TRAMEX MRH III User manual

MRH III
Non-Destructive Moisture
&
Humidity Meter
USER GUIDE
MRH05 10
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MRH III User Guide
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TRAMEX MOISTURE/HUMIDITY INSTRUMENTS
SURVEY ENCOUNTER: The intelligent moisture meter.
"State of the art" non-destructive moisture meter for measurement and
data logging of moisture in building materials.
MOISTURE ENCOUNTER PLUS
General purpose non-destructive moisture meter employing advanced
analog and digital technology.
CONCRETE ENCOUNTER CME 4
Non-destructive moisture meter for concrete floors.
CRH FLOORING
Non-destructive testing and data logging of moisture content and relative
humidity measurements in concrete (to ASTM F 2170, ASTM F 2420, BS
5325 & 8203), gypsum screeds and sub-floors.
CMEXPERT FLOORING INSPECTION KIT
Complete kit for moisture testing of concrete, hardwood flooring and sub-
flooring. Can also be used for relative humidity testing of flooring by either the
in-situ probe method (ASTM F 2170) or the RH hood method (ASTM F 2420,
BS 5325 and 8203).
PROFESSIONAL MOISTURE METER
Digital resistance meter with probes, tests deep into wood.
COMPACT MOISTURE METER
Economical pin-type resistance meter for wood.
SKIPPER PLUS
Checks wooden boats for decay and finds osmosis in GRP.
DEC SCANNER
Mobile non-destructive surveying of flat roofs.
WET WALL DETECTOR
Non-destructive moisture evaluation and tracing in EIFS.
RWS ROOF AND WALL SCANNER.
For moisture scanning and leak tracing on roofing, EIFS and the building
envelope.
MOISTURE & HUMIDITY INSPECTION KITS ARE AVAILABLE FOR
THE FOLLOWING INDUSTRIES:
Floor inspection / EIFS wall inspection / Roof inspection / Indoor Air Quality /
Water damage restoration.
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TABLE OF CONTENTS
Introduction................................................................... 4
How it works ................................................................. 4
Instrument Features ................................................ 6
Operating Instructions ............................................. 8
Non-destructive measurement mode ................. 9
Wood pin meter mode ............................................ 10
Typical MRH Displays ........................................... 12
Humidity measurement mode ............................ 14
Working with your MRH...................................... 14
Roof Scale................................................................ 14
Masonry Scale ....................................................... 15
Drywall Scale .......................................................... 16
Laminate Scale...................................................... 17
Wood Scale ............................................................. 17
Wood Pin Meter Mode ........................................... 24
RH Probe....................................................................... 40
Calibration .................................................................... 41
Warranty....................................................................... 42
.......................................... 28
Spcecies Adjustment
MRH III User Guide
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Introduction
Thank you for selecting a new MRH instrument from
Tramex.
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.
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
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Alternating
Electric Field
Material
under test
Transmit &
Receive
Electrodes
MRH
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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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.
• 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 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.
L A M I N A T E 3 3
m 0 0 0 0 0 0 -
LO
0 - 30
M D
MD
31 - 70 HI
71 - 99
Example
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• 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.
• 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.
will be extended for an additional ten minutes.
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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).
TM
W
OODH
SG.58MC05.9
%
MRH III
Phono
Socket
for Wood
Probes
LIGHT
KEY
HOLD/
AUDIO
KEY
RH Probe
Socket
SCALE
KEY
UP /
DOWN
KEY
S
Flashing
‘H’ in Hold
Mode
ON/OFF
KEY
10 minute
switch off
BACKLIT
DISPLAY
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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.
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 22
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.
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and 23. For SG greater than 0.80 please refer to species
adjustment table (Table 2 on Page 20).
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.
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.
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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 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
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 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
S.G. of the material but can be a good indication.
It is very important to note that the readings of the non-
(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 Displays
Moisture Measurement Mode
R O O F
M D 0 4 7
M A S O N R Y L O 3
D R Y W A L L H I 7 1
W O O D
S G . 6 0 M
C
1 1 . 2 %
L A M I N A T E 3 3
m 0 0 0 0 0
0
-
Battery warning
L o w B a t
t
e r y
M D
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Humidity Probe Display
METRIC
Flashing 'H' in Hold mode
Relative Humidity T ºC
R H 5 0 . 1 % H
T 2 0 C
T d 1 1 . 7 C 0
0
0 7 g m s
Dewpoint (Td) ºC Mixing Ratio g/kg
IMPERIAL
R H 5 0 . 1 % H T 6 8 F
T d 5 3 . 1 F 0
0
5 1 G R N
Wood Pin Probe Display
P I N X X
X
X X X X X
PROBEM C
=
1 0 . 8 %
Moisture Content
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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.
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.
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 trace
leaks.
b) If the waterproofing membrane develops a leak, the
water can travel within the built-up-roof structure and
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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 until bottom line of the display. The display also
shows low (Lo), medium (Md) and high (Hi) readings for
the scale.
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).
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.
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.
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.
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.
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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 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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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.
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 23. 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 22 and 23.
For SG greater than 0.80 please refer to specific gravity
adjustment chart (Table 2 on page 20). 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 19 shows the
Laminate Scale
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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.
• Wood moisture content in excess of 18% - 20%
may provide an environment for termite and wood-
boring 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.
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.
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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 to15
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
thin materials such as wood veneers it is recommended that they are stacked to at
least that thickness.
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, 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.
Relative Humidity Wood MC %
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NOTE: On the Wood, Drywall, Roofing and
Laminate Scales the depth of penetration of
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.
.G.S
Reading 0.85 0.9 0.95 1
S.G. set at 0.5 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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