Worked Example: German Classroom — DIN 18041 Acoustic Design
RT60 calculation for a German primary school classroom following DIN 18041 guidelines. Combines Ecophon ceiling with mineral wool wall treatment to meet the 0.4-0.6s target range for speech-focused rooms.
A 179.2 m³ classroom designed to DIN-18041 requires RT60 ≤ 0.6s. With Ecophon Focus E on the ceiling and Mineral wool 50mm on walls, the calculated RT60 is 0.43s — PASS.
Room Setup
Total surface area: 224.0 m². Calculation method: Sabine equation (ISO 3382-2:2008 Annex A).
Surface Materials
| Surface | Material | Area (m²) | NRC |
|---|---|---|---|
| ceiling | Ecophon Focus E | 56.0 | 0.90 |
| walls-main | Painted plaster | 84.0 | 0.04 |
| walls-treatment | Mineral wool 50mm | 12.0 | 0.75 |
| floor | Vinyl/linoleum floor | 56.0 | 0.03 |
| windows | Double glazing 6mm | 12.0 | 0.04 |
| door | Solid timber door | 4.0 | 0.08 |
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 × 7 × 3.2 = 179.2 m³
- 2
Total Surface Area
Stotal = 56.0 + 84.0 + 12.0 + 56.0 + 12.0 + 4.0 = 224.0 m²
- 3
Absorption per Surface at 500 Hz
ceiling: 56.0 m² × 0.90 = 50.40 Sabins
walls-main: 84.0 m² × 0.04 = 3.36 Sabins
walls-treatment: 12.0 m² × 0.70 = 8.40 Sabins
floor: 56.0 m² × 0.03 = 1.68 Sabins
windows: 12.0 m² × 0.04 = 0.48 Sabins
door: 4.0 m² × 0.08 = 0.32 Sabins
- 4
Total Absorption at 500 Hz
Atotal = 50.40 + 3.36 + 8.40 + 1.68 + 0.48 + 0.32 = 64.64 Sabins
- 5
Sabine RT60 at 500 Hz
RT60 = 0.161 × V / A = 0.161 × 179.2 / 64.64 = 0.45s
- 6
Compare to Target
Mid-frequency RT60 (avg of 500, 1k, 2k Hz) = 0.43s. Target: 0.4--0.6s per DIN-18041. Verdict: PASS
Octave Band Results
| Frequency | 125Hz | 250Hz | 500Hz | 1kHz | 2kHz | 4kHz |
|---|---|---|---|---|---|---|
| Total Absorption (Sabins) | 25.7 | 49.0 | 64.6 | 70.5 | 68.2 | 66.0 |
| RT60 (s) | 1.12 | 0.59 | 0.45 | 0.41 | 0.42 | 0.44 |
| Target (s) | — | — | 0.60 | 0.60 | 0.60 | — |
| Verdict | — | — | PASS | PASS | PASS | — |
Compliance Verdict
Reference: DIN 18041:2016 Table 1
DIN 18041 defines Group A rooms (speech-centric) with a target RT60 range of 0.4-0.6s for classrooms. Both minimum and maximum limits apply — over-dampening is also non-compliant.
STI result: 0.70 (per IEC 60268-16:2020)
Cost Estimate
Costs are indicative and vary by region, supplier, and installation complexity. For a detailed cost breakdown, use the AcousPlan calculator.
Open the AcousPlan calculator pre-loaded with the exact room dimensions (8m × 7m × 3.2m) and RT60 target (0.6s).
Open CalculatorField Story
A Grundschule in Munich undergoes renovation and the Bauamt requires DIN 18041 compliance documentation. The existing classroom has plaster walls and a hard ceiling producing an RT60 of 1.6 seconds. Children with hearing impairments in inclusive classes are particularly affected. The acoustic engineer must carefully balance absorption to land within the 0.4-0.6s window — too much treatment would violate the minimum threshold and create an uncomfortably dead room where students cannot hear each other during group work.
Frequently Asked Questions
What RT60 does a German Classroom — DIN 18041 Acoustic Design achieve?
With the specified materials and dimensions (8m x 7m x 3.2m, volume 179.2m3), the calculated mid-frequency RT60 is 0.43s using the Sabine equation. The target under DIN-18041 is 0.4--0.6s. The result is a PASS.
What materials are used in this education acoustic example?
This example uses Ecophon Focus E on the ceiling (NRC 0.9), Painted plaster on the walls-main (NRC 0.04), Mineral wool 50mm on the walls-treatment (NRC 0.75), Vinyl/linoleum floor on the floor (NRC 0.03), Double glazing 6mm on the windows (NRC 0.04), Solid timber door on the door (NRC 0.08). The total absorption at 500 Hz is 64.6 Sabins.
How much does acoustic treatment cost for this room?
The estimated treatment cost is €3,400 for 68 m2 of absorptive material at approximately €50/m2. Actual costs vary by region, supplier, and installation complexity.
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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.