Building Envelope Testing
Many people outside of the building trades often ask, “Why do we need testing?” as a building or structure is being constructed. Escalating construction costs seem to drive the need for saving money by eliminating those items that don’t seem to serve any real purpose.
At ABBAE we found that the best way to learn is by studying failures caused by others. Failure of a building to prevent intrusion by water or air is not only an expensive problem to remediate, it can be costly in its consumption of energy, additional equipment maintenance or replacement and in a loss of productivity. We have been very fortunate to have had the opportunity to study hundreds of building envelope failures of numerous types and designs. These failures are not just construction and material failures, but encompass areas that we feel need to be tested to ensure that the construction was designed properly; that the contractor and subcontractors followed the design intent; and that they followed proper construction methods, standards and requirements.
Water Barrier Testing
With each building envelope there are areas that have inherent risks based on our experience and forensic studies. Among those assemblies that have been noted to cause negative situations are Windows, Balconies, Decks, Podiums, Roofing, and Facades.
Construction of these systems are usually some of the identifiable aspects of a building, and as such we need to make sure that each component is tested to help mitigate the possibility of negative situations or intrusions. Part of the Benefits that testing provides are:
- A reduction in risk associated with the construction process
- Measurement and verification of building envelope systems meeting performance requirements
- Diagnose construction issues in systematic fashion
Among the water testing standards we use for New Construction and Existing Construction are:
- ASTM E 1105 – Standard Test Method for Field Determination of Water Penetration of Installed Exterior Windows, Skylights, Doors, and Curtain Walls, by Uniform or Cyclic Static Air Pressure Difference
- NAFS 2011 – AAMA/WDMA/CSA/101/I.S.1/A-440 – North American Fenestration Standard/Specification for windows, doors and skylights
- AAMA 501.2– Quality Assurance and Diagnostic Water Leakage Field Test of Installed Glazing Systems
- AAMA 502 – Standard Test Method for Water Penetration of Windows, Curtain Walls and Doors Using Dynamic Pressure
- AAMA 503 – Quality Assurance and Diagnostic Water Leakage Field Check of Installed Storefronts, Curtain Walls and Sloped Glazing Systems
- AAMA 511 – Voluntary Guideline for Forensic Water Penetration Testing of Fenestration Products
- ASTM E 2128 – Standard Guide for Evaluating Water Leakage of Building Walls
Through these tests can be conducted for new and existing construction, some tests are better suited for new construction, i.e.: AAMA 501.2., while other tests can be used for new and existing construction. We have been able to identify product defect leaks at mulled joints, leaking glazing seal failures, trickle vent gasket failure, flashing leaks and waterproofing integration leaks. Other types of building systems failures such as; drainage/slope issues that leak to the interior, high permeability rates in waterproofing membranes, clogged weep holes and discontinuous drain boards can be discovered through testing.
Integration testing, testing the completed assembly post construction and isolation testing, testing an individual component, i.e.: a window or a storefront assembly under construction, can uncover poor construction practices around windows and glazing. These tests can identify manufacturing issues such as torn or improperly placed gaskets and integration leaks as assemblies are constructed with several different components that make-up the building envelope.
At ABBAE we use ASTM E 2128 Wall and Fenestration Diagnostic Standard to systematically approach evaluating a leak.
- Review project documents and determine the design requirements.
- Prior to testing, make a visual assessment and inspection.
- Recreate the leak if possible. Trace or determine the leak pathways and correlate the test data with the observed damage.
- Analyze the information obtained and produce a report documenting observations, data, and results.
Other tests (AAMA 511, ASTM E 2128, AAMA 502) can provide specific forensic investigation criteria or other testing methods as guidelines for Forensic Water Penetration Testing of Fenestration Products.
Air Barrier Testing
Another building envelope failure is uncontrolled air leakage which can cause elevated utility costs and loss of heat or conditioned air, all of which decreases environmental controls, may increase noise through window penetration or HVAC operation, and most certainly elevates utility costs.
Part of the Benefits that air leak testing provides are:
- Ability to evaluate Mock-ups,
- Determining whole building air leakage rates,
- Discover air leakage of individual units within the building or its components.
- Find sources of air leakage
- Quantify air leakage loss
- Monetize energy loss,
- Project potential energy savings
- Justify capital improvements
It is possible to conduct a Fan Pressurization Standard Test to determine Air Leakage on an entire building through fan pressurization. An architect can calculate the leakage area based on the air barrier surface area and using a pressurization and depressurization method, which will identify areas of energy loss and areas of decreased environmental control.
In existing construction projects, testing can determine sources of air leakage and even quantify the amount of leaking air. This will illustrate the energy loss in terms of dollars flowing away from the building, but also can illustrate the potential savings that repairs or rehabilitation can produce and even justify capital improvements through those cost savings.
Several steps are implemented to determine air leakage from within a building. ASTM E 1186 is the Standard Practices for Air Leakage.
It provides for site detection in building envelopes and air barrier systems
4.2.1 Air Infiltration Site Detection Using Infrared Scanning
4.2.2 Smoke Tracers Used in Whole Building Pressurization or Depressurization
4.2.6 Smoke Tracers Used in Chamber Pressurization or Depressurization
4.2.7 Detection Liquid Air Testing
Mitigating losses in the building assembly are not limited to the walls and windows. And since we have shown how testing can provide beneficial results to those components, we need to remember that there are other assemblies that require testing as well. Roofs, podiums, and balcony decks are among these assemblies that need to checked and tested to help eliminate future failures.
Additional Assemblies Requiring Testing
Testing for horizontal surfaces such as podium decks and roofs may require ASTM D 5957 Flood Testing Horizontal Waterproofing Installations, and ASTM D 7877 Guide for Electronic Methods for Detecting and Locating Leaks in Waterproof Membranes.
In New Construction the area may be flooded or dammed partially to provide the testing area required. The process becomes more difficult once the overburden has been placed such as topping slabs, pavers, landscaping or planters and gardens.
Removing overburden and replacing it once the testing is completed is costly and time consuming, so testing during new construction is preferred. ASTM D 7877 utilizes Electronic Field Vectors to identify breaches, requires a conductive substrate and that membranes be grounded. There are however, limitations.
Drain transitions or base flashings don’t test properly, as leaks during testing can cause damage to the building and the building envelope. Also, there can be weight limitations that must be considered, breach locations for testing are limited, and sometimes testing is not recommended unless waterproofing is installed against the substrate. So even though there are several different methods of testing for leaks, care must be exercised to prevent damage to the assemblies that can be directly caused by the testing being performed.
The cost of testing during new construction is very minor when compared to the cost of repairing or replacing building envelope components after a building has been constructed. While the cost of new construction may be from $5 to $10 per square foot, once a problem has be recognized, the associated testing and repairs can exceed $200 per square foot, not to mention litigation costs, construction disruption time and inconvenience to employees or tenants.
Testing may be an additional cost in the construction of a new building, but our experience has shown that cost is minor when compared to the costs associated if, and more than likely when a failure occurs. For 30 years we at Allana, Buick & Bers have been providing the expertise and knowledge to make buildings perform better, and testing is an integral part of that expertise.