TRAMEX MRH III User manual

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NOTES
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TABLE OF CONTENTS
1.0 Introduction ……………………………………………………………. 2
2.0 How it works …………………………………………………………… 3
3.0 Instrument Features …………………………………………………. 4
4.0 Operating Instructions ……………………………………………….. 5
5.0 Non-destructive measurement mode ………………………………. 6
6.0 Wood pin meter (Pin Probe) mode …………………………………. 7
7.0 Typical MRH Displays ……………………………………………….. 8
8.0 Humidity Measurement Mode ………………………………………. 9
9.0 Working with your MRH ……………………………………………… 10
9.1 Roof Scale
9.2 Masonry Scale
9.3 Drywall Scale
9.4 Laminate Scale
9.5 Wood Scale
9.6 Relative humidity and moisture content
9.7 Wood Flooring
9.8 Chemical treatment or contamination
10.0 Table of Wood Specific Gravities (S.G.) …………………………… 16
11.0 Wood Pin Meter Mode ………………………………………………. 18
12.0 Species Correction Chart ……………………………………………. 21
13.0 RH Probe ……………………………………………………………… 28
13.1 Calibration checking of RH Probe
14.0 Calibration …………………………………………………………….. 30
15.0 Limitations …………………………………………………………….. 30
16.0 Product development ………………………………………………… 30
17.0 Warranty ………………………………………………………………. 31

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1.0 INTRODUCTION
Thank you for selecting a new MRH instrument.
The MRH has 3 modes of operation:
1. The MRH utilises “state of the art” electronic technology to provide you with an
accurate and easy to use non-invasive instrument for non-destructive testing
(NDT) of Moisture Content (MC) and tracing moisture in a wide range of building
materials.
2. By inserting one of the optional plug-in electrodes for wood and selecting Pin
Probe the instrument can then be use in Pin Probe (wood pin-meter resistance
measurement) Mode. This enables the MRH to measure the percentage
moisture content (%m.c.) of wood and give an indication of the moisture content
of wood-based products.
3. By inserting the optional plug-in RH-probe, the instrument automatically changes
to hygrometer mode. This enables the MRH to measure relative humidity (RH),
temperature, dew-point temperature and mixing ratio of the environment or
equilibrium relative humidity in a structural material. A structural material such as
a concrete slab can be tested using the in-situ (ASTM F2170) or RH Hood
(ASTM F2420) methods and British standards BS 5325 and BS 8203.
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17.0 WARRANTY
Checkline Europe (Checkline) warrants to the original purchaser that this product is
of merchantable quality and confirms in kind and quality with the descriptions and
specifications thereof. Product failure or malfunction arising out of any defect in
workmanship or material in the product existing at the time of delivery thereof which
manifests itself within one year from the sale of such product, shall be remedied by
repair or replacement of such product, at Checkline’s option, except where
unauthorized repair, disassembly, tampering, abuse or misapplication has taken
place, as determined by Checkline. All returns for warranty or non-warranty repairs
and/or replacement must be authorized byCheckline, in advance, with all repacking
and shipping expenses to the address below to be borne by the purchaser.
THE FOREGOING WARRANTYIS IN LIEU OF ALL OTHER WARRANTIES,
EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO, THE
WARRANTYOF MERCHANTABILITYAND FITNESS FOR ANYPARTICULAR
PURPOSE OR APPLICATION. CHECKLINE SHALL NOT BE RESPONSIBLE NOR
LIABLE FOR ANYCONSEQUENTIAL DAMAGE, OF ANYKIND OR NATURE,
RESULTING FROM THE USE OF SUPPLIED EQUIPMENT, WHETHER SUCH
DAMAGE OCCURS OR IS DISCOVERED BEFORE, UPON OR AFTER
REPLACEMENT OR REPAIR, AND WHETHER OR NOT SUCH DAMAGE IS
CAUSED BYMANUFACTURER’S OR SUPPLIER’S NEGLIGENCE WITHIN ONE
YEAR FROM INVOICE DATE.
Some State jurisdictions or States do not allow the exclusion or limitation of
incidental or consequential damages, so the above limitation may not apply to you.
The duration of any implied warranty, including, without limitation, fitness for any
particular purpose and merchantability with respect to this product, is limited to the
duration of the foregoing warranty. Some states do not allow limitations on how long
an implied warranty lasts but, not withstanding, this warranty, in the absence of such
limitations, shall extend for one year from the date of invoice.
CHECKLINE EUROPE
Dennenweg 225B, 7545 WE, Enschede
Tel: [phone] / Fax: [phone]
Every precaution has been taken in the preparation of this manual. Checkline-
Europe assumes no responsibility for errors or omissions. Neither is any liability
assumed for damages resulting from the use of information contained herein. Any
brand or product names mentioned herein are used for identification purposes only,
and are trademarks or registered trademarks of their respective holders.

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14.0 CALIBRATION
For regular on-site assessment of your MRH in moisture measurement mode, a
calibration-check box is available from the suppliers of your MRH. Should it be
found that readings are outside the set tolerances, it is recommended that the MRH
be returned for re-calibration. Calibration adjustments should not be carried out by
anyone other than Checkline Europe who will issue a calibration certificate on
completion.
Requirements for quality management and validation procedures, such as ISO
9001:2008, have increased the need for regulation and verification of measuring
and test instruments. It is therefore recommended that calibration of the MRH
should be checked and certified in accordance with the standards and/or protocols
laid down by your industry (usually on an annual basis) by an authorized test
provider. The name of your nearest test provider and estimate of cost is available on
request.
15.0 LIMITATIONS
The MRH will not detect or measure moisture through any electrically conductive
materials including metal sheeting or cladding, black EPDM rubber or wet surfaces.
16.0 PRODUCT DEVELOPMENT
It is the policy to continually improve and update all its products. We therefore
reserve the right to alter the specification or design of this instrument without prior
notice.
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2.0 HOW IT WORKS
In non-destructive moisture measurement mode i.e. without the plug in probes,
the instrument operates on the principle that the electrical impedance of a material
varies with its moisture content. The electrical impedance is measured by creating a
low frequency alternating electric field between the electrodes as illustrated in
Figure 1 below.
This field penetrates the material under test. The very small alternating current
flowing through the field is inversely proportional to the impedance of the material.
The instrument detects this current, determines its amplitude and thus derives the
moisture value.
Figure 1
In Pin Probe Mode (i.e. with pin probe mode selected and an electrode plugged in),
the MRH is a resistance type pin meter for determining the percentage moisture
content of wood.
In Hygrometer mode (i.e. with the RH Probe plugged in), the MRH determines the
capacitance of the RH probe sensor, which varies with the relative humidity of the
test area environment. The MRH displays this capacitance as percentage relative
humidity (%RH). It also measures temperature and displays dew-point temperature
and mixing ratio.

