TRAMEX MRH III User manual

user guide
MRH III
non-destructive
moisture & humidity meter
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TABLE OF CONTENTS
Introduction..........................................................................................3
How it works....................................................................................4-5
Instrument Features ..................................................................6-7
Operating Instructions ..................................................................8
Non-Destructive Measurement Mode ..........................9-10
Wood Pin Meter Mode ........................................................11-12
Non-DestructiveMeasurementMode
-ComparativeScales ................................................................14-17
Roof Scale ........................................................................14-15
Masonry Scale ...............................................................15-16
Drywall Scale .........................................................................16
Laminate Scale .....................................................................17
Non-Destructive Measurement Mode
- Wood Scale ............................................................................17-24
Relative Humidity & Moisture Content....................19
Wood Flooring ..............................................................20-21
Specific Gravity AdjustmentTable ............................21
Table of Wood Specific Gravities (SG) .............23-24
Wood Pin Meter Mode .......................................................25-29
Species Correction Chart .................................................30-41
Humidity Measurement Mode .......................................42-43
Moisture Testing Guidelines ...........................................44-45
Hole Liner Instructions ASTM F2170 / BS 8201,
8203, 5325 ..........................................................................46-49
Calibration Check Salts .....................................................50-51
Limitations.......................................................................................52
Calibration ......................................................................................52
Warranty............................................................................................53
Product Development................................................................54
Safety ......................................................................................................54
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INTRODUCTION
Thank you for selecting the new MRH III instrument,
from Tramex. It has 3 measurement modes.
1. The MRH III utilises electronic technology to
provide you with an accurate and easy to use
non-invasive instrument for the non-destructive
measurement and tracing of 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 used in Pin Probe (wood
pin-meter resistance measurement) Mode. This
enables the MRH III to measure the percentage
moisture content (MC%) of wood and give an
indication of the moisture content of wood-
based products.
3. By inserting the optional plug-in Hygro-i2
probe, the instrument automatically changes to
hygrometer mode. This enables the MRH III 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
method as per ASTM F2170 and the in-situ
and hood methods as per British Standards BS
8201, 8203, 5325.
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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.
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
MRH III
Receive
Electrode
Material
Sample
Alternating Electric Field
Transmiting
Electrode
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In Pin Probe Mode (i.e. with pin probe mode selected and
an electrode plugged in), the MRH III is a resistance-type
pin meter for determining the percentage moisture
content of wood.
In Hygrometer mode (i.e. with the Hygro-i2 Probe
plugged in), the MRH III determines the capacitance
of the RH probe sensor, which varies with the relative
humidity of the test area environment. The MRH
III displays this capacitance as percentage relative
humidity (%RH). It also measures temperature and
displays dew-point temperature and mixing ratio.
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INSTRUMENT FEATURES
Your MRH III 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.
●6 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 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 III (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.
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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
.
●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 will be extended for an
additional ten minutes.
●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
time set.
●Backlight display time.To adjust the backlight
display time, press the and keys together.
Then scroll with the key from 10 – 60 seconds.
When time is chosen select key to confirm and
return to scale mode.
●Language display adjustment. To adjust the
language display, press the and keys
together.Then scroll with the key through the
language library. When language is chosen select
key to confirm and return to scale mode.
●When the battery requires replacement a LOW
BATTERYmessage is shown on the LCD.
●HOLD freezes reading to facilitate ease of
recording readings. When the MRH III is in HOLD
mode, ‘H’ will flash on the display.
●If HOLD was selected prior to the MRH III
automatically powering off, the frozen display
reading is digitally memorized and restored next
time ON is selected.
Example:
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OPERATING INSTRUCTIONS
1 = Phono socket for Wood Probes.
2 = Hygro-i2 Probe Socket (automatic hygrometer mode
when plugged in).
3 = Backlit display.
4 = Hold / Audio Mode.
5 = Scale Key.
6 = UP / DOWN Keys
7 = ON / OFF Key 10 minute switch off
8 = Light Key.
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NON-DESTRUCTIVE MEASUREMENT MODE
1. Press the key to power up. With no RH 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 III directly on the wood, roof,
masonry, drywall, laminate 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.
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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
SG 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 23 and 24. For SG greater than 0.80 please
refer to species adjustment table (Table on Page
21).
8. To turn audio tone on or off, press key twice in
quick succession.
9. The MRH III 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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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 III 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 III 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
Measurement Mode
The two main types of moisture meter for measuring
moisture content in wood are the pin type meter and the
non-destructive or impedance type meter. Both types
are calibrated using gravimetric or oven-drying test
methods.
The Tramex MRH III 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
Douglas Fir with a specific gravity (SG) of 0.5.
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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 SG of the material being tested has a significant
effect on the reading.
On the MRH III 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 non-destructive 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 SG 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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Typical MRH III Displays
Moisture Measurement Mode
Battery warning
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NON-DESTRUCTIVE MEASUREMENT MODE –
Comparative Scales
The MRH III 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.
Roof Scale - Roof Testing
a. The presence of moisture in roofing systems
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 III can be used to
confirm a new roof has been installed dry and help
trace leaks.
b. If the waterproofing membrane develops a leak,
the water can travel within the 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 back to its
source.
c. As there are many different types and thicknesses
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.
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These do not necessarily indicate low, medium or high
levels of moisture but indicate the area of the 0-99
comparative scale where the reading lies.
d. If gravel surfacing is present, this should be
removed to ensure your MRH III 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).
Masonry Scale - Testing Plaster, Brick and Block
Your MRH III 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 0-99
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 III 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.
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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.
Drywall Scale
Because of its deep signal penetration, your MRH III 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 III 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 III 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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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
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.
NON-DESTRUCTIVE MEASUREMENT MODE – Wood
Scale
Testing wood and wood products
a. When testing wood, power-on, selectWood 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
21. 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 SG 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
23 and 24. For SG greater than 0.80 please refer
to specific gravity adjustment chart (Table on page
21). For species not listed a more comprehensive
list is available on the USDA website www.fpl.
fs.fed.us (in the US) or from timber importers and
forestry departments in other countries.
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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. TheTable on page
19 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%
to 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.
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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.
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.
Approx. relationship between RH and EMC.
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 +
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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 Tramex CME4 or
CMEXpert should be used.
c. Your MRH III 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.
Depth of field penetration
Depending on the density of the material being tested,
the instrument field can penetrate approximately 30mm
(1¼") 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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