Articles tagged “ashrae”
8 articles covering ashrae in acoustic engineering and building design.
ASHRAE Noise Criteria for HVAC Systems: NC, RC, and Design Limits
Master ASHRAE HVAC noise criteria — NC curves, RC Mark II method, design limits by room type, duct noise calculation, and common specification errors.
What is an NC Rating?
NC (Noise Criteria) is an octave-band rating system for background noise in buildings. Learn how NC curves work, how to read them, target values by room type, and how NC relates to NR and RC.
What is an RC Rating?
RC (Room Criteria) is an enhanced noise rating system that evaluates both level and spectral quality of background noise. Learn how RC curves, spectral balance, and quality descriptors work per ASHRAE.
HVAC Noise Control — The Ductwork Mistake Ruining Your NC 30 Spec | AcousPlan
HVAC duct velocity above 5 m/s generates noise proportional to V⁵. NC curve calculation chain with ASHRAE method. 5 noise sources, 1 worked example.
NC vs RC vs NCY — Which Noise Criterion? Most Engineers Pick Wrong | AcousPlan
NC misses rumble below 63 Hz. RC Mark II identifies spectral quality. NCY adds 5 dB penalty. Full comparison with decision matrix and worked example.
Office Background Noise Limits: BS 8233 vs WELL v2 vs ASHRAE vs AS 2107 vs DIN 4109
Office background noise criteria compared across five international standards: BS 8233, WELL v2 Feature 74, ASHRAE 189.1, AS 2107, and DIN 4109. Real limits, measurement methods, and compliance explained.
ASHRAE HVAC Noise Control: Handbook Chapter Summary for Acoustic Designers
ASHRAE HVAC Applications Chapter 49 is the authoritative guide for mechanical noise control in buildings. This summary covers RC/NC curve criteria, duct noise calculation, equipment selection, and silencer design for acoustic designers.
NC Curves Explained: Understanding NC-25, NC-35, NC-45 Background Noise Ratings
A comprehensive guide to Noise Criteria (NC) curves: how they work, how to determine an NC rating, target values for every room type, and the differences between NC, NR, and RC rating methods. Includes ASHRAE recommended levels and step-by-step calculation examples.