Surface Preparation & Treatment

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Prepared & Presented by Technical Service – PT. HEMPEL Indonesia

1 - OIL & GREASE Suitable DETERGENT + WATER

2 - SOLUBLE SALT WATER Washing (WATER JETTING)

3 - DUST VACUUM Cleaning

4 - MOISTURE HEATING & VENTILLATION

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MILLSCALE & RUST Abrasive BLASTING, Water Jetting, TOOL Cleaning

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SURFACE BLAST CLEANING STANDARD

ISO 8501- 1 and/or SSPC Visual 1

SURFACE ROUGHNESS or ANCHOR PROFILE

ISO 8503 – 1 (Comparator Gages)

SURFACE CHLORIDES or SOLUBLE SALTS

ISO 8502 – 6 & 9 (Bresle Method)

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1. Compressor

2. Supply Air

3. Blasting Pot

4. Blasting Hose

5. Deadman Switch

6. Air Filters

7. Oil/Water Trap

8. Venturi Nozzle

9. Blasting Grit

10.PPE, Ventilation &

Air Filters

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Old Paint Removal

Rust Removal

Blast Cleaning Equipment

Blasting Abrasive

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MATERIALS

NEEDED

Use any dry, white absorbent material, such as several layers of cheese

cloth or a piece of white blotter paper.

STEP 1.0 Test the air supply at an outlet that is downstream from oil & moisture

traps & as close as possible to the equipment using the air. Hold the

blotter or test material in the air stream for a minimum of 2 minutes. The

blotter or test material should be held within a distance of 24 inches

from the source of air stream being tested.

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STEP 1.1 If air from the abrasive blast nozzles is being tested, make sure that the

abrasives source is cut off & that only air is coming out of the nozzle,

prior to holding the blotter of test material in front of the nozzle.

STEP 1.2 If air is being discharged at several locations drawing from a common

manifold source, it is necessary to test the air cleanliness at each

location. The test should be run at each point of use if more than 100

feet of air hose is used or if several distant, several outlet locations are

used.

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STEP 2.0 Examine the test material immediately after the test is completed for

evidence of contamination, oil or moisture. Examination should be

made visually, as well as by feeling & smelling the test material.

FREQUENCY

OF TEST

Air supply should be tested at the frequency intervals specified for the

work. It should always be tested prior to use & at least once every 4

hours thereafter, during continuous compressor operation. When the

%RH is high, more frequent testing would be in order, since there is

more moisture in the air. If compressor operation is interrupted for

longer than 5 minutes, the air supply should be retested prior to use,

since condensation can form in the air distribution lines.

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INSPECTION

CRITERIA

ACCEPT

NO evidence of contamination, oil or moisture when blotter or test

material is examined visually & by touch. NO characteristic oil “ODOR”.

INSPECTION

CRITERIA

REJECT

Moisture beads, discoloration, or WET appearance where blotter or test

material was held in the main stream.

Test material feels WET or OILY to the touch.

Characteristic oil ODOR.

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Rust Grade A

Adherent Mill Scale

Rust Grade B

Mill Scale + Rust

Rust Grade C

100% Rust / Corrosion

Rust Grade D

Pitted Rust

Note : Extract from Pictorial Standards – ISO 8501-1

A – Sa 3

B – Sa 3

C – Sa 3

D – Sa 3

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D – Sa 2.5

B – Sa 2.5

C – Sa 2.5

A – Sa 2.5 A – Sa 2

B – Sa 2

C – Sa 2

D – Sa 2

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D – Sa 1

C – Sa 1

B – Sa 1

A – Sa 1

A – St 3

B – St 3

C – St 3

D – St 3

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Power Jig

Needle Gun

Peening Hammer

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Scraper

Needle Gun

Power Steel Brush

Hand Steel Brush

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Power Grinder / Cutter

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A – St 2

B – St 2

C – St 2

D – St 2

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ISO 8501-1 SSPC (Steel

Structure Painting

Council)

DESCRIPTION

Sa 1 SP 7 Brush-Off or Sweep Blast Cleaning

Grade

- SP 1 Solvent Cleaning

Sa 2 SP 6 Commercial Blast Cleaning Grade

Sa 2 ½ or Sa 2.5 SP 10 Near White Metal Blast Cleaning Grade

Sa 3 SP 5 White Metal Blast Cleaning Grade

St 2 SP 2 Hand or Manual Tool Cleaning Grade

St 3 SP 3 Mechanical or Power Tool Cleaning

Grade

- SP 11 Combined Hand or Power Tool Cleaning

Grade (Create a 25 microns Profile)

Note : Indicative closest/nearest equivalent only between SSPC with ISO. Refer

to actual pictorial standards and detailed description. Both standards are viewed

without magnification.

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SURFACE TYPE Sa 2.5 / SP 10

Near White Metal

Sa 3 / SP 5

White Metal

New Steel

Rust Grades A & B

Kilogram/

Meter2

Meter2 /

Man-Hour

Kilogram/

Meter2

Meter2 /

Man-Hour

SMOOTH 40 9 60 6

NORMAL 45 8 65 5.5

COMPLICATED 60 6 80 4.5

Note: Capacity = Kilogram per Square Meter & Consumption = Square Meter per Man

Hour. Indicative values only using mineral grit abrasives.

