Breaking the sound barrier

For the past two months, manufacturers researchers, insurers and others have been engaged in a frantic race against the clock. Next week, they will hold a conference where they will present a progress report on their vital work and issue a desperate appeal for assistance. They must carry out 1500 tests before the end of March – a task one participant likens to fitting a year-and-a-half of work into six months.

The goal that the teams have been striving to achieve is not, as you may have thought, saving mankind from an imminent meteor impact. It is simply to work out better soundproofing in residential accommodation.

The cause of this unprecedented burst of co-operative effort goes back to Labour's policy of promoting higher population density in urban areas. Clearly, this could be successful only if people could tolerate living in close proximity to each other's stereos, high-heeled shoes, rows, and so on. So, in January 2001, the government proposed changes to Part E of the Building Regulations to improve the standards of acoustic insulation in new dwellings.

From the housebuilders' point of view, this was a serious headache. Not only were they faced with the prospect of redesigning their houses, they were also going to be made to test every development to prove compliance with the new Part E – at a cost of up to £1000 a unit. Even worse, if walls and floors failed to make the grade, the housebuilders would have to pay for remedial work. Cue an intensive lobbying operation to persuade the policy-makers to lessen "uncertainty, delays and unnecessary costs" – preferably by scrapping the proposals altogether.

The result was a compromise. On the 5 July this year, the government gave the industry a year to design and test a series of "robust standard details". These RSDs were standard wall and floor construction designs that complied with the new regulations. The theory was that if housebuilders used these approved details, the acoustic performance of their dwellings would be assured.

So everybody was happy – assuming, of course, that the details could be designed to do what the government wanted. This brings us back to next week: at an Institute of Acoustics conference, some of the 50 wall and floor details will be revealed to the industry – and the House Builders Federation is relying on its members to try them out. Some of the candidates for robust standard detail approval have already been placed on a website run by Napier University, which is managing the project, including a 75 mm cavity wall (see diagram right). Each has to be installed and tested in at least 30 houses, which will mean fitting them in about 200 sites. All the testing has to be finished by 30 March next year, ready for the introduction of the new Part E in early 2004.

There are a number of points to make about the story so far. One is the pressure that the robust details compromise has put on manufacturers. Many of them have had to design those details, and if a construction using one of their products fails the tests, it will not be included in the pattern book of successful robust details. If this happens, any housebuilder that uses it will have to pay for tests on a sample of houses in which it is installed – in other words, failure will equal a death sentence for the product in question. And if enough products fail, the manufacturer's commercial life could be in doubt, too.

This sense of common endangerment has created unprecedented co-operation between manufacturers. To come up with successful robust details in such a short time, some are sharing the results of their research with competitors. One industry group, the Proprietary Acoustic System Manufacturers, was formed to enable firms to share the burden of devising new generic details for their product groups. "This has not been done before," says Tim Slater, technical sales manager at PASM member Monoflex Acoustics Systems. And he even manages to put a positive spin on the new rules. "A lot of housebuilders will choose details because they appear as a robust standard detail in regulation guidance – it will open up the market for us," he says.

One group of manufacturers, however, may be feeling less sanguine. When the government published its proposals for the new Part E, it removed beam-and-block from its approved construction methods. The implication was that it could never make the grade. However, the Beam and Block Association is confident that its reworked details will gain government approval.

To ensure the new details have a margin of error for poor workmanship on site, they are being designed to offer 3 dB more insulation than is required by Part E – which is itself 3 db higher than the existing acoustic requirements. Dave Baker, the HBF's technical director, says it is important the details are as robust as possible. "The detail mustn't be convoluted. It must be workmanship-proof on an average building site."

There is a danger housebuilders will work with the details and won’t try innovative products

Darren Richards, operations director, MTech

This margin of error has proved controversial. Darren Richards, operations director at consultant MTech, says it undermines the principles of RSDs. "It shouldn't just be about creating robust details; it should be about improving the performance of the material itself to avoid workmanship issues and the costs of over-engineering." And Richards is worried that over-reliance on robust details may inhibit the development of products with better sound absorption properties. "Housebuilders won't try innovative products," he says.

However, Nick Morgan, technical co-ordinator at housebuilder St James, says he would consider a new product that was not in the HBF pattern book, even if it meant carrying out compliance testing. "We would do a cost-benefit analysis to see if we could offset the costs of testing against the benefits of using the material," he says. And he adds that testing can be used to housebuilders' advantage. "Testing on site, you can fine-tune your work to create a lean and efficient building, rather than a clumsy over-detailed one."

To encourage innovation, MTech's Richards says there must be a mechanism for accepting new robust details in the future. "We should have a body of knowledgeable people that can analyse details quickly and efficiently. It must not take a year for new details to be accepted." In fact, working groups will be meeting in December to discuss how new details will be tested and incorporated into the programme. The Office of the Deputy Prime Minister, which is responsible for the Building Regulations, will not confirm whether it will allow more details to be included in the Part E guidance after the cut-off date for submissions on 31 May. It merely states that it wants to see a robust standard details system in place by 31 May and will not offer any leeway.

There are some doubts in the industry as to whether RSDs can be used to build consistently to a high standard without testing. Richards wonders whether the 30 tests by the HBF will be indicative of the work carried out in the field after the RSDs have won government approval. "If you're a builder and you're working on a test site, you'd try harder to get the detail right."

There is also a question mark over how RSDs will be checked for compliance in completed homes. The HBF says defects will be readily identified by visual inspections. It says that a checklist for each construction will identify the critical components of each wall and floor and matters that should be verified by visual inspection. But St James' Morgan is doubtful about the plans. "These days, building control officers are overloaded with work," he says.

"You can't rely on them to spot everything."

No doubt all these considerations will be going through the heads of the HBF's members as they inspect the fruits of the industry's endeavour.

And a few may reflect that building shelters to protect the population of Britain from a meteor strike may have been the softer option.