Airborne Sound Insulation Testing (NIC / NNIC / ASTC)
Absolute Laboratories provides on-site airborne sound insulation testing between adjacent rooms, measuring how effectively building elements — walls, partitions, doors, glazing, and facades — reduce airborne sound transmission. This test is widely known internationally as the STC (Sound Transmission Class) test in the US and Rw (Weighted Sound Reduction Index) in ISO standards. In Singapore and Australia, results are reported as NIC, NNIC, or ASTC.
What This Test Measures
- Sound insulation between adjacent rooms (room-to-room)
- Performance of walls, partitions, and doors
- Sound transmission through glazing and windows
- Facade sound insulation (external noise intrusion)
Test Results Explained
- NIC (Noise Isolation Class) — field measurement of sound isolation between two rooms, accounting for flanking paths. Single-number rating.
- NNIC (Normalized Noise Isolation Class) — NIC normalized to a standard reverberation time.
- ASTC (Apparent Sound Transmission Class) — field rating of apparent sound transmission loss, used in Australia and increasingly referenced in Singapore projects.
- STC equivalent — for clients familiar with US standards, NIC results are directly comparable to STC ratings.
Testing Standards
- ASTM E336 — Standard Test Method for Measurement of Airborne Sound Attenuation Between Rooms in Buildings
- ASTM E413 — Classification for Rating Sound Insulation
How the Test Works
A calibrated high-performance sound source is placed in the source room and emits broadband noise. Sound pressure levels are measured simultaneously in the source room and receiving room across multiple positions. The level difference, corrected for room absorption, gives the NIC/NNIC/ASTC rating.
Typical Applications
- Offices and open-plan workspaces with partitioned meeting rooms
- Residential developments (apartment walls, floor-ceiling assemblies)
- Hotels and serviced residences (guest room party walls)
- Hospitals (consultation rooms, patient wards)
- Educational facilities (classrooms, lecture theatres)
- Commercial buildings (tenancy fit-outs, demising walls)
Who Needs This Test?
- Main contractors — verify acoustic performance before project handover
- Developers — confirm building meets acoustic design specifications
- Architects and acoustic consultants — validate design intent in the field
- Interior designers — confirm partition and glazing systems perform as specified
- Facade contractors — verify glazing and facade sound insulation performance
- Partition contractors — confirm wall systems meet acoustic standards
- Building owners and facility managers — investigate occupant complaints about noise
Why Choose Absolute Laboratories?
- Independent and impartial results — no conflict of interest with contractors or suppliers
- Experienced acoustic engineers with professional consultation
- Professional, calibrated instruments including high-performance dodecahedral sound source
- Comprehensive technical reports supporting compliance and decision-making
- Fast turnaround to keep your project on schedule
Get in Touch
Contact our team for a quotation or to discuss your project requirements.
- Email: klenplir@alab.com.sg
- Phone: (65) 6296 8012 Ext 30 | DID: (65) 6544 8594
- Mobile: (65) 9754 6848