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3.0 INSTRUMENT FEATURES
Your MRH employs advanced digital technology to enable the incorporation of many
features, which are listed below.
3 modes of measurement: Non-destructive moisture measurement, hygrometer
and wood pin probe.
simple membrane keypad controls:
ON/OFF
SCALE
UP
DOWN
HOLD/AUDIO
BACKLIGHT
5 Scales: Wood, Roof, Masonry, Drywall and Laminate. These are selected
using the key and the or keys.
Moisture readings and scale are displayed on a clear easy to read liquid crystal
display (LCD).
Relative Humidity (RH) readings, probe temperature, dew-point temperature and
mixing ratio are automatically displayed when the RH Probe is plugged into the
MRH (Hygrometer Mode).
The Roof, Masonry, Drywall and Laminate Scales use a reference/comparative
scale that is displayed both numerically (0-99) and in a bar form on the bottom
line of the display. The display also shows low (LO), medium (MD) and high (HI)
readings for these scales.
These do not necessarily indicate low, medium or high levels of moisture but
indicate the area of the 0-100 comparative scale where the reading lies.
Example
To conserve battery life, the instrument automatically powers OFF after 10
minutes of inactivity or when the key is pressed. If a key is pressed the power off
will
Backlit display allows the display to be easily read in poor light conditions. This
is enabled by pressing the key. The backlight stays on for a period of 30
seconds.
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13.1 Calibration checking of RH Probe
Each RH probe is factory calibrated using precision equipment traceable to NIST
standards. With reasonable care in use and storage, RH probe measurements
should remain within the ±3% specification. RH probe accuracy can be degraded by
exposure to polluted atmospheres such as dust, aggressive chemical vapors, or
contaminated wetting. It is thus advisable to periodically check the RH Probe
accuracy by using RH 75 or a similar suitable reference kit. These kits contain a
saturated Sodium Chloride salt solution that creates a nominal 75% relative humidity
within the measuring cell. The precise relative humidity is temperature dependent.
The RH 75 calibration check is available from the manufacturer or the supplier of
your MRH meter.
To carry out a calibration check:
1. Remove cell from sealed plastic bag.
2. Remove white stopper plug from cell.
3. Insert plastic calibration sleeve into cell as shown in
photo on left.
4. Remove sleeve stopper plug and fully insert RH probe.
5. Place cell/probe in a stable, draft free, temperature
environment, e.g., inside a desk drawer, and leave for at
least 2 hours.
6. After 2 hours, connect probe to MRH and measure RH
value.
7. The RH reading should be 75% ±3%
8. If the value is outside this range, repeat the test after a
further 2 hours.
9. If the RH value is still outside specification, return the RH
probe for investigation.
10. When the calibration check test has been completed,
removeRH probe and sleeve from cell. Fit white stopper
plug into cell and seal cell inside the plastic bag.

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13.0 RH PROBE
The RH Probe utilises “state of the art” electronic technology to provide an “easy to
use” and accurate method for measuring relative humidity, mixing ratio, temperature
and dew point in a wide range of applications such as:
Heating, ventilation and air conditioning (HVAC) systems.
Environmental and building monitoring.
Building inspection.
Flooring (including ASTM F 2170 In Situ & ASTM F 2420 RH Hood methods)
A typical MRH display with the RH Probe attached is shown on page 8. Pressing the
on the instrument changes the temperature readings from ºC to ºF, the mixing
ratio from g/kg (gms) to Grains/Lb (GRN) or vice-versa.
NOTE: When performing Humidity tests on Concrete Flooring it should be
noted that:
A) If artificial aids for accelerated drying of concrete are being used it is
recommended that they be turned off at least four days before taking final
readings.
B) It is important that the installer ensures that the floor covering is applied at the
moisture content and or relative humidity specified by the manufacturer of the
floor coverings and/or adhesives.
C) It is very important that RH probes are handled with care and protected from
harsh environments in order to maintain their long-term stability. It is
recommended that you do not insert the RH probe into concrete until the
chemical reaction between the cement and water has taken place and the drying
process has begun. To achieve this it is recommended that you do not insert the
probe into the hole in the concrete until the moisture content of the concrete has
dropped below 5% when measured with a CME4, CRH or CMEX. RH probes
should not be left enclosed in concrete or similar environments at an RH level
greater than 93% for long periods, in these situations it is recommended to
remove the RH probe and allow the test area to continue to acclimatise by
replacing the stopper in the hole-liner sleeve.
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When the battery requires replacement a LOW BATTERY message is shown on
the LCD.
HOLD freezes reading to facilitate ease of recording readings. When the MRH is
in HOLD mode, ‘H’ will flash on the display.
If HOLD was selected prior to the MRH automatically powering off, the frozen
display reading is digitally memorized and restored next time ON is selected.
4.0 OPERATING INSTRUCTIONS
Figure 2
A diagram of the instrument face with brief notes on the push button controls and
LCD is shown above (Figure 2).

