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A-1 The Society for Protective Coatings (SSPC) Technology Guide 15, Field Methods for Extraction and Analysis of Soluble Salts on Steel and Other Nonporous Substrates A P P E N D I X A
A-2 SSPC-Guide 15 August 21, 2013 SSPC: The Society for Protective Coatings Technology Guide 15 Field Methods for Extraction and Analysis of Soluble Salts on Steel and Other Nonporous Substrates 1. Scope 1.1 methods for the extraction and analysis of soluble salts on steel and other nonporous substrates. Laboratory methods are only included for situations where more complete salt extrac- tions are desired through rigorous laboratory retrieval and analysis protocols. 2. Description and Use 2.1 INTRODUCTION: Coatings applied on surfaces contaminated with soluble salts exceeding a certain concentration exhibit diminished performance. Likewise, self-passivating metals (not intended for coating such as stain- less steel, aluminum and copper) can be compromised from elevated concentrations of residual soluble salts in corrosive environments. Soluble salt testing involves two basic steps: 1) extraction of salts from the surface into a solution and 2) the analysis of the solution. This Guide is intended to assist performing qualitative and/or quantitative soluble salts from measuring total conductivity (fully automated or multi-step) and soluble salt extraction and testing. An overview of available surface concentration calculations are provided in Tables 1 of salt removal (also called extraction) from the metal surfaces of interest are provided in Appendix C. 2.1.1 Abbreviations: Cl-1 chloride ion cm3 cubic centimeters cm2 square centimeters Fe+2 ferrous ion ÂµS microSiemens ÂµS/cm microSiemens per centimeter mg milligram ml milliliter ppm parts per million NaCl sodium chloride NO3 -1 nitrate ion SO4 -2 sulfate ion 2.2 SALT EXTRACTION SOLUTIONS All of the reagents used to extract salts from metal surfaces in this document fall into two categories: reagent water and proprietary aqueous solutions. They will be designated herein as reagent water or proprietary extraction solution. 2.2.1 Reagent Water: Reagent water used for salt extrac- tion should have a maximum conductivity of 5 ÂµS/cm. Distilled the conductivity is recommended. Alternatively, a portable demineralizer may be used to make reagent water on site. Pour tap water into the plastic bottle, attach the demineralizer cartridge in the direction indicated, invert, and squeeze out the desired amount of water (for many of the tests described below, at least 25 ml will be required). The cartridge can be used until the blue color turns brown, as indicated on the side of the cartridge. Once this occurs, replace the cartridge. Each cartridge should deionize approximately 3000 ml of water. 2.2.2 Proprietary Solutions: Proprietary extraction solu- tions may be included with some commercial test kits. These solutions should only be used for the soluble salts described in the kit instructions. Proprietary solutions are not suitable for measuring conductivity of extracted solutions. 3. Referenced Standards The standards listed below are updated on a periodic basis. The user of this guide should consult the most recent revision. 3.1 SSPC STANDARDS AND JOINT STANDARDS: SP 5/NACE No. 1 White Metal Blast Cleaning 3.2 ASTM INTERNATIONAL STANDARDS1 ASTM D4327 Standard Test Method for Anions in Water by Chemically Suppressed Ion Chromatography ASTM D512 Standard Test Methods for Chloride Ion In Water 1 ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959. For referenced ASTM standards, visit the ASTM website, <http://www.astm.org>, or contact ASTM Customer Service at <firstname.lastname@example.org>. For Annual Book of ASTM Standards volume information, refer to the standardâs Document Summary page on the ASTM website. This Guide describes the most commonly used field the user in selecting specific procedures for extracting and steel and nonporous surfaces. It includes field methods for specific ions. It also offers guidance for destructive laboratory field and laboratory techniques, methods of salt extraction and and 2 respectively. A discussion and sources on the efficiency water may be purchased at grocery stores but verification of
A-3 SSPC-Guide 15 August 21, 2013 3.2 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION (ISO) STANDARDS:2 ISO 8502 Preparation of steel substrates before application of paints and related products â Tests for the assessment of surface cleanlinessâ Part 2 Laboratory determination of chloride on cleaned surfaces (ISO 8502-2) Part 5 Measurement of chloride on steel 2 International Organization for Standardization (ISO), Case Postale 56, Geneva CH-1211, Switzerland. ISO standards may be obtained through the American National Standards Institute, 1819 L Street, NW, Suite 600, Washington, DC 20036 (www.ansi.org). surfaces prepared for paintingâIon detection tube method (ISO 8502-5) Part 6 Extraction of soluble contaminants for analysisâThe Bresle method (ISO 8502-6) Part 9 Field method for conductometric deter- mination of water-soluble salts (ISO 8502-9) Part 12 Field method for the titrimetric deter- mination of water-soluble ferrous ions (ISO 8502-12) TABLE 1 OVERVIEW OF FIELD METHODS FOR RETRIEVAL AND ANALYSIS OF SOLUBLE SALTS FROM STEEL AND OTHER NONPOROUS SURFACES Methodology (see section number for more detail) Surface Sampling via Extraction Medium (Applicable ISO Standard) Analysis of Extracted Sample Calculating Surface Concentrations of Ions (also refer to Appendix A or B) 4. Field Methods Measuring Conductivity 4.1 Fully Automated Conductivity Measurement Techniques 4.1.1 Soluble Salt Meter Employs Reagent Water for Extraction Manufacturer Calibration Magnetic Surface Attachment Integrated Conductivity Sensor Reported as conductivity ÂµS/cm mg/m2 (ISO 8502-9) mg/m2 as NaCl (IMO PSPC) 4.1.2 Surface Salinity Meter Employs Reagent Water for Extraction Manufacturer Calibration Magnetic Surface Attachment Integrated Conductivity Sensor Reported as conductivity ÂµS/cm mg/m2 (ISO 8502-9) Âµg/cm2 as chlorides 4.1.3 Continuous Flow Extraction Fiber Strip Employs Reagent Water for Extraction Manufacturer Calibration. User accuracy check provided. No-Residue Tape Surface Attachment Integrated Conductivity Sensor Reported as conductivity ÂµS/cm mg/m2 (ISO 8502-9) Âµg/cm2 total salts per ISO 8502-9 4.2 Multi Step Conductivity Measurement Techniques 4.2.1 Surface Swab or Wash Employs Reagent Water for Extraction (ISO 8502-2, Sections 5 and 6) Probe-Type Conductivity Meter Conductivity reported as ÂµS/cm (ISO 8502-9). 4.2.2 Adhesively Bonded Latex Patch or Cell Employs Reagent Water for Extraction (ISO 8502-6) Probe-Type Conductivity Meter Conductivity reported as ÂµS/cm (ISO 8502-9). 4.2.3 Saturated Special Filter Paper With Concentric Ring Conductivity Meter Employs Reagent Water for Extraction Concentric Ring Conductivity Meter Conductivity reported as Âµg/cm2, mg/cm2, ÂµS/cm, ppm, % salinity.
