A laboratory rating tells you what a wall system can do. A field test tells you what this wall, in this building, built by this crew, actually does. We test separating walls and floors on site, rate the results to AS/NZS ISO 717, and report them against the NCC Part F7 verification criteria.
When a building is being certified by the NCC verification method rather than deemed-to-satisfy construction; when the certifier or developer asks for evidence before handover; when owners dispute the sound insulation of a completed building; and — most usefully — on the first completed units of a project, so that a problem is caught before it is repeated on every floor.
The NCC verification criteria between sole-occupancy units are an airborne result of DnT,w + Ctr 45 or better, and an impact result of L'nT,w 62 or better for floors.
Measurements are made to ISO 16283-1 (airborne) and ISO 16283-2 (impact), or to the ISO 10052 survey method where that is accepted, and rated to AS/NZS ISO 717.1 and AS ISO 717.2.
A test report for each room pair: the element tested, the method, the measured spectrum, the single-number rating and the pass or fail against the criterion. Where a test fails, we note the likely weak point — a flanking path, a penetration, a junction — so the rectification is targeted.
Both rooms in each pair must be accessible and quiet, with doors, windows, ceilings and final floor finishes installed. Site time depends on the number of room pairs, so testing is best booked once a representative group of units is complete.
Per test, plus a site attendance fee, quoted once you tell us how many units and which wall and floor types need testing.
Agree the sample with the certifier before booking. A sound approach covers each distinct wall and floor type and the worst-case room pairs — for example, where a living room sits beside or above a bedroom.
The report identifies the likely cause. Once it is rectified we retest the same pair, and usually one or two others built the same way, to confirm the fix holds.
Significantly. Test with the final floor finishes installed, or record exactly which finish was tested, because swapping carpet for timber or tile changes the result.
Only as a diagnostic. An early test can find a construction problem, but it is not a compliance result for the finished building.