First interior air barrier system to be successfully tested to ASTM E2357 - Compliant with NBC of Canada part 5 and 9
Selecting appropriate materials and systems to form an inboard air barrier is a critical step in designing and building foam free, high-performance enclosure assemblies. Not only do the materials themselves need to be sufficiently airtight, but they must also perform as a complete airtightness system. With a history of proof in the field, we now provide proof in the laboratory of the airtightness of the INTELLO PLUS membrane. This membrane was tested to the highest wind/pressure load class (P3) including under extreme conditions: 1200Pa gusts. This equates to approximately 97 mph, the wind speed of a Category 2 hurricane.
We are always happy to point to successful installations of our INTELLO airtight systems as proof of the system’s ability: from hundreds of Passive House homes; to the 27 story Cornell tower; to the University of Northern British Columbia Wood Innovation Research Laboratory (WIRL); to Passive House Institute Certified prefabricated enclosure systems by ECOCOR, Passive House contractors Collective Carpentry, and The Fourth Pig. Every day our customers successfully utilize the Pro Clima INTELLO airtight system to support assemblies that exceed rigorous Passive House requirements.
Real world examples are important, but sometimes third-party laboratory testing based on industry standards is required by engineers and architects for prospective projects. For that we turn to building codes and associated testing requirements. The National Building Code of Canada prescribed a maximal air leakage rate for exterior wall assemblies in the mid-’90s, but didn’t define how to quantify it. ASTM E2178 and E2357 first standardized this in 2001. INTELLO had been tested previously to ASTM E2178 (NBC 2015 part 18.104.22.168 limit of 0.02 L/s.m²), exceeding the testing requirements for airtight materials by a factor of 80 and by PHI as a Class A, absolute airtight system (0.00m3/m2*hr).
The current National Building Code uses both CAN/ULS S742 as well as ASTM E2357 for air barrier systems requirements. For interior airbarriers, it requires that it:
- Provides a continuous barrier to air leakage
- From the interior of the building into wall, floor, attic or roof spaces, sufficient to prevent excessive moisture condensation in such spaces during winter
- Additionally, air barrier materials must comply with CAN/CGSB- 51.33 -M77 per NBC 9.25.3 or other applicable standards in that section
INTELLO has been verified for super tight construction (0.3ACH50) in buildings tested to CAN/CGSB-149.10 (or the equivalent Passive House test EN 13829), including University of Northern British Columbia Wood Innovation Research Laboratory (WIRL) , the tightest tested building in Canada.
In this blogpost, we are happy to close the loop and report on successful ASTM E2357 testing of the INTELLO system as an assembly. As a result, the products used in the INTELLO system are compliant with NBC 9.25.3, 9.25.4 and 9.36 (as well as equivalent provision in all provincial building codes following NBC2015 (AB, BC, NS, SK) or when they adopt it (ie still on NBC 2010). This means INTELLO system complies with the following standards and code requirements:
- ASHRAE 90.1 (commercial building energy standard, Section 22.214.171.124.3 b)
Both codes and standards define an air barrier assembly as having an average air leakage that does not exceed 0.2L/s*m2 (0.04 cfm/ft2) at a pressure of 75 pa (0.3 inch of water gauge), when tested in accordance with ASTM E2357. So what’s ASTM E2357?
The whole test title is ASTM E2357 Standard Test Method for Determining Air Leakage of Air Barrier Assemblies. The test is performed by a third party certified testing facility, in this case by Intertek. The test is composed typically of two mockups, one with standard prescribed penetrations and one without penetrations. Each mock-up is prepared per standard procedures and placed in a test chamber. In this chamber, positive and negative pressures are applied across the assemblies in stages as the airtightness of the barrier and system components are evaluated. The diagram below shows the test mock-up with penetrations.