A-4 SSPC-Guide 15 August 21, 2013 TABLE 1 OVERVIEW OF FIELD METHODS FOR RETRIEVAL AND ANALYSIS OF SOLUBLE SALTS FROM STEEL AND OTHER NONPOROUS SURFACES Methodology (see section number for more detail) Surface Sampling via Extraction Medium (Applicable ISO Standard) Analysis of Extracted Sample Calculating Surface Concentrations of Ions (also refer to Appendix A or B) 5.1 Fully Automated Methods 5.2.1 Chloride Ion Paper Strip Test of Swab/Wash or Latex Patch/Cell Extracts Employs Reagent Water for Extraction Swab: ISO 8502-2, Sections 5 and 6) (Latex Patch/Cell: ISO 8502-6) Commercially Available Kit. Convert âQuanTab Unitsâ to ppm per manufacture instructions. Convert solution concentration as ppm to surface concentration (Âµg/cm2) per Appendix A. Calculation of surface Cl-1 from swab as Âµg/cm2 (Cl-1 as ppm quantity of water used in ml) area sampled in cm2 5.2.2 Chloride Ion Detection Tube Test of Swab/ Wash or Latex Patch/Cell Extracts Employs Reagent Water for Extraction Swab: ISO 8502-2, Sections 5 and 6) (Latex Patch/Cell: ISO 8502-6) Commercially Available Kit. Convert solution concentration as PPM to surface concentration (Âµg/cm2) per Appendix A. Calculation of surface Cl-1 from swab as Âµg/cm2: (Cl-1 as ppm quantity of water used in ml) area sampled in cm2 5.2.3 Ferrous Ion Paper Strip Test of Swab/Wash or Latex Patch/Cell Extracts Employs Reagent Water for Extraction (Swab: ISO 8502-2, Sections 5 and 6) (Latex Patch/Cell: ISO 8502-6) Commercially Available Kits. Ferrous solution concentration is measured visually. Color comparison to charts on ferrous ion strip bottle (units in ppm or (Âµg/cm2). Convert solution concentration as ppm to surface concentration (Âµg/cm2) per Appendix A. Fe+2 from swab as Âµg/cm2: (ppm ml of water) area sampled in cm2 5.2.4 Field Drop Titration for Chloride of Swab/ Wash or Latex Patch/Cell Extracts Employs Reagent Water for Extraction (Swab: ISO 8502-2, Sections 5 and 6) (Latex Patch/Cell: ISO 8502-6) Commercially Available Test Kit used to analyze aqueous extracted solutions. Chloride ion concentration is determined by âdrop titration.â Cl-1 concentration is calculated as follows: Convert number of drops to cause color change from surface area tested to determine concentration of chloride as Âµg/cm2 5.2.5 Latex Sleeve Methodology Proprietary Extraction Solution Single ion or multi-ion prepackaged commercial kits are available. ----- 22.214.171.124 Sleeve Extract for Chloride Only Proprietary Extraction Solution Chloride Ion Detection Tube. Units reported in ppm. Calculation of Surface Cl-1 same as Âµg/cm2 (Cl-1 as ppm 10 ml Proprietary Extraction Solution with sleeve. Area sampled of 10 cm2 yields 1:1 equivalence to Âµg/cm2) (ISO 8502-5) 5. Field Methods Measuring Specific Ions No automated or single-step specific-ion extraction/analyses are currently available. 5.2 Multi-Step Ion-Specific Methods
A-5 SSPC-Guide 15 August 21, 2013 3.3 NACE INTERNATIONAL STANDARD3 NACE SP0508-2010 Methods of Validating Equivalence to ISO 8502-9 on Measurement of the Levels of Soluble Salts 4. Field Methods Measuring Total Soluble Salts by Conductivity 4.1 Fully Automated Conductivity Measurement Tech- niques: Recent innovations in salinity testing devices have 3 NACE International, 1440 South Creek, Houston, TX 77084. NACE standards are available online at <http://www.nace.org>. resulted in direct, real-time automated integrated systems that comply with ISO 8502-9. These devices are alternatives to patch cells and measure solution salinity from conductance. All of these devices attach to metal surfaces (magnetically or with automatically dispensed and agitated against the metal surface to remove (extract or retrieve) soluble salts and conductance measurements are taken in real-time. The devices process conductance data to generate surface concentration and store data and results internally. The commercially available devices are summarized in Table 1, Sections 4.1.1 Soluble Salt Meter; 4.1.2 Surface Salinity Meter; and 4.1.3 Continuous Flow TABLE 1 OVERVIEW OF FIELD METHODS FOR RETRIEVAL AND ANALYSIS OF SOLUBLE SALTS FROM STEEL AND OTHER NONPOROUS SURFACES Methodology (see section number for more detail) Surface Sampling via Extraction Medium (Applicable ISO Standard) Analysis of Extracted Sample Calculating Surface Concentrations of Ions (also refer to Appendix A or B) 126.96.36.199 Sleeve Extract for Ferrous Ion Proprietary Extraction Solution Ferrous Ion Test Strip immersed in sleeve solution to develop color. Color comparison to chart on ferrous test strip bottle. Units reported in ppm. Calculation of Surface Fe+2 same as Âµg/cm2 (Fe+2 as ppm; 10 ml proprietary extraction solution with sleeve. Area sampled of 10 cm2 yields 1:1 equivalence to Âµg/cm2) 188.8.131.52 Sleeve Extract for Chloride, Nitrate, and Sulfate (CNS) Proprietary Extraction Solution Nitrate Test Strip immersed in sleeve solution to develop color. color comparison to chart on nitrate test strip bottle.* Units reported in ppm. *See 184.108.40.206 for summary of analysis procedure for chloride and 220.127.116.11 for summary of analysis procedure for sulfate. Calculation of Surface NO3 -1 same as Âµg/cm2 (NO3 -1 as ppm; 10 ml proprietary extraction solution with sleeve. Area sampled of 10 cm2 yields 1:1 equivalence to Âµg/cm2) 18.104.22.168 Sleeve Extract for Sulfate Proprietary Extraction Solution Sulfate Analysis by Colorimetric Methods. Concentration reported in ppm. Calculation of Surface SO4 -2 same as Âµg/cm2 (SO4 -2 as ppm; 10 ml proprietary extraction solution with sleeve. Area sampled of 10 cm2 yields 1:1 equivalence to Âµg/cm2) 5.2.6 Field Detection Sulfate Ion Employs Reagent Water for Extraction ( Swab: ISO 8502-2, Sections 5 and 6) (Latex Patch/Cell: ISO 8502-6) Sulfate Analysis by Optical Comparative Method. Concentration reported in ppm Calculation of Surface SO4 -2 same as Âµg/cm2 SO4 -2 as ppm to surface concentration (Âµg/cm2) per Appendix A [or: ISO 8502-11, Sections 6 and 7] 5.2.7 Qualitative Field Detection of Ferrous Ions ---- Blotting paper is treated with potassium ferricyanide solutions and wetted with reagent water. On contact with ferrous ions, the paper shows blue spots. Not a quantitative technique. (ISO 8502-12) non-residue tape). A fixed volume of pure extraction water is
