Accuracy and functionality of hand held wood moisture content meters

Holger Forsen, Veikko Tarvainen

Research output: Book/ReportReportProfessional

2 Citations (Scopus)

Abstract

The main task of VTT in this EU project was to test and improve the reliability and performance of moisture content meters. A total of 16 resistance type and 6 capacitance type hand-held moisture meters were included in the test series. Test samples of the most important European species (pine, spruce, birch, oak, beech, alder, larch) were obtained from all over Europe. The total survey included about 2,700 pieces for comparative testing. The test material was conditioned to three different moisture contents (8 - 10%, 12 - 14% and 16 - 18%). The moisture gradients in the test specimens were small due to the long conditioning time lasting at least 1 year. The effects of various factors, such as moisture content, species, and temperature, on the electrical resistance of conditioned wood were studied. In the laboratory tests, the resistance - moisture content curves for different species from different countries were determined using conditioned wood material. The species corrections (resistance curves) are quite similar for different counties. Only the resistance curve for Maritime Pine differs clearly from the other resistance curves for the pine species originating from the different countries. The wood temperature corrections are about 0.1 - 0.15% units/°C which has to be considered when the moisture content of wood is measured at temperatures other than 20 °C. The other properties of wood, such as as sapwood/heartwood and density, do not have a significant effect on resistance values. There were no significant resistance differences related to the type of electrodes, distances between electrodes, and different measuring direction. The commercial instruments for the determination of wood moisture content were tested with respect to accuracy, reliability and ergonomy. The moisture meters were tested both under laboratory and industrial conditions. Most of the resistance meters show a systematic deviation from the actual moisture content because of incorrect MC resistance curves. When the MC was lower than 10%, the readings of all the resistance meters tended to creep. The measuring accuracy of the MC meters (95 % confidence interval) in laboratory tests with well conditioned material was about ±1.5 . ±2.5% units for the resistance meters and about ±2.5% . ±4.0% units for the capacitance meters. The corresponding accuracy of MCmeters in industry test was about 2.0 % . ±5.0% units for the resistance meters and about ±3.0% . ±5.0% units for the capacitance meters.
Original languageEnglish
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Number of pages102
EditionRevised
ISBN (Electronic)951-38-5582-1
ISBN (Print)951-38-5581-3
Publication statusPublished - 2000
MoE publication typeD4 Published development or research report or study

Publication series

NameVTT Publications
PublisherVTT
No.420
ISSN (Print)1235-0621
ISSN (Electronic)1455-0849

Fingerprint

wood moisture
meters (equipment)
hands
water content
capacitance
moisture meters
testing
electrodes
Pinus
temperature
Alnus
electrical resistance
Pinus pinaster
wood properties
heartwood
sapwood
Betula
Fagus
Picea
confidence interval

Keywords

  • wood
  • timber
  • moisture meters
  • moisture content
  • measuring instruments
  • reliability
  • tests
  • electrical resistance
  • temperature
  • species correction
  • pine
  • spruce
  • birch
  • oak
  • beech
  • alder
  • larch

Cite this

Forsen, H., & Tarvainen, V. (2000). Accuracy and functionality of hand held wood moisture content meters. (Revised ed.) Espoo: VTT Technical Research Centre of Finland. VTT Publications, No. 420
Forsen, Holger ; Tarvainen, Veikko. / Accuracy and functionality of hand held wood moisture content meters. Revised ed. Espoo : VTT Technical Research Centre of Finland, 2000. 102 p. (VTT Publications; No. 420).
@book{3ae449d10cc542c795c8b68b606d5466,
title = "Accuracy and functionality of hand held wood moisture content meters",
abstract = "The main task of VTT in this EU project was to test and improve the reliability and performance of moisture content meters. A total of 16 resistance type and 6 capacitance type hand-held moisture meters were included in the test series. Test samples of the most important European species (pine, spruce, birch, oak, beech, alder, larch) were obtained from all over Europe. The total survey included about 2,700 pieces for comparative testing. The test material was conditioned to three different moisture contents (8 - 10{\%}, 12 - 14{\%} and 16 - 18{\%}). The moisture gradients in the test specimens were small due to the long conditioning time lasting at least 1 year. The effects of various factors, such as moisture content, species, and temperature, on the electrical resistance of conditioned wood were studied. In the laboratory tests, the resistance - moisture content curves for different species from different countries were determined using conditioned wood material. The species corrections (resistance curves) are quite similar for different counties. Only the resistance curve for Maritime Pine differs clearly from the other resistance curves for the pine species originating from the different countries. The wood temperature corrections are about 0.1 - 0.15{\%} units/°C which has to be considered when the moisture content of wood is measured at temperatures other than 20 °C. The other properties of wood, such as as sapwood/heartwood and density, do not have a significant effect on resistance values. There were no significant resistance differences related to the type of electrodes, distances between electrodes, and different measuring direction. The commercial instruments for the determination of wood moisture content were tested with respect to accuracy, reliability and ergonomy. The moisture meters were tested both under laboratory and industrial conditions. Most of the resistance meters show a systematic deviation from the actual moisture content because of incorrect MC resistance curves. When the MC was lower than 10{\%}, the readings of all the resistance meters tended to creep. The measuring accuracy of the MC meters (95 {\%} confidence interval) in laboratory tests with well conditioned material was about ±1.5 . ±2.5{\%} units for the resistance meters and about ±2.5{\%} . ±4.0{\%} units for the capacitance meters. The corresponding accuracy of MCmeters in industry test was about 2.0 {\%} . ±5.0{\%} units for the resistance meters and about ±3.0{\%} . ±5.0{\%} units for the capacitance meters.",
keywords = "wood, timber, moisture meters, moisture content, measuring instruments, reliability, tests, electrical resistance, temperature, species correction, pine, spruce, birch, oak, beech, alder, larch",
author = "Holger Forsen and Veikko Tarvainen",
note = "Project code: R0SU00371",
year = "2000",
language = "English",
isbn = "951-38-5581-3",
series = "VTT Publications",
publisher = "VTT Technical Research Centre of Finland",
number = "420",
address = "Finland",
edition = "Revised",

}

Forsen, H & Tarvainen, V 2000, Accuracy and functionality of hand held wood moisture content meters. VTT Publications, no. 420, Revised edn, VTT Technical Research Centre of Finland, Espoo.

