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Elcometer 130 SCM400

Salt Contamination Meter

Operating Instructions

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The Elcometer 130 SCM400 Salt Contamination Meter has beentested in acccordance with EU regulations governing Electro-magneticcompliance 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 anylanguage, in any form or by any means (electronic, mechanical, magnetic,optical, manual or otherwise) without the prior written permission ofElcometer Limited.

Doc.No. TMA-0125 Issue 05Text with Cover No: 4373

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hCONTENTS

Section Page

1 About your meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.1 Standards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.2 What the box contains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2 Principle of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3 Specification of salt levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4 Taking a reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54.1 Before you start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54.2 Taking samples using standard sample papers. . . . . . . . . . . . . . . . . . . . 54.3 Taking samples using smaller sample papers . . . . . . . . . . . . . . . . . . . . . 84.4 Interpreting the readings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

5 Care and maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135.1 Checking calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135.2 Checking water quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135.3 Checking purity of sample papers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145.4 Removing and cleaning or replacing the electrodes . . . . . . . . . . . . . . . 145.5 Removing discolouration from electrode surfaces . . . . . . . . . . . . . . . . . 145.6 Replacing the pressure plate support pads . . . . . . . . . . . . . . . . . . . . . . 155.7 Replacing the battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155.8 Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

6 Fault diagnosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

7 Spares and accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

8 Related equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

9 Technical specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

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h hank you for your purchase of this Elcometer 130 SCM400 SaltContamination Meter. Welcome to Elcometer.

Elcometer are world leaders in the design, manufacture and supply ofinspection equipment for coatings and concrete.

Our products cover all aspects of coating inspection, from development throughapplication to post application inspection.

The Elcometer 130 SCM400 Salt Contamination Meter is a world beatingproduct. With the purchase of this product you now have access to theworldwide service and support network of Elcometer. For more information visitour website at www.elcometer.com

1 ABOUT YOUR METERThe Elcometer 130 SCM400 Salt Contamination Meter measures saltcontamination levels on metallic and non-metallic surfaces and is particularlyuseful on areas such as bends and welds.

1.1 StandardsThe instrument can be used in accordance with the following InternationalStandard :

• 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

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h2 PRINCIPLE OF OPERATIONSoluble salts on the surface are taken into solution by placing a wetted 110 mmdiameter Elcometer 130 SCM400 High Purity Sample Paper on the area to besampled.

By leaving the paper in contact for a timed period, salt removal from the surfaceis maximised. Using a paper of known size allows contamination to beexpressed in terms of surface area.

These papers retain a known amount of water because of their consistentabsorbency characteristics and therefore the concentration of the solutionformed is related to the quantity of soluble salts removed.

The sample paper containing the salt solution is placed over the electrodes onthe Elcometer 130 SCM400 and its resistivity is determined. This is achieved bymeasuring the minimum resistance of the solution over a fixed solution pathlength and cross section, governed by the electrode spacing and paperthickness respectively.

The solution concentration is inversely proportional to its resistivity. TheElcometer 130 SCM400 relates the latter to a calibration with known

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h concentrations of sodium chloride solution and the known surface areasampled, to give surface salt levels in µg.cm-2.

Figure 1. Elcometer 130 SCM400 Salt Contamination M eter

3 SPECIFICATION OF SALT LEVELSIdeally, the salt level remaining on a steel surface after surface cleaning andprior to painting or any other construction operation, should be zero.

In practice it is not possible to achieve this due to various environmental factorsand a working salt level needs to be specified. In the case of painting, this levelis a matter for discussion between the Client, the Applicator and the PaintManufacturer and it will depend on the working conditions, the paint systemused, the required service life and what can be economically achieved.

Consequently, it is not possible to specify in these Operating Instructions whichsalt standards are best suited to all industries. However, during thedevelopment of the Elcometer 130 SCM400, the effect of salt contamination onthe life of coatings under a range of realistic and accelerated environmentalconditions for a number of common generic coating systems was assessed.

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hAlthough Elcometer would not wish to recommend this as a specification, thework has shown that a salt level of better than 4 µg.cm-2 is a sensible workinglimit.

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 SamplePaper, follow procedure 4.2.

If the sample area is smaller than the Elcometer 130 SCM400 High PuritySample Paper, follow procedure 4.3.

4.2 Taking samples using standard sample papers1. 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

Papera from the pack.

If the standard 110 mm diameter sample paper is too large for the area tobe sampled, smaller papers may be used - see “Taking samples usingsmaller sample papers” on page 8.

a. Use only Elcometer 130 SCM400 High Purity Sample Papers. Commercial filterpapers are not suitable as they can contain excessive salt levels.

