Shielding effectiveness (dB)
Attenuation expressed logarithmically: 10 dB removes 90% of power density, 20 dB removes 99%, 30 dB removes 99.9%.
measurement
Last verified 12 August 2026.
- Category
- measurement
Definition
Shielding effectiveness is the ratio of incident to transmitted field, in decibels, at a stated frequency. Datasheet figures are measured on flat samples in a test fixture; installed performance is governed by seams, edges and penetrations and is routinely 10–20 dB worse. Because the scale is logarithmic, a small dB shortfall is a large change in transmitted power.
Sources
- sbm-2024 Building Biology Evaluation Guidelines for Sleeping Areas (SBM-2024) — Institut für Baubiologie + Nachhaltigkeit (IBN), 2024. ngo, link checked 2026-08-12.
Same record, other formats