A-6 SSPC-Guide 15 August 21, 2013 5 available in each manufacturerâs website (refer to Appendix D). Note: As of May 2013, NAVSEA Standard Item 009-32 FY 12 (Change 1)4 requirement for solution conductivity for a Bresle Patch is V/A = 3 ml/1,250 mm2. If NAVSEA compli- ance is required, the reader must verify that the automated unit being employed calculates surface salt concentrations invoked by the construction contract. 4.1.1 Soluble Salt Meter 22.214.171.124 Overview of the method: The soluble salt meter5 is a hand-held device that is fully automated to perform both sample extraction and analysis. The device comes with a self- volumes of reagent water for soluble salt measurements changeable silicone-rubber lined magnetic heads of different curvatures, and provides on-screen instructions for use. The meter includes an interface for connection to external periph- eral equipment. Soluble salt is measured as conductance (0-100 ÂµS/cm) or mg/m2 on manufacturerâs website. 126.96.36.199 Extraction and Testing Protocol Step 1. Attach the meter to test surface (if not magnetic, press unit against surface during testing). Step 2. Inject reagent water into measurement chamber with one press of the dose bottle. Step 3. Meter automatically agitates solution. Step 4. Meter automatically takes readings (displays reading on LCD screen and stores values electronically). Step 5. Meter indicates completion of test cycle. Step 6. Wipe remaining reagent water from surface after and injecting water from dose bottle. Unit is calibrated by the manufacturer. 188.8.131.52 Automatic Calculations reported as: conductivity ÂµS/cm mg/m2 (ISO 8502-9) mg/m2 as NaCl (IMO PSPC)6,7 4.1.2 Surface Salinity Meter 184.108.40.206 Overview of the method: The surface salinity meter8 (SSM-21PÂ®), is another hand-held device that is fully 4 NAVSEA Standard Item 009-32, âCleaning and Painting Requirementsâ is available as a .pdf from the National Surface Treatment Center website <http://www.nstcenter.biz>. 5 The SSM Model RPCT-07-001Â®, manufactured by HEDON Equipment [see Appendix D] is the only meter meeting requirements of Section 220.127.116.11 known to the committee at this time. If you are aware of alternate manufacturers, please provide this information to SSPC Standards Development staff. 6 The results of converting conductivity to any level of chloride, even under laboratory controls, have been found to be of questionable accuracy. 7 IMO PSPC refers to the Performance Standard for Protective Coatings developed by the International Maritime Organization, International Maritime Organization 4, Albert Embank- ment, London SE1 7SR United Kingdom. A list of distributors of IMO publications is available at <http://www.imo.org> 8 The Surface Salinity Meter (SSM-21PÂ®) manufactured by DKK-TOA Corporation [see Appendix D] is the only meter meeting requirements of Section 18.104.22.168 known to the committee at this time. If you are aware of alternate manufacturers, please provide this information to SSPC Standards Development staff automated to perform both sample extraction and analysis. Surface salinity (mg/m2) can be directly read in four formats: soluble salt in IMO PSPC and normal modes; sodium chloride concentration, and conductivity of solution. The measuring cell is magnetically or manually held against steel or metal surface to be tested. The cell measurement area is 1,250 mm2. Pure (reagent) water (10 ml) is injected into the measurement cell using a plastic disposal syringe. The solution is agitated and the salinity measurement is automatically calculated, reported, and stored. The meter includes an interface for connection to available on the manufacturerâs website (Appendix D). 22.214.171.124 Sample Extraction and Testing Protocol Step 1. Attach measurement cell onto the steel surface Step 2. Inject 10 ml of reagent water using the plastic syringe and press the start key on the meter Step 3. Press the solution stirrer button Step 4. Measurement result is displayed on the meter and also stored in the meterâs internal data logger Step 5. Unit is calibrated by the manufacturer. 126.96.36.199 Automatic Calculations reported as: conductivity ÂµS/cm mg/m2 (ISO 8502-9) Âµg/cm2 as chlorides6 4.1.3 Continuous Flow Extraction Fiber Strip 188.8.131.52 Overview of the method: This method9 requires use of a pre-measured solvent ampoule that is attached to a disposable sensor, and a reusable meter to analyze the extracted solution. Surface soluble salts are extracted by the extracted salt solution is collected in the sensorâs reservoir. A pair of electrodes extends out of the body of the sensor. When these electrodes are placed in the accompanying meter, a direct reading of electrical conductivity proportional to concentration of soluble salt ion is displayed on the meter. This measurement process does not require any manual manipula- tion. The contact area of the unit is approximately 1.5 cm x 2.0 cm and does not seal to the test surface. The method permits evaluation of curved, irregular, and highly constrained test areas. Many units can be used in series for higher sampling coverage. 