Glass and metals 201

An architect’s guide to glass and glazing specifications
Katy Devlin
April 5, 2011

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Designing a building demands architects think big picture. Writing specifications for those buildings, on the other hand, requires incredible attention to the smallest detail. "Glass and Metals 201" is an introductory guide to architects for developing glass and glazing specifications, based on information from representatives in various segments of the industry—from contract glaziers to suppliers to consultants.

Accurate and detailed glazing specifications create a strong foundation for the building process.

"Architects and contractors get better bids from subcontractors, and it starts the project out on a much better footing," says Christopher Matthews, vice president, senior consultant, Glazing Consultants International LLC, West Palm Beach, Fla. Specifications with incorrect, incomplete or unclear information can create costly challenges throughout the remainder of the bid, design and build process. Specification issues frequently lead to legal conflicts, he says. According to industry representatives, glazing specifications are often wrought with problems or inconsistencies, some more major than others.

"Unfortunately, it is very common to see issues with specifications. ... upwards of 90 percent have problems," says Mike Turner, vice president of marketing, YKK AP, Austell, Ga. Monica Lozano, consultant with Curtain Wall Design & Consulting Inc., Dallas, estimates that 80 percent of glass and glazing specifications miss important aspects of the performance requirements. She adds, "I've never received a set of specifications where I didn't have any alterations."

This comes as little surprise to many in the industry, as accurate specifications are difficult to produce, due to the vast scope of a project and all of its components. "Architects are looking at 12,000 or 15,000 things when they're writing specifications," says Don McCann, architectural design manager, Viracon, Owatonna, Minn. Turner adds, "The creation of specifications is a daunting task in that it touches a wide variety of products." With cutbacks at many firms, the already monumental task of spec writing has fallen onto fewer people.

The most common problems with glazing specifications are out-of-date information and misspecified products, according to industry representatives. "We see specs with information that is 10 to 12 years old—old manufacturers and products, old code requirements, in boilerplate specifications," Matthews says. John D'Amario, director of sales, C/S Erectors Inc., Architectural Wall Systems, San Ramon, Calif., says about half of the glazing specifications he sees contain out-of-date specification information that has been carried from job to job. About half also specify use of a product that is incorrect for the application, he says.

See the sidebar, "Top 10 problems in glazing specifications" for the most common errors in glazing specifications.

Informational resources

Glass industry representatives say it falls on glass and glazing companies to provide assistance, education and accurate information to architects before and during a job. "This education is critical, more so now than ever before, due to the changes in the industry, including the reduction of workforce," McCann says. "As an industry, we need to serve [in a] consultative role, providing products and services that they might not have needed four years ago. We need to fill that void."

Most glass industry product suppliers provide ample product data, including performance information, in their literature and online. Once an architect determines the performance requirements, most suppliers are able to show which of their products can meet those requirements.

Some suppliers offer assistance in specification writing itself. McCann says Viracon provides a specification review service to architects. Kris Vockler, vice president, operations, ICD High Performance Coatings, Vancouver, Wash., says some suppliers also offer sample specifications by application or product, with "detailed specifications written out that an architect can use, and information about the intended uses."

Contract glaziers also serve as an information resource for architects, McCann says. "Contract glaziers can listen to what the architect is looking for and help them understand our business a little better," he says. Lozano agrees. "If a [contract glazier] asks the architect about what they are trying to achieve with the spec they've submitted, [the glazier] might have a better idea of what will be needed to achieve it and meet performance requirements."

Coordination and early planning with all players also eliminates some problems in specifications. "Coordination is key," Lozano says. "The architect, glazing contractor and manufacturer need to be all on the same page in regard to a system. ... The team needs to sit down and make sure it can be done, under budget." McCann adds, "It's best to get all players involved early on. It doesn't streamline the process to write specs, send them to the GC, then to the glazing contractor and then to [the supplier]."

Read tips about developing glazing specifications on the following pages.

For more resources, including information about the most up-to-date codes and standards for the glazing industry, visit

Read a related article with specification tips for contract glaziers and suppliers in an upcoming issue of Glass Magazine.

Katy Devlin is editor for Glass Magazine. E-mail Katy at

  • Top 10 problems in glazing specifications

    1. Use of boilerplate specifications, where information is carried from job to job and not always modified to suit a project.

    2. References to standards that are obsolete or have been updated, or mention of reference resources that have changed or no longer exist.

    3. Call for products that can't meet requirements.

    4. Specification of improper product configurations. (For example, call for a low-emissivity coating on the wrong glass surface, or a specification for a perimeter sealant when an IG sealant is required.)

    5. Specifications calling for a product from a manufacturer or fabricator that no longer exists or that has changed business activities.

    6. Specifications focused on aesthetics instead of performance, thus creating problems where a specified system won't meet performance requirements.

    7. Lack of coordination between specifications for glass, framing, windows and other elements, creating conflicting requirements for the overall system. (For example, since glass and framing systems are typically specified independently of each other, the combination of the two might not achieve the overall performance specified for the project.)

    8. Specifying an earlier version of a product for which certification has expired, (common in areas such as Florida with frequently changing codes and re-certification requirements) or specifying a product for which an updated version exists.

    9. Specifying products that are outdated or even obsolete due to product advancements.

    10. Inconsistent warranties between what is indicated in the specification and what the product supplier will actually provide.