Elcometer SCM400 User manual

English
Elcometer 130 SCM400
Salt Contamination Meter
Operating Instructions

English
The Elcometer 130 SCM400 Salt Contamination Meter has been
tested in acccordance with EU regulations governing Electro-magnetic
compliance and it meets the required directives.
is a registered trademark of Elcometer Limited.
All other trademarks acknowledged.
© Copyright Elcometer Limited. 2009.
All rights reserved. No part of this Document may be reproduced, transmitted,
transcribed, stored (in a retrieval system or otherwise) or translated into any
language, in any form or by any means (electronic, mechanical, magnetic,
optical, manual or otherwise) without the prior written permission of
Elcometer Limited.
Doc.No. TMA-0125 Issue 05
Text with Cover No: 4373

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CONTENTS
Section Page
1 About your meter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1 Standards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 What the box contains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2 Principle of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3 Specification of salt levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4 Taking a reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.1 Before you start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.2 Taking samples using standard sample papers. . . . . . . . . . . . . . . . . . . . 5
4.3 Taking samples using smaller sample papers. . . . . . . . . . . . . . . . . . . . . 8
4.4 Interpreting the readings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5 Care and maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1 Checking calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.2 Checking water quality. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.3 Checking purity of sample papers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.4 Removing and cleaning or replacing the electrodes . . . . . . . . . . . . . . . 14
5.5 Removing discolouration from electrode surfaces. . . . . . . . . . . . . . . . . 14
5.6 Replacing the pressure plate support pads . . . . . . . . . . . . . . . . . . . . . . 15
5.7 Replacing the battery. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.8 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6 Fault diagnosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
7 Spares and accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
8 Related equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
9 Technical specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

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hank you for your purchase of this Elcometer 130 SCM400 Salt
Contamination Meter. Welcome to Elcometer.
Elcometer are world leaders in the design, manufacture and supply of
inspection equipment for coatings and concrete.
Our products cover all aspects of coating inspection, from development through
application to post application inspection.
The Elcometer 130 SCM400 Salt Contamination Meter is a world beating
product. With the purchase of this product you now have access to the
worldwide service and support network of Elcometer. For more information visit
our website at www.elcometer.com
1 ABOUT YOUR METER
The Elcometer 130 SCM400 Salt Contamination Meter measures salt
contamination levels on metallic and non-metallic surfaces and is particularly
useful on areas such as bends and welds.
1.1 Standards
The instrument can be used in accordance with the following International
Standard :
• SSPC Guide 15.
1.2 What the box contains
• Elcometer 130 SCM400 Salt Contamination Meter
• Carry Case and nylon Shoulder Strap
• High Purity Sample Papers (pack of 100)
• Plastic Tweezers (2 off)
• Self-Seal PVC Bags (pack of 20)
• Replacement Pressure Support Pads (pack of 8)
• Disposable Gloves (pack of 20) in nylon holdall
• Pack of Tissues
• 9 V Alkaline Battery
• 2 ml Syringes (3 off)
• Bottle of High Purity Water (250 ml)
• Plastic Sample Bottle
• Operating Instructions
T

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2 PRINCIPLE OF OPERATION
Soluble salts on the surface are taken into solution by placing a wetted 110 mm
diameter Elcometer 130 SCM400 High Purity Sample Paper on the area to be
sampled.
By leaving the paper in contact for a timed period, salt removal from the surface
is maximised. Using a paper of known size allows contamination to be
expressed in terms of surface area.
These papers retain a known amount of water because of their consistent
absorbency characteristics and therefore the concentration of the solution
formed is related to the quantity of soluble salts removed.
The sample paper containing the salt solution is placed over the electrodes on
the Elcometer 130 SCM400 and its resistivity is determined. This is achieved by
measuring the minimum resistance of the solution over a fixed solution path
length and cross section, governed by the electrode spacing and paper
thickness respectively.
The solution concentration is inversely proportional to its resistivity. The
Elcometer 130 SCM400 relates the latter to a calibration with known

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concentrations of sodium chloride solution and the known surface area
sampled, to give surface salt levels in µg.cm
-2
.
Figure 1. Elcometer 130 SCM400 Salt Contamination Meter
3 SPECIFICATION OF SALT LEVELS
Ideally, the salt level remaining on a steel surface after surface cleaning and
prior to painting or any other construction operation, should be zero.
In practice it is not possible to achieve this due to various environmental factors
and a working salt level needs to be specified. In the case of painting, this level
is a matter for discussion between the Client, the Applicator and the Paint
Manufacturer and it will depend on the working conditions, the paint system
used, the required service life and what can be economically achieved.
Consequently, it is not possible to specify in these Operating Instructions which
salt standards are best suited to all industries. However, during the
development of the Elcometer 130 SCM400, the effect of salt contamination on
the life of coatings under a range of realistic and accelerated environmental
conditions for a number of common generic coating systems was assessed.