184.108.40.206 Sample Extraction and Testing Protocol Step 1. Squeeze the neck of the pre-measured ampoule containing solvent to break the seal, and push onto the sensor neck. Step 2. test using standard non-residue painterâs tape. 9 The SaltSmartÂ® meter model 2000 manufactured by Louisville Solutions,Inc [see Appendix D] is the only meter meeting requirements of Section 220.127.116.11 known to the committee at this time. If you are aware of alternate manufacturers, please provide this information to SSPC Standards Development staff. Extraction Fiber Strip. Additional product-specific information is as specified by the version of NAVSEA Standard Item 009-32 contained fluid dispenser that delivers accurate pre-measured and post-measurement flushing. The device includes inter- . Additional specifications are available removing SSM and flush meter by turning over external peripheral equipment. Additional specifications are Wipe off water from test area and flush measure- men cell with additional water flow of solvent across an engineered fiber in the sensor. The Affix the disposable sensor to the surface under
A-7 amount of fluid from the ampoule is required for the test to complete, so fluid will still remain in the SSPC-Guide 15 August 21, 2013 Make sure the sensor test pad is in full contact with the surface under test. If in an overhead orientation, also apply tape to hold the ampoule to the surface just to provide additional support due to the weight of the solvent. Only a small ampoule and it should not be emptied. Step 3. ot ssecorp noitcartxe eht rof setunim 8 ot 6 tiaW complete. Step 4. Remove the sensor with ampoule attached and place the exposed electrode end in the special purpose meter. The meter will provide readings in user-selectable units. Step 5. Dispose of each ampoule and sensor after use. method for validating accuracy is provided. 18.104.22.168 Automatic Calculations reported as: conductivity ÂµS/cm mg/m2 (ISO 8502-9) Âµg/cm2 total salt per ISO 8502-96 4.1.4 Advantages of Fully Automated Conductivity Measurement Techniques 1. Some sensors will attach magnetically to some metals. 2. Methods are real-time and the display on the meter guides the user through the complete procedure. 3. All critical steps are automated and pre-measured, therefore less subject to operator error. 4. Reduced setup, salt extraction from surface, and data reduction time. 5. Testing can be performed on vertical, horizontal, and overhead surfaces. 6. Digital output and electronic recording capability. 8. Reduction in consumables and no hazardous mate- rials (such as syringe needles) required. 9. Readings may be recorded. 10. Sensor test areas are standardized and cannot be manipulated by the user. 4.1.5 Limitations of the Fully Automated Conductivity Measurement Techniques 1. Some meters may not conform to curved and irreg- ular surfaces. Manufacturers may provide curved heads to accommodate for this situation. 2. Some sensors will not adhere to a surface that is not magnetic. Units can be held in place manually. 3. The instrument measures conductivity of total soluble nitrate. 4. Fully automated conductivity measurement tech- niques must be purchased as systems and are not interchangeable. 4.2 Multi-Step Conductivity Measurement Tech- niques: The multi-step conductivity measurement techniques from a predetermined surface area. These manual extraction methods include: reagent water wetted-swabs, adhesively The techniques may or may not require mechanical agitation or rubbing of the surface to enhance the dissolution/extraction of the salt into the reagent water. Conductivity measure- ments are manual. Conductance meters are of two types: (1) Probe-type conductivity meter reporting data as ÂµS/cm (per ISO 8502-9) or (2) a concentric ring conductivity meter10 reporting data as Âµg/cm2, mg/cm2, ÂµS/cm, ppm, and percent salinity. The commercially available devices are summarized in Table 1 Sections 4.2.1 Surface Swab or Wash; 4.2.2 Adhe- sively Bonded Latex Patch or Cell; and 4.2.3 Saturated Special information is available on each manufacturerâs website (refer to Appendix D). 4.2.1 Surface Swab or Wash with Probe-Type Conductivity Meter Technique 22.214.171.124 Overview of the method: such as reagent water is used to extract salts from a steel or non-porous surface. The method requires that the operator wear chloride-free latex gloves to prevent cross-contamination of the test surface. The method requires a ruler or template, markers, clean beakers, tweezers, and reagent water. The method is simple to perform but labor-intensive. ISO 8502-2 also provides a test procedure for determination of chloride on cleaned surfaces using a swabbing procedure. 