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Taking deep breaths of buildings

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The BSRIA uses giant fans towed by Land Rovers, 2000 cigarettes whatever it takes to research building porosity

How porous are the walls of your building? Would you know how to clear smoke out of a night-club? Are you leaving enough room in your building for plant? Do you know whether a new piece of plumbing equipment will satisfy your purpose?

These are all questions which BSRIA (Building Research and Information Association), is able and keen to answer. Too of ten dismissed by architect s as not relevant to me , the organisation is eager to prove its relevance (and the AJ wants to help see below).

Chief executive Andrew Eastwell says: Despite the fact that we are principally M & E engineers, we are a very welcoming company. We don t feel threatened by any of the other sectors of the construction industry . People coming from other members of the construction team are very welcome. When they come up with other point s of view we consume them hungrily.

BSRIA s physical setting is an excel - lent metaphor. At first sight it seems a bit remote. Bracknell is not at the teeming heart of any metropolis. But in fact it is only an hour from central London by car or train, and half an hour from Reading.

And although the BSRIA building it self would not feature on anybody s list of great architecture, inside it has all sort s of intriguing corners.

The t able in the boardroom looks unusual that s because the top is made from special triple-laminated glass made for Foster & Partners Hong Kong & Shanghai Bank and tested at BSRIA. A machine smokes unmarked cigarettes at a rate that would put any tobacco addict to shame. A Land Rover parked out side tows a gigantic fan and looks as if it belongs on a film set. Above the well-resourced and organised library works a multi-lingual engineer who abstract s technical articles from all over the world with a special respect for the Germans output.

With such hidden treasures, it is not surprising that Eastwell, who initially seems the kind of thrusting executive who switches companies every three years, has actually been there almost all his working life. A physicist, he joined BSRIA in 1975 as a research engineer , in a temporary job. I looked at other jobs and thought they were nowhere near as good as this one. It is a fascinating company.

He has seen BSRIA change, both in structure from a traditional research organisation to a set of interlinked companies, and in focus. Fifteen to twenty years ago, he says, we would have had almost no interface with architect s or main contractor , or building owners and operators.

So how does he define building services one of those definitions we believe we all know until we try to formalise it? It s any aspect that affects the ability of the occupant of the building to make maximum use of the asset, he says. And under this he embraces almost everything. I don t think there is a single area of building construction or management where we would not have an interest.

The thermal mass of the building affect s the heating and ventilation system. The glazing has an effect on solar gain, on glare and on the lighting requirement, including colour rendition.

Landscaping materials can affect the building s performance. Cladding is import ant because there is an interrelation with the services installation and, more significantly , because of the all import ant issue of porosity .

Air leakage through blockwork is one of the major problems that BSRIA has identified, and it recommends that asking the manufacturer about air leakage rates should be an essential p art of the specification especially if the blockwork is not to be rendered. There is not enough understanding of porosity in design, says Eastwell. An understanding of the porosity of the building envelope should be a fundament al p art of the design.

This whole issue is the rationale behind those Land Rovers towing fans.

The fan rovers are actually powered by the car s engine and travel around the country to help measure the leakage of buildings. This is an initiative usually driven by client s and especially by super - markets, who are very concerned about the loss of precious refrigeration and about customer comfort. This is especially significant in those supermarket s which have air curtains rather than conventional doors, as out side air will be sucked in at a phenomenal rate if the building is leaky .

The process is conceptually simple.

The test typically takes place three weeks before handover. All the external doors and windows are closed and the air-handling equipment sealed of f, then the building is pressurised and leakage rate measured. Supermarket s now typically aspire to a rate of about 5m 3/h/m 2 of surface but on a flabbily detailed building it could be between four and six times as high, which means that none of the environment al systems will operate effectively .

Typically the failure rate on new superstores is about 15 per cent, and on new offices about 30 per cent. If the building fails then the weak spot s can be identified by a smoke test.

Many of the porosity failures under - line one of Eastwell s convictions, that it has become more obvious that it is not actually the processes that are a problem but the interfaces between elements. And he has some useful advice for designers. For instance, trying to make a mansard roof airtight is incredibly difficult. Much better , he believes, to isolate the box below it and make that airtight.

Other areas where BSRIA can help include product testing. For instance, new models of sanitary equipment, which may be very attractive sometimes have not tested in all the conditions to which they may be subject. BSRIA can do these test s.

Other useful activities include the modelling of p art s of buildings to test their performance and the integration of the services with the structure. This can be done both physically and through the CFD (computational fluid dynamics) programme developed by Flomerics specially with BSRIA, and which is now impressively three-dimensional and realistic.

And what about those unbranded cigarettes? They are an indication of just how quick the organisation can be on it s feet. Extracting smoke from nightclubs is both import ant and not technically easy because the p articles are so small. The answer is to use an electrostatic mechanism.

A group of manufacturers of this equipment came to BSRIA and asked it to write a draft standard and test this. It managed this in a very impressive four months, but it involved the virtual smoking of a lot of cigarettes. Smoke from four cigarettes was drawn into a clean room and the rate of decay of p articles in the air measured both with and with - out the cleaners. And if this was not unpalatable enough, an adjacent bit of equipment tested the life span of the filters by testing them with a constant input of 2000 cigarettes. Unappealing, but useful.

Other areas of investigation are even more quirky for instance a look at the toxic output from crematoria typically 12kg a year of mercury vapour from fillings, plus cadmium from the batteries in pacemakers and dioxins from the Teflon in artificial hip joint s.

But what does all this, and the work of BSRIA, mean to architect s ? W h y should they be interested? For 90 per cent of their working life they won t be, said Eastwell. But for 10 per cent of their time they will not know how to resolve an issue. BSRIA is a phone call away.

BSRIA is hosting an open day specially tailored for AJ readers on Thursday 30 March 2000 The day will include:

a hands-on demonstration of the latest physical and computer modelling techniques how to pressure-test a building and its benefits

sustainability in construction.

The event is free, but places are limited. All registrations must be received by 17 March 2000.

If you wish to attend please fax back the form that will appear in next week s AJ to Marketing Services at BSRIA on 01344 487575 or register on the BSRIA website at: www.bsria.co.uk.

AGENDA 09.30 Coffee and registration in the Information Centre 10.00 Introduction, Andrew Eastwell - chief executive of BSRIA 10.30 Tour of Bracknell facilities 11.00 Demonstration of building pressure test 11.15 Tour of Crowthorne facilities 11.30 Demonstration of room modelling 12.45 Lunch 13.30 Flomerics 14.00 Practical demonstration of computer modelling 14.50 Talks on sustainability and photovoltaics 15.15 Tea and close

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