Drying hardwood lumber

Denig, Joseph; Wengert, Eugene M.; Simpson, William T.

doi:10.2737/fpl-gtr-118

Cited by 53 publications

(37 citation statements)

References 8 publications

(1 reference statement)

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“…Graphs of the same form as Figure 12 have subsequently been published, presumably based on the completed data set, and no longer considered to be under revision and correction (Voorhies and Loughborough 1943;Smith 1947Smith , 1963Denig et al 2000).…”

Section: Figure 12 Emc-humidity-temperature Chart (Us Department Omentioning

confidence: 99%

“…Figures of this type have been widely published (Peck 1932;FPL 1935FPL , 1940FPL , 1944FPL , 1951FPL , 1955; U.S. Army Air Forces 1944; Denig et al 2000). Figure 14 shows relative humidity versus vapor pressure with curves of constant EMC and of constant temperature (Loughborough 1942).…”

Section: Several Variations Onmentioning

confidence: 99%

“…These data have primarily served practical, technological purposes related to drying lumber and controlling moisture content. The importance of the FPL EMC data can be appreciated by considering how widely they have been reprinted in literature of a practical nature: the data appear in the Wood Handbook (FPL 1935(FPL , 1940(FPL , 1955(FPL , 1974(FPL , 1987(FPL , 1999b(FPL , 2010; in publications relating to the use of wood in aircraft construction (FPL 1919c(FPL , 1928(FPL , 1941a(FPL , 1942(FPL , 1943(FPL , 1944(FPL , 1946(FPL , 1951; U.S. Army Air Forces 1944; Voorhies and Loughborough 1943); in wood drying manuals such as the Dry Kiln Operator's Manual (Rasmussen 1961;Simpson 1991), Air Drying of Lumber (FPL 1999a), and Drying Hardwood Lumber (Denig et al 2000); and in international standards, particularly the Standard Guide for Moisture Conditioning of Wood and Wood-Based Materials (ASTM 2010). The Forest Products Laboratory and other organizations in North America have long considered the FPL EMC data set to be the first place to go for such data.…”

Section: Introductionmentioning

confidence: 99%

“…Despite these imperfections, the data have served their practical purpose well for many years." More recently, Denig et al (2000) commented, "These standard EMC data, which were collected more than 50 years ago, are primarily based on the drying of small shavings of Sitka spruce in a dryer with a small oscillation in RH. In spite of the potential shortcomings of the data, they serve very well for drying hardwood lumber.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of Historic Equilibrium Moisture Content Data from the Forest Products Laboratory

Glass¹,

Zelinka²,

Johnson³

2014

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The use of trade or firm names in this publication is for reader information and does not imply endorsement by the United States Department of Agriculture (USDA) of any product or service.The USDA prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410, or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. AbstractThe Forest Products Laboratory (FPL) has provided equilibrium moisture content (EMC) values of wood for given temperature and relative humidity (RH) conditions in various forms over the course of its history, primarily for practical purposes related to drying lumber and controlling moisture content. The FPL EMC data have been widely cited and reprinted, not only in literature of a practical nature such as the Wood Handbook, but also in textbooks and journal articles as a basis for scientific discourse on the thermodynamics of water vapor sorption in wood and evaluation of physical models. Using the data for such scientific purposes presupposes that the methods by which the data were acquired are well documented and accepted. This report questions previous assumptions about the historic EMC data and attempts to uncover and evaluate the original data sources. It also addresses a number of related topics, including how the presentation of data has evolved in the literature and whether the data are practically applicable to all wood species. We find that the data are unreliable for scientific purposes, such as thermodynamic analysis and testing of physical models, for three reasons: lack of proper documentation of methodology; the unsolvable problem of knowing which values are determined from direct observations and which are interpolated; and the absence of definitive measurement error analysis. However, we affirm that the data are indeed useful for practical applications, such as lumber drying, conditioning of wood specimens prior to testing physical or mechanical properties, and modeling of moisture content of wood members in buildings. We show that a number of mathematical models provide adequate fits to the data for practical use.

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Section: Figure 12 Emc-humidity-temperature Chart (Us Department Omentioning

confidence: 99%

Section: Several Variations Onmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Investigation of Historic Equilibrium Moisture Content Data from the Forest Products Laboratory

Glass¹,

Zelinka²,

Johnson³

2014

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show abstract

“…In addition, Elustondo and Oliveira (2009) reported that the energy consumption to evaporate cold water used for humidifi cation in small kilns accounts for more than 15 % of the total energy consumption, and if high both dry-bulb and wet-bulb temperatures (over 60 °C) are used, it can reach almost 50 %. Generally, in industrial conditions, the percentage of energy needed for heating of air and wood is relatively low (around 5 %, according to Denig et al, 2000). When oscillations of drying parameters are used, the humidifi cation system will be switched on more frequently than with conventional schedules, so it is expected that the energy consumption for heating of air and wood in those schedules will also be somewhat higher, but still low compared to the total energy consumption.…”

Section: Rezultati I Raspravamentioning

confidence: 99%