rather than relying on a laboratory rating of the product. It is the verification method (F7V1) required when a Class 2 or Class 3 separating element is taken down the Performance Solution path instead of Deemed-to-Satisfy. Two metrics are measured: DnT,w+Ctr for airborne sound (speech, music) and LnT,w for impact sound (footsteps and dropped objects on the floor above).
The NCC 2022 field-test thresholds under F7V1 are:
| Metric | Requirement |
|---|---|
| Airborne (walls and floors), DnT,w+Ctr | not less than 45 |
| Impact (floors), LnT,w | not more than 62 |
Testing is carried out to AS ISO 16283.
The field figure is lower than the laboratory rating for the same product, typically by 5 to 8 dB, because it captures the real room geometry and the flanking paths (sound travelling around the element through junctions, service penetrations, and the structure) that a controlled lab chamber excludes. Flanking is the leading cause of in-situ failures, which is why a wall built from a compliant DTS system can still fail a field test if the junctions are sloppy.
Field testing is not mandatory on the DTS path, but voluntary post-completion testing of a sample of separating elements is good practice on multi-storey residential jobs: it catches flanking failures while they are still cheap to fix. See NCC sound insulation in residential for the full Part F7 requirements, the Rw+Ctr lab metric, and the DTS construction forms.
Also known as: In-situ acoustic test, field acoustic test, F7V1 verification.
Category: Acoustics / NCC Part F7.
Related
See also
References
- NCC 2022 Volume One Part F7 Sound transmission and insulation, ABCB (verified 2026-05-09)
- AS ISO 16283 (Acoustics, Field measurement of sound insulation in buildings), Standards Australia (verified 2026-05-09)
Last updated: 2026-05-30. Verified: 2026-05-09. Quarterly review for currency.