Optimizing Use of Low-Iron Glass for Project Budgets and Performance
Clear glass is extremely common, and is popular in a variety of architectural design applications. From applications ranging from vision glass to spandrel glass, clear glass is often specified due to its versatility and ability to serve as a substrate for low-emissivity (low-E) coatings. In addition to its compatibility with solar control or passive low-E coatings, clear glass is also relatively inexpensive and is frequently selected for its neutral color.
However, when specifying glass to achieve a desired aesthetic, design professionals know that clear glass isn’t completely clear—it has a distinct green hue when under light. When viewing a lite of clear glass, you may notice its slight green tint, which becomes more pronounced when viewed from an angle and becomes even darker at increased thicknesses. This can often compromise the designer’s intent of creating a vibrant space that displays true color fidelity or allows for brilliant views of the outdoors.
Iron oxide content within glass grants it this green tint, and it is a leftover from the manufacturing process. Known somewhat ambiguously as “clear float glass," “conventional clear glass,” or “standard clear glass,” this physical property is an attribute that experienced design professionals are all too familiar with.
Low-Iron and High Performance
Low-iron glass eliminates the green cast associated with clear glasses due to its low iron content. However, because there is no ASTM specification for low-iron glass, clarity levels can vary widely based on how it is manufactured and the levels of iron found in its formula.
Due to its composition, low-iron glass can transmit up to 91 percent of light compared to the 83 percent associated with conventional clear glass, allowing it to be used in a variety of different applications. Low-iron glass is ideal for enabling clear and brilliant interior views because it allows light to pass through unfiltered, and it features a high degree of color fidelity unseen in other glass types.
Low-iron glass is typically used for applications that include the following:
- Where clarity and connectivity between spaces is important
- Where the project requires maximized views from the inside-out
- Interior features such as balustrades, handrails, backsplashes, partitions, and display cases
Since low-iron glass can serve as a substrate for low-e coatings, it also can be used for vision or spandrel glass applications where performance and clarity are both critical.
Acuity™ Low-Iron Glass by Vitro Architectural Glass provides neutral aesthetics in addition to higher visible light transmittance (VLT), making it ideal for vision glazing applications. It also is ideal for painted spandrel glass for excellent color rendition and laminated glass to eliminate the green cast of conventional clear glass, all while allowing designers to stay on-budget.
Commercial building design is often an exercise in balance—between performance and aesthetics or budget and quality. Often, when a high-performance or highly aesthetic product is specified, owners or other project stakeholders may value-engineer the product out of the specification. Fortunately, options are available that allow design professionals to avoid compromising performance, aesthetics, budget, and quality—all while protecting the original design intent.