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h 4. Using the tweezers to hold the sample paper, eject 1.6 ml of water onto itssurface (Figure 2), taking care to retain as much water as possible on thepaper..

Figure 2. Applying Water to Elcometer 130 SCM400High Purity Sample Paper

5. Place wetted paper on the area to be sampled, pressing it firmly into itscontours and surface irregularities.

6. Press out as much entrapped air as possible from beneath the paper. Ifhand pressure is required to exclude air, the gloved hand should not beused. Instead, turn one of the plastic bags provided inside out, place it overthe gloved hand and press the surface, discarding the plastic bag whenfinished.

7. Switch the Elcometer 130 SCM400 on by pressing the red pushbuttononceb. The display will show:

8. When the sample paper is in position, press the red pushbutton again tostart the 2 minute timerc. The display will show:

b. When ‘SCM Ready’, ‘SALT LEVELS TOO LOW’ or ‘SALT LEVEL>20 µg.cm-2’ isdisplayed, the instrument will automatically switch off if not used within 20 seconds.

SCM........Ready

TIMER STARTED

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h9. When 2 minutes have elapsed the Elcometer 130 SCM400 emits anintermittent 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 excludedfrom 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 orwhen 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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h 14.Lift the lid and remove the sample paper. The sample paper may be kept inone of the resealable bags for further chemical analysis.

15.When all samples have been taken, switch the instrument off by pressingthe 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 papersIf the standard 110 mm diameter High Purity Sample Papers are too large forthe area to be sampled, half size, quarter size or 22 mm wide strip papers canbe used as follows. Care must be taken to ensure that sample papers do notbecome 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 foldline.

For quarter size paper fold standard paper into quarters and cut intoquadrants along fold lines.

For 22 mm wide strip fold standard paper into half and cut 11 mm eitherside 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 ontoits 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 allentrapped air is removed:

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hIf using half size papers - coverexactly half the inner and outerelectrodes.

If using quarter size papers -cover exactly quarter of the innerand outer electrodes.

If using 22 mm wide strips - laythe paper across the inner and theouter electrodes, to completelycover 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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h 4.4 Interpreting the readingsIn most practical situations where measurements of surface salt contaminationare required, it is unlikely that the precise ionic make-up of the contaminationwill be known.

The Elcometer 130 SCM400 is calibrated against known concentrations of themost common constituent of atmospheric contamination, namely sodiumchloride.

However, the specific resistivities of other contaminating salts do vary slightlyfrom that for sodium chloride and could give lower or higher readings.

To determine the accuracy of readings when the contamination does notconsist entirely of sodium chloride, test measurements have been made on theinstrument with salt mixtures which are known to be present on atmosphericallycontaminated surfaces:

The results are compared with sodium chloride (Figure 4) in terms of ActualSalt Level vs Salt Level Indicated on the Elcometer 130 SCM400 .

This shows that the difference between readings for these salts and for sodiumchloride are acceptably small, particularly at levels of most interest, i.e. thosebelow 10 µg.cm-2.

Simulated Marine Contamination BS 3900: Part F4 (Salt Spray) Simulated Urban Contam ination76.8% 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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hIf the exact make-up of the contaminant is known, calibration curves shown inFigure 4 can be produced with solutions of known concentration. These can beused 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 hasbeen calibrated with sodium chloride at 25°C. Figur e 5 illustrates the smallvariation that might be expected in the range 15°C to 35°C. In most cases it islikely that this variation will not be significant. However, the temperature can becorrected by using the graphs given in Figure 5 and as detailed in “Technicalspecification” on page 19.

The proportion of the soluble salt present on the surface being tested which isremoved by the sample paper will also affect readings. This factor is commonto all surface sampling methods. Tests have shown that removal rates are asfollows:-

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 2 4 1086 161412 18 20

2

10

8

6

4

14

12

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20SODIUM CHLORIDE

MARINE CONTAMINATION

URBAN CONTAMINATION

SA

LT L

EV

EL

RE

AD

ING

(

µg c

m -

2 )

ACTUAL SALT LEVEL (µg cm -2)

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h If surfaces are heavily pitted (i.e. >1000 µm) it is possible that soluble salts willbe retained within the pits. If so, following the qualitative PotassiumFerricyanide test (BS 5493- Appendix G) would aid interpretation on carbonsteel and low alloy steel surfaces. This test will only work on ferritic steelsurfaces.

