What’s in Your Spec? The Keys to Spotting Errors and Deviations

By Steve Marino

Premium unitized curtainwall and custom-built façades are par for the course in today’s highly creative building designs. Framed by tightening schedules and smaller budgets, successful commercial building projects need all stakeholders pulling on the same rope.

With the increased complexity of façades, glazing contractors rely even more heavily on accurate glass specifications to carry out their jobs. From project conception to completion, specifications provide a necessary “check and balance” to ensure that the proper products are being used and that current industry standards are being followed.

Although glazing contractors need to follow industry best practices, such as proper procedures for glass setting and using the proper glazing sealants, when installing the fabricated product, it’s equally important for them to review the glass specifications in their entirety to identify any red flags, errors, deviations from industry standards, special requirements or specific architect requests.

That’s not to say the entire responsibility falls on the glazing contractor. Not all specifications are created equal and every party in the supply chain that receives the specification for a particular project—architect/specifier, general contractor, fabricator or raw materials suppliers—is accountable for ensuring that the product it manufactures complies with current standards.

An enormous amount of detail makes up a specification. It can address edicts ranging from general industry-accepted practices to precise performance criteria, such as glass characteristics, thermal and optical properties, and surface orientation for low-E coatings in an insulating glass unit (IGU). Yet, with building designs becoming more intricate and complex, it’s increasingly likely that an architect or specifier will add a spec to a construction document that deviates from industry standards.

So, how can glazing contractors best ensure that nothing falls through the cracks, and that the installation of the fabricated IGUs will comply with the specification and meet all stakeholder expectations?


With hundreds of potential variables in any single glass specification, it’s understandable that a detail might get overlooked at any point in the process. The impact of such an oversight, though, can range from a developer who is dissatisfied with the appearance of the constructed building to the replacement of all the glass on a project because a performance specification was missed. So, regardless of the fallout, there is a “price to pay” for an inaccurate spec.

It’s not a stretch to say that a successful project—one that is completed on time and on budget, and that meets the expectations of the architect, building owner and all other stakeholders—hinges to a large extent on accurate specifications that comply with current industry standards. Being aware of and staying on top of potential issues serves the whole supply chain well. At each stage, it’s a good idea to conduct a self-check by reviewing
the following questions:

• Are critical specs for the project properly addressed and highlighted sufficiently?

• Do generic specifications (e.g. general guidelines for glazing) reflect the most current language and standards?

• Is the glazing product written into the glass specification still manufactured by the supplier?

• Does the glass product specified for the project meet or exceed the related ASTM Standard?

• What process is in place to ensure that changes to the specs are properly communicated?

Identifying issues in a specification doesn’t require a “needle in a haystack” approach. Checking for these common errors first can often quickly reveal inaccuracies:

Copied and pasted specs. Although a time-saver, copying and pasting information from similar projects can result in references to incorrect products and documents that have been decommissioned. Even though specifications contain standard, generic language, it’s critical to review that language for each project, as glass specs and building codes occasionally change.

Outdated standard and test method references. Obsolete standards and test methods can yield additional costs or installations that aren’t up to code. In addition, customers can receive inferior products or products that don’t meet current standards. Be aware of industry performance standards that have been updated or withdrawn and double-check that any standard referenced in a specification reflects the most current version.

Incorrect products. This issue manifests itself in several ways, including an erroneous or discontinued product that has been specified for a specific application, or a product brand that doesn’t correspond to the specified manufacturer. It’s a good idea to question specifications of custom products (e.g. tempered glass might not be needed to meet code). Also make sure that treatments such as low-E coatings, opacifiers and frits are appropriate for the surfaces in IGUs and spandrels.

Other areas to check include:
• Are Master Format numbers current?
• Are the referenced companies and suppliers still in business?
• Consistency of requirements—Do they agree across all sections of the spec document?
• Are performance requirements attributed to specific products correct?
• Composition of the product being specified—Is the information provided sufficiently specific? Once issues are identified, it’s critical that glazing contractors inform their subcontractors.


So, the specification for a project arrives, and all seems to be in order. It’s a
fairly standard job.

Or is it?

Perhaps the project isn’t so “standard.” If glazing contractors focus only on, for instance, the performance criteria for the glass makeup or received just a few select pages of the specification—not the entire Master Spec document—key information could be missed, resulting in a building that falls short of expectations.

Consider the following situation:

The architect has developed a very detailed spec that calls for heat-treated
glass to meet the strength criteria for the building. To avoid a distorted, wavy look, the architect designates a “critical performance spec” for flatness. However, this information ends up in a section of the specification that other parts of the supply chain don’t typically review. The resulting glass product does not meet the architect’s requirements and he or she starts looking for a supplier to blame.

Although the work glazing contractors perform is based only on what the general contractor or architect provides, a little “detective work” can go a long way. Check the entire specification, if feasible, for deviations or critical performance requirements that may be in a different part of the specification.

In addition, communication with upstream and downstream partners is vital. Because they are often more familiar with the overall scope of a project, general contractors can provide valuable insight into the visibility of, or expectations for, the project. For example, the glass specification for a new building being constructed in a major city and surrounded by iconic structures will likely have unique characteristics —perhaps the ASTM specification for a ¼-inch coating void is changing to 1/8-inch because the glass is in a high-traffic area of the building. Knowing the project’s prominence, the general contractor can tip off the glazing contractor of a potential deviation in the specs, such as a requirement that is tighter than normal ASTM specifications.


One of the keys to a successful building project—one that achieves the look architects envisioned when they designed and spec’d the job—involves the development of and adherence to accurate specifications. Architects set the tone for building projects, but every other element in the supply chain, including the glazing contractor, fabricator and raw materials suppliers, is responsible not only for providing its selected component in compliance with the final glass specification, but also ensuring that those specs are accurate and thorough and reflect the most current industry standards.

Steve Marino is the technical services manager for Vitro Architectural Glass based in Cheswick, Pa.

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