Part L
Air tightness testing
Pressure testing to measure air leakage against the design target, with a certificate for building control.
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Testing & commissioning
Passive House airtightness testing
A qualified tester carries out airtightness testing to the Passivhaus method, with intermediate tests while the airtight layer can still be reached and a final test for certification, and reports the n50 result against the Passivhaus limit.
When you need it
Passivhaus certification requires an n50 result of no more than 0.6 air changes per hour at 50 Pa. The test follows ISO 9972 Method 1 with Passivhaus requirements, including measurements under both pressurisation and depressurisation and the room-by-room air volume set out in the certification criteria.
The Passive House Institute recommends testing as soon as the airtight layer is complete, while leaks can still be found and sealed. Passivhaus is a voluntary standard: the Building Regulations air test is separate and reports air permeability on a different basis, so tell us if you need both.
What is included
Included
- Review of the airtightness strategy and the air volume figure for the test
- Intermediate tests while the airtight layer is accessible, as set out in your quotation
- Leak search during intermediate tests
- Final test under pressurisation and depressurisation
- Report with the test data your Passivhaus certifier needs
Priced separately
- Sealing and remedial work
- Extra tests beyond those in your quotation
- A separate Building Regulations air test report, where needed
- Passivhaus certification, which is carried out by an accredited certifier
Your written quotation confirms the exact scope, what is included and any limits for your building.
What you receive
A report for each test giving the n50 result against the 0.6 limit, with the test data your Passivhaus certifier needs for the final test.
Sent as a PDF. We can send it to your building control body or agent on request.
Our reports and testing support the compliance process. Approval and completion decisions remain with your building control body: the local authority, a registered building control approver, or the Building Safety Regulator for higher-risk buildings.
How to prepare
- Drawings and the airtightness strategy
- Air volume figure (Vn50) from the PHPP, if calculated
- Your Passivhaus designer and certifier contact details
- Programme showing when the airtight layer will be complete
- Windows and doors fitted, and ventilation openings able to be temporarily sealed
- Mains power and safe access
Send what you have. Missing details will not stop an enquiry; we will tell you anything still needed.
How it works
Tell usChoose the service or describe the job.
Written quotationScope, deliverables and price, confirmed in writing.
We manage the workArranged and coordinated by RegulaBuild. Technical work is carried out by appropriately qualified professionals.
Your reportThe output named in your quotation, with any follow-up.
Questions
When should the first test happen?
As soon as the airtight layer is complete and before it is covered by finishes, so any leaks can be found and repaired.
Can one test serve both Passivhaus and Building Regulations?
The two use different reporting bases and requirements. Tell us both targets when you enquire and the quotation will set out how the tests are arranged.
What about EnerPHit retrofits?
EnerPHit has its own airtightness criterion. Tell us which standard your project is aiming for.
Often booked with
Combine them in one quote request
Part L
Air leakage diagnostics
Finding where air escapes after a failed or borderline test, so it can be sealed before a retest.
TestingView service
Part F
MVHR commissioning and balancing
Setting up and balancing whole-house heat recovery systems to the design flow rates.
TestingView service
Where we work
Passive House airtightness testing across England
Request a quote
Discuss passive house airtightness testing
Start with this service and add anything else you need. If you are unsure, say so and we will advise.