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Every current technical document for the range — install guides, IM-QA site sign-off records, technical and product data sheets, safety data sheets, construction detail drawings, certificates and test reports — is collected on one page.
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NBS clause library
Every product, grouped by the NBS clause it is specified under, with Uniclass codes and clause wording you can copy straight into NBS Chorus or your specification.
Air and vapour control layer
- P10/310 Air and vapour control layer
- P10/60 Air and vapour control layer
- H92/780 Air and vapour control layer
- Pr_25_57_65_60 Plastics sheets
Clause wording
AIR AND VAPOUR CONTROL LAYER Manufacturer: Intelligent Membranes Ltd, Cambridge. Tel 01223 208174. intelligentmembranes.com Product reference: Passive Purple® liquid-applied airtight vapour control membrane, spray/roller grade, with Passive Purple Brush for joints, junctions and penetrations. Certification: BBA certified. Passivhaus Institute certified component. Reaction to fire: Class C to EN 13501-1. Substrates: Concrete, brick and blockwork, timber/OSB, plasterboard and cement board, prepared and primed as recommended by the manufacturer. Detailing: Passive Purple Brush applied first to joints, junctions, frames and service penetrations in a 100 mm band (150 mm on rough masonry and high-movement joints). Field coats: Two coats to a minimum total consumption of 0.8–1.0 kg/m² on boards and 1.2–1.4 kg/m² on brick/blockwork. Plastering/dry lining over: Apply Supergrip primer over the cured membrane before plaster or dot-and-dab. Installation: In accordance with the manufacturer's current technical data sheet and installation guide. Testing: Verify airtightness by pressure test on completion.
- P10/310 Air and vapour control layer
- P10/60 Air and vapour control layer
- Pr_25_57_65_60 Plastics sheets
Clause wording
AIR AND VAPOUR CONTROL LAYER – DETAILING Manufacturer: Intelligent Membranes Ltd, Cambridge. Tel 01223 208174. intelligentmembranes.com Product reference: Passive Purple Brush, brush-applied airtight vapour control membrane for joints, junctions, corners, window and door perimeters and service penetrations. Certification: BBA certified. Passivhaus Institute certified component. Band width: 100 mm total (approx. 50 mm either side of the joint); 150 mm on rough masonry and high-movement joints. Gaps: Up to 3 mm bridged directly; 3–10 mm backed with backer rod or compatible sealant then coated; over 10 mm closed mechanically first. Field area: Passive Purple spray/roller grade over the detailing. Installation: In accordance with the manufacturer's current technical data sheet and installation guide.
Breather membrane
- P10/320 Breather membrane
- H92/785 Breather membrane
- H22/130 Breather membrane
- Pr_25_57_10_94 Vapour-permeable sheets
Clause wording
BREATHER MEMBRANE – LIQUID APPLIED Manufacturer: Intelligent Membranes Ltd, Cambridge. Tel 01223 208174. intelligentmembranes.com Product reference: Passive Purple External / Passive Purple X liquid-applied airtight, rain-tight, vapour-permeable membrane, spray/roller grade, with Passive Purple External Brush for detailing. Use: Internal and external faces of the building envelope, including façades. Reaction to fire: Class B to EN 13501-1 (Passive Purple X: B-s1,d0 on A1 substrates of density 653 kg/m³ or more). Certification: Passivhaus Institute certified. KIWA approved. Properties: Airtight, rain-tight, vapour-permeable, crack-bridging and UV resistant. Installation: In accordance with the manufacturer's current technical data sheet and installation guide. Note: Designer and building control body to confirm suitability against the fire strategy for the building.
- P10/320 Breather membrane
- H92/785 Breather membrane
- Pr_25_57_10_94 Vapour-permeable sheets
Clause wording
BREATHER MEMBRANE – DETAILING Manufacturer: Intelligent Membranes Ltd, Cambridge. Tel 01223 208174. intelligentmembranes.com Product reference: Passive Purple External Brush, brush-applied airtight, rain-tight, vapour-permeable membrane for joints, junctions, openings and penetrations. Reaction to fire: Class B to EN 13501-1. Field area: Passive Purple External / Passive Purple X spray/roller grade over the detailing. Installation: In accordance with the manufacturer's current technical data sheet and installation guide.
