🍽️BS 8233:2014 · United Kingdom

Restaurant Acoustic Design to BS 8233:2014

Restaurant acoustics must balance conversation intelligibility with ambient atmosphere. Excessive reverberation triggers the Lombard effect, where diners progressively raise their voices, creating an escalating noise spiral that can reach 85+ dBA at peak service.

TL;DR

Under BS 8233:2014, a restaurant of 300-500 m³ (typical dimensions 15m × 10m × 3.5m) requires an RT60 of ≤ 1s at 500-2000 Hz. Background noise must not exceed 55 dBA. BS 8233:2014 Table 4 recommends RT60 <= 1.

RT60 Target

≤ 1s

Noise Limit

55 dBA

STI Minimum

N/A

Frequency Range

500-2000 Hz

Specific Requirements

Parameter	Target	Clause Reference	Notes
Reverberation Time (RT60)	≤ 1s	§7.7	500-2000 Hz, Furnished, unoccupied
Background Noise Limit	≤ 45 LAeq,T	Table 4	HVAC + building services, unoccupied
Frequency Range	500-2000 Hz	—	Octave bands for compliance assessment

Step-by-Step Compliance Calculation

1
Define acoustic ambiance target
Fine dining: RT60 0.6-0.8s, LAeq 65-70 dB. Casual: RT60 0.8-1.0s, LAeq 70-75 dB. Lively: RT60 up to 1.0s.
2
Calculate absorption deficit
Assess existing surfaces and calculate additional absorption needed to achieve target RT60 at mid-frequencies.
3
Design invisible treatment
Use acoustic plaster, concealed baffles, upholstered seating, and under-table panels to maintain design aesthetic.
4
Isolate kitchen noise
Specify kitchen partition STC 45+ or design acoustic pass-through with baffles for open-kitchen concepts.
5
Verify during service
Measure RT60 when empty and monitor LAeq during peak service to confirm acoustic comfort targets are met.

Recommended Materials

Surface	Material Category	Min NRC	Coverage %
Ceiling	Acoustic ceiling or baffles	0.80	60%
Walls	Upholstered banquette or panel	0.60	30%
Under table	Acoustic panel	0.70	20%

Browse the full acoustic materials database for absorption coefficients and product specifications.

Common Failure Modes

⚠️Industrial aesthetic conflicts

Exposed brick, concrete, and metal surfaces in trendy restaurant designs produce RT60 of 1.5-2.0s without treatment.

⚠️Lombard effect escalation

RT60 above 1.2s triggers the Lombard effect where diners raise voices progressively, reaching uncomfortable 80+ dBA levels.

⚠️Kitchen noise breakthrough

Open-plan kitchens or inadequate kitchen partitions allow cooking and extraction noise to dominate the dining space.

Frequently Asked Questions

What RT60 does BS 8233:2014 require for a restaurant?

BS 8233:2014 requires a reverberation time of ≤1s at 500-2000 Hz for restaurant spaces. BS 8233:2014 Table 4 recommends RT60 <= 1.0s for restaurants with ambient noise levels of 45-55 dBA considered acceptable during service. Lower RT60 of 0.6-0.8s improves conversation quality in fine dining. The Lombard effect causes noise escalation above 75 dBA if RT60 exceeds 1.2s.

What is the maximum background noise level for a restaurant under BS 8233:2014?

BS 8233:2014 sets a maximum background noise level of 55 dBA for restaurant spaces. This includes noise from HVAC systems, building services, and external intrusion, measured with the room unoccupied. Exceeding this limit degrades speech intelligibility and occupant comfort.

How much acoustic treatment does a restaurant need to comply with BS 8233:2014?

A typical restaurant (300-500 m³) requires Acoustic ceiling or baffles (NRC ≥0.8) covering 60% of the ceiling as the primary treatment. Additional wall absorption on 2 surface(s) is typically needed. Use the AcousPlan calculator with the pre-loaded dimensions (15m × 10m × 3.5m) to calculate the exact absorption deficit for your room.

Calculate BS 8233:2014 Compliance for Your Restaurant

Pre-loaded with typical restaurant dimensions (15m × 10m × 3.5m) and an RT60 target of 0.8s per BS 8233:2014. Enter your actual dimensions, select materials, and verify compliance instantly.

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