Who is permitted to use BS4142?
Qualified and professional engineers use the BS4142 standard. They are experienced and proficient in conducting noise measurements, surveys and assessments. Usually corporate members of the Institute and Acoustics.
Why is BS4142 used?
The BS 4142 standard
How is BS4142 used?
Sound level meters measure sound levels. The sound levels are rated at outdoor locations for:
- sources of sound in commercial and industrial areas and facilities
- ambient, background and residual sound levels
For what is BS 4142 used?
The methods for rating and assessing industrial and commercial sound are applicable to:
- sound from industrial and commercial premises and from manufacturing processes
- sound from stationary systems, like mechanical and electrical plants and equipment;
- sound from the loading and unloading of items at industrial at or in industrial and commercial facilities;
- sound from mobile machinery that is the core of the total sound emanating from the commercial property, i.e. cranes, forklift trucks, and for harbour equipment and machinery.
The methods described in this British Standard use outdoor sound levels to assess the likely effects of sound on people who might be inside or outside a dwelling or premises used for residential purposes upon which sound is incident.
Assessing the impact of the noise
- The greater this difference in sound level measured, the greater the scale of the impact. Hence. the greater the concern by the enforcement body. And the more effective the mitigation measures should be.
- If a sound source is approximately 10 dB higher than the surrounding or ambient sound level. The level will have a significant impact. All depending on the context.
- If a sound source is approximately 5 dB higher than the surrounding or ambient sound level. The level will have an adverse impact All depending on the context.8
- The lesser the difference in sound level measured, the lesser the scale of the impact. Hence, the lesser the concern by the enforcement body. And lower the likelihood of requiring mitigation measures.
- Where the level is lower than the background level, it implies a low likelihood of having an impact. Yet, action required is still dependent on the context.
The information included in the report
- Statement of qualifications, competency, professional memberships and experience relevant to the application of this British Standard of all personnel contributing to the assessment.
- Assessed and surveyed source
- description of the main sound sources and of the specific sound;
- operational hours of the day;
- mode of operation (e.g. continuous, intermittent, or is it dependent on the weather conditions);
- is the source of the sound running at full load, or partial load
- layout of the premises in which the main sound source is located
- Subjective impression s of the person taking the recordings
- Does a sensitive receptor exist int he area, i.e. school, care home etc.
- Locality of the source to receptors, and the topography of the landscape and buildings.
- equipment used for the assessment
- Weather conditions
There is much more to adhere to in this standard. But, it's directed at the person making the assessment recordings.
Desirable mitigation measures
Providing desirable noise reduction or mitigation measures is usually requested. Yet, we add the mitigation measures to the conclusion of the BS 4142 noise assessment report.
People concerned about specific noise levels request sound level assessments. And if someone is concerned about a noise level. it does suggest that they already know the outcome.
In our experience, mitigation measures were always required after noise assessments. And it was a pleasure to provide the mitigation measures and put them in place.
We are an engineering company with acousticians and mechanical engineers. We address the source of the noise. As we have an appreciation of how the industrial equipment function. From this we can determine the source of the sound. And how to mitigated it. How the noise emanates from the machines and equipment or plants.
It is our ability to dig deep, to find the source and mitigate the noise at its source.
One of our projects this year involved that of noise and vibration - structure-borne sound. It was for planning permission of a building modification.
Several flats were constructed above the ground floor of an existing building. And businesses occupied the ground floor. These businesses had auxiliary equipment. Which included industrial extractor fans, compressors and boilers. All installed at the rear of the premises. The council had a concern about the noise impacting on the future residents of the building.
At the request of the landlord, we performed a noise survey according to BS4142:2019. And reported on the impact on the future residents and proposed mitigation actions.
We provided the customer with a report of our findings. The noise levels, the impact thereof and the mitigation actions.
Our goal was to help the customer. And to provide the relevant data to the enforcement officer.
Through communications with all the parties involved, we succeeded in resolving the concerns. By suggesting cost effective mitigation actions and putting them in place.
The mitigation measures included:
- Replacement of the extractor fan with a lower sound level (49dB).
- anti-vibration mounts for the compressor to isolate the compressor from building structure.