Noise rating
BG 87/2024, Useful Information Guide, written by Chin Hang “Kay” Lam and published by BSRIA in 2024, defines noise rating (NR) as: ‘A criterion, often used in building specifications, for acceptable noise levels. A noise rating gives sound pressure levels (in decibels – dB) which must not be exceeded for a range of octave bands.’
'Noise ratings are a means of specifying acceptable indoor noise levels. Each noise rating (NR) curve gives sound pressure levels which must not be exceeded for a range of octave bands. This acknowledges that higher-frequency sound is considered more intrusive than lower-frequency sound. The graph below shows the maximum allowable sound pressure levels at each octave band for each noise rating. It also illustrates that for NR30, the maximum is 40 dB at 250 Hz, 34 dB at 500 Hz, and 30 dB at 1,000 Hz. Typical noise ratings for a variety of spaces can be found in BG 85 (BG 85/2024 Mechanical Criteria).'
--BSRIA
[edit] Related articles on Designing Buildings
Featured articles and news
Building Control Independent Panel final report
A precis of a key report led by Dame Hackitt with full recommendations and link to the government response.
Guide to ISO 19650 for Architecture Firms (2026)
A user gives their low down.
A UK training and membership provider for mould remediation professionals.
Building Safety recap April, 2026
A short and longer run-through of the month, with links to further information and sources.
CIAT May 2026 briefing.
Independent NSI and BAFE study exploring how organisations are changing the way they buy fire safety services.
From medieval scribes to modern word art.
ECA welcomes crackdown on late payment and push for clean energy, whilst CIOB seek fixed cladding removal timeframes.
Cyber Security in the Built Environment
Protecting projects, data, and digital assets: A CIOB Academy TIS.
Managing competence in the built environment
ITFG publishes new industry guide on how to meet the ICC principles.
The UK's campaign to reduce noise pollution: Mythbusting, articles and topic guides.
Setting Expectations on Competence Management
Industry Competence Committee.
New Scottish and Welsh governments
CIOB stresses importance of construction after new parliament elections.
The sad story of Derby Hippodrome
An historic building left to decay.
ECA, JIB and JTL back Fabian Society call to invest in skills for a stronger built environment workforce.





















