October 2001 (Volume 23, Number 4)
EXCELLENCE IN WOOD PRODUCTS MANUFACTURING
NC State University will offer "Excellence in Wood Products Manufacturing." This is a distance learning wood products graduate course taught via the Internet. The objectives of this course are: apply common sense approaches to improve manufacturing efficiency; learn what measures are important; learn the systematic approach for process improvement; and challenge students to apply what they learn in their workplace environment. This is an interactive course designed around the book, The Goal by Eli Goldratt. Individuals wishing to take this course must have an undergraduate degree, be currently employed in the wood products industry, have your employer's permission to participate, and be highly motivated to excel in the wood manufacturing field. Course instructors are Joe Denig and Phil Mitchell, wood products extension specialists. For more information contact Joe Denig at 919-515-5582 (voice), 919-515-8739 (fax) or joe_denig@ncsu.edu (e-mail) or Phil Mitchell at 919-515-5581 (voice), 919-515-8739 (fax) or phil_mitchell@ncsu.edu (e-mail).
CCA TREATED WOOD AND LEACHING
Concerns have increased that arsenic pentoxide, chromium trioxide or copper oxide released from the surface of chromated copper arsenate (CCA) treated wood used in playground equipment and decks can harm people or the environment. Although experts disagree on the severity of the threat posed to children or other users of treated wood products, many consumers are seeking methods to minimize any risk of chemical exposure. Coatings or sealers are often recommended, but their efficacy in preventing leaching has undergone little evaluation. To address this question, researchers at the Forest Products Lab (FPL) recently evaluated the ability of three common coatings to reduce leaching from CCA treated wood. Replicate matched specimens of treated 2 by 6 lumber were given one of the following coatings: (1) latex primer followed by one coat of outdoor latex paint, (2) oil-based primer followed by one coat of oil-based paint or (3) two coats of a penetrating oil semi-transparent deck stain. The specimens were then exposed to 30 inches of artificial rainfall for three weeks. The water running off the specimens was collected and analyzed for preservative components. The results were very promising. All three coatings reduced leaching of arsenic pentoxide, chromium trioxide, and copper oxide by over 99% in comparison to uncoated specimens. None of the water collected from the specimens coated with latex or oil-based paint contained any detectable copper, chromium or arsenic. In some cases, water collected from the specimens that were coated with the penetrating oil stain did contain detectable levels, but the highest level of arsenic detected in these samples was still well below the EPA's drinking water standard. This study suggests that the application of these common coatings is an excellent recommendation for consumers who are worried about chemical exposure from CCA treated wood. For more detailed information on this study contact Stan Lebow, Wood Preservation and Fire Research Work Unit, FPL at 608 231-9411 (voice), 608 231-9592 (fax), slebow@fs.fed.us (e-mail). It should be pointed out, however, that this test did not address how well these coatings stood up to wear and tear. Previous research on this issue has resulted in the following recommendations when considering the maintenance of a deck. A water repellent preservative (WRP) is the easiest to maintain on a deck. Since WRP's are considered a penetrating finish, they let the wood breathe and do not peel. The next best finish is a semi-transparent oil-based stain also considered a penetrating finish. Film forming finishes such as paints are prone to fail by peeling and are not recommended for decks due to the issue of higher maintenance. Although water repellents require more frequent application than other kinds of finishes, the ease of refinishing compensates for the increased frequency of application.
PLYWOOD MANUFACTURING SHORT COURSE OFFERED
The Hardwood Plywood & Veneer Association and NC State University's Wood Products Extension will conduct Hardwood Plywood Manufacturing 101: Common Problems and How to Solve Them on October 15-16, 2001 at NC State University in Raleigh, NC. The updated and improved course is designed to provide participants with troubleshooting and problem-solving tips and techniques in all areas of hardwood plywood production, and is therefore ideal for managers, supervisors, quality control personnel, and others involved in hardwood plywood manufacturing. The short course registration fee of $295 will cover the cost of the course and materials, breaks, and lunches (other meals and lodging are not included). The class size will be limited to 40 and will be offered on a first-come, first-served basis. For more information contact Larry Jahn at 919-515-5579 (voice), 919-515-8739 (fax) or larry_jahn@ncsu.edu (e-mail).
STEEL VERSUS WOOD
The first findings are in on a field study that compared the cost of framing a new house with cold-formed light-gauge steel versus the cost of conventional wood framing. The two identical houses were built side-by-side in Valparaiso, IN, in the winter of 1999. Researchers kept track of the cost of all materials and used the Group-Timing Technique (GTT) to measure the hours of labor put into each house. GTT is a work measurement procedure for multiple activities that allows one observer using a stopwatch to make a detailed time study of an entire work crew at the same time. The study showed that the total cost of framing the steel house was $27,624 versus a total cost of $25,729 for the stick-built house. Despite the fact that fasteners and insulation (rigid foam) cost more for the steel house, its material costs were still $1,143 lower than the wood house. This was calculated with lumber prices at $393 per thousand board feet. It was in labor costs that steel lost ground. The steel house required a few more man-hours to frame than did the wood house (316 versus 293), due almost entirely to the work required to install the exterior rigid foam insulation. Moreover, the per-hour rate paid to the steel workers was substantially higher, $38.34 versus $30.96. Overall, the study suggests that steel framing was most advantageous in floor and non load-bearing wall applications and least advantageous in load-bearing walls and ceilings.
SCRAP WOOD PUBLICATIONS AVAILABLE
Scrap Wood Availability in the Triangle J Region and Markets for Scrap Wood in the Triangle J Region produced by the North Carolina Cooperative Extension Service and the Triangle J Council of Governments are now available. The first report addresses the origin and characteristics of scrap wood generated in the six North Carolina counties served by Triangle J Council Governments which includes Chatham, Durham, Johnston, Lee, Orange, and Wake. The second report identifies reuse and recycling markets for the scrap wood currently sent to landfills from the Triangle J Region. A limited number of these free publications are available from Urs Buehlmann at 919-515-5580 (voice), 919-515-8739 (fax), urs_buehlmann@ncsu.edu (e-mail).
Edited by: Larry G. Jahn
Wood Products Extension Specialist