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STEEL

Surface Roughness, Rz = Arithmetical Mean or Average of the 5 points Valleys (V)

and 5 points Peaks (P)

Note: Surface Roughness or Anchor Profile are expressed in 3 values:

Rz, Ra and Ry or Rmax.

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Sharp / Angular

Dimpled/ Rounded

Medium

Less/ Low

Medium Coarse

Depth = 40 – 75

microns Rz

Note: Grit create sharp & angular profile while shot create dimpled & rounded

Profile. High profiles result to increase in primer consumption known as

DEAD VOLUME due to increased surface area & porosity.

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0

20

40

60

80

100

120

140

160

180

Rugotest

No. 3

ISO

8503G

Keane-

Tator

G/S

0

25

50

75

100

125

150

175

200

Note : Rugotest No. 3 – Swiss origin (Ra), ISO 8503 G (Grit) & Keane Tator

- US origin G/S (Grit & Shot), both are Rz values.

25 – 180 microns 25 – 150 microns 35 – 140 / 10 – 100 microns

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1 – Rugotest No. 3 Comparator

2 – Keane-Tator G/S Comparator

3 – ISO 8503G Comparator

4 – Profile Needle Gage (Direct)

5 – Replica Testex Tape & Micrometer

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e

Checking profile of blast cleaned steel surfaces

with Keane-Tator Comparator & Light Magnifier. ISO 8503G Comparator consists of4-segments

(quadrant) indicating surface profiles/ roughness

ranging from fine to coarse for visual (or magnified)

comparison.

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1 – Using a fingernail, feel the Surface

Roughness created on a new blast cleaned

steel (biting sensation). Ensure to cover all

surfaces and make at least 2-3 times feel.

2 – Compare the Surface Roughness felt on a

new blast cleaned steel (biting sensation)

against with the comparator corresponding

Roughness using the fingernail. Repeat the

steps 2-3 times until a closest comparison

or similarity is achieved.

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Step 1 – Testex Replica Tape – Take surface

Profile imprint on the blast cleaned surface

using a Testex replica tape by affixing on the

surface and by rubbing using a plastic pointer

with rounded end or pencil rubber eraser.

Step 2 – Micrometer – Remove tape carefully

and check surface profile imprint on the

tape using Micrometer. Ensure to zero the

Micrometer and deduct the thickness of the

Tape (eg. 2 mils or 50 microns), this will give

the profile reading. Keep tape for record.

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BRESLE’ Method Field Test Kit

1 – Bresle Sampler Extraction Cell

2 – Syringes

3 – Distilled Water (with Zero

Conductivity)

4 – Pocket Conductivity Meter (Digital)

5 – Steel Surface Dial Thermometer

(with Magnetic back)

6 – Blast Cleaned Steel Surface

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Step 1

Carefully open a

BRESLE sampler cell

& remove backing.

Step 2

Carefully affix the

BRESLE sampler cell

on blast cleaned

steel surfaces.

Step 3

Remove the entrapped

air inside the cell

using the syringe to

create vacuum.

Step 4

Open a bottle of the

Distilled water and

fill in the syringe

approx. 25 ml.

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Step 6

Carefully extract the

distilled water from

the cell with the

syringe. Ensure that

same volume is

extracted.

Step 7

Transfer the extracted

water into the clean

Conductivity Meter

sampling cup.

Step 8

Measure out the

conductivity of the

extract with the

Conductivity Meter.

Record & run a blank.

Step 5

Inject & fill-in with 25 ml

of distilled water into

the cell with the syringe.

Massage lightly the cell

to stir for 1-2 minutes.

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Conductivity,

mS/m* @ 20 oC

Equiv.

Chloride

microgram /

cm2 @ 20oC

Equiv. NaCl

microgram /

cm2 @ 20oC

Remarks

0.50 0.70 1.00 mS = Micro

Siemens

1.00 1.30 2.10

2.00 2.60 4.20

3.00 3.90 6.20

4.00 5.20 8.30

5.00 6.50 10.40

5.30 7.00 11.20

5.50 7.20 11.40 Maximum

Limit

6.00 7.80 12.50

Temperature of

Water, oC

Correction

Factor

15.0 1.10

17.5 1.05

20.0 1.00

22.5 0.95

25.0 0.90

NOTE:

Always run a blank test with the distilled

water used for salt extraction & check

both water temperature & conductivity

Temperature Corrected Conductivity , mS/m = Actual Water Temperature x

Correction Factor @20 degree C. Conductivity Reading – Blank Conductivity.

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Checking the pH value (Alkalinity

and/or Acidity of the surface using

Litmus Indicator Strip & compare

with the table to determine the

approx. quantitative value.

pH = below 7.0 (Acidic)

pH = 7.0 (Neutral)

pH = above 7 to 14 (Alkaline)

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