126.96.36.199 Extraction and Testing Protocol Step 1. Measure and draw a template over a known area on the surface to be tested (e.g., 15 cm x 15 cm, or 225 cm2). Step 2. Pour a measured volume of reagent water into a plastic beaker (e.g., 22.5 ml). Water may be purchased or demineralized on site. Step 3. Dampen a sterile cotton ball in the beaker of water and thoroughly swab the interior of the template area. Be certain to use tweezers or a chloride- free latex glove. Avoid drips, especially from vertical surfaces. Step 4. Swirl the cotton ball in the beaker of water, then wring the cotton against beaker wall to completely remove all of the reagent water (which contains the extracted soluble salts). Step 5. Repeat the swabbing and rinsing procedure four more times. Use a new cotton ball each time. Step 6. Dry the area using a clean cotton ball. Place all cotton balls in beaker. Step 7. Stir the cotton balls in the water for 2 minutes, then 10 The Elcometer Model 130 Salt Contamination Meter Â® manufactured by Elcometer, Inc. [see Appendix D] is the only concentric ring conductivity meter known to the committee at this time. If you are aware of alternate manufacturers, please provide this information to SSPC Standards Development staff. Each unit is calibrated at the time of manufacture. A field salts rather than a specific ion such as chloride or are traditional field methods for salt extraction and testing bonded surface patch or cells, or wetted special-filter paper. Filter Paper Conductivity Meter. Additional product-specific A low-conductivity fluid wring all and measure the final water volume.
A-8 SSPC-Guide 15 August 21, 2013 Step 8. Obtain a control sample using the same proce- dure (i.e., eliminate the surface swabbing steps). Cover and sit for 3 minutes. Step 9. Analyze the swabbing extracts with the probe- type conductivity meter per manufacturer instructions and/or ISO 8502-9. Total process time is variable and all background correc- tion calibrations are manual. Chloride-free latex gloves should be worn for all steps of this test. 188.8.131.52 Calculations: Conductivity is reported as ÂµS/cm; other equivalency calculations must be performed manually. 184.108.40.206 Advantages of the Surface Swab or Wash with Probe-Type Conductivity Meter Technique 1. 1. The swabbing retrieval method provides a means for acquiring samples of salt from steel or other non- porous surfaces using readily available materials. 2. Extractions can be conducted on a range of surfaces without regard to surface irregularities or condition. 3. The swabbing method can be used on large areas to indicate general surface contamination by salts. several analyses to be performed for different ions. 220.127.116.11 Limitations of the Surface Swab or Wash with Probe-Type Conductivity Meter Technique head or vertical position. Extracted liquid may be lost dripping from the swabs. 2. Swabbing is not well-suited for measuring salt levels of small, localized contamination such as craters or pits. 3. There is a risk of contamination of a sample by the operator if gloves or any other equipment used for these procedures become damaged. 4. 4. In hot weather or on hot surfaces, the extraction liquid may evaporate on the surface prior to its removal. 4.2.2 Adhesively Bonded Latex Patch or Cell/Probe- Type Conductivity Meter Technique 18.104.22.168 Overview of the method (ISO 8502-6 and ISO 8502-9): This method utilizes a small adhesive patch covered cavity.11 Self-contained adhesive edges allow the cell to adhere to the surface. Reagent water or a proprietary extraction liquid is then injected into its center with a hypodermic needle. The needle, the liquid is then sucked out of the compartment and reinjected a minimum of 4 times before being retrieved from the patch using the hypodermic needle, and tested for concen- tration of ions with probe-type conductivity meter. The patch cell sampling procedure is described in detail in ISO 8502-6. 11 The most commonly encountered patch cell is the Bresle patch, however, patch cells are available from other manufacturers. Standardization of practices for soluble salt retrieval patch cells and equivalence in conductometric measurements is also available on manufacturer and distributor websites (Appendix D). 22.214.171.124 Extraction and Testing Protocol Step 1. Remove the backing and the foam insert from to a dry test surface. All orientations, including vertical, horizontal, or overhead are acceptable. Step 2. Insert the needle attached to the 5 ml syringe into the cell through its spongy foam perimeter, taking care not to inject beneath the foam or area by pulling back on the plunger. Expel the air from the syringe. Fill the syringe with 3 ml of the extraction liquid. Step 3. Inject 3 ml or other designated quantity of extrac- tion liquid into the above cell taking care to keep air bubbles out of the syringe. Hold the cell liquid leakage. Step 4. Step 5. Step 6. Without removing the needle from the cell center, reinject it into the cell center a minimum of 4 times 12 of the extraction liquid as possible and place it in a clean vial or other container for testing. Loss of extracting solution will reduce the measured levels of soluble salt. A new clean container should be used for each test, or if reused, the container should be rinsed two or more times with reagent water. higher volume of extraction liquid is required than achievable in Steps 3 to 5. It is permissible to add extraction liquid to the test sample of Step 5. The new test sample volume used must be recorded so a dilution percentage can be calculated. Step 7. When multiple samples are to be taken, always use a fresh cell and clean syringe and needle to avoid cross- contamination between samples. reagent water. Background correction calibrations are manual. 126.96.36.199 Calculations: Conductivity is reported as ÂµS/cm; other equivalency calculations must be manually calculated. 12 the substrate. The dwell times recommended in kit usage instructions vary. A non-manda- tory note to Section 5.6 of ISO 8502-6 states: âOn unpitted blast-cleaned areas a period of 10 minutes [dwell time] has been found satisfactory, as by then more than 90% of the soluble salts have usually been dissolved.