Worked Example: Open-Plan Kitchen-Living — BS 8233 Design
120 m³ open-plan space with mixed flooring, plasterboard walls, and soft furnishings
A 120 m³ residential living designed to BS-8233 requires RT60 ≤ 0.8s. With Painted plaster on the ceiling, the calculated RT60 is 0.81s — MARGINAL.
Room Setup
Total surface area: 186.0 m². Calculation method: Sabine equation (ISO 3382-2:2008 Annex A).
Surface Materials
| Surface | Material | Area (m²) | NRC |
|---|---|---|---|
| Ceiling | Painted plaster | 60.0 | 0.04 |
| Floor — kitchen (vinyl) | Vinyl/linoleum floor | 24.0 | 0.04 |
| Floor — living (carpet) | Heavy carpet | 36.0 | 0.29 |
| Walls — plasterboard | Plasterboard on studs | 40.0 | 0.07 |
| Kitchen wall — tile | Exposed concrete | 6.0 | 0.02 |
| Sofa + chairs | Upholstered seating | 6.0 | 0.55 |
| Curtains | Curtains (medium weight) | 5.0 | 0.56 |
| Windows | Double glazing 6mm | 6.0 | 0.03 |
| Doors | 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 = 10 × 6 × 2 = 120 m³
- 2
Total Surface Area
Stotal = 60.0 + 24.0 + 36.0 + 40.0 + 6.0 + 6.0 + 5.0 + 6.0 + 3.0 = 186.0 m²
- 3
Absorption per Surface at 500 Hz
Ceiling: 60.0 m² × 0.04 = 2.40 Sabins
Floor — kitchen (vinyl): 24.0 m² × 0.03 = 0.72 Sabins
Floor — living (carpet): 36.0 m² × 0.14 = 5.04 Sabins
Walls — plasterboard: 40.0 m² × 0.05 = 2.00 Sabins
Kitchen wall — tile: 6.0 m² × 0.02 = 0.12 Sabins
Sofa + chairs: 6.0 m² × 0.56 = 3.36 Sabins
Curtains: 5.0 m² × 0.49 = 2.45 Sabins
Windows: 6.0 m² × 0.04 = 0.24 Sabins
Doors: 3.0 m² × 0.08 = 0.24 Sabins
- 4
Total Absorption at 500 Hz
Atotal = 2.40 + 0.72 + 5.04 + 2.00 + 0.12 + 3.36 + 2.45 + 0.24 + 0.24 = 16.57 Sabins
- 5
Sabine RT60 at 500 Hz
RT60 = 0.161 × V / A = 0.161 × 120 / 16.57 = 1.17s
- 6
Compare to Target
Mid-frequency RT60 (avg of 500, 1k, 2k Hz) = 0.81s. Target: 0.5--0.8s per BS-8233. Verdict: MARGINAL
Octave Band Results
| Frequency | 125Hz | 250Hz | 500Hz | 1kHz | 2kHz | 4kHz |
|---|---|---|---|---|---|---|
| Total Absorption (Sabins) | 16.3 | 12.5 | 16.6 | 27.2 | 36.0 | 38.4 |
| RT60 (s) | 1.19 | 1.54 | 1.17 | 0.71 | 0.54 | 0.50 |
| Target (s) | — | — | 0.80 | 0.80 | 0.80 | — |
| Verdict | — | — | FAIL | PASS | PASS | — |
Compliance Verdict
Reference:
Open the AcousPlan calculator pre-loaded with the exact room dimensions (10m × 6m × 2m) and RT60 target (0.8s).
Open CalculatorField Story
The ubiquitous open-plan kitchen-living room is the acoustic challenge of modern British housing. A family in Milton Keynes finds conversation at the dining table drowned out when someone cooks — clattering pans on hard kitchen surfaces reverberate through 120 m³. The vinyl kitchen floor and tiled splashback create a reflective zone that acoustically dominates the softer living area. This calculation maps actual absorption distribution: carpet, sofa, curtains, and plasterboard in the living zone provide the majority, while the kitchen contributes almost nothing. The painted plaster ceiling across both zones reflects sound energy uniformly. BS 8233 suggests 0.8 s or below; the calculation reveals whether developer-spec finish achieves this, or whether the homeowner needs a rug or acoustic artwork in the kitchen end.
Frequently Asked Questions
What RT60 does a Open-Plan Kitchen-Living — BS 8233 Design achieve?
With the specified materials and dimensions (10m x 6m x 2m, volume 120m3), the calculated mid-frequency RT60 is 0.81s using the Sabine equation. The target under BS-8233 is 0.5--0.8s. The result is a MARGINAL.
What materials are used in this residential acoustic example?
This example uses Painted plaster on the Ceiling (NRC 0.04), Vinyl/linoleum floor on the Floor — kitchen (vinyl) (NRC 0.04), Heavy carpet on the Floor — living (carpet) (NRC 0.29), Plasterboard on studs on the Walls — plasterboard (NRC 0.07), Exposed concrete on the Kitchen wall — tile (NRC 0.02), Upholstered seating on the Sofa + chairs (NRC 0.55), Curtains (medium weight) on the Curtains (NRC 0.56), Double glazing 6mm on the Windows (NRC 0.03), Solid timber door on the Doors (NRC 0.09). The total absorption at 500 Hz is 16.6 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.