Air Barrier Auditing: The Time is Now
In a previous RLInsight article, we defined and discussed the importance of air barriers in buildings as they relate to energy. As a refresher to our article in Issue 5, The Air Barrier Association of America (ABAA) defines an air barrier as “a system of building assemblies within the building enclosure—designed, installed and integrated in such a manner as to stop the uncontrolled flow of air into and out of the building enclosure,” which accounts for 40% of the energy used to heat and cool a building. We also discussed in that article that air barriers would soon become a code requirement for all new projects across the country as new code cycles are accepted by the individual states. The California Energy Commission (CEC) recently revised the building energy standards, California Title 24 (2013), which incorporates the new air tightness testing protocols for new homes and commercial buildings. Effective January 1, 2014, the State of California requires air barriers in all nonresidential, commercial, high-rise residential and all hotel/motel occupancies. ASHRAE/IES Standard 90.1-2010, 90.1-2013 and the commercial provisions of the 2012 International Energy Conservation Code (2012 IECC) also contain new provisions regarding air barriers. The time has come – the time is now! Buildings permitted after January 1, 2014 in California must have an air barrier in the design in order to be permitted. The building must have an air leakage rate not exceeding 0.40 CFM per square foot at a pressure differential of 0.3 in. wg. (1.57 psf) (2.0L/M2 at 75 pascals), using the ASTM E799 blower door test method.
How Does This Affect Design?
These new code requirements mandate that the building envelope be designed to limit uncontrolled air leakage into and out of the building. Uncontrolled air leakage leads to increased energy usage throughout the year and includes the roof, wall and floor systems that surround the space being heated and cooled. For design purposes, it requires that all seams, penetrations and transitions between approved materials or assemblies selected don’t exceed the maximum air leakage requirements and that all transitions are properly sealed. During the construction process, air barrier installation can have effects on the scheduling process, so additional planning is required.
Why is it Important?
As the diagram above indicates, air leakage is detrimental in several ways. It affects our indoor comfort and air quality; can cause damage to the structure, and increases the need for a larger HVAC system in the building. The air barrier needs to be strong and resilient to resist the positive and negative pressure from wind, stack effect and mechanical ventilation. The air barrier also needs to last the life of the building.
Title 24 Building Energy Efficiency Standards that go into effect in 2014 require that all commercial buildings are to be constructed with a continuous Air Barrier System and tested to verify that they do not exceed 0.40 cfm/ft2 at 75 pascals, in accordance with ASTM E799. Using the most recent ASTM standards, Randall Lamb provides Building Envelope Consulting Commissioning or BECx and Consulting, as well as Air Barrier Testing and Thermal Imaging Services to verify performance and troubleshoot air barrier systems. Randall Lamb also provides quality control services during the construction process, as well as ABAA Auditing Services. In conjunction with the testing, thermal imaging is used as a diagnostic tool to determine air leakage pathways. Theatrical smoke generation during pressure testing is also an excellent leak detection method.
More Title 24 Changes
In addition to the air barrier requirements that are to be implemented January 1, 2014, there are numerous other mandates that also take effect. The California Energy Commission took 2-3 years to complete these updates, which were approved in 2012; they anticipate a 25 percent reduction in building energy usage as a result. The Standards address lighting, heating, cooling, ventilation and water heating. The goal is also to save 200 million gallons of water per year and 170,500 tons of greenhouse gas emissions. Again, the stringent requirements are in response to the net zero energy challenge by 2030
Mandatory measures (no tradeoffs allowed) include the following:
- Stringent air leakage requirements (see above article)
- Commissioning plan, system manuals and training
- Performance testing of systems
- A “solar ready roof” – a minimum of 15% of roof space for future solar photovoltaic or solar thermal panels
- Max voltage drop requirements
- Lighting dimming controls/demand-response capability
- Rigid insulation on new metal stud walls
- Better thermal performance on new curtain walls and spandrel panels
- Motion sensors for outdoor lighting mounted lower than 24 feet
- Occupancy sensors in most spaces
- Occupant controlled smart thermostats to set and maintain desired temperature
- Advanced lighting controls to synchronize light levels with daylight and building occupancy
- P.E. sign offs at each phase of a project
- HVAC fault detection on certain systems
Additional measures (tradeoffs allowed) include the following:
- High-performance glazing and improved U-factor, solar heat gain coefficient and visible transmittance levels for new construction to avoid unnecessary use of installed lighting
- High-performance glazing – comparable to LEED Platinum levels – for existing buildings
- Cool roof technologies
- Increased HVAC efficiency
How Can We Help?
With the new code requirements at our doorstep, we can assist you with air barrier installation auditing, building envelope ASTM testing, and building envelope thermal imaging studies. In addition to meeting the code requirements, our goal is to help you achieve increased building efficiency, reduced costs, and healthy buildings.
As one of the first ABAA Audit firms in California, Randall Lamb is committed and equipped to adapt to these new regulations. Call Mike Kohler, CxA, CBCP, CBST, ABAA Auditor, at (619) 713-5775 or email at for more information.Posted in Commissioning, Project Insights