Q: What is an Air Barrier?

A: An Air Barrier is defined by the Air Barrier Association of America as an assembly to “control the unintended movement of air into and out of a building enclosure.”

Q: Why has Air Barrier Tightness become a USACE certified requirement?

A: The reasons why air barrier tightness has become a requirement is due to the many ways air may escape from the building envelope. Over 40% of the nation’s energy expenditure stems from the operation of buildings where the majority of this energy is used to condition the indoor environment. Because wind is constantly changing the positive and negative pressures on the building envelope, a proper enclosure is vital to reductions in energy consumption.

Q: What are some common causes of air leakage?

A: There are three common causes of air leakage:

1. Improper sealing and climate changes: In warmer seasons, the air rises to the top of the building, and since buildings are not totally sealed, the air escapes through open windows and/or ventilation openings. In turn, the rising warming indoor air reduces the pressure at the buildings base which then causes cold air to be drawn through openings near the building’s base. During coolers seasons, the adverse occurs.
2. The Buoyancy Force or Stack effect: Is the movement of air into and out of the buildings, chimneys, flue gas stacks and other containers. The movement is driven by buoyancy that occurs because of a difference in indoor-to-outdoor air density that stems from temperature and air density. Thus, the greater the thermal difference and the height of the structure, the more air moves in and out of a building
3. A third force is the design of a buildings mechanical system where heating and ventilation systems promote either positive or negative pressures within the building.

 

Q: What is the USACE?

A: The USACE (United States Army Corps of Engineers) is a federal organization and the world’s largest design and construction management agency. Their mission is to “provide vital public engineering services in peace and war to strengthen our Nations security, energizes the economy, and reduce risks from diseases.” The Corps vision is to breed a “great engineering force of highly disciplined people working with partners through disciplined thought and action to deliver innovative and sustainable solutions to the Nations engineering challenges.”

Q: What are the benefits of the USACE regulations?

A: The USACE regulations on Air Barrier Tightness support the Energy Independence and Security Act of 2007. The air barrier is an important addition to optimize the HVAC’s system performance. The regulations on air barrier tightness improve smoke and fire control and reduce energy consumption.

By reducing the amount of air from entering and exiting a buildings envelope energy consumption decreases by way of lowering cooling and heating costs as well as allowing designers to reduce the building envelopes HVAC demands.

The 2008 regulations on air barrier tightness also improves Indoor Environmental Quality (IEQ) by reducing drafts in the building that causes occupant discomfort as well as decreases noise pollution by patching leakage paths.

The air barrier system also eliminates degradation of the building’s materials caused by interstitial condensation. Interstitial condensation is condensation that is hidden in cavities and gaps that if undetected can accumulate and lead to mold and decay where its cause is due to the leakage of uncontrolled air flow. A more efficient building envelope will help decrease condensation in a building’s cavities which leads to a reduction in the amount of microbial growth, or bacterial growth.

Air Barrier tightness also improves poor air quality by decreasing the amount of fumes, dust, and other toxic particles from entering the buildings air circulation systems. Moreover, air barrier tightness also eliminates a buildings inability to balance pressure conditions as well as improve its control and balance of its HVAC systems.

Q: Why hire a Registered Roof Observer (RRO)?

A: Systems Building Envelope Consultants has had the RRO designation through the Roof Consultants Institute (RCI) since 1997. USACE projects are beginning to require the presence of an RRO to perform daily oversight and quality control on all roof work. We have met that challenge using our staff’s credentials well in advance of any requirements from the USACE.

Our other roofing specialties include designing, specifying repairs/replacement and managing roofing, waterproofing and exterior wall systems. Our senior building science consultants also specialize in forensic investigation, expert witness testimony and construction document preparation.

Our RRO’s operate without conflict of interest, and are not connected with any manufacturer or product. They strive to be unbiased and are governed by an established code of ethics. We keep a working knowledge of the latest industry technologies and methodologies. We are committed to maintaining annual requirements for continuing education.

Roof consultants plan roof design solutions, perform evaluations of existing roofs, prepare construction documents, perform forensic inspections, monitor construction and serve as expert witnesses. Roof consultants possess a broad base of practical knowledge about the roofing industry at large. Many choose to focus their work and become experts on specific roof types and materials.

Roofing Quality Assurance Observers monitor the construction process. They strive to make sure the roof is built to code and specification. They work to assure proper application procedures are followed and that criteria for validation of manufacturer’s warranties are met.

