This document is intended to assist licensed sites with the assessment of their potential and
actual noise impact on the local environment. It provides the relevant knowledge and guidance
to licensees together with their consultants, regulators and interested third parties.
The Agency has previously issued three documents in relation to the assessment and
management of noise emissions from licensed facilities, namely the Environmental Noise Survey
Guidance Document1 (commonly referred to as NG1), Guidance Note For Noise In Relation To
Scheduled Activities – 2nd Edition2 (commonly referred to as NG2) and Guidance Note on Noise
Assessment of Wind Turbine Operations at EPA Licensed Sites3 (NG3). It has been decided to
amalgamate NG1 and NG2 into one document, designated NG4, for ease of reference and to
avoid repetition and confusion which may occur with the use of two separate documents. These
two earlier noise guidance notes (NG1, NG2) are now withdrawn with immediate effect.
Where noise limits are currently set for licensed sites they are typically expressed in terms of day-time and night-time limits at levels of 55 dB(A) and 45 dB(A), respectively. The new guidance introduces an evening-time limit of 50 dB(A), with corresponding adjustments to the day-time and night-time periods:
- Day: 07:00-19:00, 55 dB(A) LAr,T
- Evening: 19:00-23:00, 50 dB(A) LAr,T
- Night: 23:00-07:00, 45 dB(A) LAeq,T
Day-time is generally defined in relevant licenses as being between 08:00 to 22:00. While the guidance does not propose that the limits set out in current licenses will be updated to the new limits, it is intended that both new licenses and licenses that are subject to review, will be eventually amended to adopt the new noise limits.