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5.0 NON-DESTRUCTIVE MEASUREMENT MODE
1. Press the key to power up. With no RH probe or pin probe connected the last
used scale will be displayed on the LCD. Press key again to power off.
2. To change scale, press key to select the wood scale or the comparative
material scales. Select the required material scale using the or key.
3. Hold your MRH directly on the wood, roof, masonry, drywall or other material
being tested, ensuring both conductive-rubber electrodes are fully in contact with
the surface
4. For the Roof, Masonry, Drywall and Laminate scales the readings are
comparative from 0 to 99. A visual indication is also given by the bar display on
the bottom line of the LCD. The display also shows low (LO), medium (MD) and
high (HI) readings for these scales. LO is displayed for readings from 0 to 30,
MD for readings from 31 to 70 and HI for readings from 71 to 99.
These do not necessarily indicate low, medium or high levels of moisture
but indicate the area of the 0-100 comparative scale where the reading lies.
5. The readings on these scales are not to be interpreted as a measurement of
percentage moisture content (% MC) or relative humidity (RH). It is not a relative
humidity reading and it does not have any linear correlation with Relative
Humidity measurements. This scale should be regarded as a comparative or
qualitative scale only.
6. When the Wood Scale is selected the moisture content (MC) in percent of wood
is shown on the right-hand side of the bottom line of the display. The left-hand
side of this line shows the specific gravity (SG) being used.
The SG is changed by using the or key to adjust to the required SG value.
The range of SG covered is 0.30 to 0.80. The S.G. increases and decreases in
increments of 0.01
7. A chart showing the approximate specific gravity of a wide range of different
species is shown on pages 16 and 17. For SG greater than 0.80 please refer to
species adjustment table (Table 2 on Page 14).
8. To turn audio tone on or off, press key twice in quick succession.
9. The MRH will automatically power-off after ten minutes if no key is pressed. If a
key is pressed the power-off will be extended for an additional ten minutes.
10. To freeze readings press the key once. While on HOLD, H will flash slowly on
the upper line of the display. If the unit powers OFF while on HOLD, the frozen
meter reading is digitally memorized and restored next time ON is selected. To
remove freeze, press key again.
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Meter reading (% moisture) 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Species Correct moisture content Tingle, yellow 9 10 11 12 13 14 15 17 18 19 20 21 22 23 25 26 27 28 Totara 8 9 10 10 11 12 12 13 14 14 15 16 16 17 18 18 19 19 Touriga, red 11 11 12 13 14 14 15 16 17 17 18 19 20 20 21 22 23 23 Tuart 9 10 11 12 12 13 14 15 15 16 17 17 18 19 20 20 21 22 Turpentine 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 24 Vitex, New Guinea 7 8 8 9 10 11 12 13 13 14 15 16 17 18 18 19 20 21 22 Walnut, African 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 Walnut, American Black 8 9 10 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Walnut, Brazilian 8 9 10 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Walnut, blush 10 11 11 12 12 13 14 14 15 16 16 17 18 18 19 19 20 21 Walnut, European 9 10 11 12 13 14 15 16 17 18 19 20 22 23 24 25 26 27 Walnut, New Guinea 7 8 9 10 11 12 13 14 15 16 17 17 18 19 20 - - - Walnut, Peruvian 7 8 9 11 12 13 14 15 16 17 18 18 20 21 22 23 24 25 Walnut, Qld 9 10 11 12 13 14 15 16 17 18 19 20 22 23 24 25 25 27 Walnut, yellow 7 8 8 9 10 10 11 12 12 13 14 14 15 16 17 17 18 19 Wandoo 10 11 12 13 14 15 16 16 17 18 19 20 21 22 23 24 25 25 Wattle, hicory 8 9 10 11 11 12 13 13 14 14 15 16 16 17 18 18 19 20 Wattle, silver 9 10 10 11 12 13 13 14 15 16 16 17 18 19 20 20 21 22 Western Hemlock 7 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Western red spruce 7 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Wollybutt 10 10 11 12 13 14 15 15 16 17 18 19 20 20 21 22 23 24

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Meter reading (% moisture) 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Species Correct moisture content Rosarosa 8 9 10 10 11 12 13 13 14 15 15 16 17 18 18 19 - - Sapele 9 10 11 12 13 14 15 16 17 18 19 20 22 23 24 25 26 27 Sassafras 8 9 10 10 11 12 13 13 14 15 16 16 17 18 18 19 20 21 Sassafras, southern 9 10 11 11 12 13 13 14 15 15 16 17 17 18 19 19 20 21 Satinash, grey 8 9 9 10 11 12 13 14 15 16 16 17 18 19 20 21 22 23 Satinash, New Guinea 7 8 8 9 10 11 11 12 13 13 14 15 16 16 17 18 19 19 Satinash, rose 7 7 8 8 9 10 10 11 12 12 13 13 14 15 16 16 - - Satinay 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Satinheart, green 9 10 10 11 11 12 12 13 13 14 14 15 15 16 16 17 - - Sepetir 8 9 10 12 13 14 15 16 17 18 20 21 22 23 24 25 26 27 Sheoak, river 8 9 10 10 11 11 12 12 13 14 14 15 16 16 17 17 18 - Sheoak, rose 9 10 11 11 12 13 13 14 14 15 15 16 16 17 18 18 19 19 Sheoak, WA 9 10 11 11 12 12 13 14 14 15 16 16 17 18 18 19 20 20 Silkwood, bolly 9 10 11 11 12 12 13 13 14 14 15 15 16 16 17 17 18 18 Silkwood, red 6 7 7 8 9 10 10 11 12 12 13 14 14 15 16 17 17 18 Silkwood, silver 9 10 11 12 12 13 14 15 15 16 17 18 18 19 20 20 21 22 Spruce, Sitka 7 8 9 11 11 12 13 15 16 17 18 19 20 21 22 23 25 26 Spruce, western white 7 8 10 11 12 13 14 15 16 17 18 19 20 21 21 23 24 25 Stringybark, brown 9 10 11 11 12 13 14 15 16 17 18 19 19 20 21 22 23 24 Stringybark, Darwin 8 8 9 10 11 12 13 14 15 15 16 17 18 19 20 21 22 22 Stringybark, yellow 11 12 13 14 14 15 16 17 18 18 19 20 21 21 22 23 24 24 Sycamore 7 7 8 9 10 11 12 13 14 15 15 16 17 18 19 19 20 21 Sycamore, satin 9 9 10 11 11 12 12 13 14 14 15 16 16 17 18 18 19 20 Sycamore, silver 9 10 10 11 12 12 13 13 14 14 15 16 16 17 17 18 19 19 Tallowwood 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Tawa 9 10 10 11 11 12 12 13 13 14 14 15 15 16 16 17 17 18 Teak, Brazilian 8 9 10 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Teak 7 7 8 9 10 11 12 13 14 14 15 15 16 16 17 18 19 20 Tingle, red 9 10 11 12 13 15 16 17 18 19 21 22 23 24 25 27 28 29
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6.0 WOOD PIN METER (PIN PROBE) MODE
This mode is activated by plugging one of the optional Wood Electrodes into the
socket at the top of the instrument and selecting Pin Probe using the key. In pin
probe mode the MRH works on the principle of electrical resistance. When the
electrode pins are pressed or driven into the wood, the electrical resistance between
the electrodes is measured and indicated on the digital display. If the wood is dry,
the resistance is very high. The higher the moisture content, the lower the
resistance. This resistance is accurately measured by the instrument, which
translates it into percentage moisture content for wood. The MRH gives moisture
readings from 7% to 40%. It should be noted that readings above 27% (nominal
value of the fibre-saturation point) are indicative only.
Wood Pin Meter Mode Vs. Non
-
Destructive
Measu
rement Mode
The two main types of moisture meter for measuring moisture content in wood
are the pin type meter and the nondestructive or impedance type meter. Both
types are calibrated using gravimetric or oven-drying test methods.
The Tramex MRH combines both of the above methods in one instrument
so it is important to understand how each test method works as the
results from the two tests may sometimes be different and appear to be
contradictory.
The pin type meter measures the resistance between two pins, which are
inserted into the timber. The standard calibration for this type of meter is based
on a Douglas Fir with a specific gravity (S.G.) of 0.5.
The impedance or non-destructive type meter has two electrodes, which
transmit a low frequency signal into the timber up to a maximum depth of 1¼ “
(30mm). This meter takes an average reading over a much larger area but the
S.G. of the material being tested affects the reading more.
On the MRH non-destructive test it is possible to adjust the specific gravity for
better species-dependant readings if the material is of sufficient thickness. If the
SG of the material is not known it is possible to use the readings from the pin
meter to give an approximation of the SG for the nondestructive meter. This is
done by Adjusting the SG on the non invasive test until both tests give
approximately the same reading. This is not as accurate as knowing the exact
S.G. of the material but can be a good indication.
It is very important to note that the readings of the non-destructive meter will
penetrate up to 1¼ “ (30mm) into the material being tested. If the material is less
than 1¼ “ (30mm) thick it is possible to get false readings from another material
in contact with it. A typical example of this would be a laminate floor over
concrete.

