Download a Fast Facts on HRA finger-jointed lumber
Following extensive industry testing, finger-jointed lumber joined with heat-resistant adhesives is now available from WWPA mills. Finger-jointed lumber carrying the HRA label, as shown in the sample gradestamp, is suitable for wood-frame assemblies where a fire rating is required.
U.S. building codes require fire-rated assemblies in multistory/multifamily structures between living units or common party walls in commercial buildings. Detached single-family houses under current codes do not require one-hour fire-rated assemblies.
Finger-jointed lumber made with adhesives that are not heat resistant are marked as Non-HRA. Finger-jointed lumber without the HRA and Non-HRA marks are assumed to be not suitable for use where a fire rating is required.
Use the WWPA Online Lumber Buyers Guide to find mills that produce HRA-labeled finger-jointed lumber. Under Product Types, select HRA Finger-Jointed to generate as list of sales and contact information on WWPA mills producing these products.
Code acceptance
Finger-jointed lumber and other structural-glued products have gained wide acceptance in the building and construction industry. These products are accepted for use under both the International Building Code (IBC) and the International Residential Code (IRC), and are considered interchangeable with solid-sawn dimension lumber of the same size, grade and species. IBC Section 2303.1.1 Sawn Lumber, states, "Approved end-jointed lumber is permitted to be used interchangeably with solid-sawn members of the same species and grade."
The new HRA marks are intended to provide regulators and users additional information to identify which finger-jointed products meet elevated-temperature performance requirements. HRA-marked finger-jointed lumber should be used for assemblies that require a fire resistance rating under the IBC and IRC. Typically, one-hour fire ratings are required for multistory or multifamily structures in separations between living units. Common walls in commercial structures may also require one-hour fire rated assemblies.
Non-HRA grademarked lumber is suited for most residential construction. Under current building codes, detached single-family homes do not require one-hour fire-rated assemblies. Non-HRA marked lumber and finger-jointed products with no HRA designations can continue to be used in construction for most single-family homes.
Performance testing
Heat-resistant adhesives are evaluated according to the American Forest & Paper Association's Elevated-Temperature Adhesive Qualification Procedure. This protocol requires an adhesive to be exposed to elevated temperatures during a standard ASTM E119 fire test of a load-bearing end-jointed stud-wall assembly loaded to 100 percent of the lumber's allowable design load.
Fire tests are conducted on wall assembly designs specified in the 2003 and 2006 editions of the International Building Code Table 720.1(2), Item Number 15-1.14. Adhesives qualify for HRA designation if the wall assembly performs to design specifications for at least one hour in the E119 fire test. All tests are conducted in International Accreditation Service, Inc. accredited laboratories in the U.S. and Canada.
WWPA is the West's top agency for finger-jointed lumber quality control, providing services to more finger-jointed lumber mills than any other Western grading agency. WWPA is approved by the American Lumber Standard Committee, Inc. (ALSC), under U.S. Department of Commerce (DOC) Voluntary Product Standard PS-20, to certify structural-glued products in all species and species combinations. The American Lumber Standard PS-20 provides the framework for quality control of structural-glued lumber under its Glued Lumber Policy, which results in predictable, reliable products that may be used for structural purposes with confidence. DOC PS-20 is the referenced standard for lumber products in the I-Codes and predecessor Legacy" codes.
For more information on HRA finger-jointed lumber, download the WWPA Fast Facts Heat-Resistant Adhesives (HRA) and Finger-Jointed Lumber. The Fast Facts shows HRA and Non-HRA marks on gradestamps for finger-jointed lumber and explains how these products should be used in construction. Additional information on finger-jointed lumber is also available in the WWPA TIP Sheet Structural-Glued Lumber.