Accuracy and functionality of hand held wood moisture content meters. / Forsen, Holger; Tarvainen, Veikko.

Revised ed. Espoo : VTT Technical Research Centre of Finland, 2000. 102 p. (VTT Publications; No. 420).

Research output: Book/ReportReportProfessional

TY - BOOK

T1 - Accuracy and functionality of hand held wood moisture content meters

AU - Forsen, Holger

AU - Tarvainen, Veikko

N1 - Project code: R0SU00371

PY - 2000

Y1 - 2000

N2 - The main task of VTT in this EU project was to test and improve the reliability and performance of moisture content meters. A total of 16 resistance type and 6 capacitance type hand-held moisture meters were included in the test series. Test samples of the most important European species (pine, spruce, birch, oak, beech, alder, larch) were obtained from all over Europe. The total survey included about 2,700 pieces for comparative testing. The test material was conditioned to three different moisture contents (8 - 10%, 12 - 14% and 16 - 18%). The moisture gradients in the test specimens were small due to the long conditioning time lasting at least 1 year. The effects of various factors, such as moisture content, species, and temperature, on the electrical resistance of conditioned wood were studied. In the laboratory tests, the resistance - moisture content curves for different species from different countries were determined using conditioned wood material. The species corrections (resistance curves) are quite similar for different counties. Only the resistance curve for Maritime Pine differs clearly from the other resistance curves for the pine species originating from the different countries. The wood temperature corrections are about 0.1 - 0.15% units/°C which has to be considered when the moisture content of wood is measured at temperatures other than 20 °C. The other properties of wood, such as as sapwood/heartwood and density, do not have a significant effect on resistance values. There were no significant resistance differences related to the type of electrodes, distances between electrodes, and different measuring direction. The commercial instruments for the determination of wood moisture content were tested with respect to accuracy, reliability and ergonomy. The moisture meters were tested both under laboratory and industrial conditions. Most of the resistance meters show a systematic deviation from the actual moisture content because of incorrect MC resistance curves. When the MC was lower than 10%, the readings of all the resistance meters tended to creep. The measuring accuracy of the MC meters (95 % confidence interval) in laboratory tests with well conditioned material was about ±1.5 . ±2.5% units for the resistance meters and about ±2.5% . ±4.0% units for the capacitance meters. The corresponding accuracy of MCmeters in industry test was about 2.0 % . ±5.0% units for the resistance meters and about ±3.0% . ±5.0% units for the capacitance meters.

AB - The main task of VTT in this EU project was to test and improve the reliability and performance of moisture content meters. A total of 16 resistance type and 6 capacitance type hand-held moisture meters were included in the test series. Test samples of the most important European species (pine, spruce, birch, oak, beech, alder, larch) were obtained from all over Europe. The total survey included about 2,700 pieces for comparative testing. The test material was conditioned to three different moisture contents (8 - 10%, 12 - 14% and 16 - 18%). The moisture gradients in the test specimens were small due to the long conditioning time lasting at least 1 year. The effects of various factors, such as moisture content, species, and temperature, on the electrical resistance of conditioned wood were studied. In the laboratory tests, the resistance - moisture content curves for different species from different countries were determined using conditioned wood material. The species corrections (resistance curves) are quite similar for different counties. Only the resistance curve for Maritime Pine differs clearly from the other resistance curves for the pine species originating from the different countries. The wood temperature corrections are about 0.1 - 0.15% units/°C which has to be considered when the moisture content of wood is measured at temperatures other than 20 °C. The other properties of wood, such as as sapwood/heartwood and density, do not have a significant effect on resistance values. There were no significant resistance differences related to the type of electrodes, distances between electrodes, and different measuring direction. The commercial instruments for the determination of wood moisture content were tested with respect to accuracy, reliability and ergonomy. The moisture meters were tested both under laboratory and industrial conditions. Most of the resistance meters show a systematic deviation from the actual moisture content because of incorrect MC resistance curves. When the MC was lower than 10%, the readings of all the resistance meters tended to creep. The measuring accuracy of the MC meters (95 % confidence interval) in laboratory tests with well conditioned material was about ±1.5 . ±2.5% units for the resistance meters and about ±2.5% . ±4.0% units for the capacitance meters. The corresponding accuracy of MCmeters in industry test was about 2.0 % . ±5.0% units for the resistance meters and about ±3.0% . ±5.0% units for the capacitance meters.

KW - wood

KW - timber

KW - moisture meters

KW - moisture content

KW - measuring instruments

KW - reliability

KW - tests

KW - electrical resistance

KW - temperature

KW - species correction

KW - pine

KW - spruce

KW - birch

KW - oak

KW - beech

KW - alder

KW - larch

M3 - Report

SN - 951-38-5581-3

T3 - VTT Publications

BT - Accuracy and functionality of hand held wood moisture content meters

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Forsen H, Tarvainen V. Accuracy and functionality of hand held wood moisture content meters. Revised ed. Espoo: VTT Technical Research Centre of Finland, 2000. 102 p. (VTT Publications; No. 420).