What are the maximum NC values for Open Office & Lobbies, Enclosed Offices, Conference/Breakout Room, and Teleconference Room?

• A. Open Office & Lobbies = max 40 NC; Enclosed Offices = max NC 35; Conference/Breakout Room = max NC 30 (25 recommended); Teleconference Room = max NC 20.
• B. Open Office & Lobbies = max 42 NC; Enclosed Offices = max NC 37; Conference/Breakout Room = max NC 28; Teleconference Room = max NC 22.
• C. Open Office & Lobbies = max 40 NC; Enclosed Offices = max NC 35; Conference/Breakout Room = max NC 25 (20 recommended); Teleconference Room = max NC 18.
• D. Open Office & Lobbies = max 45 NC; Enclosed Offices = max NC 40; Conference/Breakout Room = max NC 32; Teleconference Room = max NC 30.

Answer: (A)

Focus on what NC values mean for different spaces. NC, or Noise Criterion, is a measure of the ambient background noise level that a space should not exceed. Higher NC values tolerate louder environments, while lower values require quieter spaces to support speech intelligibility and comfort.

For Open Office and Lobbies, a maximum NC of 40 reflects the naturally noisier, high-traffic character of these areas. It allows everyday activity, machines, and conversations without making the space feel unnaturally quiet.

Enclosed Offices should have a tighter limit, about 35, because privacy and concentration are important in such rooms. The lower limit helps reduce distractions from nearby activity.

Conference or Breakout Rooms have a target around 30, since these spaces are used for meetings where clear communication is essential. A commonly recommended value is 25 to improve speech intelligibility, with 30 as the upper cap.

Teleconference Rooms require the quietest environment of these spaces, with a maximum NC of 20 to ensure audio clarity during calls.

The other options mix numbers that don’t align with these typical WELL targets, such as higher caps for spaces that should be quieter or lower caps for spaces that can tolerate more noise. The stated set matches the well-established targets: Open Office & Lobbies 40, Enclosed Offices 35, Conference/Breakout Rooms 30 (25 recommended), Teleconference Rooms 20.