Codes & Standards
Beyond the lab: Strengthening field testing
By Jason Seals
Performance-path code compliance means field testing is getting more important.
By Jason Seals
Because they are critical components of a building’s weather- resistant barrier, fenestration products are often the focus of investigations of real or perceived water penetration or excessive air infiltration.
However, faulty fenestration design is not likely to be the cause of such leakage problems. Products that meet the appropriate performance class defined by the code-mandated North American Fenestration Standard, must pass laboratory water leakage tests of increasing stringency, depending on the product’s performance class and grade. Regardless, water penetration at an installed fenestration product may actually be attributable to poor installation, as well as shipping, handling, acts of subsequent trades, aging and other environmental conditions.
Because installed fenestration can be very difficult and expensive to fix after the building envelope is complete, specifiers and contractors are well advised to require field testing during or immediately after installation begins. The FGIA publishes field testing methods to aid in this mission. Of these, AAMA 502, Voluntary specification for field testing of newly installed fenestration products is the proper test method for determining water penetration and air leakage resistance of any type of newly-installed (prior to issuance of the building occupancy permit but no later than six months after installation of the fenestration product) factory-built windows, doors and skylights. It is based on ASTM E783, Standard test method for field measurement of air leakage through installed exterior windows and doors and ASTM E1105, Test method for field determination of water penetration of installed exterior windows, curtain walls and doors by uniform or cyclic static air pressure difference. Newly installed curtain walls and storefronts are tested per AAMA 503, Voluntary specification for field testing of newly installed storefronts, curtain walls and sloped glazing systems.
AAMA 502 specifies that one percent of the fenestration products to be installed on the project, but no fewer than three, shall be tested as soon as possible after installation begins to verify performance of both the fenestration product and its installation. To test for resistance to air leakage per ASTM E783, a differential pressure is created across either the interior or exterior of the test specimen using a chamber erected on site. The differential pressure should be equivalent to that originally used in the laboratory: a minimum uniform static test pressure of 75 pascals (or as specified for the project) but not to exceed 300 pascals. Unless otherwise specified, the allowable rates for field-measured air leakage must be a maximum of 1.5 times the applicable NAFS rate for the product type and performance class. Using this same chamber, the water penetration test is performed in accordance with ASTM E1105 procedure “B” (cyclic static air pressure difference), except AW-class windows are tested per procedure “A” (uniform static air pressure difference). AAMA 502 specifies the static water test pressure differential should not exceed two-thirds of that used in the laboratory. These reductions in air leakage rate and water test pressure are considered a reasonable adjustment for the differences between conditions found in a laboratory test environment versus those found in the field.
A newly-released 2021 edition of AAMA 502 is a significant revision from the previous 2012 version, with major changes including:
- All testing must be conducted by an FGIA-accredited laboratory or field test agency (FTA) that meets the requirements of FGIA/AAMA LAP-3, Laboratory accreditation program operations manual – Laboratories and test agencies performing on-site testing of fenestration products. Additionally, key personnel must be a currently registered FenestrationMaster or FenestrationAssociate.
- Prior to testing the FTA, the tester, in conjunction with the specifying authority, must issue a field test plan that summarizes test methods, failure criteria, number and type of products to be tested and locations, among other things;
- The fenestration manufacturer and the installer are allowed to perform an inspection and correct any deficiencies prior to testing;
- A new section concerning calibration and validation of test equipment (previously found only in LAP-3) is included. A diagram has been added depicting the appropriate validation apparatus;
- More precise parameters for describing observable water penetration are provided, as are new illustrations showing the planes of controlled and uncontrolled water penetration for various installation types and flashing conditions;
- Finally, the list of required information to be included in test reports has been expanded, notably requiring photographs of the test specimen and other relevant details.
To facilitate its use, AAMA 502 conveniently provides a recommended short-form model specification that allows the specifier to prescribe essential information such as the number of products to be tested; the test pressure for both air leakage resistance and water penetration resistance testing; and the pass and fail criteria.
Understanding field testing methods for air/water ingress is likely to become more urgent for window and door providers in the future. This is because, as energy efficiency rules tighten, homebuilders may begin to show more interest in whole-home performance-path compliance options. Jurisdictions such as B.C. and Ontario already offer builders the option to show compliance with energy regulations through modeling and testing of entire houses. The 2020 National Energy Building Code will offer compliance with higher tiers on a performance path measured against a reference building. The Canadian Commission on Building and Fire Codes had instructed the standing committees to defer airtightness testing requirements to future code development. The Standing Committee on Energy Efficiency included these testing requirements in the 2020 code recommendations. At the urging of CCBFC to remove airtightness requirements, SC-EE struck a working group from its members. The conclusion was to retain airtightness testing in the current code cycle. This recommendation will be forwarded to CCBFC and the industry will have the opportunity to appeal this inclusion. Airtightness will be further addressed in future editions of the National Building Code, requiring compliance with various levels of air changes per hour, normalized leakage area and normalized flow rate.
Sometimes prescriptive paths to compliance will remain, but as builders look for savings and creative ways to hit higher efficiency targets, they may wish to work with fenestration suppliers to find trade-offs. Could better quality windows enable them to install a less expensive HVAC system? Could continuous insulation enable them to install double-glazed rather than triple-glazed units? Could a tighter installation method help them pass air/water ingress requirements with little cost added? Field testing of models and one day even renovation projects will be needed to answer these questions.
AAMA 502-20 and AAMA 503-14 may be obtained by visiting the FGIA online store.
Jason Seals is FGIA’s certification services manager for fenestration.