The role of ČSN 73 0532
ČSN 73 0532 ("Acoustics — Protection against noise in buildings — Requirements") is the central Czech standard covering acoustic requirements in buildings. It is published and periodically updated by the Czech Office for Standards, Metrology and Testing (ÚNMZ). The current version in force is from 2010 with later amendments.
The standard applies to new construction and to alterations that change the acoustic conditions of a building. It defines minimum performance values for separating elements — walls, floors, roofs — and for secondary elements such as doors and windows. Values are given in terms of the weighted sound reduction index (Rw, measured in a laboratory) and the apparent weighted sound reduction index (R'w, measured in the field), with the latter being lower due to flanking transmission.
Key performance indicators
Three quantities are most frequently referenced in Czech residential acoustic work:
- Rw (weighted sound reduction index): a single-number laboratory rating of a construction element's resistance to airborne sound. Higher is better. Measured according to EN ISO 10140.
- R'w (apparent weighted sound reduction index): the in-situ equivalent, accounting for flanking paths through connected structure. Always lower than Rw. Measured according to EN ISO 140-4.
- L'nw (weighted normalised impact sound pressure level): the in-situ measurement of how much impact sound passes through a floor to the space below. Lower is better. Measured according to EN ISO 140-7.
Minimum values for apartments
The table below summarises the minimum values from ČSN 73 0532 for standard residential buildings (apartments). These apply to new-build and major renovation. Minor cosmetic renovation does not trigger the full standard, but new separating elements must meet the values when they are part of the work scope.
| Building element | Minimum R'w (dB) | Maximum L'nw (dB) |
|---|---|---|
| Floor between apartments (airborne) | 52 | — |
| Floor between apartments (impact) | — | 58 |
| Wall between apartments | 52 | — |
| Floor between apartment and stairwell | 47 | 58 |
| Wall between apartment and stairwell | 47 | — |
| Wall between apartment and commercial | 57 | — |
| Apartment entrance door | 32 | — |
How the standard interacts with Czech building regulations
The Czech Building Act (Zákon č. 183/2006 Sb.) and the related implementing decrees require that new buildings and specified categories of renovation satisfy declared acoustic performance values. In practice this means that a building permit (stavební povolení) for a new residential building must include documentation showing compliance with ČSN 73 0532, typically in the form of an acoustic report prepared by a certified specialist.
For renovation projects that involve replacing an existing separating element — a floor or a dividing wall — the same requirement applies. Purely cosmetic renovations (replacing floor finishes, repainting walls) do not trigger the acoustic requirement unless the work materially changes the acoustic properties of the element.
The gap between laboratory and field performance
A product tested in a laboratory to Rw 60 dB will not achieve that figure in a real building. The difference, typically 3–8 dB, comes from flanking transmission: sound bypassing the intended element by travelling through connected structure — the floor slab, the ceiling, the walls perpendicular to the partition. In Czech panel-block construction (panelák buildings), flanking is often significant because the concrete structure is highly interconnected.
The practical consequence is that achieving the minimum R'w 52 dB in a panelák apartment often requires either double-leaf construction with significant mass, resilient decoupling, or a combination of both. A single-layer plasterboard partition that meets R'w 52 dB in a standard timber-frame test building is unlikely to do so in an existing panel block without additional treatment of flanking paths.
Noise from building services
ČSN 73 0532 also sets limits for noise from building installations — pipes, ventilation ducts, and lift machinery. The permitted equivalent continuous sound pressure level (LAeq) in a bedroom is 25 dB(A) at night, and 30 dB(A) in a living room during the day. Compliance with these values is increasingly scrutinised in building inspections for new apartment buildings, particularly those with mechanical ventilation and heat recovery systems.
External noise: the role of zoning and planning
For apartments near busy roads, railways, or airports, the external noise environment is governed separately, primarily by Government Regulation No. 272/2011 Coll. (Nařízení vlády č. 272/2011 Sb.) on protection against noise and vibration. This regulation sets outdoor and indoor noise limits by zone type and time of day. It is enforced by Public Health Protection Authorities (krajské hygienické stanice). Where external noise exceeds limit values, the building facade — including windows and ventilation openings — must provide sufficient attenuation to meet the indoor limit.
The Czech Environmental Inspectorate (ČIŽP) publishes noise maps for major road and rail routes; cizp.cz is a starting point for reviewing measured noise levels by location.
Finding the official standard
ČSN 73 0532 is available for purchase through the ÚNMZ catalogue at unmz.cz. Selected acoustic consultants also publish summaries of the key values for practical reference. TZB-info.cz maintains a free technical reference section covering Czech acoustic requirements.