All toolsCalculatorsMechanicalPlant Noise at Distance / Boundary Check

Plant Noise at Distance / Boundary Check

Predict plant noise at a site boundary or neighbour façade from sound power (or Lp@1m) sources, combined logarithmically, with barrier and façade corrections, verdicted against an entered limit.

Assessment scenario

Propagation model

Q=2 hemispherical is the default for plant on ground or a wall bracket

Distance to boundary/receiver

Shared by every source below

Boundary/background limit

dB(A)

The limit this scenario is verdicted against

MCS 020 note (domestic ASHP context — not applied automatically)

MCS-020(a) is mandatory for Permitted Development from 20 Sep 2025; the 42 dB(A) figure is historical

Corrections (editable, sourced advisory defaults)

Barrier attenuation

Advisory band 5–10 dB for a garden-fence-scale barrier

Façade reflection

Applies only when assessing close to a receiver's own reflecting wall

Plant sources

Label

Level type

Level

dB(A)

Count

Source	Type	Level	Count
ASHP outdoor unit	Lw	65 dB(A)	1
Pool pump	Lp@1m	55 dB(A)	1

Check field values — distance, boundary limit and every source level must be valid, counts must be whole numbers ≥ 1