Conference and Exhibition

October 31-November 3, 2011

Houston Marriott West Loop, Houston, Texas, USA

 Call for paper (http://www.clarion.org/ERRP/ERRP-2011/index.php)

Papers are now invited for this international forum which will address key issues in oil and gas pipeline-rehabilitation.  The conference program will be divided into the following broad areas of interest:

• Inspection – internal and external
• Integrity assessment
• Repair and rehabilitation practices and technologies
• Internal issues – including black powder, microbial corrosion
• External issues – including coatings, DCVG, direct assessment.

The link contains additional information on the submission of abstracts and the conference.

Prepared by Lydia Frenzel from a specific Proprietary Inhibitor and Cleaner manufacturer’s sheet. Most of the manufacturers have letters or tests results from specific coatings manufacturers. If you contact me, I will send you the link to the source material.

OBJECTIVE: This document provides guidelines for testing Proprietary Inhibitor and Cleaner used according to its manufacturer’s instructions. These test guidelines are necessary because applicable ASTM test procedures specifically require that tests be conducted in a manner consistent with the manufacturer=s instructions for use of the product tested. Since the performance of the product is application sensitive, this step by step test procedure should be helpful in the evaluation of its performance in various surface preparation methods.

Background: This gives the specific background of the Proprietary Inhibitor and Cleaner.

TEST PROCEDURE: Panel Preparation Steel test panels should be used when testing for rust formation. The size of the panels may vary but generally are 3″ x 5″ x 0.25″. Ten panels per coating is generally adequate to test for both salt removal and coating adhesion. All panels, with the exception of the control panel, should be immersed for 100 hours in an 8-10% weight by weight (w/w) sodium chloride solution to accelerate rust development. The control panel which was not immersed in salt water solution will establish the baseline reading for salts and other contaminants levels. In addition to the control panel, leave one test panel out of the blast sequence to measure the salt levels deposited after 100 hours of immersion. The other eight panels will be blasted to SSPC-SP10 (NACE 2)(Near White) using the either the water-abrasive blasting method or the dry blast method.

For Water-Abrasive Blasting: Per manufacturer’s recommendation for water-abrasive blasting, Proprietary Inhibitor and Cleaner should be used in both the blast and the wash down cycles. In the blast cycle the product can be injected into the blast stream by using an injection pump at low dilution of 50:1 ratio of Proprietary Inhibitor and Cleaner to water or higher (as high as 250:1) only with potable water.

Pre-mixing of the product is also acceptable as long as the mixing ratio is the same (50 parts potable water or higher with 1 part Proprietary Inhibitor and Cleaner or higher).

In the wash down cycle in water-abrasive blasting it is critical that the mixing ratio not exceed 100:1, because the wash down cycle is the final rinse of the surface. Wash down not only cleans contaminants that were present before the blast but also removes shattered abrasive particles embedded in the surface profile during the blast cycle. These embedded particles have a potential to form rust on the surface because they are wet, may contain chlorides, sulfates, and other contaminants, and will attract oxygen in the air. Therefore, to get these particles out of the surface profile and achieve a perfectly cleaned surface a wash down is necessary.

Wash down as defined by the manufacturer should have at least 500 psi pressure @ 1-3 g.p.m. of water (potable) mixed with Proprietary Inhibitor and Cleaner at a 50:1 to 100:1 ratio (see manufacturer’s instructions).

WARNING: Dipping the test panels in Proprietary Inhibitor and Cleaner solution without using a pressure rinse will not remove the embedded abrasive particles and the salts trapped in the corrosion pits but will only wet them, virtually guaranteeing premature coating failure. Using Proprietary Inhibitor and Cleaner both in the blast and wash down cycles is a failsafe method to obtain maximum cleanliness of the substrate. After the wash down cycle is completed, allow the test panels to dry, usually 15-30 minutes, before they are coated or subjected to any other test. Failure to allow the surface to dry will also lead to premature coating failure. Understandably, for test purposes, higher than recommended concentrations may be used. The greater the concentration, the longer the drying time, but under no circumstances should a coating be applied over a wet or damp surface.

For UHP Water Jetting, waterjetting, water blasting (water with little or no abrasive at 25,000+ p.s.i.)

Typically chemicals are NOT used in the BLAST CYCLE.

