Restaurant Acoustic Design to ASHRAE 189.1-2020
Restaurant acoustics must balance conversation intelligibility with ambient atmosphere. Excessive reverberation triggers the Lombard effect, where diners progressively raise their voices, creating an escalating noise spiral that can reach 85+ dBA at peak service.
Under ASHRAE 189.1-2020, a restaurant of 300-500 m³ (typical dimensions 15m × 10m × 3.5m) requires an RT60 of ≤ 1s at broadband. Background noise must not exceed 45 NC. ASHRAE Handbook Chapter 49 recommends NC 40-45 for restaurants, reflecting the higher acceptable ambient noise levels in dining environments.
Specific Requirements
| Parameter | Target | Clause Reference | Notes |
|---|---|---|---|
| Frequency Range | broadband | — | Octave bands for compliance assessment |
Step-by-Step Compliance Calculation
- 1
Set NC 40-45 target
Restaurants: NC 40-45 per ASHRAE. Fine dining may target NC 35-40 for premium acoustic experience.
- 2
Design kitchen extraction
Size extraction ductwork with silencers to limit hood noise contribution at the dining room boundary.
- 3
Control make-up air noise
Specify make-up air units with acoustic enclosures and attenuated supply to dining room diffusers.
- 4
Verify with measurement
Measure octave-band noise with kitchen at full operation and plot against target NC curve.
Recommended Materials
| Surface | Material Category | Min NRC | Coverage % |
|---|---|---|---|
| Ceiling | Acoustic ceiling or baffles | 0.75 | 55% |
| Extraction hood | Acoustic lined extraction duct | 0.70 | 100% |
Browse the full acoustic materials database for absorption coefficients and product specifications.
Common Failure Modes
⚠️Kitchen extraction at full speed
Extraction hoods at maximum speed produce 60-70 dBA at the pass, dominating the dining room acoustic environment.
⚠️Make-up air unit noise
Make-up air systems replacing extracted kitchen air introduce supply fan noise through dining room diffusers.
Frequently Asked Questions
What RT60 does ASHRAE 189.1-2020 require for a restaurant?
ASHRAE 189.1-2020 requires a reverberation time of ≤1s at broadband for restaurant spaces. ASHRAE Handbook Chapter 49 recommends NC 40-45 for restaurants, reflecting the higher acceptable ambient noise levels in dining environments. Kitchen extraction systems are the dominant HVAC noise source, requiring careful duct routing, fan selection, and make-up air system design.
What is the maximum background noise level for a restaurant under ASHRAE 189.1-2020?
ASHRAE 189.1-2020 sets a maximum background noise level of 45 NC for restaurant spaces. This includes noise from HVAC systems, building services, and external intrusion, measured with the room unoccupied. Exceeding this limit degrades speech intelligibility and occupant comfort.
How much acoustic treatment does a restaurant need to comply with ASHRAE 189.1-2020?
A typical restaurant (300-500 m³) requires Acoustic ceiling or baffles (NRC ≥0.75) covering 55% of the ceiling as the primary treatment. Additional wall absorption on 1 surface(s) is typically needed. Use the AcousPlan calculator with the pre-loaded dimensions (15m × 10m × 3.5m) to calculate the exact absorption deficit for your room.
Calculate ASHRAE 189.1-2020 Compliance for Your Restaurant
Pre-loaded with typical restaurant dimensions (15m × 10m × 3.5m) and an RT60 target of 1s per ASHRAE 189.1-2020. Enter your actual dimensions, select materials, and verify compliance instantly.
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Further Reading
Complete restaurant acoustic design guide with all applicable standards, failure modes, and material recommendations.
Full ASHRAE 189.1-2020 standard overview: scope, key clauses, all room type requirements, and implementation guidance.
Browse 5,000+ acoustic materials with absorption coefficients, NRC ratings, and specifications from 115 manufacturers.
In-depth guides on RT60 calculation, acoustic treatment design, and compliance methodology.