- P10/320 Breather membrane
- H92/785 Breather membrane
- H22/130 Breather membrane
- Pr_25_57_10_94 Vapour-permeable sheets
Clause wording
BREATHER MEMBRANE – LIQUID APPLIED Manufacturer: Intelligent Membranes Ltd, Cambridge. Tel 01223 208174. intelligentmembranes.com Product reference: Passive Purple External / Passive Purple X liquid-applied airtight, rain-tight, vapour-permeable membrane, spray/roller grade, with Passive Purple External Brush for detailing. Use: Internal and external faces of the building envelope, including façades. Reaction to fire: Class B to EN 13501-1 (Passive Purple X: B-s1,d0 on A1 substrates of density 653 kg/m³ or more). Certification: Passivhaus Institute certified. KIWA approved. Properties: Airtight, rain-tight, vapour-permeable, crack-bridging and UV resistant. Installation: In accordance with the manufacturer's current technical data sheet and installation guide. Note: Designer and building control body to confirm suitability against the fire strategy for the building.
- P10/320 Breather membrane
- H92/785 Breather membrane
- H22/130 Breather membrane
- Pr_25_57_10_94 Vapour-permeable sheets
Clause wording
BREATHER MEMBRANE – LIQUID APPLIED Manufacturer: Intelligent Membranes Ltd, Cambridge. Tel 01223 208174. intelligentmembranes.com Product reference: Passive Purple External / Passive Purple X liquid-applied airtight, rain-tight, vapour-permeable membrane, spray/roller grade, with Passive Purple External Brush for detailing. Use: Internal and external faces of the building envelope, including façades. Reaction to fire: Class B to EN 13501-1 (Passive Purple X: B-s1,d0 on A1 substrates of density 653 kg/m³ or more). Certification: Passivhaus Institute certified. KIWA approved. Properties: Airtight, rain-tight, vapour-permeable, crack-bridging and UV resistant. Installation: In accordance with the manufacturer's current technical data sheet and installation guide. Note: Designer and building control body to confirm suitability against the fire strategy for the building.
Check clause wording against the current technical data sheet before issue.
Why Specify Intelligent Membranes?
Intelligent Membranes produces the UK's first Passivhaus-certified liquid-applied airtight, vapour control and waterproofing membranes. Liquid application eliminates the failure points inherent in overlapping sheet membranes and tapes — giving your project a seamless, independently tested airtight layer that performs reliably over the building's lifetime.
🏆 Passivhaus Certified
Certified by the Passivhaus Institut — the highest performance standard in airtightness. Suitable for Passivhaus Classic, Plus, and Premium projects.
📋 BBA Certified
Passive Purple Internal and Passive Purple Brush hold BBA Certificate 22/6002 — independent third-party assurance for specification confidence.
🔬 WUFI Database Listed
Tested material properties registered in WUFI, enabling moisture control design compliant with EN 15026, ASHRAE 160 and DIN 4108.
🏛️ RIBA Product Selector
Listed on the RIBA Product Selector — reference our products directly within your RIBA workflow and NBS specifications.
🔥 Fire Rated Options
Passive Purple X and Passive Purple External carry Class B fire ratings, suitable for facades on buildings over 11m and Approved Document B compliance.
🌿 Low VOC
Water-based, low-VOC formulation assessed for indoor air emissions — suitable for occupied buildings, schools and healthcare projects.