Blast cycle: (optional) (applicable if, and only if, pump manufacturer approves.) Start with 250:1 Proprietary Inhibitor and Cleaner. If flash occurs, decrease water portion (increase portion) until there is no flash.

Wash down (rinse) cycle: Begin as soon as practical after the blast. If Proprietary Inhibitor and Cleaner was used in blast cycle, start with 200:1. If Proprietary Inhibitor and Cleaner was not used in blast cycle, start with 100:1. (In either case, wash downwater pressure should be at least 500 p.s.i. with a water flow rate of at least 2 g.p.m..). If the surface is highly contaminated with chlorides and/or the water is very hard (contains elevated levels of carbonates or bicarbonates) and/or the surface is deeply pitted or profiled and/or weather conditions are marginal, it may be necessary to decrease water and increase Proprietary Inhibitor and Cleaner from the recommended start ratios to 100:1 or 50:1, respectively.

For Dry Abrasive Blasting (wash down only, of course) Start with 50:1. Wash down pressure should be no less than 500 p.s.i. at 2+ g.p.m. 1,500+ p.s.i. is highly recommended to totally remove the dust and contaminants from the anchor profile. Then increase water portion (or decrease Proprietary Inhibitor and Cleaner ) until flash appears or appears before you wish it to (i.e., until your blast window is unsatisfactory.)

Three most critical points for wash downs:

1. Always use the appropriate ratio of Proprietary Inhibitor and Cleaner for the specific blasting application with potable water.

2. Always use recommended minimum pressure and flow corresponding to the blasting application used.

3. Do not dip in or brush the surface with Proprietary Inhibitor and Cleaner as a substitute for a pressurized rinse..

RECOMMENDED COATING TESTS: Test panels prepared in the earlier section can now be subjected to the following tests. These are ASTM tests, approved and recommended by both SSPC and NACE. Coating compatibility approvals of Proprietary Inhibitor and Cleaner from several coating manufacturer’s i.e. Sherwin-Williams, Carboline, Ameron, PPG, Tnemec, etc. are based on the result of these tests (please see Representative Coating Compatibility Chart). Some tests were completed at the coating company’s laboratory and some of them were conducted at an independent laboratory under the supervision of coating company corrosion specialist. The test results are available on request.

1. ASTM D 5894 – 96 Standard Practice for Cyclic Salt Fog / UV Exposure of Painted Metal, (Alternating Exposures in a Fog / Dry Cabinet and a UV / Condensation Cabinet)

2. ASTM D 4541 – 95 Standard Test Method for Pull-Off Strength of Coatings Using Portable Adhesion Testers

3. ASTM D 610 – 95 Standard Test Method for Evaluating Degree of Rusting on Painted Steel Surfaces

4. ASTM D 714 – 87 Standard Test Method for Evaluating Degree of Blistering of Paints

5. ASTM D 1654 – 92 Standard Test Method for Evaluation of Painted or Coated Specimens Subjected to Corrosive Environments

RECOMMENDED CHLORIDE REMOVAL TESTS: The following tests are recommended if the panels are tested for soluble salts or any other contaminant which Proprietary Inhibitor and Cleaner may effectively remove. These test are also described in SSPC-TU 4 – Field Methods for Retrieval and Analysis of Soluble Salts on Substrates.

1. ISO 8502-6 Bresle Sampling Method, (SSPC-TU 4, Section 3.3 – Adhesively Bonded Cell)

2. ISO 8502-5 Chloride Ion Detection Tube (SSPC-TU 4, Section 4.3 – Field Detection of Chloride Ion by Kitigawa Tube)

3. ISO 8502-1 Field Test for Iron II Salts in Abrasive Blast Cleaned Surfaces (Field Test for Soluble Iron Corrosion Products) (SSPC-TU 4, Section 4.8 Qualitative Field Detection of Ferrous Ion)

4. Quantab Strip (SSPC-TU 4, Section 4.4 – Field Detection of Chlorine Ion by Quantab Method)

 4. Based on the subjective methods, Flash Rust is classified as
           • None
           • Light
           • Moderate
           • Heavy

The following metric table was developed by Pete Ault, Elzly Technology Corporation. Click Table to enlarge.

