Wave Dynamics GuidesEPA NG4 Explained
What the EPA Guidance Note for Noise (NG4) covers, the default noise limits, quiet area screening and survey requirements for licensed sites.
In Short
NG4 is the Environmental Protection Agency guidance note on noise for licence applications, noise surveys and assessments at EPA-licensed sites in Ireland, such as industrial, waste and intensive agriculture facilities. It sets out how surveys should be done and the typical noise limits applied at nearby sensitive locations.
- Applies to Industrial Emissions, IPC and Waste licensed facilities.
- Typical limits: 55 dB day, 50 dB evening and 45 dB night (LAr,T) at sensitive locations.
- Lower limits can apply in quiet areas or areas of low background noise.
- Sets out survey methods, reporting and tonal and impulsive checks.
Who Needs to Follow NG4?
NG4 applies to facilities that hold or are applying for an EPA licence. It is used for baseline surveys for new licence applications, annual or periodic compliance surveys and investigations after complaints. Planning authorities sometimes refer to it for non-licensed sites too.
Typical Noise Limits
For most sites, NG4 recommends limits at noise-sensitive locations of 55 dB LAr,T by day (07:00 to 19:00), 50 dB in the evening (19:00 to 23:00) and 45 dB LAeq,T at night (23:00 to 07:00). There should be no clearly audible tonal or impulsive noise at night. Where an area screens as quiet, or background noise is low, lower limits may be set.
Quiet Area and Low Background Screening
NG4 includes a screening process to decide whether a site is in a quiet area, based on distance from roads, towns and industry, or an area of low background noise, based on measured LA90 levels. This screening often decides which limits apply, so it needs careful, well-documented survey data.
Survey and Reporting Requirements
- Class 1 sound level meters with current calibration.
- Measurements at the nearest noise-sensitive locations and at boundaries.
- Day, evening and night periods, with notes on audible sources.
- Checks for tonal and impulsive characteristics.
- A clear statement of compliance and any recommended actions.
Frequently Asked Questions
How often are NG4 compliance surveys needed?
The frequency is set in the site licence. Many licences require annual surveys, with extra surveys after complaints or changes to the site.
Does Wave Dynamics carry out EPA licence surveys?
Yes. We carry out NG4 noise surveys and EPA air quality surveys for licensed sites across Ireland.
This guide gives general information and is not a substitute for project-specific advice. Requirements change, so always check the current regulations, guidance and your planning conditions. Ask our team about your project.
Jon Maguire (BSc Hons MIOA) brings over 8 years of expertise in acoustic consultancy, specialising in environmental acoustics with a focus on 3D modelling, assessments, and detailed design for industrial, commercial, and energy projects. He has lead noise assessments for key clients while thriving in multidisciplinary environments. Jon’s diplomatic communication skills are ideal for stakeholder consultation.
Jack is a Field Engineer at Wave Dynamics, supporting the delivery of environmental monitoring and acoustic consultancy services through detailed on-site fieldwork. He has hands-on experience in noise monitoring, vibration monitoring, and dust monitoring across a variety of infrastructure, construction, and environmental projects. Jack is involved in the setup, operation, and maintenance of monitoring equipment, ensuring accurate data collection in line with relevant standards and project requirements. He works closely with consultants and project teams, providing reliable field support that underpins high-quality assessments and reporting.
Aidan is the Director for all U.K Operations and has worked in multiple industries including for clients in the UK and internationally operating in the residential, industry, healthcare, education, and construction sectors.