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7.0 TYPICAL MRH DISPLAYS Moisture Measurement Mode
Battery warning
Humidity Probe Display Metric
Relative Humidity T °C
Flashing ‘H’ in Hold mode
Dewpoint (Td) °C Mixing Ratio g/kg
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Meter reading (% moisture) 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Species Correct moisture content
Obeche 7 8 9 10 10 1 12 13 14 15 15 16 16 17 18 18 19 20
Padauk, African 7 7 8 9 10 11 12 13 14 15 15 16 17 18 19 19 20 21
Peppermint, broad-leaved 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
Peppermint, narrow-leaved 10 11 11 12 13 14 14 15 16 17 18 18 19 20 21 22 22 23
Persimmon 7 8 9 10 10 11 12 13 14 15 15 16 16 17 18 18 19 20
Pine, bunya 10 11 12 12 13 14 14 15 16 16 17 18 18 19 20 21 21 22
Pine, Corsican 9 10 11 12 13 14 15 16 17 18 19 20 22 23 24 25 26 27
Pine, cypress, white 9 10 11 11 12 13 14 15 17 17 18 19 20 21 22 22 23 24
Pine, hoop 10 11 11 12 13 14 15 16 17 17 18 19 20 21 22 22 23 24
Pine, Huon 10 10 12 12 13 13 14 15 15 16 17 18 18 19 20 20 21 22
Pine, King William 9 9 11 12 12 13 14 14 15 16 16 17 18 18 19 20 20 21
Pine, klinki 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Pine, longleaf 9 10 11 12 13 14 15 16 17 18 19 20 22 23 24 25 26 27
Pine, lodgerpole 7 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Pine, maritime 10 11 12 12 13 14 15 15 16 17 18 18 19 20 21 21 22 23
Pine, white, NZ - - - 11 12 12 13 14 15 16 16 17 18 19 19 20 21 22
Pine, Parana 7 8 9 10 11 12 13 14 15 16 16 17 18 19 20 21 22 23
Pine, ponderosa 7 9 10 11 13 14 15 16 17 18 19 20 21 22 22 23 24 25
Pine, radiata 10 11 11 12 13 14 15 16 17 18 19 20 21 22 24 25 26 27
Pine, scots/shortleaf 7 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Pine, slash 8 9 10 11 12 13 14 15 16 17 17 18 19 20 21 22 23 24
Pine, sugar 8 9 10 11 12 13 14 15 16 17 18 20 21 22 23 24 25 26
Pine, white, western - 8 9 10 11 11 12 13 14 15 16 17 17 18 19 20 21 22
Poplar 7 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Quandong, silver 7 8 9 10 10 11 12 12 13 14 14 15 16 16 17 18 18 19
Redwood 9 9 10 11 12 13 14 15 16 16 17 18 19 20 20 21 22 23
Redwood, European 7 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Rosewood, Patagonian 8 9 10 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
Rosewood, Tiete 8 9 10 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

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Meter reading (% moisture) 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Species Correct moisture content
Mahogany, miva 10 11 12 12 13 14 15 15 16 17 18 18 19 20 20 21 22 23
Mahogany, red 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 24 25 26
Mahogany, rose 9 10 10 11 12 12 13 14 14 15 16 16 17 18 18 19 20 20
Mahogany, santos 8 9 10 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
Mahogany, southern 8 9 10 11 12 12 13 14 15 16 17 18 19 20 20 21 22 23
Mahogany, Honduras 7 7 8 9 10 11 12 13 14 15 16 17 18 19 19 20 21 22
Mahogany, white 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
Makoré 9 10 11 12 13 14 15 15 16 17 18 18 19 20 21 22 23 24
Malas 7 8 9 9 10 11 12 12 13 14 15 15 16 17 18 19 19 20
Maple, Canadian 7 8 9 10 11 12 13 14 15 16 17 18 18 20 21 22 23 24
Maple, Qld 10 10 11 12 13 14 15 16 17 18 18 19 20 21 22 23 24 24
Maple, rose 8 8 9 10 10 11 12 12 13 14 14 15 16 16 17 18 18 19
Maple, sugar 7 7 8 10 12 13 14 15 16 17 18 19 20 21 22 23 24 -
Mararie 10 11 11 12 13 14 14 15 16 17 18 18 19 20 21 21 22 23
Marri 7 8 9 9 10 11 11 12 13 13 14 15 15 16 17 17 18 19
Matai 9 9 10 11 12 12 13 14 15 16 16 17 18 18 19 20 21 22
Meranti 7 8 9 10 11 12 13 14 13 16 17 18 19 20 21 22 23 24
Messmate 10 11 12 12 13 14 15 16 16 17 18 18 19 20 21 22 22 23
Nutmeg (Fiji source) 7 8 9 10 11 11 12 13 14 14 15 16 17 18 18 19 20 21
Oak, American red 7 8 9 11 12 13 14 15 16 17 18 18 20 21 22 23 21 25
Oak, European 7 8 9 10 11 12 13 14 15 16 17 18 19 21 22 23 24 25
Oak, New Guinea 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Oak, silky, northern 8 8 9 10 11 12 13 14 15 16 17 17 18 19 20 21 22 23
Oak, silky, red 8 9 9 10 11 11 12 13 13 14 15 16 16 17 18 18 19 20
Oak, silky, southern 7 10 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Oak, tulip, blush 7 11 12 12 13 14 15 16 16 17 18 19 20 21 22 23 24 25
Oak, tulip, brown 10 11 12 12 13 13 14 14 15 16 16 17 18 18 19 19 20 20
Oak, tulip, red 11 12 13 14 15 16 17 18 18 19 20 21 22 23 24 25 25 26
Oak, white 6 7 8 9 10 11 12 13 14 15 16 17 18 18 19 20 21 22
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Imperial
Wood Pin Probe Display 8.0 HUMIDITY MEASUREMENT MODE The optional Relative Humidity (RH) Probe can be plugged into the socket at the top of the instrument. The display shows relative humidity (RH), temperature (T), dew- point temperature (Td) and mixing ratio in grains/lb (GRN) or g/kg (gms). When the RH Probe is plugged into the MRH, the or key is used for changing the
temperature between ºC and ºF and the mixing ratio between g/kg and grains/lb.
Moisture Content

