Worked Example: Mental Health Quiet Room — BS 8233 Compliance
120 m³ therapeutic space with acoustic ceiling, fabric panels, and carpet
A 120 m³ hospital ward designed to BS-8233 requires RT60 ≤ 0.6s. With Ecophon Focus E ceiling tile on the ceiling and Fabric-wrapped panel 50mm on walls, the calculated RT60 is 0.41s — PASS.
Room Setup
Total surface area: 166.0 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 | 20.0 | 0.86 |
| Ceiling — plaster | Painted plaster | 28.0 | 0.04 |
| Floor | Heavy carpet | 48.0 | 0.29 |
| Walls — plaster | Painted plaster | 42.0 | 0.04 |
| Walls — fabric panels | Fabric-wrapped panel 50mm | 10.0 | 0.78 |
| Walls — plasterboard | Plasterboard on studs | 10.0 | 0.07 |
| Window | Double glazing 6mm | 6.0 | 0.03 |
| Door | Solid timber door | 2.0 | 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 = 8 × 6 × 2.5 = 120 m³
- 2
Total Surface Area
Stotal = 20.0 + 28.0 + 48.0 + 42.0 + 10.0 + 10.0 + 6.0 + 2.0 = 166.0 m²
- 3
Absorption per Surface at 500 Hz
Ceiling — Ecophon Focus E: 20.0 m² × 0.90 = 18.00 Sabins
Ceiling — plaster: 28.0 m² × 0.04 = 1.12 Sabins
Floor: 48.0 m² × 0.14 = 6.72 Sabins
Walls — plaster: 42.0 m² × 0.04 = 1.68 Sabins
Walls — fabric panels: 10.0 m² × 0.78 = 7.80 Sabins
Walls — plasterboard: 10.0 m² × 0.05 = 0.50 Sabins
Window: 6.0 m² × 0.04 = 0.24 Sabins
Door: 2.0 m² × 0.08 = 0.16 Sabins
- 4
Total Absorption at 500 Hz
Atotal = 18.00 + 1.12 + 6.72 + 1.68 + 7.80 + 0.50 + 0.24 + 0.16 = 36.22 Sabins
- 5
Sabine RT60 at 500 Hz
RT60 = 0.161 × V / A = 0.161 × 120 / 36.22 = 0.53s
- 6
Compare to Target
Mid-frequency RT60 (avg of 500, 1k, 2k Hz) = 0.41s. Target: 0.4--0.6s per BS-8233. Verdict: PASS
Octave Band Results
| Frequency | 125Hz | 250Hz | 500Hz | 1kHz | 2kHz | 4kHz |
|---|---|---|---|---|---|---|
| Total Absorption (Sabins) | 14.2 | 25.8 | 36.2 | 49.5 | 60.3 | 61.4 |
| RT60 (s) | 1.36 | 0.75 | 0.53 | 0.39 | 0.32 | 0.31 |
| 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 (8m × 6m × 2.5m) and RT60 target (0.6s).
Open CalculatorField Story
A new psychiatric inpatient unit in Sheffield requires ultra-quiet therapy rooms where patients recovering from acute episodes can find calm. The 8 m by 6 m room uses Ecophon Focus E tiles on 40% of the ceiling — chosen for their Class A absorption and anti-ligature mounting system critical in mental health settings. Heavy carpet provides warmth and mid-frequency absorption while reducing impact noise from footfall. The 10 m² of fabric-wrapped panels on one wall use tamper-proof fixings filled with non-removable mineral wool. The remaining walls are painted plaster with a plasterboard partition to the adjacent room providing panel absorption at low frequencies. BS 8233:2014 Table 4 recommends indoor ambient levels of 30–35 dB LAeq for hospital wards; the controlled reverberation time ensures therapist speech remains intelligible without raised voice levels.
Frequently Asked Questions
What RT60 does a Mental Health Quiet Room — BS 8233 Compliance achieve?
With the specified materials and dimensions (8m x 6m x 2.5m, volume 120m3), the calculated mid-frequency RT60 is 0.41s using the Sabine equation. The target under BS-8233 is 0.4--0.6s. The result is a PASS.
What materials are used in this healthcare acoustic example?
This example uses Ecophon Focus E ceiling tile on the Ceiling — Ecophon Focus E (NRC 0.86), Painted plaster on the Ceiling — plaster (NRC 0.04), Heavy carpet on the Floor (NRC 0.29), Painted plaster on the Walls — plaster (NRC 0.04), Fabric-wrapped panel 50mm on the Walls — fabric panels (NRC 0.78), Plasterboard on studs on the Walls — plasterboard (NRC 0.07), 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 36.2 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.