The system components for our INTELLO assembly test included:
- INTELLO PLUS smart vapour retarder stapled to wood studs
- TESCON VANA (2-3/8” / 60mm width) tape for horizontal and vertical join overlaps of membrane - including “stitch taping” at unsupported seams
- CONTEGA SOLIDO SL (3-1/8” / 85mm) tape at window frame opening
- ROFLEX EPDM gasket with TESCON VANA tape at pipe penetration
- TESCON PROFIL to seal square 100mm x 100mm penetration
- CONTEGA HF to seal outlet boxes (screws/holes) and bottom sill connection
The assembly includes horizontal battens 16” o.c. that further fix the INTELLO in place and provide a service cavity per Pro Clima’s standard installation instructions (use precautions as noted for highly exposed locations). The battens in this test, not normal service life, also supported the INTELLO Plus membrane when withstanding the high load wind cycling (positive and negative). More on that later.
Look Mom, No Sheathing!
Typically, tested assemblies utilize rigid sheathing as part of their system, but our system does not. There is no sheathing to restrict airflow or support the membrane. This is the only successfully tested system without sheathing and the first ever tested without sheathing, period.
You Don’t Need to Tape Staples
Our installation instructions require the use of staples to mount the INTELLO PLUS membrane to the studs. For commercial, dense-pack, and wind loaded locations, we reduce the required staple spacing to 2” with 3/8”crown+leg T50 staples, such as occurs in the test.
But in the test, as on the jobsite, the staples attaching the INTELLO PLUS membrane to the framing were left untaped. Of course after such drastic wind loading with negative and positive pressures, small leakages at staples do occur. Charlotte Abele, 475’s technical and code expert witnessed these very small leakages first hand, however, our air barrier system remains very airtight even after this highest class wind/pressure loading.
As we tested at such high pressures in ASTM E2357, we have now also proven in the lab that, taping of staples is not necessary to achieve excellent results. Yes, you can tape the staples, but their impact only becomes noticeable below approximately 0.25ACH50 or 0.02CFM/SF75 and is related compactness and building size. The smaller the building, the more effect taping staples will have.
Additionally, we tested INTELLO at the highest level of windloading (P3 up to 1200Pa and deflection to 1440Pa) to show its durability, even without sheathing. This assures builders they can finish an interior INTELLO air barrier before the exterior is buttoned up without worries of wind pressures negatively affecting the interior airbarrier system...
0.0493 L/s.m2 at 75Pa for the penetrated wall after wind loading - 4x tighter than the code requirement of 0.2 L/s.m2 @75 Pa.Even though we won’t call the code requirement particularly airtight as 0.2L/s*m2 @75Pa is a 1” (2.5mm) diameter hole in ~100 SF (9m2) of tested airbarrier assembly, which horrifies us and most serious high performance builders and contractors.
Location specific: The test has been run with the highest wind pressure and deflection loading. - per NBC 2015 this means that in the large majority of locations/cities per NBC2015 A-126.96.36.199 (1) INTELLO Plus is code compliant as the building will not be subjected to sustained wind loads calculated based on a 1-in-50 hourly wind pressure that exceed 0.65 kPa in that note.
ASTM E2357 and Blower Door Testing
475 and Pro Clima advocate for blower door testing all new construction and gut renovated projects. This quantifiable test verifies that air barriers are not only designed and detailed correctly, but also installation was properly executed in the field.
Buildings codes are moving towards compliance verification with blower door tests per CAN/CGSB 149.10-M86, ASTM 779, USACE version 3-2012D as per Provincial building codes or cities stretch codes. For example Vancouver currently requires 3.2 or 2.5ACH, other rely on 0.4CFM/SF envelope leakage. Both are a good starting point to increase comfort, reduce damages and lower heating/cooling costs. Being 3rd party ASTM E2357 verified, INTELLO airbarrier system is a NBC2015 compliant solution which allows customers (architects, builders, designers and installers) to specify and use this air barrier system with confidence. Both to comply with code and meet such “easy” air-tightness targets... easily.