The National Planning Policy Framework requires planning authorities in England to consider noise as a material planning consideration. It does not set noise limits. Instead, it establishes the policy principles that govern when noise assessments are required, how significance is determined, and what mitigation is appropriate. The two most important principles for developers are the agent of change principle (the party introducing a noise-sensitive use near a noise source bears responsibility for managing the acoustic consequences), and the requirement to avoid placing noise-sensitive development in high-noise locations unless unacceptable impacts can be adequately mitigated. In practice, NPPF noise policy is implemented through technical standards including BS4142 and BS8233, and professional guidance including ProPG.

BS8233:2014 is the British Standard used to assess whether residential development near roads, railways, or other noise sources can achieve acceptable internal and external noise levels for future occupants. It sets out criteria for bedrooms, living rooms, and gardens across daytime and night-time periods. The most commonly referenced targets are 35 dB LAeq during the day and 30 dB LAeq at night for bedrooms. A BS8233 assessment is almost always required for residential planning applications in noise-sensitive locations, and is often conditioned by the local planning authority. ProPG (2017) sits alongside BS8233 and provides professional guidance on how assessments should be scoped and presented. This guide covers both.

Open plan office acoustics comes down to three things: controlling reverberation so speech is clear, managing background noise so people can concentrate, and achieving speech privacy so conversations do not travel. The key targets for open plan offices are a reverberation time (RT60) of 0.4 to 0.6 seconds, a background noise level of around 40 to 45 dB LAeq, and a Speech Transmission Index (STI) that limits intelligible speech to the immediate vicinity of the speaker. Achieving these consistently requires an integrated approach. Acoustic panels alone are rarely sufficient without also considering layout, screening, ventilation noise, and room geometry. This guide covers the principles, the targets, and the practical steps to get there.