Building Performance Tests for USACE Commercial Projects

Whole Building Air Barrier Tightness Testing is Critical for all Buildings to Maximize Energy Efficiency—Now an USACE Commerical Project Standard

The United States Army Corps of Engineers (USACE) has adopted an air barrier tightness standard that requires all buildings to be tested and subsequently pass a stringent building air barrier tightness test. Modern buildings need to meet even more stringent air leakage standards. It is our belief that these standards will become increasing more stringent requiring designers and the constructors to be more mindful of the buildings’ air barriers and related construction components.

Engineers are using smaller allowances for air leaks in their HVAC systems. Testing larger buildings for air barrier tightness requires multiple blower doors working in unison, in conjunction with guarded pressure zones, to measure the leakage rate of the building enclosure.

SYSTEMS Building Envelope Consultants owns and utilizes the latest technology, in combination with multiple blower doors, to measure the air leakage through the building enclosure, in accordance with ASTM E779 methodologies as well as the USACE Building Air Tightness Testing Protocol. We are trained in providing the Large Building Air Tightness Tests and have conducted hundreds of tests on a variety of building types.

Our diagnostic evaluations are followed up with an Infrared Thermography test. This involves scanning the areas of the building envelope for air leakage, thermal bridges, and/or missing insulation. These tests are performed in general accordance with ASTM C 1060 (2003) and conform to USACE.

 

This Thermogram was taken during a building performance test while the building was pressurized. The cooler air (yellow) was escaping the building. This is a demonstration of air leakage.  

 

 

Infrared Thermography Helps Find the Source of the Leak

Infrared Moisture Surveys can find the Source of the Leak without Unnecessary Invasive Investigation which can lead to Significant Cost Savings

During the day, the sun radiates energy onto the roof and into the roof substrate. At night, the roof radiates the heat back into outer space. This is called radiational cooling. Areas of a roof that are of a higher mass (wet) retain this heat longer than do lower mass (dry) areas. Infrared imagers can detect this heat and “see” the warmer, higher mass areas, during the “window” of uneven heat dissipation.

The above images show how certain wet areas of the roof retain heat longer than dry areas. Some roofs, insulation types or combinations do not absorb any water. These roofs leak straight into the building. Even roofs with insulation types that do absorb water, do not always exhibit a good infrared signal, primarily for two reasons. 1) The surface is too reflective, and/or 2) the roof’s ballast is so thick (or dense), that daylight radiation is not absorbed into the substrate (insulation), therefore it cannot be emitted back into the atmosphere at night.

Even with a strong infrared signal, multiple roof factors can affect the analysis and interpretation of the data. Some of these factors include: 1) water between multiple layers, 2) old patches, 3) heavy flood coats, 4) reflective coatings, 5) heat-producing equipment under the roof – or heat blowing down onto the roof, 6) stains, 7) ponding water on the roof, and 8) heavy build-up of ballast at parapet walls and along edges, etc. These roofs should be inspected by other methods as well.

Water Penetration Testing ensures Quality during Commecial Construction

Systems Building Envelope Consultants can Field Test for Water Penetration to Ensure Work Quality and Specifications are met during Commercial Construction

Our water penetration consultants can provide third party independent water penetration testing to validate that windows, doors, storefronts, and curtain wall assemblies are installed to meet the project specifications and product manufacturers’ installation requirements. Field testing for water penetration will determine the quality of work of subcontractors and ensure their accountability. Field testing will also ensure that proper specifications were followed during the construction process.

These water penetration tests may include:

• Mock up and in-field testing for Curtain Wall and/or Masonry - We provide pre-design and/or forensic site related testing of curtain walls, masonry and exterior wall. Depending on the height of the facility, swing stage rigging may be required along with the services of a waterproofing contractor to remove and replace masonry units so that the shelf angle and the flashing can be observed.
• Moisture Testing Services for Roofing - This service is typically performed in conjunction with our preliminary design service for roofing and only after we have physically determined that a small percentage (less than 20%) of insulation is wet. The testing tool will identify those small areas of wet insulation. The wet areas are then outlined on the roof with paint. From this determination, a design can be developed to remove only the isolated wet areas and overlay the existing dry areas. This methodology keeps your costs to a minimum and often entails using capacitance meters as well as Infrared Thermography.