Invest in Evaluations of Your Existing Buildings—Including Fenestration Products—Before Renovation to Save Money Down the Road

NAFS has two driving principles that make it objective, reliable and simple to use. First, it is performance-based. NAFS rates complete, fabricated products according to how well they perform under prescribed conditions. Second, it is material-neutral. Again, because it is performance-based, the framing material does not matter. It can be metal, wood, composite or vinyl as long as it meets the minimum requirements and performs to the desired ratings.

The MONTREAT CONFERENCE CENTER, Montreat, N.C., required more than 600 windows in approximately 25 different sizes. To meet aesthetic requirements, combinations of fixed and outswing casement windows, along with radius transom windows from Kawneer, were used to replicate the appearance of the original windows. PHOTOS: Progress Photo, courtesy Kawneer

The MONTREAT CONFERENCE CENTER, Montreat, N.C., required more than 600 windows in approximately 25 different sizes. To meet aesthetic requirements, combinations of fixed and outswing casement windows, along with radius transom windows from Kawneer, were used to replicate the appearance of the original windows. PHOTOS: Progress Photo, courtesy Kawneer

Start with determining a Performance Class. This is a description of the likely target application for a window, door or skylight. These are based on minimum gateway sizes for testing with R being the smallest and AW the largest. Since 2008, NAFS has identified four Performance Classes, defined as:

  • R: commonly used in one- and two- family dwellings.
  • LC: commonly used in low- and mid-rise multifamily dwellings and other buildings where larger sizes and higher loading requirements are expected.
  • CW: commonly used in low- and mid-rise buildings where larger sizes, higher loading requirements, limits on deflection and heavy use are expected.
  • AW: commonly used in mid- and high-rise buildings to meet increased loading requirements and limits on deflection and in buildings where frequent and extreme use of the fenestration products is expected.

Next, understand the Performance Grade (PG). To have a PG rating on a NAFS-compliant fenestration product, the product must pass all the applicable testing requirements. At a minimum, this includes the Design Pressure corresponding to a specified maximum expected wind velocity (ASTM E330), maximum structural performance (ASTM E330), water-penetration resistance (ASTM E547 or E331), air-infiltration resistance (ASTM E283), uniform load-deflection testing (ASTM E330) and forced-entry testing (ASTM F588 or F842).

Rather than providing a multi-page, material-based specification that calls out every detail, a specifier can simply state the operator type (fixed, casement, etc.), the material (aluminum, wood, steel, vinyl, etc.), the Performance Class (R, LC, CW or AW) and the Performance Grade (PG-50, for example).

Next, the basic configuration and the desired performance requirements for the product can be defined. Color, screens and thermal performance may need to be addressed with the manufacturer, but the playing field has been leveled to more easily compare specifications from multiple fenestration product suppliers.

Additional Assurance

Runkle has witnessed firsthand the benefit of a building evaluation. In a New York high-rise project, a vapor-permeable air barrier was sprayed to the interior of the masonry to create a continuous air barrier across the entire assembly. That air barrier was tied into the new replacement windows; the exterior cladding remained in place. There was some minor tuckpointing and a new roof was put on. At the end of the project, the air-leakage performance of the building was almost 10 times better than the original performance.

Thanks to early conversations regarding the project’s building-enclosure upgrades, the mechanical engineer was able to create a smaller, more efficient system. Both annual and initial savings were realized by looking at the enclosure differently.

“We were not doing this even five years ago. More often than not, we can be successful, not just in achieving energy savings, but also in solving performance problems and extending maintenance cycles. There are lots of other tangible benefits like better occupant comfort and increased property values,” Runkle explains.

In addition to helping specify the correct product, AAMA product certification provides assurance that the manufacturers’ products should consistently meet the established standards. AAMA 103, “Procedural Guide for Certification of Window, Door and Skylight Assemblies”, outlines the process for certification of windows, doors and skylights for air-water-structural and thermal performance. This program provides a third-party inspection and labeling program to ensure products are built to the same high standard as the tested products.

“Getting the right product makes a big difference,” Barnes says. “You can have a good design, but if you’re not using the best materials and specifying the best products, it doesn’t really matter.”

CHARLOTTE HIGH SCHOOL, Rochester, N.Y., required a dual-glazed window to help reduce the cost of glass replacement in lieu of standard insulated units, as well as needed to meet thermal performance mandated by the State Education Department. Along with the technology upgrades and added building space, EFCO Corp. was able to provide windows and curtainwall materials, installed by Rochester-based BRG Corp., that met the project’s needs. PHOTO: EFCO Corp.

CHARLOTTE HIGH SCHOOL, Rochester, N.Y., required a dual-glazed window to help reduce the cost of glass replacement in lieu of standard insulated units, as well as needed to meet thermal performance mandated by the State Education Department. Along with the technology upgrades and added building space, EFCO Corp. was able to provide windows and curtainwall materials, installed by Rochester-based BRG Corp., that met the project’s needs. PHOTO: EFCO Corp.

To confirm product installations are done correctly, AAMA offers additional testing protocol. AAMA 501.2, “Quality Assurance and Diagnostic Water Leakage Field Check of Installed Storefronts, Curtain Walls, and Sloped Glazing Systems”, and AAMA 502, “Voluntary Specification for Field Testing of Newly Installed Fenestration Products”, are two common standards for this purpose. (Note: If using these standards in the field to verify compliance, it is recommended all interested parties agree to the method and level of testing during the contract phase.)

“Often, inspectors will find things like work that hasn’t been done properly, inadvertently or not, and that’s important to find early on,” Barnes adds.

Inspection costs vary based on the size and scope of any project. In some cases, with extremely large buildings, the evaluation cost is based on a percentage of the property’s sale price, sometimes 1 or 2 percent. An average cost for a commercial real-estate inspection is approximately 10 cents per square foot. Naturally, when spaces are especially large or involve unusual features, this amount may increase.

Every project should perform an evaluation. Doing this step upfront will save money in the end.

About the Author

Steven Saffell
Steven Saffell serves as technical director for the Schaumburg, Ill.-based American Architectural Manufacturers Association.

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