Since its inclusion in Building Regulations in 2006, many newly constructed sites in England and Wales have needed air testing as a mandatory step before final sign-off.
This is to prove the build quality is so good that only a small amount of heat is lost through gaps and cracks in the construction materials.
As requirements have evolved to improve energy efficiency, the number of buildings being tested has increased, and the air test targets have become increasingly stringent.
When the proposed new Approved Document Part L goes live, not only will air testing become mandatory on 100% of dwellings, and the maximum allowable result cut by 20%, but it will also introduce an alternative method known as Pulse Testing.
This is one of several big changes that are happening to Building Regulations as part of the Future Homes Standard review.
So what is a Pulse Test?
Pulse Testing measures the air permeability of a building by sending out a shockwave of air from a compressed cylinder which is positioned in the centre of the house. A sensor calculates the result based on how long it takes the air pressure to return to normal.
This is a very different approach to the conventional testing approach where a fan is sealed to an external door, and the building is then depressurised.
Whether you are keen to stick with the door-fan method or jump to the pulse method, remember that both options have their pros and cons…
The big disadvantage for pulse testing is that it is not yet recognised by Building Regulations, so can’t be used for sign-off.
The new AD L is expected to go live in Spring 2022 so, until then, door-fan testing must be used.
Another negative is diagnostics. By using the door-fan approach, an air tester can walk around a dwelling mid-test and pinpoint any areas where air is escaping. That can’t happen during a pulse test.
But there are plenty of positives for using pulse: The equipment is so light you can carry it as a backpack, it’s possible to test three or four dwellings in an hour, there’s far less setting up to worry about, and the test is completed without having to depressurise the building first.
There will be space in the market for both testing methods to work side by side.
Following the regulation changes to allow pulse testing on English and Welsh sites, a developer may choose to have their first batch of dwellings tested the old fashioned way to pick up on any issues with the build quality and diagnose issues based on the air tester’s advice.
Or, maybe a developer will test every dwelling using the pulse test approach and then revisit the poorer performing dwellings with the door-fan approach to work out why results are so high.
The final details of the new AD L have not been released, so there are still some unknowns about how the two testing methods will work alongside each other, such as whether the use of one method will give an advantage in the SAP and SBEM calculations.
We’ll be releasing further articles as the Government releases more details about the new AD L requirements. For more information about the Future Homes Standard or SAP10, and how these changes will impact future sites, speak to the Energist Technical Team.