Worked Example: Fine Dining Restaurant — NRA French Standard
250 m³ fine dining room with Ecophon ceiling, carpet, and curtain alcoves
A 250 m³ restaurant designed to NRA requires RT60 ≤ 0.6s. With Ecophon Focus E ceiling tile on the ceiling and Curtains (medium weight) on walls, the calculated RT60 is 0.4s — PASS.
Room Setup
Total surface area: 337.0 m². Calculation method: Sabine equation (ISO 3382-2:2008 Annex A).
Surface Materials
| Surface | Material | Area (m²) | NRC |
|---|---|---|---|
| Ceiling — Ecophon Focus E | Ecophon Focus E ceiling tile | 40.0 | 0.86 |
| Ceiling — ornamental plaster | Painted plaster | 85.0 | 0.04 |
| Floor | Heavy carpet | 125.0 | 0.29 |
| Walls — painted plaster | Painted plaster | 48.0 | 0.04 |
| Walls — curtains | Curtains (medium weight) | 12.0 | 0.56 |
| Seating (40 covers) | Upholstered seating | 12.0 | 0.55 |
| Walls — fabric panels | Fabric-wrapped panel 50mm | 4.0 | 0.78 |
| Window | Double glazing 6mm | 8.0 | 0.03 |
| Door | Solid timber door | 3.0 | 0.09 |
Absorption coefficients sourced from manufacturer datasheets and ISO 354 test reports. Browse the full acoustic materials database.
Step-by-Step Calculation
- 1
Room Volume
V = L × W × H = 12.5 × 10 × 2 = 250 m³
- 2
Total Surface Area
Stotal = 40.0 + 85.0 + 125.0 + 48.0 + 12.0 + 12.0 + 4.0 + 8.0 + 3.0 = 337.0 m²
- 3
Absorption per Surface at 500 Hz
Ceiling — Ecophon Focus E: 40.0 m² × 0.90 = 36.00 Sabins
Ceiling — ornamental plaster: 85.0 m² × 0.04 = 3.40 Sabins
Floor: 125.0 m² × 0.14 = 17.50 Sabins
Walls — painted plaster: 48.0 m² × 0.04 = 1.92 Sabins
Walls — curtains: 12.0 m² × 0.49 = 5.88 Sabins
Seating (40 covers): 12.0 m² × 0.56 = 6.72 Sabins
Walls — fabric panels: 4.0 m² × 0.78 = 3.12 Sabins
Window: 8.0 m² × 0.04 = 0.32 Sabins
Door: 3.0 m² × 0.08 = 0.24 Sabins
- 4
Total Absorption at 500 Hz
Atotal = 36.00 + 3.40 + 17.50 + 1.92 + 5.88 + 6.72 + 3.12 + 0.32 + 0.24 = 75.10 Sabins
- 5
Sabine RT60 at 500 Hz
RT60 = 0.161 × V / A = 0.161 × 250 / 75.10 = 0.54s
- 6
Compare to Target
Mid-frequency RT60 (avg of 500, 1k, 2k Hz) = 0.4s. Target: 0.4--0.6s per NRA. Verdict: PASS
Octave Band Results
| Frequency | 125Hz | 250Hz | 500Hz | 1kHz | 2kHz | 4kHz |
|---|---|---|---|---|---|---|
| Total Absorption (Sabins) | 23.2 | 49.4 | 75.1 | 111.8 | 137.4 | 140.0 |
| RT60 (s) | 1.74 | 0.81 | 0.54 | 0.36 | 0.29 | 0.29 |
| Target (s) | — | — | 0.60 | 0.60 | 0.60 | — |
| Verdict | — | — | PASS | MARGINAL | FAIL | — |
Compliance Verdict
Reference:
Open the AcousPlan calculator pre-loaded with the exact room dimensions (12.5m × 10m × 2m) and RT60 target (0.6s).
Open CalculatorField Story
A two-Michelin-star restaurant in Lyon seats 40 diners across an intimate 12.5 m by 10 m dining room. French gastronomic tradition demands guests converse at a whisper — acoustic privacy between tables is as important as the cuisine. The Ecophon Focus E ceiling covers just under half the ceiling area, with ornamental plaster mouldings preserved on the remainder. Deep wool carpet eliminates cutlery and footstep noise from attentive wait staff. Full-length silk curtains at the window alcoves serve as both light control and acoustic absorption. Every seat is fully upholstered, contributing meaningful absorption at speech frequencies. Fabric-wrapped panels behind banquettes add targeted treatment. The NRA target of 0.6 s or below ensures the intimate atmosphere is preserved even during a fully booked Saturday evening service.
Frequently Asked Questions
What RT60 does a Fine Dining Restaurant — NRA French Standard achieve?
With the specified materials and dimensions (12.5m x 10m x 2m, volume 250m3), the calculated mid-frequency RT60 is 0.4s using the Sabine equation. The target under NRA is 0.4--0.6s. The result is a PASS.
What materials are used in this hospitality acoustic example?
This example uses Ecophon Focus E ceiling tile on the Ceiling — Ecophon Focus E (NRC 0.86), Painted plaster on the Ceiling — ornamental plaster (NRC 0.04), Heavy carpet on the Floor (NRC 0.29), Painted plaster on the Walls — painted plaster (NRC 0.04), Curtains (medium weight) on the Walls — curtains (NRC 0.56), Upholstered seating on the Seating (40 covers) (NRC 0.55), Fabric-wrapped panel 50mm on the Walls — fabric panels (NRC 0.78), Double glazing 6mm on the Window (NRC 0.03), Solid timber door on the Door (NRC 0.09). The total absorption at 500 Hz is 75.1 Sabins.
How much does acoustic treatment cost for this room?
Cost data is not available for this example. Use the AcousPlan calculator to estimate treatment costs for your specific room configuration.
Related Examples
Restaurant Dining Room — BS 8233 Acoustic Design
Hotel Bedroom — BS 8233 Sleep Quality Design
Hotel Lobby — ASHRAE RC 35-40 Design
Bar/Lounge — NRA French Acoustic Regulation
Explore More
All calculations are advisory and based on the Sabine equation (ISO 3382-2:2008 Annex A). Results require professional verification for compliance submissions. Absorption coefficients are sourced from manufacturer datasheets and ISO 354 test reports.