Worked Example: Wedding Venue — BS 8233 Multi-Use Design
800 m³ barn conversion with acoustic plaster, stone walls, and timber floor
A 800 m³ meeting room designed to BS-8233 requires RT60 ≤ 1.2s. With Acoustic plaster 15mm on the ceiling and Curtains (medium weight) on walls, the calculated RT60 is 0.8s — PASS.
Room Setup
Total surface area: 814.0 m². Calculation method: Sabine equation (ISO 3382-2:2008 Annex A).
Surface Materials
| Surface | Material | Area (m²) | NRC |
|---|---|---|---|
| Ceiling — acoustic plaster | Acoustic plaster 15mm | 130.0 | 0.66 |
| Ceiling — painted plaster | Painted plaster | 190.0 | 0.04 |
| Floor | Timber floor (sealed) | 320.0 | 0.09 |
| Walls — stone | Stone/granite wall | 110.0 | 0.04 |
| Walls — curtains | Curtains (medium weight) | 24.0 | 0.56 |
| Walls — fabric panels | Fabric-wrapped panel 50mm | 10.0 | 0.78 |
| Windows (tall arched) | Double glazing 6mm | 24.0 | 0.03 |
| Doors | Solid timber door | 6.0 | 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 = 20 × 16 × 2.5 = 800 m³
- 2
Total Surface Area
Stotal = 130.0 + 190.0 + 320.0 + 110.0 + 24.0 + 10.0 + 24.0 + 6.0 = 814.0 m²
- 3
Absorption per Surface at 500 Hz
Ceiling — acoustic plaster: 130.0 m² × 0.65 = 84.50 Sabins
Ceiling — painted plaster: 190.0 m² × 0.04 = 7.60 Sabins
Floor: 320.0 m² × 0.10 = 32.00 Sabins
Walls — stone: 110.0 m² × 0.03 = 3.30 Sabins
Walls — curtains: 24.0 m² × 0.49 = 11.76 Sabins
Walls — fabric panels: 10.0 m² × 0.78 = 7.80 Sabins
Windows (tall arched): 24.0 m² × 0.04 = 0.96 Sabins
Doors: 6.0 m² × 0.08 = 0.48 Sabins
- 4
Total Absorption at 500 Hz
Atotal = 84.50 + 7.60 + 32.00 + 3.30 + 11.76 + 7.80 + 0.96 + 0.48 = 148.40 Sabins
- 5
Sabine RT60 at 500 Hz
RT60 = 0.161 × V / A = 0.161 × 800 / 148.40 = 0.87s
- 6
Compare to Target
Mid-frequency RT60 (avg of 500, 1k, 2k Hz) = 0.8s. Target: 0.8--1.2s per BS-8233. Verdict: PASS
Octave Band Results
| Frequency | 125Hz | 250Hz | 500Hz | 1kHz | 2kHz | 4kHz |
|---|---|---|---|---|---|---|
| Total Absorption (Sabins) | 72.7 | 101.9 | 148.4 | 168.0 | 171.5 | 158.8 |
| RT60 (s) | 1.77 | 1.26 | 0.87 | 0.77 | 0.75 | 0.81 |
| Target (s) | — | — | 1.20 | 1.20 | 1.20 | — |
| Verdict | — | — | PASS | MARGINAL | MARGINAL | — |
Compliance Verdict
Reference:
Open the AcousPlan calculator pre-loaded with the exact room dimensions (20m × 16m × 2.5m) and RT60 target (1.2s).
Open CalculatorField Story
A Grade II listed stone barn in the Cotswolds is being converted into a wedding venue seating 100 for ceremonies and 150 for evening receptions. The heritage listing prohibits altering original stone walls, so acoustic treatment must be invisible. Acoustic plaster on 40% of the new plasterboard ceiling lining provides primary absorption, with the remainder painted plaster where original roof timbers are exposed. Floor-length curtains hung from recessed tracks frame the tall arched windows and can be closed for intimate ceremonies. Fabric-wrapped panels concealed behind bench seating provide targeted mid-frequency absorption. The sealed timber dance floor provides modest low-frequency absorption. BS 8233 suggests 0.8-1.2 s for multi-use halls; the design achieves a balanced RT60 suitable for both speech and amplified music events.
Frequently Asked Questions
What RT60 does a Wedding Venue — BS 8233 Multi-Use Design achieve?
With the specified materials and dimensions (20m x 16m x 2.5m, volume 800m3), the calculated mid-frequency RT60 is 0.8s using the Sabine equation. The target under BS-8233 is 0.8--1.2s. The result is a PASS.
What materials are used in this hospitality acoustic example?
This example uses Acoustic plaster 15mm on the Ceiling — acoustic plaster (NRC 0.66), Painted plaster on the Ceiling — painted plaster (NRC 0.04), Timber floor (sealed) on the Floor (NRC 0.09), Stone/granite wall on the Walls — stone (NRC 0.04), Curtains (medium weight) on the Walls — curtains (NRC 0.56), Fabric-wrapped panel 50mm on the Walls — fabric panels (NRC 0.78), Double glazing 6mm on the Windows (tall arched) (NRC 0.03), Solid timber door on the Doors (NRC 0.09). The total absorption at 500 Hz is 148.4 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.
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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.