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Although Elcometer would not wish to recommend this as a specification, the
work has shown that a salt level of better than 4 µg.cm
-2
is a sensible working
limit.
4 TAKING A READING
4.1 Before you start
•Is the electrode (Figure 1) clean?
See “Removing and cleaning or replacing the electrodes” on page 14.
•Is the sampling water to the correct specification, i.e. BS 3978 (ISO 3696) -
Water for Laboratory Use, Grade 3?
See “Spares and accessories” on page 18 for replacement water
If the sample area is larger than the Elcometer 130 SCM400 High Purity Sample
Paper, follow procedure 4.2.
If the sample area is smaller than the Elcometer 130 SCM400 High Purity
Sample Paper, follow procedure 4.3.
4.2 Taking samples using standard sample papers
1. Put on a pair of clean disposable gloves.
2. Fill a 2 ml syringe with precisely 1.6 ml of high purity water.
3. Using tweezers, remove an Elcometer 130 SCM400 High Purity Sample
Paper
a
from the pack.
If the standard 110 mm diameter sample paper is too large for the area to
be sampled, smaller papers may be used - see “Taking samples using
smaller sample papers” on page 8.
a. Use only Elcometer 130 SCM400 High Purity Sample Papers. Commercial filter
papers are not suitable as they can contain excessive salt levels.

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4. Using the tweezers to hold the sample paper, eject 1.6 ml of water onto its
surface (Figure 2), taking care to retain as much water as possible on the
paper..
Figure 2. Applying Water to Elcometer 130 SCM400
High Purity Sample Paper
5. Place wetted paper on the area to be sampled, pressing it firmly into its
contours and surface irregularities.
6. Press out as much entrapped air as possible from beneath the paper. If
hand pressure is required to exclude air, the gloved hand should not be
used. Instead, turn one of the plastic bags provided inside out, place it over
the gloved hand and press the surface, discarding the plastic bag when
finished.
7. Switch the Elcometer 130 SCM400 on by pressing the red pushbutton
once
b
. The display will show:
8. When the sample paper is in position, press the red pushbutton again to
start the 2 minute timer
c
. The display will show:
b. When ‘SCM Ready’, ‘SALT LEVELS TOO LOW’ or ‘SALT LEVEL>20 µg.cm
-2’
is
displayed, the instrument will automatically switch off if not used within 20 seconds.
SCM........Ready
TIMER STARTED

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9. When 2 minutes have elapsed the Elcometer 130 SCM400 emits an
intermittent bleep and the display shows:
10.Remove the sample paper from the surface.
11.Place the sample paper over the concentric copper electrodes (Figure 3)
ensuring that the outer ring is completely covered. All air must be excluded
from beneath the paper.
Figure 3. Placing Elcometer 130 SCM400 High Purity Sample Paper onto
the Electrode for Measurement
12.Close the lid, ensuring that the magnetic catch is fully engaged.
13.Within 5 seconds, press the green pushbutton and a reading will be
displayed:-
or:-
c. The Elcometer 130 SCM400 cannot be switched off when the timer is operating or
when measurements are being made.
SAMPLE READY
SALT LEVEL 9 µg.cm
-2
SALT LEVELS TOO LOW > 20 µg.cm
-2
If Salt Level <0.1 µg.cm
-2
If Salt Level >20 µg.cm
-2

