Worked Example: Airport Business Lounge — ASHRAE RC 35-40
1000 m³ lounge with perforated metal ceiling, carpet, and airside glazing wall
A 1000 m³ restaurant designed to ASHRAE requires RT60 ≤ 1s. With Perforated metal ceiling on the ceiling and Fabric-wrapped panel 50mm on walls, the calculated RT60 is 0.61s — PASS.
Room Setup
Total surface area: 1002.0 m². Calculation method: Sabine equation (ISO 3382-2:2008 Annex A).
Surface Materials
| Surface | Material | Area (m²) | NRC |
|---|---|---|---|
| Ceiling — perforated metal | Perforated metal ceiling | 120.0 | 0.78 |
| Ceiling — plaster | Painted plaster | 280.0 | 0.04 |
| Floor | Heavy carpet | 400.0 | 0.29 |
| Walls — glazing (airside) | Double glazing 6mm | 80.0 | 0.03 |
| Walls — plasterboard | Plasterboard on studs | 80.0 | 0.07 |
| Seating (80 seats) | Upholstered seating | 24.0 | 0.55 |
| Walls — fabric panels | Fabric-wrapped panel 50mm | 10.0 | 0.78 |
| Bar/counter area | Stone/granite wall | 8.0 | 0.04 |
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 = 40 × 10 × 2.5 = 1000 m³
- 2
Total Surface Area
Stotal = 120.0 + 280.0 + 400.0 + 80.0 + 80.0 + 24.0 + 10.0 + 8.0 = 1002.0 m²
- 3
Absorption per Surface at 500 Hz
Ceiling — perforated metal: 120.0 m² × 0.80 = 96.00 Sabins
Ceiling — plaster: 280.0 m² × 0.04 = 11.20 Sabins
Floor: 400.0 m² × 0.14 = 56.00 Sabins
Walls — glazing (airside): 80.0 m² × 0.04 = 3.20 Sabins
Walls — plasterboard: 80.0 m² × 0.05 = 4.00 Sabins
Seating (80 seats): 24.0 m² × 0.56 = 13.44 Sabins
Walls — fabric panels: 10.0 m² × 0.78 = 7.80 Sabins
Bar/counter area: 8.0 m² × 0.03 = 0.24 Sabins
- 4
Total Absorption at 500 Hz
Atotal = 96.00 + 11.20 + 56.00 + 3.20 + 4.00 + 13.44 + 7.80 + 0.24 = 191.88 Sabins
- 5
Sabine RT60 at 500 Hz
RT60 = 0.161 × V / A = 0.161 × 1000 / 191.88 = 0.84s
- 6
Compare to Target
Mid-frequency RT60 (avg of 500, 1k, 2k Hz) = 0.61s. Target: 0.6--1s per ASHRAE. Verdict: PASS
Octave Band Results
| Frequency | 125Hz | 250Hz | 500Hz | 1kHz | 2kHz | 4kHz |
|---|---|---|---|---|---|---|
| Total Absorption (Sabins) | 100.2 | 140.6 | 191.9 | 294.5 | 375.2 | 383.9 |
| RT60 (s) | 1.61 | 1.14 | 0.84 | 0.55 | 0.43 | 0.42 |
| Target (s) | — | — | 1.00 | 1.00 | 1.00 | — |
| Verdict | — | — | PASS | MARGINAL | FAIL | — |
Compliance Verdict
Reference:
Open the AcousPlan calculator pre-loaded with the exact room dimensions (40m × 10m × 2.5m) and RT60 target (1s).
Open CalculatorField Story
An international airline is upgrading its business class lounge at Singapore Changi Airport to accommodate 80 guests across a 40 m long, 10 m deep space overlooking the taxiway. The full-height airside glazing wall is the dominant reflective surface. Perforated aluminium ceiling with 300 mm plenum cavity covers half the ceiling area, with painted plaster at service runs. Deep-pile carpet throughout eliminates luggage noise and creates the hushed atmosphere expected of a premium lounge. Clusters of high-backed upholstered seating create semi-private zones for working travellers. Fabric-wrapped panels at column reveals absorb speech at ear level. The ASHRAE RC 35-40 target ensures the lounge remains a sanctuary from the gate-area chaos despite constant PA announcements bleeding through partition walls.
Frequently Asked Questions
What RT60 does a Airport Business Lounge — ASHRAE RC 35-40 achieve?
With the specified materials and dimensions (40m x 10m x 2.5m, volume 1000m3), the calculated mid-frequency RT60 is 0.61s using the Sabine equation. The target under ASHRAE is 0.6--1s. The result is a PASS.
What materials are used in this hospitality acoustic example?
This example uses Perforated metal ceiling on the Ceiling — perforated metal (NRC 0.78), Painted plaster on the Ceiling — plaster (NRC 0.04), Heavy carpet on the Floor (NRC 0.29), Double glazing 6mm on the Walls — glazing (airside) (NRC 0.03), Plasterboard on studs on the Walls — plasterboard (NRC 0.07), Upholstered seating on the Seating (80 seats) (NRC 0.55), Fabric-wrapped panel 50mm on the Walls — fabric panels (NRC 0.78), Stone/granite wall on the Bar/counter area (NRC 0.04). The total absorption at 500 Hz is 191.9 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.