â NACE SP0508-2010 recommends a minimum the test cell and apply the cell firmly and tightly given in NACE SP0508-2010. Additional specifications are The extractions also provide sufficient sample size for Swabbing methods are difficult to perform in an over into the latex film. Evacuate the air from the test perimeter firmly during this operation to prevent withdraw the extraction fluid into the syringe and during the specified dwell time. After the specified dwell time, withdraw as much When ion-specific salt testing is required, a Note: To clean syringe, flush it 3 to 4 times with There is no industry standard defining the length of the dwell time of the extraction liquid on dwell time of 90 seconds. Longer dwell times may increase extraction efficiency; however cost and time constraints, as well as field conditions, should be considered when specifying a dwell time. with a latex film, which attaches to the structure forming a cell patch fills up like a large paint blister. Using the hypodermic
A-9 SSPC-Guide 15 August 21, 2013 188.8.131.52 Advantages of the Patch Cell Multi-Step Conductivity Measurement Technique 1. The cells, as attached with adhesive, can conform to curved and irregular surfaces. 2. Cells such as these are commercially available in a variety of sizes; the most commonly used size retrieves salt from a surface of 12.5 cm2. Smaller cell sizes permit extraction of surface salts to be made at local corrosion sites. 3. If reagent water has been used as the extraction liquid, conductivity can be determined using commer- cially available conductivity meters. 184.108.40.206 Limitations of the Patch Cell Multi-Step Conductivity Measurement Technique 1. The patch cells only accommodate a small amount of extraction liquid. With the most commonly used cell size (12.5 cm2 surface area), the actual quantity of cell liquid contacting the surface is 3 ml. This can limit the range of analyses that can be performed. 2. No in-series determination of conductivity can be performed with these cells. 3. The cell may not adhere well to heavily rusted surfaces, but it may adhere to abrasive blast cleaned 4. The cell may leak through the hole introduced by the syringe. 5. The cells are consumable and can be used only once. 6. The patch cell will add background conductivity. 7. Dilution of extraction liquid introduces greater error in final result. 8. No standard procedure exists for the intensity of rubbing, thus making the result subject to operator. 9. Flexible patches can be stretched to 10% more than 10. When acidic extraction solutions are used, the patch cell is not suitable for conductivity measurement. 4.2.3 Saturated Special Filter Paper with Concentric Ring Conductivity Meter Technique 220.127.116.11 Overview of the method: This method incorpo- and analysis using conductivity. The paper wets the surface and extracts soluble salts through absorbance. After a pre- determined time, the paper is removed from the surface and placed over the electrodes of a proprietary concentric ring conductivity meter. The meter indicates the conductivity of the wetted paper. turerâs website (Appendix D). 18.104.22.168 Extraction and Testing Protocol Step 1. according to manufacturerâs instructions. Step 2. Place saturated paper onto surface and push paper into the surface texture using tweezers Step 3. Prepare salt contamination meter per manufac- turer operating instructions Step 4. Remove paper and position onto central area of the concentric ring conductivity meter Step 5. Close lid, activate meter, and read value from the display (Âµg/cm2, mg/cm2, ÂµS/cm, ppm, percent salinity) Total process time is variable. The concentric ring conduc- tivity meter is calibrated by the manufacturer; background Chloride-free latex gloves should be worn during all steps of this technique. 22.214.171.124 Calculations: Conductivity is reported as Âµg/cm2, mg/cm2, ÂµS/cm, ppm, percent salinity. 126.96.36.199 Advantages of Saturated Special Filter Paper with Concentric Ring Conductivity Meter Technique 1. Suitable for a wide range of shapes, orientations, 2. Battery operated and portable. surface and finishes. 3. On-board temperature compensation 4. Multiple readings can be downloaded in real time via US-B or Bluetooth or stored in multiple batches with date and time stamps, temperature and size of test paper. 5. Measuring range up to 50 Âµg/cm2 (3000 ppm) 188.8.131.52 Limitations of Saturated Special Filter Paper with Concentric Ring Conductivity Meter Technique 1. No in-series determination of conductivity can be performed using this unit. 2. evaporation) introducing error. 3. only once to extract salts. 4. must be manually performed. 5. FIELD METHODS MEASURING SPECIFIC IONS analysis systems are available. Additional specifications are available on the manufac- rates soluble salt extraction with water-saturated filter paper Water may be lost from the filter paper (via dripping or The filter paper is a consumable and can be used Background calibrations for the blank filter paper 5.1 Fully Automated Ion-Specific Field Methods To date, no automated or single-step specific ion extraction/ Saturate filter paper disc with reagent water calibrations are required for the special filter paper. The instrument is available with conductivity calibration tiles for field verification of accuracy. surfaces so well as to cause difficulty in removing the patch. their original intended footprint, influencing the final result. Saturate filter paper disc with reagent water according to manufacturerâs instructions.
