Standard for Performance-Rated Cross-Laminated Timber

ANSI/APA PRG 320-2019: Standard for Performance-Rated Cross-Laminated Timber

For engineers and designers pushing the boundaries of mass timber construction, understanding the performance and quality assurance of Cross-Laminated Timber (CLT) is paramount. ANSI/APA PRG 320-2019 provides the essential framework for specifying and utilizing this innovative building material, ensuring predictable performance and structural integrity.

What is ANSI/APA PRG 320-2019?

ANSI/APA PRG 320-2019, the "Standard for Performance-Rated Cross-Laminated Timber," is an authoritative industry-leading standard developed by APA – The Engineered Wood Association. It establishes comprehensive criteria for the qualification, manufacturing, and quality assurance of CLT. Its primary purpose is to provide engineers, architects, and specifiers with confidence in the performance characteristics of CLT products.

Scope & Purpose

This standard governs the performance-rated qualification and quality assurance of Cross-Laminated Timber (CLT) intended for structural applications in construction. It covers the requirements for laminations, adhesives, panel construction, and the testing necessary to qualify CLT for specific performance classes. The scope specifically addresses the manufacturing processes and product characteristics that ensure consistent structural performance and durability, but it does not cover design methodologies or installation procedures themselves.

Who Must Comply?

• • Primary Audience: Structural Engineers, Architects, Building Inspectors, Material Scientists, and CLT Product Manufacturers.
• • Industries Affected: Construction, Wood Products Manufacturing, Building Materials.
• • Compliance Nature: While the use of American National Standards is voluntary, compliance with ANSI/APA PRG 320-2019 is essential for manufacturers seeking to market and sell performance-rated CLT products and for designers specifying such materials to meet building code requirements and ensure proven performance.
• • Enforcement: Compliance is typically overseen by third-party certification bodies and building code officials who rely on the standard for product evaluation and acceptance.

Key Requirements Overview

The standard requires manufacturers to demonstrate the structural performance of their CLT products through rigorous testing protocols. Professionals must ensure that the CLT specified meets defined performance classes and adheres to dimensional tolerances for squareness and straightness. Key provisions include stringent requirements for the quality and bonding of individual laminations and the selection of approved adhesives that meet elevated temperature performance criteria. Furthermore, the standard mandates comprehensive quality assurance programs to maintain consistent product quality throughout the manufacturing process.

Related Standards & References

ANSI/APA PRG 320-2019 builds upon and is complemented by other industry standards. It references various ASTM International standards for material testing and component requirements, providing a foundation for material properties and test methods. Additionally, it integrates considerations for Canadian standards, ensuring broader applicability. Designers often also reference standards like the National Building Code of Canada or the International Building Code, which may reference or permit the use of CLT qualified under this APA standard.