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9.0 WORKING WITH YOUR MRH Comparative Material Scales The MRH has 4 comparative material scales: Roof, Masonry, Drywall and Laminate. The comparative material scales are selected using the key and switching
between the various scales using or key.
9.1 Roof Scale Roof Testing a) The presence of moisture in built-up roofs covered with multi-ply roofing felt,
PVC, modified bitumen and all non-conductive membranes (See Limitations Section), can cause blistering and splitting of the roof covering. In addition moisture can cause considerable damage to the contents and fabric of the building as well as heat loss through wet insulation. Your MRH can be used to
confirm a new roof has been installed dry and help tracé leaks.
b) If the waterproofing membrane develops a leak, the water can travel within the
built-up-roof structure and enter the building some distance away. Testing the membrane surface and comparing the dry areas with areas where moisture is present below the surface can assist in tracing such a leak to its source.
c) As there are many different types and thickness sizes of roofing membranes, it
is not possible to give a calibrated percentage measurement. Instead, a comparative scale is displayed both numerically, (0 to 99) and in a bar form on the bottom line of the display. The display also shows low (Lo), medium (Md) and high (Hi) readings for the scale.
These do not necessarily indicate low, medium or high levels of moisture but indicate the area of the 0-100 comparative scale where the reading lies.
d) If gravel surfacing is present, this should be removed to ensure your MRH
comes into direct contact with the surface of the membrane.
e) It is recommended that a core be cut to determine the depth and density of the
moisture before carrying out roof repairs. Alternatively, the area can be checked with a resistance-type moisture meter with insulated pins up to a length of 7”(180mm).
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Meter reading (% moisture) 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Species Correct moisture content
Gum, American, red 10 11 12 12 13 14 15 16 17 18 18 19 20 21 22 23 24 24
Gum, red, river 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
Gum, rose 9 10 11 12 13 14 14 15 16 17 18 18 19 20 21 22 23 24
Gum, shining 8 9 10 11 11 12 13 14 15 16 17 18 19 20 20 21 22 23
Gum, yellow 9 10 11 12 12 13 14 15 15 16 17 18 18 19 20 21 21 22
Hemlock, western 8 9 10 11 12 13 15 16 17 18 19 20 21 22 23 24 26 27
Hickory - 7 9 11 13 14 16 17 18 20 21 22 24 - - - - -
Iroko 7 7 8 9 10 11 12 13 14 15 15 16 17 18 19 19 20 21
Ironbark, red 11 12 12 13 14 15 16 16 17 18 19 20 21 22 22 23 24 24
Ironbark, red, broad-leaved 11 12 12 13 14 15 16 16 17 18 19 20 21 22 22 23 24 25
Ironbark, red, narrow-leaved 8 9 10 11 12 13 14 14 15 16 17 18 19 20 21 22 23 24
Jarrah 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Jelutong 8 9 10 11 12 12 13 14 15 16 16 17 18 19 20 21 21 22
Kamarere (PGN source) 8 9 10 10 11 12 13 14 15 16 17 18 19 19 20 21 22 23
Kamarere (Fiji source) 7 8 8 9 10 11 11 12 13 13 14 15 15 16 17 17 18 19
Kapur 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Karri 7 8 9 10 11 12 13 13 14 15 16 17 18 18 19 20 21 22
Kauri, Qld 10 11 12 13 14 15 16 16 17 18 19 20 21 22 23 24 24 25
Kauri, NZ 9 10 10 11 12 12 13 13 14 14 15 16 16 17 17 18 18 19
Kauri, Vanikoro 11 12 13 13 14 14 15 15 15 16 16 17 17 18 18 18 19 19
Kempas 10 11 11 12 13 14 14 15 16 16 17 18 19 19 20 21 21 22
Laran 8 8 9 10 11 11 12 13 14 14 15 16 17 17 18 18 19 19
Larch, European 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Lodgepole Pine 7 8 9 10 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Lumbayau 8 9 10 11 12 12 13 14 15 15 16 17 18 19 19 20 21 22
Mahogany, African 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
Mahogany, American 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Mahogany, Brazilian - - - 10 10 11 12 13 14 15 15 16 17 18 19 20 21 22
Mahogany, brush 8 9 10 10 11 11 12 12 13 14 14 15 15 16 16 17 18 18

