Noise Feature - How and when to use the WHO

Back ...authorities fully appreciate the precautionary nature of the WHO guideline values - that's all they are, guidelines. Local authorities don't necessarily take into account the noise level in the area that the development is going into."

In particular, existing houses may already be exposed to higher levels, she points out.

Ealing Council sets its own design criteria: 50dB LAeq,1hr for gardens; 35dB LAeq,1hr for living rooms (which is half way between BS 8233's "good" and "reasonable"); and 30dB LAeq,1hr and 45dB LAeq,1hr for bedrooms. This guidance is not over-strict in the context of the other advice available, feels Cyril Pennington, a senior environmental health officer with a specialist role in noise and nuisance in relation to planning.

The use of a one hour time period goes beyond WHO's use of eight or 16 hours. The reason for adopting one hour is to build a safety factor into the calculations, explains Pennington. The intention is that, in practice, 16 hour and eight hour values will be achieved. "We come across many inaccuracies in practice with theoretical calculations," he says.

Stigwood finds that local authorities are facing considerable pressure from developers who are saying that the authority cannot object if the levels are below the WHO guidelines.

"The guidelines can be used by consultants to meet their own ends," says South Northamptonshire environmental protection officer John Penny. He recalls a case involving a grain drying unit where WHO values would be inappropriate.

A consultant was trying to get the development to go ahead, using arguments and a report based on assessment against the WHO guidelines. "I was saying that it needed to be tested in accordance with BS 4142."

Some local authorities do not have the expertise or resources to push noise issues, Pennington adds. Developers are using guidelines and ambiguity to their own ends, he says. "This may sound cynical, but developers are in it for the money and not the good of the new residents," he says.

Newham wouldn't prohibit building on noisy NEC category D sites, says lead environmental health officer Robin Whitehouse, but it would ~ire a noise report prior to construction to show that a reasonable development could be made there.

Whitehouse points out that insulation has improved since the C and D bands were defined. People would be asked to produce "good" under BS8223, but the policy is flexible. As a fallback, they would certainly have to achieve reasonable, he says.

Parts of the borough near London City Airport could have an Lmax problem using the criteria, perhaps failing to meet the "good" standard in BS8233 because of one or two early flights. "We adopt a flexible approach and will look at the whole development. There may be a situation where two or three buildings out of a whole development might just fail to meet 'good'." In a large development, at least some of the amenity areas should meet the standard, says Whitehouse, and some of the noisier spaces might have other attractions, such as good views of the airport runway.

“There is a serious problem of people taking the guidelines out of context” Mike Stigwood, MAS

A rigid and inflexible application of the WHO guidelines can present significant problems in achieving the objectives of sustainable residential re-development of brownfield land, believes Fiumicelli. He and colleague Nigel Triner presented a paper to the Institute of Acoustics, exploring whether the guidelines were a help or hindrance to sustainable development.

Noise is an inevitable consequence of a thriving and flourishing economy, they said. "It should be possible to permit some noise-sensitive development on a case by case judgment of the merits of each proposal, provided the final noise conditions are controlled so that significant negative impacts are unlikely."

Fiumicelli refers to a case concerning planning permission for a site categorised as NEC D under PPG 24. 'Noise issues were to the fore though planning permission was eventually refused on appeal on other grounds. The inspector's report did however discuss the noise issues. Some external noise levels would have exceeded the 50dB LAeq,1hr set by the local authority's policy, but the inspector felt there would be some justification in considering instead the higher figures from PPG24.

Internally, no habitable rooms or windows would overlook the busy dual carriageway and the inspector felt that acceptable levels could be obtained with windows closed at night. The development would also have reduced the noise for some existing residents, by providing screening.

Ealing's Pennington regrets that there has been a focus in meetings and seminars about local authorities being wrong in setting what they feel are rightful and good standards for their residents. There has, he says, been very little talk, if any, about the known inaccuracy of calculations and models and how to put this right.

"There is widescale abuse of objective noise rating procedures," believes Cobbing - and this is not restricted to WHO. Cobbing encounters situations where objective procedures are used far too slavishly. "A lot of noise consultants think that you can only make objective judgements about noise nuisance if you use objective criteria, more often to the exclusion of all of the other tools which are available."

"People get so absorbed in the maths, the readings and the technology that they often lose sight of what they are trying to do, which is to use numbers to represent the noise in as accurate and objective a manner as possible," is the personal view of Telford & Wrekin Council environmental health team manager Tony Higgins. A number or series of numbers will not necessarily describe the nature of the noise or where the readings were taken and arguments often start because the numbers can be interpreted a hundred different ways, he believes. He is also concerned by an increasing use of predictive noise modelling programs, which produce results that cannot readily be checked. "A potentially disastrous noise problem can appear on paper to be acceptable because of an inconsistent use of a model. Conversely, developments that should go ahead may be quashed."

"I wish somebody would do a sting-type operation on some noise consultants to see what they are prepared to say on their clients' behalf" says Stigwood.

Some spurious results are permitting developments to go ahead. "A lot of local authorities simply don't have the expertise and only spend limited time on noise." They will permit a development when presented with a noise impact assessment that says it is acceptable. "It's only after it's developed that the EHO ends up having to pick up the pieces."

NOISE BULLETIN March 2007