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14.Lift the lid and remove the sample paper. The sample paper may be kept in
one of the resealable bags for further chemical analysis.
15.When all samples have been taken, switch the instrument off by pressing
the red pushbutton twice in quick succession.
16.Close the lid and ensure that the magnetic catch is fully engaged.
4.3 Taking samples using smaller sample papers
If the standard 110 mm diameter High Purity Sample Papers are too large for
the area to be sampled, half size, quarter size or 22 mm wide strip papers can
be used as follows. Care must be taken to ensure that sample papers do not
become contaminated.
1. Put on a pair of clean disposable gloves.
2. Using tweezers, remove an Elcometer 130 SCM400 High Purity Sample
Paper from the pack.
3. Fold paper as follows:-
For half size paper fold standard paper in half and cut into two along fold
line.
For quarter size paper fold standard paper into quarters and cut into
quadrants along fold lines.
For 22 mm wide strip fold standard paper into half and cut 11 mm either
side of fold line.
4. Fill a 2 ml syringe with an appropriate amount of high purity water:-
For a half size paper use 0.8 ml
For a quarter size paper use 0.4 ml
For a 22 mm wide strip use 0.4 ml
5. Holding sample paper in tweezers, eject the correct amount of water onto
its surface. Take care to retain as much water as possible on the paper.
6. Follow Steps 5 to 10 (inclusive) in Section 4.2.
7. Using the central marker on the inner electrode to aid positioning, place the
sample paper over the concentric electrodes as appropriate, ensuring all
entrapped air is removed:

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If using half size papers - cover
exactly half the inner and outer
electrodes.
If using quarter size papers -
cover exactly quarter of the inner
and outer electrodes.
If using 22 mm wide strips - lay
the paper across the inner and the
outer electrodes, to completely
cover the inner electrode.
8. Close the lid ensuring that the magnetic catch is fully engaged.
9. Within 5 seconds, press the green pushbutton once to obtain a reading.
10.Multiply the reading by an appropriate factor to account for the reduced
area sampled:-
For half size paper multiply the reading by 2
For quarter size paper multiply the reading by 4
For 22 mm wide strips multiply the reading by 2.8
11.Follow Steps 5 to 10 (inclusive) in Section 4.2.
Outer Electrode
Central Marker
Inner Electrode
Half Size Sample Paper
Outer Electrode
Central Marker
Inner Electrode
Quarter Size Sample Paper
Outer Electrode
Central Marker
Inner Electrode
22 mm Wide Sample Paper

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4.4 Interpreting the readings
In most practical situations where measurements of surface salt contamination
are required, it is unlikely that the precise ionic make-up of the contamination
will be known.
The Elcometer 130 SCM400 is calibrated against known concentrations of the
most common constituent of atmospheric contamination, namely sodium
chloride.
However, the specific resistivities of other contaminating salts do vary slightly
from that for sodium chloride and could give lower or higher readings.
To determine the accuracy of readings when the contamination does not
consist entirely of sodium chloride, test measurements have been made on the
instrument with salt mixtures which are known to be present on atmospherically
contaminated surfaces:
The results are compared with sodium chloride (Figure 4) in terms of Actual
Salt Level vs Salt Level Indicated on the Elcometer 130 SCM400.
This shows that the difference between readings for these salts and for sodium
chloride are acceptably small, particularly at levels of most interest, i.e. those
below 10 µg.cm
-2
.
Simulated Marine Contamination
BS 3900: Part F4 (Salt Spray) Simulated Urban Contamination
76.8% w/o sodium chloride
9.6% w/o magnesium sulphate
6.9% w/o magnesium chloride
3.2% w/o calcium chloride
2.1% w/o potassium chloride
0.8% w/o sodium bromide
0.6% w/o sodium bicarbonate
41% w/o ammonium sulphate
37% w/o sodium sulphate
12% w/o sodium chloride
10% w/o sodium nitrite

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If the exact make-up of the contaminant is known, calibration curves shown in
Figure 4 can be produced with solutions of known concentration. These can be
used to interpret readings more accurately.
Figure 4. Readings obtained with Different Salts
(All Measurements taken at 25°C)
Temperature could affect readings taken. The Elcometer 130 SCM400 has
been calibrated with sodium chloride at 25°C. Figure 5 illustrates the small
variation that might be expected in the range 15°C to 35°C. In most cases it is
likely that this variation will not be significant. However, the temperature can be
corrected by using the graphs given in Figure 5 and as detailed in “Technical
specification” on page 19.
The proportion of the soluble salt present on the surface being tested which is
removed by the sample paper will also affect readings. This factor is common
to all surface sampling methods. Tests have shown that removal rates are as
follows:-
Smooth machined surfaces: >95%
Grit blasted steel (to Swedish Standard >85%
Sa3) with a surface profile of 100 µm:
For coarser surface finishes: 70% (approximately)
0
24
10
8
6
16
14
12
18
20
2
10
8
6
4
14
12
18
16
20
SODIUM CHLORIDE
MARINE CONTAMINATION
URBAN CONTAMINATION
S
A
L
T
L
E
V
E
L
R
E
A
D
I
N
G
(µgcm-2)
ACTUAL SALT LEVEL
(µg cm -2)

