Room Noise Assessment (NC Rating)
Absolute Laboratories provides on-site room noise assessments to measure indoor background noise generated by HVAC systems and building services. Results are evaluated against NC (Noise Criteria) rating curves, which define acceptable noise levels for different occupancy types. This assessment helps verify occupant comfort, compliance with project specifications, and building commissioning requirements.
What This Assessment Measures
- Background noise levels generated by HVAC systems
- Noise from mechanical and electrical services (air handling units, fans, pumps, transformers)
- Steady-state background noise in occupied spaces
- Compliance with NC rating criteria specified in project acoustic reports
Understanding NC Ratings
NC (Noise Criteria) ratings are single-number ratings derived from octave-band sound pressure level measurements. Lower NC values indicate quieter environments.
- NC-20 to NC-25 — Broadcast studios, concert halls, very quiet spaces
- NC-25 to NC-35 — Private offices, boardrooms, high-end hotel rooms
- NC-30 to NC-40 — Open offices, classrooms, hospitals
- NC-35 to NC-45 — Restaurants, lobbies, general commercial spaces
Many Singapore building specifications reference NC ratings as part of acoustic performance requirements. Our assessment identifies whether HVAC noise levels comply with the specified NC target.
Testing Standard
- ANSI/ASA S12.2 — Criteria for Evaluating Room Noise
How the Assessment Works
A sound level meter and vibration analyser are used to measure octave-band sound pressure levels in the room with HVAC systems operating at typical settings. Measurements are taken at multiple positions. The results are plotted against NC curves to determine the NC rating of the space.
Typical Applications
- Offices and open-plan workspaces
- Boardrooms and executive offices
- Classrooms and lecture theatres
- Hospitals and clinics
- Hotels and serviced residences
- Commercial buildings at project handover
- Any space where HVAC noise is a concern
Who Needs This Assessment?
- Main contractors — verify HVAC noise compliance before handover
- Developers — confirm building meets acoustic specifications
- M&E contractors — assess noise from building services and mechanical systems
- Architects — validate acoustic design intent
- Building owners and facility managers — investigate occupant complaints about noisy air-conditioning or mechanical systems
- Healthcare and educational facilities — ensure environments support healing and learning
Why Choose Absolute Laboratories?
- Independent measurement — impartial assessment with no conflict of interest
- Calibrated instruments meeting international accuracy requirements
- Clear technical reports with NC curve plots and compliance findings
- Practical recommendations to address non-compliance
- Fast turnaround to support project commissioning schedules
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