When trying to build airtight, the real magic is NOT the airtightness testing itself, it’s actually the Building Design, continuous QA(Air Barrier Integrity Auditing) during construction and ensuring an airtightness champion has been appointed by the builder.
The key features of conducting air barrier integrity auditing are:
- Locating areas of concern with exact locations of the issues.
- Verification of building materials being used, that will enable an air barrier that lasts
- Timely reporting of the issues, so that remediation can be undertaken before finishes
- Capturing photographs of remediation works
- Confirming or finding issues in building facades/junctions for a continuous air barrier using Ultrasonic technology.
- Recommendation of remediation, with materials/products that comply with the Australian Building code.
If a QA process is not conducted regularly at key intervals during construction,
- airtightness targets can become a very expensive exercise,
- remediation works that happen after construction can have the potential to not last the test of time,
- or remediation works may not even be possible due to safety.
Location, Location, Location
Commercial Buildings can be large and complicated, so it is important, that plans are marked up with problematic details, if trades cannot find issues, they just won’t fix them. If issues cannot be relocated to verify remediation, then the whole process of air barrier integrity auditing is rendered ineffective and pointless.
Verification of building materials.
In some circumstances, building materials specified for the air barrier may be inadvertently costed out, or supplied with an inappropriate product. Certain tapes or sealants may not be compatible together or may react undesirably when exposed to environments during construction. It’s important to catch these issues during construction so that they can be repaired in a timely manner before finishes.
Projects can move extremely fast, and it is not uncommon for the fit-out to begin before service risers are complete. Once an inspection is conducted, a report must be issued with all the location details marked off an up to date floor plan, recommended fix and dimensions of the issue, with the direction of how the air barrier should be continued.
Photo’s of issues should be marked up to clearly articulate to trades the whole that must be closed in. Airtightness is not always obvious.
Troubleshooting during construction
Troubleshooting and confirming air leakage through the air barrier when the building is under construction is difficult. There are technologies available to help confirm non-obvious gaps in building elements. Ultrasonic sound auditing can add significant value.
An array of ultrasonic transmitters which generate ultrasonic waves are set up on the outside. This makes it possible to find gaps in curtain wall facades, leaks through building elements, door frames/window frames and window/door seals, even ducts and plenums.
The ultrasonic detector picks up ultrasound via a microphone and converts the inaudible ultrasound into an audible frequency and in some circumstances overlays the frequency emission location on top of a visual image with a representative highlighted colour. A visual representation is bundled together using a directional array of receivers capable of picking up ultrasonic sound waves while suppressing other noise and outputting onto an image. Because ultrasonic waves are so directional, from the emission source surveys can be undertaken on partly completed wall details. When auditing ultrasonic sound gets louder the closer you get to the leak and is quickly muffled as it moves through the air. The ultrasonic leak detection can pinpoint even the smallest leaks, during a partly constructed building, which is the most economic time to organise a solution.
During construction, drawings sometimes miss air barrier continuity. Different materials that make up the air barrier have different surfaces and therefore different products need to be used depending on the circumstances to ensure the longevity of the air barrier over the life of the building.
Air Barrier Integrity Auditing, is a critical part of building commissioning, combination with an Airtightness champion who is an integral part of the construction team, coupled with good building design and detailing, airtightness targets of the likes of Passive house or even more stringent can be achieved as economically as possible.