The sound insulation of a partition (wall, screen, door) is measured by the index Rw (laboratory) or DnTw (in-situ). It expresses by how many decibels the sound passing from one side of the partition to the other is attenuated. A higher index means better insulation. In-situ values are usually 2–5 dB lower than laboratory ones due to flanking (lateral sound transmission through the ceiling, floor and adjacent partitions).
The Polish standard PN-B-02151-3:2015 sets out the minimum requirements for internal partitions:
- Walls between offices (one person or a small company): R'w ≥ 35 dB
- Walls between a conference room and an office: R'w ≥ 45 dB
- Walls next to noisy rooms (call centre, production): R'w ≥ 50 dB
- Doors to private offices and rooms: R'w ≥ 30 dB
It is worth noting that the standard applies to new buildings or those after a major renovation. In practice, many offices operate below these requirements, especially when partitions were installed without an acoustic design.
The insulation of office partition systems differs significantly depending on the construction:
- Desktop screens (Soft and similar): Rw < 15 dB. Not intended for insulation.
- System 20, 32 mm upholstered infill: Rw ≈ 25–30 dB. Zone separation.
- System 32, 52 mm upholstered infill: Rw ≈ 38–42 dB. Meets the standard for offices.
- System 32, 10 mm laminated glass (VSG): Rw ≈ 40–44 dB. Similar to upholstery.
- Double partition with an air gap: Rw ≈ 50–55 dB. For extreme requirements.
Important: these values apply to the partition itself, without penetrations, gaps beneath it or flanking. In reality, every leaky joint lowers the insulation by 5–15 dB.
The starting noise level in a call centre is 70–80 dB. The permissible noise level for office rooms with intellectual work is 55 dB. Required insulation: 80 − 55 = 25 dB. Add a margin for flanking and leaks: +10 dB. Required partition insulation: 35 dB. System 32 with upholstery meets this requirement with room to spare.
For a typical open-plan office (noise level 65 dB) and a private office (target 45 dB): 65 − 45 + 10 = 30 dB. Here System 20, or even System 32 in a simplified configuration, is enough.
Flanking is the transmission of sound "around" a partition: through a suspended ceiling, through a raised floor, through adjacent walls. In offices with a modular ceiling, sound freely passes above the partitions if no acoustic inserts have been used. A good partition without a sealed ceiling loses 10–20 dB of effective insulation. That is why conference room designs with high requirements always account for ceiling insulation, not just the partitions.