The Fenestration and Glazing Industry Alliance (FGIA) has released an updated technical information report that clarifies how sound is transmitted, measured and controlled in exterior fenestration products, and it spells out when to use Sound Transmission Class (STC) versus Outdoor-Indoor Transmission Class (OITC) ratings. According to an FGIA bulletin, the document was last updated in 2015 and is now available through the FGIA online store.
The report, AAMA TIR-A1, Acoustical Performance of Exterior Fenestration Products, consolidates the IGMA TM-6000 and AAMA TIR-A1 documents into a single, unified reference. It was prepared under guidance from the Residential Products Council, Architectural Product Council, and Glass Products Council Co-chairs, according to the bulletin.
“This document is significant because it consolidates the IGMA TM-6000 and AAMA TIR-A1 documents into a single, unified reference that delivers clear guidance on acoustical information as it relates to glazing and fenestration,” said Meghan Chamberlin (Lippert Components), Residential Products Council (RPC) Co-chair of the FGIA Acoustical Information Document Development Task Group. “It outlines the key components involved in measuring acoustics and explains how various factors influence the acoustical performance of a product. The document explains foundational acoustical concepts in a technical yet approachable way, helping audiences of all backgrounds grasp the key principles of acoustical performance for fenestration and glazing systems.”
What the report covers
The FGIA bulletin says the updated report walks readers through the fundamentals: what sound is, how it is transmitted through fenestration, how acoustical performance is measured, and what design choices can control sound transmission. It is written for a wide range of users, from a fenestration designer trying to meet an architect's sound control specification to a salesperson helping a customer understand how sound travels and what can be done to cut down on noise.
The report also clarifies the two product classification methods that appear most often in glazing specifications. STC and OITC are both used to describe acoustical performance, but they serve different purposes. FGIA's bulletin notes the report differentiates between the two methods and explains their appropriate use, helping specifiers avoid confusion when reviewing product literature or test reports.
As the FGIA store listing puts it, “This document was prepared for anyone who requires information on what sound is, how it is transmitted, how it is measured and how its transmission can be controlled.”
The report’s key topics include:
- What sound is and how it is transmitted through fenestration
- How acoustical performance is measured and controlled
- The key components involved in measuring acoustics
- Factors that influence product acoustical performance
- The appropriate use of STC versus OITC
Why the consolidation matters
Before this update, industry professionals could consult AAMA TIR-A1 or the separate IGMA TM-6000. The new edition combines both into one reference, a move the FGIA bulletin says was designed to deliver clear guidance on acoustical information as it relates to glazing and fenestration. For manufacturers and specifiers, a single document reduces the need to cross-reference two sources when evaluating acoustical performance.
Chamberlin's statement in the bulletin underscores that the document is not just for acoustics specialists. It explains the key components involved in measuring acoustics and factors that influence performance in a way that is technical yet approachable, making it useful for sales teams and designers alike. The previous edition dated from 2015, according to FGIA, and the update brings the consolidated guidance back into step with current residential and commercial project needs.
The involvement of the Residential Products Council, Architectural Product Council, and Glass Products Council Co-chairs means the report reflects both residential and commercial perspectives. That breadth matters in Canada, where high-rise condominium and office projects often specify different acoustical performance levels for the same window system depending on site conditions and local noise exposure. Designers can use the report to compare product ratings against project specifications without having to reconcile two older documents.
Canadian applications for STC and OITC
Canadian architects and manufacturers are familiar with both STC and OITC ratings, but their roles are not always clear in project documents. The updated report's clarification is timely for projects governed by the National Building Code of Canada and provincial codes, including Ontario's Building Code, which set acoustic performance expectations for separating assemblies and building envelopes. CSA A440, the core Canadian standard for windows, doors and skylights, sits within the same technical landscape as FGIA's documents, and many Canadian manufacturers test to both North American and Canadian requirements.
In dense urban markets such as Toronto, Vancouver and Montreal, sound transmission through glazing is a persistent concern for multi-family and mixed-use buildings. A clearer explanation of when to apply STC versus OITC can help specifiers select products that meet both code requirements and occupant expectations for noise control, without adding unnecessary cost. The report focuses on measurement and classification, which design teams can apply to the thresholds set in Canadian codes.
FGIA describes the document as a technical information report rather than a test standard, so it does not impose new thresholds or compliance obligations. Instead, it gives specifiers and manufacturers a common language for acoustical performance. For Canadian manufacturers selling into the U.S. or American suppliers working on Ontario projects, having one report that aligns the legacy AAMA and IGMA documents reduces translation work when preparing technical data sheets.
Availability and pricing
AAMA TIR-A1 is available for purchase from the FGIA online store at a discounted member rate of $25 or the non-member price of $70. The FGIA bulletin notes that other FGIA documents may also be purchased from the same store. Building Enclosure reported the release with the same pricing and consolidation details. More information about FGIA and its activities is available at FGIAonline.org.