AWC’s WCD #3. Design of Wood Formwork for Concrete Structures (T13). 1987 NO LONGER IN PRINT. For archival information, contact AWC.
APA-The Engineered Wood Association publishes Concrete Forming available for free on their website.
The American Concrete Institute (ACI) published the Guide to Formwork for Concrete available on their website.
Concrete Form Plywood
Concrete form plywood panels are manufactured in conformance with the requirements of the U.S. Department of Commerce Voluntary Product Standard PS 1, Structural Plywood. PS 1 establishes minimum requirements for the principle types and grades of construction and industrial plywood including wood species, veneer grading, glue bond, panel construction and workmanship, dimensions and tolerances, marking, moisture content, quality control and certification.
Concrete form meets the requirements for an “Exterior” bond classification and is manufactured with “B” face and back veneers and “C” or better inner plies. Bond classification is related to the moisture resistance of the glue bond under intended end-use conditions and does not relate to the physical (erosion, ultraviolet, etc.) or biological (mold, fungal decay, insect, etc.) resistance of the panel.
Class 1 concrete form plywood is designed to provide superior performance in the most demanding applications. A Class 1 panel, as defined in PS 1, is a panel with a Group 1 species in the face veneers, Group 1 or Group 2 species in the crossbands and Group 1, 2, 3, or 4 species in the center plies. A Group number is used to classify species covered by PS 1. Numbers range from 1 to 5. Strength and stiffness properties of species in Group 1 are typically highest, while the strength and stiffness properties of species in Group 5 are the lowest.
Structural I plywood used for formwork is manufactured with Group 1 species in all plies. It is specifically designed for applications where higher strength properties are required.
PS 1 is written in such a way that Class I or Class II concrete form plywood can only be so-designated if produced by manufacturers located in North America. Since many non-North American manufacturers produce concrete form panels, another grade marking approach is used in these situations. Such products cannot be identified as either Class I or Class II, but – under PS 1 – these products can be tested (by an accredited laboratory in accordance with approved acceptance criteria) to determine a Group Classification, which is then shown on the grade stamp. As a result, there is a designation: BB O & ES [BB grade, (release) oiled, and edge-sealed] for concrete form plywood manufactured outside of North America.
It is generally true that test reports must come from laboratories accredited (for the specific test method under consideration) by organizations such as the International Accreditation Service, Inc. (IAS), or by another accreditation body that is a signatory to the Mutual Recognition Arrangement (MRA) of the International Laboratory Accreditation Cooperation (ILAC). As regards evaluation reports requiring periodic inspections of the manufacturing facility by a third-party agency, the inspection agency must be accredited by IAS or by an accreditation body that is a partner of IAS in an MRA.