Figure 5. Readings obtained at Various Temperatureswith Sodium Chloride

0 2 4 1086 161412 18 20

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8

6

4

14

12

18

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20

SA

LT L

EV

EL

RE

AD

ING

(

µg c

m -

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ACTUAL SALT LEVEL (µg cm -2)

35°C

15°C

25°C

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h5 CARE AND MAINTENANCEThe Elcometer 130 SCM400 does not contain any user-serviceablecomponents. In the unlikely event of a fault, return the Elcometer 130 SCM400to your Elcometer supplier or directly to Elcometer. The warranty will beinvalidated 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 beremoved by the User - doing so could affect the calibration.

5.1 Checking calibrationThe Elcometer 130 SCM400 has been factory calibrated and cannot becalibrated by the User.

However, it is possible to check that the instrument is measuring correctly. Todo this, take samples as detailed in “Taking samples using standard samplepapers” 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 qualityWater quality can be checked on the Elcometer 130 SCM400 as follows:-

1. Switch the Elcometer 130 SCM400 on by pressing the red pushbuttononce. The display will show:-

2. Eject 1 ml of the water in question onto the electrode surface using the 2 mlsyringe (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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h 5.3 Checking purity of sample papersSample 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 (Figure2).

5. Switch the Elcometer 130 SCM400 on by pressing the red pushbuttononce. The display will show:-

6. Place the sample paper on the concentric electrodes and follow steps 5 to10 (inclusive) in Section 4.2.

If a reading other than SALT LEVELS TOO LOW is obtained the sample paperis too contaminated for use and should be discarded.

5.4 Removing and cleaning or replacing the electrod es1. 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 surfacesDuring use, the electrode will become slightly discoloured due to surfaceoxidation. 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 brownring will form, initially at the edge of the electrode and gradually increasing insurface coverage. This could slightly affect the accuracy of the Elcometer 130SCM400 and should be removed by gentle rubbing with a very fine abrasivepaper (1200 grit).

Over a period of time, or by rubbing too hard with the abrasive paper, theelectrodes 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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h5.6 Replacing the pressure plate support padsThe pressure plate is held in position by a series of self adhesive support padsbetween the plate and the underside of the lid (Figure 6).

These pads ensure that the correct pressure is applied to the sample papersurface by the pressure plate. If these pads lose their adhesive properties theycan 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 batteryIt is essential that alkaline batteriesd are used in the Elcometer 130 SCM400.

The battery compartment is under the name plate on the underside of theinstrument.

Replace the battery by removing the six screws and fit the new battery, ensuringcorrect polarity.

5.8 StorageThis meter incorporates a Liquid Crystal Display. If the display isheated above 50°C (120°F) it may be damaged. This c an happen if themeter 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 yourregion. Do not dispose of any batteries in fire.

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Figure 6. Replacement parts

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h6 FAULT DIAGNOSISThere are no User serviceable parts inside this instrument and the back plateshould not be removed. If faults of this nature are suspected, please contactElcometer or your local Elcometer supplier.

Faults that may occur which can be corrected by the User are detailed in theTable 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 pressure plate or 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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h 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 EQUIPMENTIn addition to the Elcometer 130 SCM400 Salt Contamination Meter, Elcometerproduces a wide range of other equipment for testing and measuring thecharacteristics of coatings. Users of the Elcometer 130 may also benefit fromthe 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 visitwww.elcometer.com

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h9 TECHNICAL SPECIFICATION

Chemical

Measuring range: 0.1 µg.cm-2 to 20 µg.cm-2 soluble salt (assodium chloride) when using recommendedHigh Purity Sample Papers and water with aconductivity of <0.25 microsiemens

Resolution: 0.1 µg.cm-2 (with sodium chloride)

Measuring accuracy: ±10% of reading

Temperature correction: Calibrated at 25°CBelow 25°C: -1.7% /°CAbove 25°C: +1.7% /°C

Electrical

Electrodes: Copper

Display: 20 digit LCD

Sampling timer: 2 minutes

Battery: 9 V Alkaline PP3 (6LR61)

Timeout: 20 seconds

Working limits

Temperature range: 5°C to 40°C

Maximum relative humidity: 80%

Physical

Dimensions: 200 mm x 190 mm x 60 mm

Weight: 1.5 kg

Case: Damage resistant polyurethane

Sealing: Splash proof

Sampling capability

Substrate: Metallic or non-metallic

Area required: 110 mm diameter

Position: Any horizontal, vertical, curved or inclinedsurface where sample paper can be placed

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