🏢WELL v2 Feature S01 (Sound) · International

Open Plan Office Acoustic Design to WELL v2 Feature S01 (Sound)

Open plan offices present a unique acoustic paradox: speech must be intelligible within conversation groups but unintelligible beyond the distraction distance to preserve privacy and concentration. ISO 3382-3:2012 defines the key metrics — spatial decay rate D2,S, distraction distance rD, and A-weighted SPL of speech at 4 m (Lp,A,S,4m).

TL;DR

Under WELL v2 Feature S01 (Sound), a open plan office of 400-600 m³ (typical dimensions 20m × 10m × 2.8m) requires an RT60 of ≤ 0.5s at 500-2000 Hz. Background noise must not exceed 45 dBA. WELL v2 Feature 74 has three parts for open-plan offices: Part 1 sets RT60 <= 0.

RT60 Target

≤ 0.5s

Noise Limit

45 dBA

STI Minimum

N/A

Frequency Range

500-2000 Hz

Specific Requirements

Parameter	Target	Clause Reference	Notes
Reverberation Time (RT60)	≤ 0.6s	S04	500-2000 Hz, Furnished, unoccupied, <500 m³
Background Noise Limit	≤ 40 NC	S01 Part 2	HVAC + building services, unoccupied
Frequency Range	500-2000 Hz	—	Octave bands for compliance assessment

Step-by-Step Compliance Calculation

1
Map WELL Feature 74 parts
Identify which of the three parts apply: Part 1 (RT60), Part 2 (background noise), Part 3 (speech privacy).
2
Design absorption strategy
Achieve RT60 <= 0.5s in enclosed rooms and maximise absorption in open areas for speech privacy.
3
Specify sound masking
Design sound masking system at 45 dBA with spectrum shaped for speech frequency masking. Zone for different areas.
4
Install desk screening
Specify absorptive screens at least 400mm above desk level to block direct speech paths between workstations.
5
Commission and verify
Engage WELL-approved acoustician to measure RT60, background noise, and STI at representative positions for certification.

Recommended Materials

Surface	Material Category	Min NRC	Coverage %
Ceiling	Mineral wool ceiling tile	0.90	85%
Desk screens	Absorptive desk divider	0.80	100%
Masking system	Sound masking speakers	0.00	100%
Floor	Carpet tile	0.30	100%

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

Common Failure Modes

⚠️Part 3 speech privacy failure

STI between workstations exceeds 0.50 without sound masking, the most commonly failed WELL acoustic requirement.

⚠️Masking system calibration

Sound masking installed but not professionally calibrated produces uneven coverage with audible hotspots and gaps.

⚠️Enclosed room leakage

Meeting rooms within the open plan have insufficient partition STC, allowing speech to be intelligible at adjacent desks.

Frequently Asked Questions

What RT60 does WELL v2 Feature S01 (Sound) require for a open plan office?

WELL v2 Feature S01 (Sound) requires a reverberation time of ≤0.5s at 500-2000 Hz for open plan office spaces. WELL v2 Feature 74 has three parts for open-plan offices: Part 1 sets RT60 <= 0.5s for meeting rooms within the floor plate; Part 2 limits background noise; Part 3 requires speech privacy with STI < 0.50 between workstations. Sound masking to 45 dBA is typically needed for Part 3 compliance.

What is the maximum background noise level for a open plan office under WELL v2 Feature S01 (Sound)?

WELL v2 Feature S01 (Sound) sets a maximum background noise level of 45 dBA for open plan office 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 open plan office need to comply with WELL v2 Feature S01 (Sound)?

A typical open plan office (400-600 m³) requires Mineral wool ceiling tile (NRC ≥0.9) covering 85% of the ceiling as the primary treatment. Additional wall absorption on 3 surface(s) is typically needed. Use the AcousPlan calculator with the pre-loaded dimensions (20m × 15m × 2.8m) to calculate the exact absorption deficit for your room.

Calculate WELL v2 Feature S01 (Sound) Compliance for Your Open Plan Office

Pre-loaded with typical open plan office dimensions (20m × 15m × 2.8m) and an RT60 target of 0.5s per WELL v2 Feature S01 (Sound). Enter your actual dimensions, select materials, and verify compliance instantly.

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