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If surfaces are heavily pitted (i.e. >1000 µm) it is possible that soluble salts will
be retained within the pits. If so, following the qualitative Potassium
Ferricyanide test (BS 5493- Appendix G) would aid interpretation on carbon
steel and low alloy steel surfaces. This test will only work on ferritic steel
surfaces.
Figure 5. Readings obtained at Various Temperatures
with Sodium Chloride
0
24
10
86
16
14
12
18
20
2
10
8
6
4
14
12
18
16
20
S
A
L
T
L
E
V
E
L
R
E
A
D
I
N
G
(
µ
g
c
m
-
2
)
ACTUAL SALT LEVEL
(µg cm -2)
35°C
15°C
25°C

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5 CARE AND MAINTENANCE
The Elcometer 130 SCM400 does not contain any user-serviceable
components. In the unlikely event of a fault, return the Elcometer 130 SCM400
to your Elcometer supplier or directly to Elcometer. The warranty will be
invalidated if the instrument has been opened.
Contact details can be found:
• On the outside cover of these operating instructions.
• At www.elcometer.com
Please note that the back plate of the Elcometer 130 SCM400 should not be
removed by the User - doing so could affect the calibration.
5.1 Checking calibration
The Elcometer 130 SCM400 has been factory calibrated and cannot be
calibrated by the User.
However, it is possible to check that the instrument is measuring correctly. To
do this, take samples as detailed in “Taking samples using standard sample
papers” on page 5, but using precisely 1.5 ml of a solution of 31.6 mg (±0.1)
analar sodium chloride, dissolved in 100 ml of high purity water.
The reading should be in the range 5 µg.cm
-2
(±10%) at 25°C.
For temperatures below 25°C apply a correction factor of -1.7%/°C.
For temperatures above 25°C apply a correction factor of +1.7%/°C.
Note: When finished, thoroughly clean the syringe using high purity water.
5.2 Checking water quality
Water quality can be checked on the Elcometer 130 SCM400 as follows:-
1. Switch the Elcometer 130 SCM400 on by pressing the red pushbutton
once. The display will show:-
2. Eject 1 ml of the water in question onto the electrode surface using the 2 ml
syringe (Figure 2).
3. Close the lid and press the green pushbutton.
4. If a reading other than SALT LEVELS TOO LOW is obtained, then the water
purity is not adequate for use with the Elcometer 130 SCM400
SCM........Ready

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5.3 Checking purity of sample papers
Sample papers can be checked as follows:-
1. Put on a pair of clean disposable gloves.
2. Fill the 2 ml syringe with precisely 1.5 ml of high purity water.
3. Using tweezers, remove the sample paper to be checked from the pack.
4. Use tweezers to hold the sample paper and eject 1.5 ml of high purity water
onto its surface, retaining as much water as possible on the paper (Figure
2).
5. Switch the Elcometer 130 SCM400 on by pressing the red pushbutton
once. The display will show:-
6. Place the sample paper on the concentric electrodes and follow steps 5 to
10 (inclusive) in Section 4.2.
If a reading other than SALT LEVELS TOO LOW is obtained the sample paper
is too contaminated for use and should be discarded.
5.4 Removing and cleaning or replacing the electrodes
1. Remove the electrode and gasket by releasing the four retaining screws
(Figure 6).
2. To clean the electrode: Wipe the electrode, gasket, pressure plate and the
electrode well with clean tissues, ensuring all are properly dry.
3. When refitting or replacing the electrode ensure that the four retaining
screws are below the surface of the electrode.
5.5 Removing discolouration from electrode surfaces
During use, the electrode will become slightly discoloured due to surface
oxidation. This does not significantly affect operation of the Elcometer 130.
However, long term use may create heavier corrosion of the electrode surface.
This will be particularly obvious on the central electrode where a dark brown
ring will form, initially at the edge of the electrode and gradually increasing in
surface coverage. This could slightly affect the accuracy of the Elcometer 130
SCM400 and should be removed by gentle rubbing with a very fine abrasive
paper (1200 grit).
Over a period of time, or by rubbing too hard with the abrasive paper, the
electrodes may become damaged and should then be replaced - see
“Removing and cleaning or replacing the electrodes” on page 14.
SCM........Ready

