Who'd be a pressure tester?
I spent yesterday morning with Keith Bartlett who runs a business called Air Leakage Testing based in Saffron Walden in Essex. Keith had a pressure test booked on a renovated house in Greenwich, SE London, and I was getting to ride shot gun with him, picking his brains as we travelled down the M11 in his van with all the kit in the back.
Keith’s background is running a building business erecting steel structures as industrial units. A requirement for air pressure testing for buildings larger than 1000m2 in floor area came into effect in 2002 and Keith took a view that this was the start of a trend and decided, with two partners, to start this new venture to get in on the beginning of a new business opportunity. Together, they have invested something like £150,000, not to mention thousands of hours labour, to get things up and running and they fully expected to be rushed off their feet by now, since the requirement for air pressure testing was extended to new homes in April this year, under the changes to Part L of the building regs.
But it hasn’t worked out quite that way. At least, not yet. Building inspectors have yet to get to grips with the changes in Part L and there is still only a tiny trickle of work coming their way, despite their being less than a dozen firms offering a similar service. In theory, when the new Part L bites, air pressure tests should be carried out on every dwelling type used in a development. That’s a difficult figure to put an exact number to but it must be of the order of 10 to 20 thousand a year throughout the country, not to mention a significant increase in commercial work as well as here the size limit for testing has been reduced from 1000m2 to 500m2. If Keith’s business is typical, it appears that the actual number of air pressure tests being carried out is less than 10% of this figure.
What appears to be happening is that as many as 80% of qualifying commercial buildings are passed by building control without a pressure test. It seems building control are happy to accept “robust details” as an alternative method of compliance, despite there being officially no allowance for this in Part L. This may also prove to be the case with domestic work as well, although the reasons here for slow take-up of pressure testing are to do with the delayed adoption of the 2006 Part L regulations by local authorities.
Thus far the main take up in the domestic sector has been from architects and interested clients who are testing the water and trying to get to grips with the concept air pressure testing. Keith told me: “Architects are in fact often their own worst enemies because the buildings they design are over-complex and full of junctions, just the type of structures that perform badly in an air pressure test.”
The actual test normally takes a couple of hours but there is usually a costly transport element to be taken into account because testers are thin on the ground and one test frequently takes up a full day. So the cost is typically around £300 plus transport for a single house, though it can be much less if there are multiple houses ready to test on the same site. “Most builders feel that they have carried out a reasonable job and are deeply suspicious of pressure testing. If the readings suggest that the house is leaky, they start questioning the accuracy of the equipment. So then we do a smoke test and this shows precisely where the leaks are. Then they believe.”
I was hoping to witness and photograph the test in Greenwich. But the traffic around the Blackwall Tunnel was gridlocked and after sitting in the van for two and a half hours without even reaching our destination, Keith aborted the mission and rescheduled for another day. With more than a touch of irony, I reflected on how the intention of an air pressure test is to save energy consumption, but London’s chaotic road system had ended up with us wasting rather a lot of fuel, achieving precisely nothing. That’s the politics of energy for you.