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Meter reading (% moisture) 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Species Correct moisture content Box, grey 10 11 12 12 13 14 14 15 16 17 17 18 19 20 20 21 22 23 Box, grey, coast 9 10 11 11 12 13 14 14 15 16 17 18 18 19 20 21 22 22 Box, kanuka 8 9 10 11 12 12 13 14 15 16 16 17 18 19 20 20 21 22 Brownbarrel 7 8 9 10 11 12 12 13 14 15 16 17 18 18 19 20 21 22 Buchanania 6 7 8 9 10 10 11 12 13 14 14 15 16 17 18 19 19 20 Candlenut 5 8 10 12 14 16 18 21 23 25 27 29 31 34 36 38 40 42 Carabeen, yellow 8 9 9 10 11 12 12 13 14 14 15 16 16 17 18 18 19 20 Cedar, red 9 10 11 12 13 14 16 17 18 19 20 21 22 23 25 26 27 27 Cedar, red, western 7 9 10 11 12 13 13 14 15 17 18 19 20 21 22 23 24 25 Cedar, South American 9 10 11 12 13 13 14 15 16 17 17 18 19 20 21 22 22 23 Cherry 8 9 10 11 12 13 14 15 16 17 18 19 20 22 23 24 25 26 Cherry, Brazilian 8 9 10 11 12 13 14 15 16 17 18 19 20 22 23 24 25 26 Coachwood 6 7 8 9 10 11 12 13 14 14 15 16 17 18 19 20 21 22 Dakua salusalu 9 10 11 11 12 13 14 15 16 17 18 19 19 20 21 22 23 24 Douglas Fir 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Elm 6 7 7 8 9 10 12 13 13 14 15 15 16 17 18 19 20 20 Erima 8 8 9 10 11 12 12 13 14 15 15 16 17 18 19 19 20 21 Fir, Alpine 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Fir, amabilis 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Fir, red 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 25 26 Fir, white 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 25 26 Gum, blue, southern 9 10 11 12 13 14 15 15 16 17 18 18 19 20 21 22 23 24 Gum, blue Tasmanian 8 9 10 11 12 12 13 14 15 16 17 17 18 19 20 21 22 22 Gum, grey 8 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Gum, grey, mountain 9 9 10 11 12 13 14 14 15 16 17 18 19 19 20 21 22 23 Gum, lemon-scented 6 7 8 9 10 10 11 12 13 13 14 15 16 17 17 18 19 20 Gum, Maiden’s 10 11 11 12 13 14 15 16 16 17 18 19 20 20 21 22 23 24 Gum, manna 7 7 8 9 10 11 12 13 14 14 15 16 17 18 19 20 21 21 Gum, mountain 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
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9.2 Masonry Scale
Testing plaster, brick and Block
Your MRH gives comparative (relative) readings (0 to 99) on plaster, brick and
block. These readings are displayed both numerically and in bar form on the LCD.
The display also shows low (Lo), medium (Md) and high (Hi) readings for the scale.
These do not necessarily indicate low, medium or high levels of moisture but
indicate the area of the 0-100 comparative scale where the reading lies.
For plaster, brick and block use the Masonry scale. For Drywall the more sensitive
dedicated Drywall scale is used. Always press the electrodes firmly against the
surface.
The moisture profile of a masonry wall can be determined by moving your MRH
across the surface where it will read through most paints and wall coverings. It will
help identify the different levels of moisture even if not apparent on the surface.
Moisture can often be trapped behind wall coverings.
Rising damp and moisture migration from leaks and defective, or non-existent,
vapor barriers can be identified and profiled and often its source identified by
moving the instrument across the wall surface. Water damage following flooding or
fire fighting can be checked and the drying out and de-humidification process can be
monitored.
9.3 Drywall Scale
Because of its deep signal penetration, your MRH can identify excess moisture
behind drywall, ceramic tile and other wall coverings when used on the Drywall
Scale.
Testing on ceramic tiles, other wall and floor coverings
Excess moisture trapped behind covering materials such as ceramic tiles, carpet,
wall coverings etc can cause major problems. For instance, excess moisture behind
ceramic tiles on drywall or other substrates can cause decay, delamination and
mold growth. The longer these problems go undetected, the worse the problem can
get, eventually leading to system failure.
Your MRH can be used to detect and identify areas of elevated moisture within or
behind most types of wall and floor coverings. For example the MRH can detect
elevated moisture behind most types of ceramic tiles.
Should the Drywall Scale prove to be too sensitive for testing ceramic tiles or other
coverings, reduce sensitivity by choosing the Laminate Scale and take readings on
a comparative basis.

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9.4 Laminate Scale
For applications where the Roof or Drywall scales are too sensitive and the Masonry
scale is not sensitive enough, the Laminate scale can be used. This scale used can
be used for testing on ceramic tiles and other wall and floor coverings. It can also be
used in many other applications where the other scales do not have the required
sensitivity.
9.5 Wood Scale
Testing wood and wood products
a) When testing wood, power-on, select Wood Scale using the key.
b) When the Wood Scale is selected the moisture content (MC) in percent is shown
on the right-hand side of the bottom line of the display. The left-hand side of this
line shows the specific gravity (SG) being used. See note on specific gravity on
page 17. The SG is changed by using the or key to adjust to the required
SG value. The range of SG covered is 0.30 to 0.80. The S.G. increases and
decreases in increments of 0.01.
c) A chart showing the approximate specific gravity of a range of different species
is shown on pages 16 and 17. For SG greater than 0.80 please refer to specific
gravity adjustment chart (Table 2 on page 14). For species not listed a more
comprehensive list is available on the USDA website www2.fpl.fs.fed.us/ (in the
US) or from timber importers and forestry departments in other countries.
d) If possible, always take readings with the length of the instrument parallel to the
direction of the wood grain.
e) Calibration tests were carried out by Forbairt, the Irish Institute for Industrial
Research and Standards, and are based on Douglas Fir, which had a published
specific gravity (SG) of 0.50.
f) Acceptable levels of moisture content depend on climatic conditions and we
advise you check the levels acceptable in your area. Table 1 on page 13 shows
the approximate relationship between the ambient relative humidity and
equilibrium moisture content in woods.
g) The following moisture content levels are given as a guide.
Furniture: 5% to 6% when used in locations of low relative humidity and up
to 10% to 11% may be acceptable where the relative humidity is higher.
Interior wood: 6% in low humidity areas. Up to 12% in higher humidity
locations.
Exterior wood: 10% to 15% depending on local humidity levels.
Generally, wood with a moisture content in excess of 23% - 25% is
susceptible to rot.
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12.0 SPECIES CORRECTION CHART
Meter reading (% moisture) 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Species Correct moisture content Alder, brown 9 10 10 11 12 13 13 14 15 15 16 17 18 18 19 20 20 21 Amberoi 7 7 8 9 9 10 11 12 12 13 14 14 15 16 17 17 18 19 Ash, alpine 9 10 11 12 13 14 15 16 17 18 18 19 20 21 22 23 24 25 Ash, American 9 10 11 11 12 13 14 14 15 16 17 18 19 20 21 23 24 25 Ash, Crow’s 9 10 10 11 12 12 12 14 14 15 16 17 17 18 19 20 20 21 Ash, European 8 9 10 11 12 12 13 14 14 15 16 17 18 18 19 20 21 21 Ash, mountain 9 10 11 12 13 14 15 16 17 18 18 19 20 21 22 23 24 25 Ash, silvertop 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 Balsa 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Baltic, red 9 10 11 12 13 14 15 15 16 17 18 18 19 20 21 22 23 24 Baltic, white 9 10 11 12 13 14 15 16 17 18 19 20 22 23 24 25 26 27 Bauvudi 7 8 9 9 10 11 11 12 13 13 14 15 15 16 17 17 18 18 Bean, black 9 10 11 12 13 14 15 16 16 17 18 19 20 21 22 23 24 25 Beech, American 7 8 10 11 12 13 14 15 16 13 18 19 20 21 23 23 24 25 Beech, Japan 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Beech, myrtle 8 9 10 11 11 12 13 14 14 15 16 17 18 18 19 20 21 22 Beech, silver 9 10 10 11 12 12 13 13 14 14 15 16 16 17 17 18 19 19 Beech, Wau 9 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 Beech, white 8 9 10 11 12 13 14 14 15 16 17 18 19 19 20 21 22 23 Birch, European 7 8 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Birch, white 9 10 11 12 12 13 14 15 15 16 17 18 18 19 20 21 22 22 Blackbutt 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Blackbutt, WA 9 10 11 12 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Blackwood 9 9 10 11 12 12 13 14 15 16 16 17 18 19 20 20 21 22 Bloodwood, red 10 10 11 12 13 14 15 15 16 17 18 19 19 20 21 22 23 23 Bollywood 7 8 9 10 11 12 12 13 14 15 16 16 17 18 19 20 21 22 Box, brush 7 7 8 8 9 9 10 10 11 11 12 13 13 14 14 15 15 16

