McLaughlin & Harvey | Wester Hailes High School | Edinburgh | Passivhaus School

Passive Purple X is a Class B fire-rated, spray-applied airtight vapour control membrane developed for projects where airtightness, fire performance and long-term durability are essential. Suitable for education, healthcare, commercial and Passivhaus developments, Passive Purple X creates a seamless airtight layer across walls, junctions and penetrations, helping buildings achieve exceptional airtightness, improved energy efficiency and compliance with modern building performance standards. When combined with IM Airtight Fleece Tape and Passive Purple X Brush Grade, the system delivers a complete airtight solution for even the most complex building envelopes.

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INTERNAL

Pre-air test result: 0.078 ACH. Requirement: 0.6. A result McLaughlin & Harvey describe as one of the lowest ever recorded in the UK - on a £44 million school.

The project

Wester Hailes High School is the City of Edinburgh Council’s new £44m secondary school, designed by Architype and delivered by main contractor McLaughlin & Harvey through the SCAPE Scotland framework. The building is being executed and certified to full Passivhaus standard, increasing the benchmark for UK schools because reliable building performance means lower energy bills and better comfort for pupils and staff.

Passivhaus certification demands an air test at 0.6 ACH or better. On a building this size, with a structural frame and thousands of panel joints, that’s a serious ask.

The system: fire-rated airtightness

Schools demand more than airtight; the envelope has to perform in a fire. That’s why this project ran on Passive Purple X, our fire Class B-rated airtight vapour control membrane:

  • Windows and frame connections - IM Fleece Tape around every window and across the panel-to-frame connections, locking the airtight line through the trickiest interfaces.
  • Joints - Passive Purple X brush grade worked into every joint and junction.
  • Walls - Passive Purple X spray-applied across the whole wall area: one continuous, seamless, fire-rated airtight layer.

The result: 0.078

The full-building pre-air test came back at 0.078 ACH, almost eight times tighter than the Passivhaus requirement, and a result McLaughlin & Harvey describe on their own project page as “one of the lowest recorded results ever achieved within the UK”.

Numbers like this only happen when the whole site buys in, and this team was invested from day one. Every trade protected the airtight line; every junction got detailed properly. After the 004 at Swindon, there’s only one nickname left for our MD: 007. Licence to seal.

Walk the building yourself

We captured the installation in full 360°. Step inside the school and see the purple walls for yourself on our 360° images page.

Another guaranteed result, delivered

Wester Hailes ran on our guaranteed 0.6 ACH or lower supply-and-install service, and once again the result didn’t just meet the guarantee, it smashed it. If your school, commercial or Passivhaus project has an air test it can’t afford to fail, talk to us or send us your drawings and we’ll mark up the airtight line for free.

One of the lowest air test results ever recorded in the UK: 0.078 ACH at the new Wester Hailes High School in Edinburgh, delivered with fire-rated Passive Purple X, IM Fleece Tape and a fully invested site team, on our guaranteed-result service.