Certifications at a Glance
Products Available for Specification
| Product | Application | Key Certifications | Typical Use |
|---|---|---|---|
| Passive Purple Internal | Spray / Roller | Passivhaus, BBA, WUFI | Internal VCL & airtight layer — new build & retrofit |
| Passive Purple Brush | Brush | Passivhaus, BBA | Junctions, penetrations, small areas, blockwork sealing |
| Passive Purple External | Spray / Brush | Passivhaus, Fire Rated Class B | External airtight & weatherproof facade membrane |
| Passive Purple X | Spray / Brush | Class B Fire, Passivhaus | Fire-rated facades, buildings over 11m |
| Passive Purple Retrofit | Spray / Brush | Passivhaus | Retrofit airtightness on existing masonry & substrates |
| Airtight White | Spray / Brush | Airtight, VCL | Internal airtight membrane where white finish is required |
| Poseidon | Spray / Roller | Waterproof | Bathroom, wet room, internal waterproofing (internal use only) |
| FRED | Spray / Roller / Brush | Warrington Fire Tested | Intumescent flame retardant coating — internal & external |
NBS Specification Support
We provide NBS specification clauses for our key products to make it straightforward to write Intelligent Membranes into your project specification. Our products are listed on the RIBA Product Selector, so you can link directly from NBS Chorus to our product pages.
Request NBS Clauses
Contact our specification team to receive ready-to-use NBS clause wording for Passive Purple Internal, Passive Purple Brush, Passive Purple External and Passive Purple X. We respond within one working day.
Request Spec Clauses View on NBS Source
Technical Data & CAD Details
📥 All Downloads
Install guides, IM-QA site sign-off records, technical and product data sheets, safety data sheets, detail drawings and certificates — every current document, in one place, organised by document type.
📄 Technical Data Sheets
Product datasheets covering coverage rates, application method, substrate compatibility, performance data and curing times.
📐 Application & Coverage Rates
Detailed application guides including coverage rates per substrate type, recommended film thicknesses, and quantities for estimating.
🏗️ Junction Detail Drawings
Wall–roof, wall–floor, window reveals, service penetrations and other critical airtightness junctions, grouped by construction method — timber frame, SIPS, steel frame, ICF, masonry and more.
📊 WUFI Hygrothermal Data
Tested material properties registered in the WUFI database for use in condensation risk and moisture transfer analysis.
RIBA-Accredited CPD
We offer RIBA-accredited CPD seminars for architectural practices, contractor teams and building control officers — available in-person or online, free of charge.
CPD Topics
- Airtightness in Modern Construction — UK standards, methods of achieving airtightness, and how liquid membranes compare to sheet systems
- Passivhaus Principles for Mainstream Projects — The five Passivhaus principles and how to apply them without full certification
- Retrofit Airtightness & Vapour Control — Condensation risk, vapour control strategies and liquid membranes in retrofit scenarios
- Fire-Rated Membranes & Facade Compliance — Fire performance requirements for membranes in facades post-Grenfell
- Waterproofing & DPM Solutions — Liquid-applied waterproofing for wet rooms, roofs, floors and DPM applications
Book a CPD Session
Sessions are free, approximately 45–60 minutes, and available in your office, on site, or via Teams/Zoom.
Book a CPD SessionHow to Specify
- Identify the right productUse our Solutions pages or contact our spec team to confirm the correct product for your substrate, application and performance requirement.
- Download technical data and certificationsAll datasheets, BBA certificates, Passivhaus certifications, install guides and QA records are on the Downloads page.
- Request NBS specification clausesWe provide ready-to-use NBS clause wording. Contact us and we'll respond within one working day.
- Request CAD junction detailsWe supply CAD details for critical airtightness interfaces. Contact our technical team with your construction type.
- Arrange a technical consultationFor complex projects our team can review drawings to advise on airtightness strategy, specification and coverage quantities.
- Locate an approved installer or order directView our Approved Installer & Distributor list or order products from our online store.
Talk to Our Specification Team
Our technical team supports your specification from design stage through to site. NBS clauses, CPD, WUFI data, site surveys — we respond within one working day.
Contact the Spec Team All Downloads Download Brochures