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Sounding out the facts

technical & practice - The recent AJ Part E conference looked at designing for compliance and making sense of the new sound regulations

Les Fothergill is a civil servant's civil servant. The monotone, the detatchment and, most importantly, the lack of deviation from the facts and the official line make Fothergill an ideal conference speaker. You know what you are going to get: an insight into backroom legislative discussion without any frills or the intrusion of a personal opinion; a clinical presentation of what is likely to happen (far be it from Fothergill to tell you definitively what will happen. ) Fortunately then, it was Fothergill who kicked off the AJ 'Part E: Designing for Compliance' conference at the RIBA last month. Fortunate in that we started the day with some hard realities of what the legislation will mean to architects and fortunate in that we could then settle down to a day of more entertaining presentations.

As it happens, this event built into a real critical analysis of acoustic issues for architects and acoustic designers alike.

BRE surveys indicate that 25 per cent of separating walls and 40 per cent of separating floors in new dwellings failed to meet the 1992 Part E standards. This shocking opener does not bode well for compliance with the new Part E, which has been in force since July 2003.

For a large number of dwellings already in production when the subsidiary Robust Detail requirements came into force in July 2004, non-compliance will be more readily recorded in pre-completion testing. There will be an awful lot of tears shed and money laid out over the remedial works that will now be mandatory before a compliance certificate will be issued.

Fothergill's parting shot that the new amendments to the Approved Document E 'will be consolidated in due course' was enough to set teeth on edge.

Sean Smith of Napier University and co-project manager of the Robust Standard Details (RSDs) project then took the stage and outlined the history of the development of robust details as a working mechanism for compliance, bearing in mind that RSDs are not deemed to satisfy and normal building-control checks still apply.

Smith was at pains to describe the amount of research work and field testing that has gone into the production of the RSDs. He said each detail was tested a minimum of 30 times over a minimum of four different sites using three or more acoustic contractors. He pointed out that the current situation, whereby the RSD is designed such that construction to suit will result in a 5db overengineered acoustic solution, was intended to allow scope for (poor) on-site workmanship standards.

As Rod Pearson, design executive with Crest Nicholson South, put it: 'It is a failsafe margin which gives some protection against pre-completion testing.' Designing to the limit, as has often been the case with cost-conscious contractors, might tempt fate, and anyway, as Pearson pointed out, correct detailing ought not to cost any more. He proceeded to show a comparison between the old and the new approved standards for a variety of constructions and showed that to meet the new requirements normally required detailing to the same specification.

Also, as convenor Paul Finch explained, construction cost increases are regularly translated into reducing the price paid for the land, rather than being passed on to the consumer.

Improved performance standards, it was suggested, should therefore represent a win-win situation for purchasers, and depress inflated land values.

Sign, don't sign Ben Derbyshire, managing director of HTA Architects, who was standing in for HTA's in-house acoustician, gave somewhat overly casual advice to conference that architects should sign the Compliance Certificate at the end of a job.

'Architects cannot ignore these things, ' he said. 'They should sign.' Unfortunately, since The Architects' Journal flagged up the fact that there may be serious liability implications arising from signing a compliance certificate (AJ 1.7.04) it has raised it with RIBA Practice committee, which we understand hopes to consider the matter in the next session. As yet, the RIBA has not issued advice on this and so caution is advisable.

Derbyshire, who proclaimed himself 'a great believer in market research data', looked at the subjective nature of noise disturbance and reported that 'even with good insulation a substantial number of people may still report that they are disturbed by noise from neighbours'. This did not necessarily square with his suggestion that the increasing number of complaints about noise therefore represented an increased problem of noise. In the same way that crime has gone down but fear of crime has risen, the fact that more people complain about noise may simply reflect the heightened realisation of noise as an issue. This is a societal issue, as much about what people expect as what people can tolerate, and might be a political issue even more than it is a technocratic one. This could have been an interesting avenue to explore, looking at whether the promotion of increased acoustic separation itself causes a heightened sensitisation to otherwise everyday noise levels.

Andrew Corkhill, managing director of Spectrum Acoustics, provided a reasoned explanation of the problems and dangers inherent in the revised regulations. Since manufacturers can add their tried-and-tested (to compliance) elements to the continually evolving pack of RSDs, he said that RSDs 'could end up being manufacturers' proprietary products because they have the financial resources to fund testing and approval processes'.

In other words, architects may find themselves using RSDs that tie them into proprietary systems.

Instead, he suggested that the use of generic details and reasonable building standards will tend to meet the new regulations anyway. He usefully reminded the audience that use of an RSD is no guarantee of compliance, nor should architects simply accept lab-tested results data from manufacturers, which test the single product in isolation rather than the element in situ. While a product might provide suitable acoustic separation in theory, in practice, flanking transmissions can eradicate any meaningful acoustic separation.

Unreliable failures After this useful presentation, the lugubrious Phil Dunbavin, principal consultant with PDA, took the stage.

As chair of the Robust Detail Inspectorate, he will be one of the people who might be doorstepping your siteworks any day now to test compliance. He is undoubtedly going to be a difficult man to please. While he is very much a letter of the law man - 'we will not be intimidated? if you fail, you fail' - he spent the first half of his presentation stating how unreliable - or at least questionable - is the accuracy of test results.

As Rod Pearson said later: 'Acoustics seem to be a very chancy sort of science, and the test results on a given form of construction can vary enormously;

and this has, justly or not, instilled a lack of confidence in the process.' Not only that, but the convoluted methodology to calculate reverberation times and db ratings - which effectively cannot be done by an architect because they are too specialised - may push architects to use Method B in Table 7.1, which lists the absorption coefficients of a series of standard materials. Andy Jobling, technical manager with Levitt Bernstein, was concerned that, as a consequence, architects will not bother to use challenging, experimental materials 'because the information on their absorption coefficients is impossible to find'.

Jobling outlined the interminable calculation sheets required to apply retrospectively to standard housing types (using a case study of a phased housing development that had taken such a long time to start on site that the Part E regulations had to be applied to later phases). Concluding that there is an awful lot of bureaucracy involved in the calculation method, he refreshingly bemoaned the fact that many of the problems of noise reduction could be solved by people letting their neighbours know 'if they're not behaving reasonably'.

Complaints reverberate In the Q&A session, the audience rose to the challenge of what some seemed to see as a technical response to acoustics offered by the new regulations. A question by Catherine Day of Acoustic Design Consultants blew the discussion wide open when she pointed out to Dunbavin et al that, in all her years of professional practice, she had only ever come across one instance of reverberation in common areas being a problem: 'Are we creating a bureaucratic solution to a problem that doesn't exist?' With criticism hanging in the air, Michßl Cohen of Walters & Cohen, responsible for the design of an exemplar at Bedales School in Hampshire, condemned the new BB93 regulatory guidance for being too prescriptive and blocking good design. She showed examples of experimental schools in Scandinavia that would not be possible in this country under the new inflexible regime. Following on, Max Fordham started his introduction by saying that Part E is a 'bloody mess?.

The whole thing is driven by litigiousness and risk aversion. If you want to make regulatory changes, ' he said, 'you need to test them before they're imposed? it's a bad way of going about regulating.' He added: 'If conflicts arise between different approaches like Part L and E we need to be very careful and think things through before implementing them.' His attack summed up the increasingly strained mood of the audience.

There was exasperation that Part E (just like Part L before it) has been introduced and is being tested in practice even though there are obvious flaws and inconsistencies.

Even this might be reasonable if it was not for the inflexible 'a fail is a fail' response of some of those responsible for bringing it into force and for monitoring its progress.

A thoroughly thought-provoking, educative and challenging conference.

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