A-10 SSPC-Guide 15 August 21, 2013 5.2.1 Chloride Ion Paper Strip Test of Swab/Wash or Latex Patch/Cell Extracts 184.108.40.206 Overview of the method: In this technique chlo- ride ion paper test strips13 are utilized to determine chloride ion concentrations of swab- or patch cell-extracted solutions. Advantages and limitations of the swab extraction method are discussed in Sections 220.127.116.11 and 18.104.22.168 respectively. Advan- tages and limitations of the patch cell extraction methods are discussed in Sections 22.214.171.124 and 126.96.36.199 respectively. 188.8.131.52 Sample Extraction and Testing Protocol: Please see Section 184.108.40.206 for swab extraction and testing protocol (Step 1 through Step 8). Please see Section 220.127.116.11 for patch cell extraction and testing protocol. Extraction solu- tion is obtained using either the swab or patch cell method. The lower end of a chloride ion paper strip is placed into the extracted solution. The solution wicks up and saturates the test strip, as indicated by the yellow band across the top of the strip turning blue (about 5 minutes). Then, the scale number at the top edge of the white column is recorded (chloride ion causes the existing tan color on the strip to turn white) and compared with the conversion chart enclosed with the test strip bottle. The range of concentration over which this method is useful is from 30 to 600+ ppm chloride ion. The precision reported by the manufacturer is Â± 10% chloride. 18.104.22.168 Calculations: The reading from the paper strips must be converted to ppm using the conversion chart supplied by the manufacturer corresponding to the batch of test strips used for the analysis. See Appendix A for information on converting from a solution concentration in ppm to a surface concentration in Âµg/cm2. 5.2.2 Chloride Ion Detection Tube Test of Swab/Wash or Latex Patch/Cell Extracts 22.214.171.124 Overview of the Method: In this technique, sealed vacuum tubes are utilized to determine chloride ion concentra- tions of swab- or patch cell-extracted solutions. 126.96.36.199 Sample Extraction and Testing Protocol: Please see Section 188.8.131.52 for swab extraction and testing protocol (Step 1 through Step 8). Please see Section 184.108.40.206 for patch cell extraction and testing protocol. Extraction solu- tion is obtained using either the swab or patch cell method. The tubes contain crystals impregnated with silver dichromate (pink). The ends of the tube are snapped off, opening the tube much like a straw. When one end of the tube is immersed in the extract solution, capillary action wicks the solution to the top of the tube. On contact with the chloride ion the silver dichromate converts to silver chloride (white). When the solution reaches 13 Hach, Inc, (QuanTabÂ®,) and EMD Chemicals (EM QuantÂ®,) are the only manufacturers of these test strips known to the committee at this time [see Appendix D]. If you are aware of alternate manufacturers, please provide this information to SSPC Standards Development staff. the top of the tube, the white cotton at the top changes color to amber. This indicates the titration is complete. Graduations on the side of the tube provide the level of chloride ions pres ent in the solution. 220.127.116.11 Calculations: This method, described in ISO 8502-5, can detect chloride levels from 1 to 2000 ppm, using tubes with varying ranges of detection. 5.2.3 Ferrous Ion Paper Strip Test of Swab/Wash or Latex Patch/Cell Extracts 18.104.22.168 Overview of the method: In this technique, ferrous ion paper test strips are utilized to determine ferrous ion concentrations of swab- or patch cell-extracted solutions. Advantages and limitations of the swab extraction method are discussed in Sections 4.2.14 and 4.2.15 respectively. Advan- tages and limitations of the patch cell extraction methods are discussed in Sections 22.214.171.124 and 126.96.36.199 respectively. 188.8.131.52 Sample Extraction and Testing Protocol: Please see Section 184.108.40.206 for swab extraction and testing protocol (Step 1 through Step 8). Please see Section 220.127.116.11 for patch cell extraction and testing protocol. Extraction solu- tion is obtained using either the swab or patch cell method. To determine the ferrous ion concentration in parts per million, moisten a ferrous ion test strip with the solution being tested and compare the resulting color to the color chart on the container label. A complex is formed between 1,10-phenanth- roline and ferrous ion that has a vivid red color. Color changes are seen even at ferrous ion concentrations below 1 ppm. Typical concentration ranges for test strips are between 0.5 and 10 ppm ferrous ion. Iron test strips from one manufacturer are graduated in unequal steps: 0-3-10-15-50-100-250-500 ppm. No data is available on the precision of this technique. 18.104.22.168 Calculations: See Appendix A for information on converting from a solution concentration in ppm of solution to a surface concentration in Âµg/cm2. Note that a proprietary kit (see Section 22.214.171.124) provides the readings directly in Âµg/cm2. 5.2.4 Field Drop Titration for Chloride of Swab/Wash or Latex Patch/Cell Extracts 126.96.36.199 Overview of the method: In this method a commercially available test kit14 is used to analyze the solution collected from the surface using swab or patch cell extraction methods. Advantages and limitations of the swab extraction method are discussed in Sections 4.2.3 and 4.2.4 respectively. Advantages and limitations of the patch cell extraction methods are discussed in Sections 188.8.131.52 and 184.108.40.206 respectively. 220.127.116.11 Sample Extraction and Testing Protocol: Please see Section 18.104.22.168 for swab extraction and testing protocol (Step 1 through Step 8). Please see Section 22.214.171.124 14 The SCAT Swab KitÂ®, manufactured by KTA-Tator Inc., is the only kit meeting the descrip- tion of Section 5.2.4 known to the committee at this time [see Appendix D]. If you are aware of alternate manufacturers, please provide this information to SSPC Standards Develop- ment staff. 5.2 Multi-Step Ion-Specific Field Methods
