AWPA - U1
USE CATEGORY SYSTEM: USER SPECIFICATION FOR TREATED WOOD
|Publication Date:||1 January 2021|
Introduction & Scope:
This standard provides information on specific nonpressure treated composite wood products, without the use of trade names or manufacturer's names. Products listed in this standard are categorized using species or species mix, preservative type, adhesive type, manufacturing process and use class. All of these factors play an integral role in determining the performance of the finished product in specific applications. Users and specifiers of these products are urged to consult closely with the manufacturer of the treated composite to ensure it meets the criteria in AWPA Standard T1, Section J.
Nonpressure treated composite (NPTC) wood products are complex materials whose strength and biodegradation resistance properties depend closely on the parameters of the manufacturing process. Each manufacturer of nonpressure treated composites typically uses processes considered proprietary. While listing under AWPA cannot include trade names, the categories in AWPA Standard T1, Section J are designed to allow for a unique description of the finished product and thus protect the proprietary interests of the manufacturer.
To be specified in this standard, manufacturers of NPTC wood products must submit a data package and have it evaluated and offered for ballot to Subcommittee T-8, Composites. To prepare for this process, candidates are directed to AWPA Guidance Document F: "Guidelines for Evaluating Composite Wood Products Preservative Treated Using Non-Pressure Processes".
NPTC are a unique commodity in that their performance in exposures to elevated humidity and/or liquid water is much different than solid wood or laminated wood. The information presented in Table 1 is intended to assist users of NPTC to better understand the relationship between the level of moisture exposure to an appropriate Use Category.