Worked Example: Mosque — ISO 3382 Quranic Recitation Acoustics
3000 m³ mosque with domed plaster ceiling, stone walls, and full prayer carpet
A 3000 m³ worship space designed to ISO-3382 requires RT60 ≤ 2s. With Painted plaster on the ceiling, the calculated RT60 is 1.91s — PASS.
Room Setup
Total surface area: 1698.0 m². Calculation method: Sabine equation (ISO 3382-2:2008 Annex A).
Surface Materials
| Surface | Material | Area (m²) | NRC |
|---|---|---|---|
| Ceiling — dome (plaster) | Painted plaster | 600.0 | 0.04 |
| Floor — prayer carpet | Heavy carpet | 600.0 | 0.29 |
| Walls — stone/marble | Stone/granite wall | 300.0 | 0.04 |
| Walls — painted plaster | Painted plaster | 120.0 | 0.04 |
| Mihrab — acoustic plaster | Acoustic plaster 15mm | 30.0 | 0.66 |
| Curtains (women section) | Curtains (medium weight) | 20.0 | 0.56 |
| Windows | Single glazing | 20.0 | 0.16 |
| Doors | Solid timber door | 8.0 | 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 = 30 × 20 × 5 = 3000 m³
- 2
Total Surface Area
Stotal = 600.0 + 600.0 + 300.0 + 120.0 + 30.0 + 20.0 + 20.0 + 8.0 = 1698.0 m²
- 3
Absorption per Surface at 500 Hz
Ceiling — dome (plaster): 600.0 m² × 0.04 = 24.00 Sabins
Floor — prayer carpet: 600.0 m² × 0.14 = 84.00 Sabins
Walls — stone/marble: 300.0 m² × 0.03 = 9.00 Sabins
Walls — painted plaster: 120.0 m² × 0.04 = 4.80 Sabins
Mihrab — acoustic plaster: 30.0 m² × 0.65 = 19.50 Sabins
Curtains (women section): 20.0 m² × 0.49 = 9.80 Sabins
Windows: 20.0 m² × 0.18 = 3.60 Sabins
Doors: 8.0 m² × 0.08 = 0.64 Sabins
- 4
Total Absorption at 500 Hz
Atotal = 24.00 + 84.00 + 9.00 + 4.80 + 19.50 + 9.80 + 3.60 + 0.64 = 155.34 Sabins
- 5
Sabine RT60 at 500 Hz
RT60 = 0.161 × V / A = 0.161 × 3000 / 155.34 = 3.11s
- 6
Compare to Target
Mid-frequency RT60 (avg of 500, 1k, 2k Hz) = 1.91s. Target: 1.5--2s per ISO-3382. Verdict: PASS
Octave Band Results
| Frequency | 125Hz | 250Hz | 500Hz | 1kHz | 2kHz | 4kHz |
|---|---|---|---|---|---|---|
| Total Absorption (Sabins) | 37.7 | 78.9 | 155.3 | 312.0 | 452.5 | 476.9 |
| RT60 (s) | 12.80 | 6.12 | 3.11 | 1.55 | 1.07 | 1.01 |
| Target (s) | — | — | 2.00 | 2.00 | 2.00 | — |
| Verdict | — | — | FAIL | PASS | FAIL | — |
Compliance Verdict
Reference:
Open the AcousPlan calculator pre-loaded with the exact room dimensions (30m × 20m × 5m) and RT60 target (2s).
Open CalculatorField Story
A new Jami Masjid in Istanbul accommodates 1,200 worshippers in a 30 m by 20 m prayer hall beneath a 5 m high dome. Mosque acoustics require a delicate balance: enough reverberation for Quranic recitation ethereal quality, yet sufficient clarity for the Friday sermon to be understood from the rear. The full prayer carpet — covering 600 m² — is the largest absorber, reducing what would otherwise be 4+ seconds RT60. Acoustic plaster on the mihrab wall ensures the imam voice projects clearly. The domed ceiling creates focused reflections enhancing chanting. Heavy curtains separating the women mezzanine provide variable absorption. Stone walls and painted plaster maintain the reverberant character essential to Islamic worship. ISO 3382 guidance for worship spaces suggests 1.5-2.0 s as the ideal balance between resonance and clarity.
Frequently Asked Questions
What RT60 does a Mosque — ISO 3382 Quranic Recitation Acoustics achieve?
With the specified materials and dimensions (30m x 20m x 5m, volume 3000m3), the calculated mid-frequency RT60 is 1.91s using the Sabine equation. The target under ISO-3382 is 1.5--2s. The result is a PASS.
What materials are used in this performance acoustic example?
This example uses Painted plaster on the Ceiling — dome (plaster) (NRC 0.04), Heavy carpet on the Floor — prayer carpet (NRC 0.29), Stone/granite wall on the Walls — stone/marble (NRC 0.04), Painted plaster on the Walls — painted plaster (NRC 0.04), Acoustic plaster 15mm on the Mihrab — acoustic plaster (NRC 0.66), Curtains (medium weight) on the Curtains (women section) (NRC 0.56), Single glazing on the Windows (NRC 0.16), Solid timber door on the Doors (NRC 0.09). The total absorption at 500 Hz is 155.3 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.