What is the legal noise limit for construction sites?

There is no single legal limit, but local authorities typically set daytime limits of 65-75 dB(A) LAeq at the nearest noise-sensitive receiver. BS 5228 provides guidance values: 65 dB for low ambient areas, 70 dB for suburban, and 75 dB for urban/industrial areas. Work outside permitted hours (usually 08:00-18:00 Mon-Fri, 08:00-13:00 Sat) is generally not allowed.

How does distance affect construction noise?

For a point source, noise decreases by approximately 6 dB for every doubling of distance. So if a concrete breaker is 95 dB at 10m, it will be approximately 89 dB at 20m, 83 dB at 40m, and 77 dB at 80m. This is the inverse-square law. Line sources (e.g., traffic) decrease by only 3 dB per doubling of distance.

How much noise does a barrier reduce?

A solid construction site barrier (2.4m high hoarding) typically reduces noise by 5-15 dB depending on its height relative to the line of sight between source and receiver. A barrier that just breaks the line of sight gives about 5 dB reduction. Higher barriers or earth bunds can achieve 10-15 dB. The barrier must have no gaps to be effective.

What is a Section 61 consent?

Under Section 61 of the Control of Pollution Act 1974, a contractor can apply to the local authority for prior consent for construction works. This sets agreed noise levels, working hours, and best practicable means (BPM) of noise control. Having Section 61 consent provides a defence against prosecution under Section 60 noise nuisance notices.

What is on-time percentage in noise assessment?

On-time percentage represents the proportion of the assessment period during which the noise source is actually operating. For example, a concrete breaker that operates for 4 hours in an 8-hour day has 50% on-time. The LAeq is adjusted by 10 × log10(on-time/100) — so 50% on-time reduces the LAeq by 3 dB compared to continuous operation.

TradeCalculator

Noise Assessment Calculator

Estimate construction noise levels at a receiver position, accounting for distance attenuation, barriers and on-time percentage. Based on BS 5228.

Activity / Source

Select or enter custom dB level

Distance to Receiver

From noise source to nearest property

On-Time Percentage

% of working day equipment operates

Working Hours Per Day

Duration of noisy works

Noise barrier present

Solid hoarding or earth bund between source and receiver

How We Calculate This

This calculator estimates noise levels at a receiver position using source noise data from BS 5228, distance attenuation (inverse-square law), barrier correction, and on-time percentage adjustment.

The formula

Attenuation = 20 × log10(Distance ÷ Reference distance)
Level at receiver = Source dB - Attenuation - Barrier
LAeq = Level + 10 × log10(On-time % ÷ 100)

For a concrete breaker at 95 dB(A) at 10m, receiver at 50m, 10 dB barrier, 50% on-time: attenuation = 14 dB, level = 95 - 14 - 10 = 71 dB, LAeq = 71 - 3 = 68 dB(A).

Typical noise levels

Concrete breaking: 95 dB(A) at 10m
Piling: 90 dB(A) at 10m
Demolition: 85 dB(A) at 10m
General construction: 75 dB(A) at 10m

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.