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Temperature Adjustment Chart
For use in pin-meter only. The instrument had been calibrated on wood at an
ambient temperature of 20°C (68°F). When measuring moisture in wood at a
different temperature, the following temperature adjustment needs to be applied.
(Figures rounded to the nearest whole number).
Wood temp. Meter reading
°C °F 7% 10% 12% 15% 20% 26% 30%
Adjustment
5 40 +1 +2 +2 +3 +4 +5 +7
10 50 +0 +1 +1 +2 +2 +3 +4
20 68 +0 +0 +0 +0 +0 +0 +0
30 80 +0 -1 -1 -1 -1 -2 -2
40 100 -1 -2 -2 -3 -3 -3 -4
50 122 -1 -3 -3 -4 -5 -7 -8
60 140 -2 -3 -4 -5 -6 -8 -10
70 158 -3 -4 -5 -6 -8 -10 -12
Example 1:
If meter reads 15% and temperature of wood is 10°C (50°F), actual moisture content
is 17%. i.e.15%+2%=17%
Example 2:
If meter reads 15% and temperature of wood is 50°C (122°F), the actual moisture
content is 11%. i.e.15%-4%=11%
Combined Species/Temperature Correction
Example 1
If meter gives reading 15% on a sample of Sitka Spruce and the wood temperature
is 40°C, the correction is as follows:
Species correction @15% = 16%
Temperature correction @ 40°C = - 3%
Corrected reading: 13%
Example 2
If meter gives reading 24% on sample of Teak and the wood temperature is 10°C,
the correction is as follows:
Species correction @24% = 20%
Temperature correction @ 10°C = + 2%
Corrected reading: 22%
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Wood moisture content in excess of 18% - 20% may provide an environment
for termite and woodboring insects to thrive and multiply. Wood at these high
levels can also support mold and biological growth.
Wood at 28% moisture content is considered to have reached fiber
saturation point.
h) Avoid taking readings on wood from the top of a stack stored outside as these
may be affected by surface moisture from recent rain.
i) When taking readings in chemically treated wood, it is advisable to allow for
possible effects that the treatment may have on readings.
9.6 Relative humidity and moisture content
The following table shows the approximate relationship between relative humidity
(RH) and equilibrium moisture content (EMC) of some woods. These figures are
approximate values and may vary for different species.
Relative Humidity Wood MC%
10% 3 to 5
20% 5 to 6
30% 6 to 8
40% 8 to 10
50% 10 to 11
60% 11 to 13
70% 13 to 15
80% 15 to 18
90% 18 to 23
100% 23 +
Table 1. Approx relationship between RH and EMC.
Depth of field penetration
Depending on the density of the material being tested, the instrument field can
penetrate approximately 30mm (1 ¼ inches) below the surface. When testing
thin materials such as wood veneers it is recommended that they are stacked to
at
least that thickness.

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9.7 Wood Flooring
a) Excess moisture in wood flooring or concrete sub-floors can cause major
problems. For instance, if installed with excess moisture, the wood can
subsequently shrink leading to job failure.
b) If a wood floor (solid, laminated or engineered) is installed above wet concrete
the wood can absorb moisture emitting from the concrete causing the wood to
swell and buckle and even cause structural damage to the building. For
measuring the moisture in concrete, the CME4, CRH or CMEXpert should be
used.
c) Your MRH can be used to measure the moisture content of the wood floor to
ensure it meets specification. Likewise it can be used to check, on a
comparative basis, through the floor covering, to identify elevated moisture in
the substrate.
NOTE: On the Wood, Drywall, Roofing and Laminate Scales the depth of
penetration of the MRH signal can be up to 1¼” (30mm). When using any of these
scales on wood or laminate over concrete or other screeds, the MRH will be reading
through the material and may be giving a much higher than expected reading. This
is invariably due to the fact that concrete is a much denser material than wood or
wood-based products. In such instances, the wetter areas can be identified non-
invasively and the wood probe can then be used to make select intrusions to
determine the moisture content of the wood or laminate.
Reading S.G.
set at 0.5 S.G.
0.85 0.9 0.95 1
Adjustment
5 to 9 -3 -4 -4 -4
10 to 12 -4 -5 -5 -5
13 to 15 -5 -6 -6 -6
16 to 18 -6 -7 -7 -8
19 to 21 -7 -8 -9 10
22 to 24 -9 -9 -11 -11
25 to 27 -11 -11 -12 -13
28 to 30 -12 -13 -13 -14
31 to 33 -14 -14 -14 -15
34 to 36 -15 -15 -15 -16
Table 2. Specific Gravity Adjustment Table (S.G. > 0.80)
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Testing wood and wood products
a) When testing wood, power-on, insert wood probe into phono-socket at the top of
the MRH and select Pin Probe Mode using the key.
b) When a wood probe is inserted the moisture content (MC) in percent is shown
on the righthand side of the bottom line of the display.
c) If possible, always take readings with the pins parallel to the direction of the
wood grain.
d) Calibration tests are based on Douglas fir, which has a published specific gravity
(SG) of 0.50.
e) Acceptable levels of moisture content depend on climatic conditions and we
advise you check the levels acceptable in your area. Table 1 on page 13 shows
the approximate relationship between the ambient relative humidity and
equilibrium moisture content in woods.
f) The following moisture content levels are often quoted in the wood industry and
should be used as a guide only. Please contact industry associations and
manufacturers for their specifications.
Furniture: 5% to 6% when used in locations of low relative humidity and up
to 10% to 11% may be acceptable where the relative humidity is higher.
Interior wood: 6% in low humidity areas. Up to 12% in higher humidity
locations.
Exterior wood: 10% to 15% depending on local humidity levels.
Generally, wood with moisture content in excess of 23% - 25% is susceptible
to rot.
Wood moisture content in excess of 18% to 20% may provide an
environment for termite and woodboring insects to thrive and multiply. Wood
at these high levels can also support mold and biological growth.
Wood at 28% moisture content is considered to have reached fiber
saturation point.
g) Avoid taking readings on wood from the top of a stack stored outside as these
may be affected by surface moisture from recent rain.
h) When taking readings in chemically treated wood, it is advisable to allow for
possible effects that the treatment may have on readings.
Temperature Adjustment Chart
The Pin Probe has been calibrated on wood at an ambient temperature of 20°C
(68°F). When measuring moisture in wood at a differ ent temperature, the following
temperature adjustment needs to be applied. (Figures rounded to the nearest whole
number).