Table of Metrics used in Flash Rust

ALL of the VISUAL GUIDES are used in the SAME WAY!
 Look at the flash rust
• straight on,
• within arm’s length,
• in good lighting,
• prior to painting.
 Allow time to remove, if necessary, excess loose flash rust prior to painting

Look at the surface and decide if you can see through the rust or if it obscures the surface.  Make sure that the rust is not splotchy black.

Look at the color.   Color can vary depending on the type of steel. The color is affected by the age and type of steel and, in the field, certainly might appear differently than the descriptive terms. Current language being adopted by NACE and SSPC will remove the COLOR language. 

Determine Quantity of loose rust dust. Lightly wipe the surface with a cloth.

The methods to evaluate Flash Rust are Subjective.
• Visual Appearance and
• Assessment of amount of Loose Dust
 Cloth Wipe in hand
 Cloth Swatch in hand
 Cloth around a Brush
 Tape

Below: the substrate is dry- but it is  darker (overall) than the original substrate.
This surface is dry within 5 minutes. The standard pictures in VIS-4 do not provide these types of illustrations of pressure-washed surfaces. The upper half is not washed; the lower half has been pressure washed.

Brush test on the Pressure Washed Surface.

Brush Test before Pressure Wash.

After Pressure Wash- there is very little faint color on cloth
After pressure washing the substrate, there is a faint marking at the upper edge of the cloth where the brush bristles contacted the surface.
The area has been mitigated from moderate to light flash rust.

 Prior to the application of paint, the substrate must meet the procurement specifications.
 Typical field remediation includes:
 Pressure washing
 Broom brushing
 Blowing off with pressurized air
 Solvent cloth or dry cloth wiping
 Vacuum

Upon polling contractors, it appears that pressure washing is the preferred practice. The appearance after pressure washing when the surface dries will be DIFFERENT; rust dust is washed away.  Typically the surface has a darker appearance.  The metallic sheen might disappear.  The standard pictures in VIS-4 do not provide illustrations of pressure-washed surfaces.
In the first two pictures, the substrate was pressure washed (ca 1000 psi) to remove the loose dust so that the substrate would meet a “light” flash rust requirement..
The substrate dried in a few minutes.  Flat surface can take longer to dry.

INSPECT the AREA AFTER PRESSURE WASHING.
Note that the loose dust is removed.
However, the stains on the right have remained.
The inspector, contractor, paint manufacturers, and owners (all the responsible parties in a coatings project) should note streaked areas and obvious runs. 

In this example, the source of the water that created the original flash rust came from a hole in the ship that most likely had salts or oil and greases.  Special attention should be given to those areas. Look to the project specifications as to what other inspections might be required.

At the right, notice that some areas are not washed, some have dried, and some are still drying.

Here are more pictures showing the same type of situation, where some areas are not yet washed, some are dry, and some are still drying.

Close up of area on right in picture above.

To Repeat: the inspector, contractor, paint manufacturers, and owners (all the responsible parties in a coatings project) should note streaked areas and obvious runs. 

In this example, the source of the water that created the original flash rust came from a hole in the ship that most likely had salts or oil and greases.  Special attention should be given to those areas. Look to the project specifications as to what other inspections might be required.
All the defects can be seen.  There are stains, but NO loose rust dust.

All the defects can be seen.  There are stains, but NO loose rust dust.

This is the result of the Brush Wipe Test on Heavily Stained & Heavy Flash Rust Area

Before Pressure Washing

Before Pressure Washing.

After Pressure Washing. Hand wiping test.

After Pressure washing. Brust test.

A direct comparison between hand wipe and brush test on pressure washed moderate flash rust indicates no differences.

 Easy to prepare the swatches.
 Keeps a constant light pressure.
 Gives a clear distinction between light, moderate, and heavy.
 The color transfers to only the cloth that is in contact with the surface. It can be difficult to interpret the various spots of color.

 Make a bundle of cloth in your hand.
 Swipe the dry cloth across the surface.
 Make one swipe, up or down or sideways with the cloth touching the surface.
 Try to avoid pressing the fingers against the surface.

The following four pictures are examples of hand held wips and light flash rust.

Close up of two Light Flash Rust cloths.

In the two pictures above, the top one shows transference where the fingertips met the surface. There might be some color, but not much.