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5.6 Replacing the pressure plate support pads
The pressure plate is held in position by a series of self adhesive support pads
between the plate and the underside of the lid (Figure 6).
These pads ensure that the correct pressure is applied to the sample paper
surface by the pressure plate. If these pads lose their adhesive properties they
can be replaced as follows:-
1. Gently lever the pressure plate away from the lid.
2. Remove the remains of the support pads.
3. Remove any remaining adhesive with methylated spirits.
4. Remove the protective paper from one side of four replacement pads.
5. Place them on the underside of the lid in the same places as the old ones
were removed from.
6. Remove the protective paper from the other side of the pads carefully
position the pressure plate in the centre of the lid recess.
7. Apply firm pressure to the plate to achieve adhesion.
8. Thoroughly clean the electrode and pressure plate surfaces - see
“Removing and cleaning or replacing the electrodes” on page 14.
5.7 Replacing the battery
It is essential that alkaline batteries
d
are used in the Elcometer 130 SCM400.
The battery compartment is under the name plate on the underside of the
instrument.
Replace the battery by removing the six screws and fit the new battery, ensuring
correct polarity.
5.8 Storage
This meter incorporates a Liquid Crystal Display. If the display is
heated above 50°C (120°F) it may be damaged. This c an happen if the
meter is left in a car parked in strong sunlight.
d. Alkaline batteries must be disposed of carefully to avoid environmental contamination.
Please consult your local environmental authority for information on disposal in your
region. Do not dispose of any batteries in fire.

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Figure 6. Replacement parts

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6 FAULT DIAGNOSIS
There are no User serviceable parts inside this instrument and the back plate
should not be removed. If faults of this nature are suspected, please contact
Elcometer or your local Elcometer supplier.
Faults that may occur which can be corrected by the User are detailed in the
Table below.
Fault Cause Remedy
Erratic salt level
readings Battery level too low Replace battery.
See Section 5.7
‘Replace Battery’
message Battery level too low Replace battery.
See Section 5.7
Salt level readings
are indicated when
no sampling paper
is on the electrode
Water may be underneath the
electrode Remove and dry electrode.
See Section 5.4
Pressure plate
becomes detached Support pads have lost their adhesion Replace support pads.
See Section 5.6
Salt level readings
are higher than
expected
Contaminated pressureplateor
electrode Clean the surface of the electrode and pressure plate.
See Section 5.4
Water conductivity is too high
(i.e. >0.25 µS.cm
-1
)Check the quality of the water.
See Section 5.2
Sample papers are
contaminated Check the sample papers.
See Section 5.3
Electrodes are
heavily discoloured Oxidation/corrosion due to salt solutions Thoroughly clean the electrode.
See Section 5.4

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7 SPARES AND ACCESSORIES
High Purity Sample Papers: T1304469- (pack of 100)
Disposable Gloves: T1304470-
Self-Seal Plastic Bags: T1304471- (pack of 100)
Tissues: T1304472-
2 ml Syringe: T1304473-
Set of Plastic Tweezers: T1304474-
250 ml High Purity Water: T99911344-
to BS 3978
Electrode: T1304476-
Pressure Plate: T1304477-
Pressure Plate Support Pads: T1304475- (pack of 8)
8 RELATED EQUIPMENT
In addition to the Elcometer 130 SCM400 Salt Contamination Meter, Elcometer
produces a wide range of other equipment for testing and measuring the
characteristics of coatings. Users of the Elcometer 130 may also benefit from
the following Elcometer products:
• Elcometer 134A Chloride Ion Test Kit for Abrasives
• Elcometer 134S Salt Detection Kit for Blast Cleaned Surfaces
• Elcometer 134W Chloride Ion Test Kit for Water/Liquids
• Elcometer 138 Bresle Kit and Patches
• Elcometer 138/2 Surface Contamination Kit
For further information contact Elcometer Limited, your local supplier or visit
www.elcometer.com