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11.0 WOOD PIN METER MODE
Factors Affecting Moisture Readings
The readings of all moisture meters are influenced by the characteristics of different
species of wood as well as temperature and other factors listed below.
Species
Different species of wood can vary in density and conductivity, which can have an
effect on the electrical resistance of the wood. This can influence meter readings for
the same moisture content and can also apply to similar species from different
origins. A species adjustment table is provided on page 21 to 27.
Temperature
Meter readings can be affected by wood temperature. The Wood Probe is calibrated
at 20°C (68°F). At wood temperatures above 20°C (68 °F), the meter readings are
higher and at wood temperatures below 20°C (68°F) t he meter readings are lower.
A temperature adjustment chart is provided on page 20.
Chemical treatment or contamination
Readings may be affected by certain flame retardants, preservatives, aluminium
paint and by contamination by salt water. Treat all readings on such wood as
indicative readings only.
Surface Moisture
Surface moisture due to wetting or condensation can affect readings when
uninsulated pins are used. It is recommended that insulated pins such as SP-52 are
used in conjunction with HA-22 Hammer Action electrode. As the pins are driven
into the wood, readings can be taken at different depths unaffected by moisture on
the surface.
Wood Flooring
a) Excess moisture in wood flooring can cause major problems.
b) For instance, if installed with excess moisture, the wood can subsequently
shrink leading to job failure.
c) If a wood floor (solid, laminated or engineered) is installed above wet concrete
the wood can absorb moisture emitting from the concrete causing the wood to
swell and buckle and even cause structural damage to the building.
d) Your MRH in PIN Probe mode can be used to measure the moisture content of
the wood floor to ensure it meets specification.
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9.8 Chemical treatment or contamination
Readings may be affected by certain flame-retardants, preservatives, aluminium
paint and by contamination by salt water. Treat all readings on such wood as
indicative readings only.
Adhesives
The presence of different species, treatments, adhesives, etc., within products
such as plywood, particleboard, OSB (oriented strand board), laminated and
engineered woods will affect measurements. If in doubt please contact us and, if
you wish, we can work with you in developing your own calibration for a specific
product.
Concrete
Your MRH is not calibrated for concrete. The Concrete Encounter CME4,
CMExpert and CRH instruments are specifically designed for concrete flooring
and are recommended where quantitative measurements are required. However
a comparative indication of the moisture condition of a concrete or sub floor can
be obtained with the MRH set on the Masonry scale. Comparative readings can
also be obtained through coverings such as vinyl, carpet and laminated wood
flooring by using the Laminate Scale.

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10.0 TABLE OF WOOD SPECIFIC GRAVITIES (S.G.)
Hardwoods
(Am. = American)
Alder, Red (Am. Alder, Western Alder) Alnus rubra 0.41
Ash, White (Northern / Southern Ash) F. americana 0.60
Aspen, Quaking (Am. Aspen) Populus tremuloides 0.38
Basswood (Am. Basswood, Linden) Tilia americana 0.37
Beech Fagus Grandifolia 0.64
Birch, Yellow (Gray, Silver, Swamp)B. alleghaniensis 0.62
Cherry (Am. Black Cherry) Prunus serotina 0.50
Cottonwood (Eastern Cottonwood) Populus deltoides 0.40
Elm, Red (Slippery elm) Ulmus rubra 0.53
Hackberry (Common Hackberry) Celtic occidentalis 0.53
Hickory (Pignut, True Hickory) Carya glabra 0.75
Maple, Am. Hard (Sugar Maple) Acer saccharum 0.63
Maple Am. Soft (Red Maple) Acer rubrum 0.54
Maple, Silver Acer saccharinum 0.47
Maple, Black Acer nigrum 0.57
Oak, Northern Red Quercus rubra 0.63
Oak, Southern Red (Cherrybark) Quercus falcata 0.68
Oak, White (Am. White Oak) Quercus alba 0.68
Pecan Hickory (Am. Pecan) CaryaiIllinoensis 0.66
Red Gum (Sweetgum) Liquidamber styraciflua 0.52
Sassafras (Golden Elm) Sassafras albidum 0.46
Sycamore(Am. Planetree, Buttonwood) P. occidentalis 0.49
Walnut, Black (Am. Walnut) Juglans nigra 0.55
Willow, black (Am. Willow) Salix nigra 0.39
Yellow Poplar (Am. Tulipwood, Tulip Poplar, Canarywood) Liriodendron tulipifera
0.42
Softwoods
Cedar, Alaska (Alaskan Yellow) 0.44
Cedar, Incense 0.37
Cedar, Port-Orford 0.43
Cedar, Western Red 0.32
Douglas Fir, Coast 0.48
Douglas Fir, Interior West 0.50
Fir, California Red 0.38
Fir, Grand 0.37
Fir, noble 0.39
Fir, Pacific Silver 0.43
Fir, White 0.39
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Hemlock, Western 0.45
Larch, Western 0.52
Pine, Lodgepole 0.41
Pine, Ponderosa 0.40
Pine, Sugar 0.36
Pine, Western White (Idaho) 0.38
Spruce, Engelmann 0.35
Spruce, Sitka 0.40
Exotic
Balsa 0.16
Ebony 1.10
Karri 0.82
Padauk 0.77
Tulipwood 0.96
Source: USDA: Wood Handbook 1987.
Note on specific gravity (S.G.):
The specific gravity (S.G.) of wood is the ratio of the density of wood to the density
of water at a specified temperature (generally 4ºC where the density of water is at
its maximum). The density of wood is usually based on the oven-dry weight and the
volume at the specified moisture content (M.C.), generally 12%.

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TRAMEX MRH III
PORTABLE MOISTURE METER
OPERATING INSTRUCTIONS