Methods & Personnel
Planning Guidance on Commercial & Industrial Noise
It is usual to assess commercial and industrial noise affecting the site of proposed residential development, as prescribed in The Scottish Executive Development Department publication Planning Advice Note 56 Planning and Noise (PAN56). This suggests various ways of dealing with the noise, depending on its source, as described below. Generally the principle is to predict what level of noise the new development will generate at and/or inside the nearest houses. We do this based on measuring the noise of a similar operation, or using sound level data measured elsewhere in the past, as described below.

Method of Assessing Industrial Noise
The most obvious way of dealing with industrial noise is to assess it to British Standard 4142: 1997 Method for Rating industrial noise affecting mixed residential and industrial areas. Most local authority planning officers stipulate that industrial noise be considered in this way. This involves predicting what the level of industrial noise will be at the houses or flats once the project is up and running, and comparing it to the existing background noise.

Prediction of the industrial noise is often done by visiting a similar site and measuring the noise. The results of the measurements can then be used to calculate what levels will emanate from the new development and propagate to the nearest houses or flats. Prediction of the industrial noise is often done using our extensive database of levels measured in the past on previous projects. This avoids having to visit similar premises to measure the noise and so keeps the cost of the exercise down. Similarly, sometimes manufacturer’s data can be used to predict the noise, for example, earth moving plant comes with good information on noise levels. If, however, we do not have any information on file, because the industrial process is unusual to us, we will visit the site of a similar factory, process, or plant, and measure the noise. The results of the noise level measurements can then be used as described earlier to calculate what levels will exist in future at the houses/flats affected.

Measurement of the background noise is generally straightforward. It is measured at the house/flat which will be most affected by the industrial noise. As the background noise varies with time, it has to be measured over a period of several hours. It is, of course, measured at a time when the business is going to be in production. For a business which is going to operate during the day, the reference time interval, as it is called in BS4142, is one hour. As the background noise varies, it is usually measured over 2 or 3 hours to encompass the changes in level. At night, the reference time interval, is 5 minutes, and so the background noise is measured over 24 or 36 consecutive 5 minute periods, depending on when the factory or plant is going to be in production.

Unfortunately, for the developers, the assessment to BS4142 almost invariably concludes that the noise will lead to complaints. As well as recommending how to control the noise, what we also do, to help present the planning application in the best possible light for the developer, is calculate the noise levels inside the houses. These can then be compared to the limits at which sleep and day-time living disturbance are taken to occur. This is not as punitive as using BS4142, and so can be used to support a development where the assessment to BS4142 does not.

Method of Assessing Leisure Noise
We have measured the noise in dozens of restaurants, pubs and night-clubs and kept the results in a large database. These noise levels can be put, on paper, into your proposed restaurant, pub, or night-club. Then, using details of the construction of the building, we can calculate how much noise will get out of the building and propagate to the residential properties affected. From the noise level at the façade of the residential properties, we can calculate how much will get into them. The internal noise level is then compared to the criterion known as inaudibility which all local authorities in Scotland apply. If the noise proves to be excessive we recommend how to modify the structure of the licensed premises to contain the noise. We can also recommend how to control the noise by modifying the sound system in the premises.

Method of Assessing Commercial Noise
As this is very often mechanical services plant noise, it is quite common to collect the noise data from the manufacturer of the plant and use this to calculate how much will propagate to the nearest flats or houses. From the noise level at the façade of the residential properties, we can calculate how much will get into them. Virtually all local authorities in Scotland apply a limit of noise rating (NR) 35 to this type of noise during the day, and NR25 to it at night. If the noise proves to be excessive, we recommend how to control it by provision of silencers, acoustic enclosures, barriers and other means.

Other forms of commercial noise generally stray into what would be more appropriately termed industrial. That is, where the noise of the commercial activity itself is likely to be problematic, such that from a garage or car body repair shop, it is classed as an industrial noise.

Method of Assessing Construction Site Noise
This, being temporary, is not usually of concern to the planning officer. Occasionally, on long term projects, the officer issues a Notice of Prior Consent. This often includes noise level limits, applicable at the houses/flats in the area. These are often based on the existing ambient noise levels, which of course we can measure. For example, we recently did exactly this in connection with the upgrading of the A8000 link to the Forth Road Bridge.

Often the Consent stipulates that the contractor must use best practicable means to control the noise as specified in British Standard 5228: 1997 Noise and vibration control on construction and open sites. This document has 4 large volumes and is pretty daunting to the uninitiated. We can advise on how to comply with its recommendations.

Method of Assessing Traffic Noise
Occasionally, when a new road is planned, or an existing one modified, the planning officer asks that the noise of the traffic be predicted at houses/flats in the vicinity. We can do this using the procedures set out in Calculation of Road Traffic Noise published by the Department of Transport. The noise levels are then compared the limits, given in the Noise Insulation Regulations, at which grants must be given to insulate the houses/flats. Sometimes the noise is compared to the 45dB(A) and 35dB(A) day and night-time limits given in PAN56 with respect to transportation noise.

Method of Assessing Railway Noise
Even less common than new roads are new railways. We have, however, been asked to consider noise from the new railway from Stirling to Kincardine, and the proposed south suburban line in Edinburgh. This has been done using Calculation of Railway Noise and our extensive database of noise levels measured beside existing railways. We have also been asked to work out whether noise from the proposed tram system in Edinburgh and light rail link from the airport to the city centre would bother residents along their routes.

Assessment Position
A single assessment position is usually sufficient, at the most exposed house or flat. The principle in this is that, if the noise is acceptable at the most exposed house or flat, it follows that it will also be acceptable at the other, less exposed ones. In any event, the planning officer will not accept the results of assessments made on houses or flats which are not the most exposed to the noise.

Instruments
We use only Brüel & Kjær instruments. These are the “Rolls Royce” of acoustical instrumentation and give more accurate results than the equipment used by some of our competitors. This is important, as inaccurate readings can lead to you having to incorporate expensive noise control measures in the factory, pub, ventilation system, etc, which may not, in fact, be necessary.

Personnel
Noise measurements are made by either Charlie Fleming or Peter Hubbard. Other companies may leave their instruments supervised by a technician or person with no knowledge of acoustics. (Peter has an honours degree in acoustics and several years experience in environmental noise). Analysis of the results and calculations are usually carried out by Peter, supervised by Charlie. The report is prepared by Charlie.

From start to finish your planning application is dealt with by experienced, highly qualified acousticians. Some other companies do not have this experience and the consequences of this are outlined in Why Choose Charlie Fleming Associates?