Gate-To-Gate Life-Cycle Inventory of I-Joist Production

James B. Wilson, Eric R. Dancer


A life-cycle inventory (LCI) study is conducted of wood composite I-joists manufacturing. This gate-to-gate study includes all materials, fuels, and electricity inputs to produce I-joists, co-products, and emissions. The inputs included the laminated veneer lumber (LVL) used for the I-joist's flanges and the oriented strandboard (OSB) used for the web, but it excluded the LCI for their input logs. Data were collected through surveys of manufacturing facilities in the Pacific Northwest and the Southeast. In addition to LCI data, transportation distances for delivery of materials are also provided. SimaPro software, a program to conduct life-cycle inventory and assessment studies, is used to process the data and determine environmental impacts in terms of material and energy use, and emissions. The impact data are allocated on a mass basis to I-joist based on their mass contribution to the sum of all product and co-product generated during the manufacturing process. All data are provided on a production unit basis of 1.0 km and 1.0 MLF (one thousand linear feet), the U.S. industry practice. In addition to LCI data, carbon flow data are also given. These LCI data are publicly available through comprehensive reports, this summary publication, and the U.S. Life-Cycle Inventory Database Project. The data are useful for generating cradle-to-gate product LCIs when combined with the LCIs to produce logs for the mills and material transportation impacts, and are useful as a benchmark for assessing process performance, and for conducting life-cycle analysis of floor and roof assemblies and residential structures using I-joists.


Life-cycle inventory;LCI;I-joists;building materials;carbon balance;energy;emissions

Full Text:



  • There are currently no refbacks.