A-11 SSPC-Guide 15 August 21, 2013 for patch cell extraction and testing protocol. Extraction solu- tion is obtained using either the swab or patch cell method. The titration (sometimes referred to as âdrop titrationâ) is performed on a small sample (2 to 3 ml) from the extracted solution. The kit includes three solutions contained in separate reagent bottles. The procedure is as follows: Step 1. Using reagent bottle 1, press (squeeze) out 2 drops of red indicator liquid into a plastic vial containing the sample solution. Carefully agitate the liquid until it is homogeneous in color. Step 2. Using reagent bottle 2, squeeze out 2 drops into the vial. The sample liquid should be yellow in color. Step 3. Add, drop by drop, the contents from reagent bottle 4 (note that there is no reagent bottle 3). Count the number of drops required to turn the solution from yellow to blue, thoroughly agitating the solution after the addition of each drop. The procedure is described in ISO 8502-10. Step 4: Use the following chart to determine the concen- tration of chloride ion (in Âµg/cm2) in the sample. Number of Drops from Bottle 4 Concentration of Chloride Ion 1 Less than 2 Âµg/cm2 2 2 to 4 Âµg/cm2 3 4 to 6 Âµg/cm2 4 8 to 10 Âµg/cm2 Note: This method does not determine a specific concen- tration of chloride ion, but rather the results are reported as a range, e.g., greater than 10 and less than 20 ppm chloride ion. The manufacturer reports a sampling accuracy of 1 to 2 Âµg/cm2. No information on precision was provided. 5.2.5 Latex Sleeve Methodology 126.96.36.199 Sleeve Extract for Chloride only: Uses a propri- etary solution.15 188.8.131.52.1 Overview of the method: This method uses a small flexible chloride-free latex sleeve (sock) with a self- contained adhesive edge. A proprietary solution is dosed into the sleeve, and the sleeve is attached to the structure being tested forming a cavity. The solution is massaged against the surface being tested for a specified period of time and is then removed. The sleeve then is removed and the extracted solu- tion tested for levels of chlorides. 184.108.40.206.2 Sample Extraction and Testing Protocol for Chloride Testing procedures may be conducted on intact painted surfaces and/or bare metal/nonmetal surfaces. Remove all rust, loose paint and dust prior to testing. Step 1. Remove the cap from the sealed ampoule of pre- measured extract solution and pour the entire contents into the sleeve. Step 2. Remove the pressure sensitive backing from the sleeve adhesive ring. Step 3. Remove most of the air from within the sleeve by squeezing the sleeve between fingers and thumb. Do not spill any extraction solution from the sleeve when evacuating air. Step 4. Firmly apply the sleeve to the test surface. Lift and hold the free end of sleeve upright to allow the extraction liquid to come into contact with the surface. Step 5. Use the other hand to massage the solution through the sleeve against the surface for 2 minutes. It should be noted that increasing the massage time (e.g., up to up to 6 minutes) will increase the extent of salt removal. When the massage is complete, remove the sleeve and solution from the surface. For vertical or over- head surfaces, the extract solution will return to the lowered area in test sleeve. For horizontal surfaces, press and slide a finger across the sleeve to move the solution to the closed end of the sleeve prior to removal. 220.127.116.11.3 Chloride Calculation Step 1. When the test is complete, the white cotton at the very top of the tube will turn amber. Step 2. Remove the tube from the solution and record the number on the tube at the interface of the color change (pink is the original color; any white color above the thick blue line is the chloride level). This number represents parts per million and micrograms per square centimeter of chlorides. Step 3. If the tube turns completely white, the chloride level is above the limit of the tube. If there is no white showing on the tube, the level of chlorides is not detectable by this test. This test is specifically designed for ppm and Âµg/cm2 to be the same numeric value. NOTE: The yellow color that has risen with the solution during the test should have either risen above the pink area or have dissipated. Do not read the yellow. 18.104.22.168 Sleeve Extract for Ferrous Ion: Please see Section 22.214.171.124. 126.96.36.199.1 Overview of the Method: Please see Section 188.8.131.52.1. 184.108.40.206.2 Sample Extraction and Testing Protocol: Please see Step 1 through Step 5 of Section 220.127.116.11.2. 15 The Chlor-Test Kits manufactured by Chlor*Rid, Inc., [see Appendix D] are the only kits meeting the description of Sections 5.2.5 and 5.2.6 known to the committee at this time. If you are aware of alternate manufacturers, please provide this information to SSPC Stan- dards Development staff.
A-12 SSPC-Guide 15 August 21, 2013 18.104.22.168.3 Calculations: Measurement of ferrous ion per kit operating instructions for proprietary solution. 22.214.171.124 Sleeve Extract for Chloride, Nitrate and Sulfate (CNS): 126.96.36.199.1 Sample Extraction and Testing Protocol for Chloride, Nitrate and Sulfate (CNS): Testing procedures may be conducted on intact painted surfaces and/or bare metal/ nonmetal surfaces. Remove all rust, loose paint and dust prior to testing. Follow Steps 1 through 5 listed in Section 188.8.131.52.2 above. Continue with Step 6. Step 6: Remove plunger from autovial filter assembly and insert funnel. Pour extract solution from the sleeve through the funnel into the filter. Discard funnel. NOTE: There must be at least 7 (seven) ml of filtered solution in the filter assembly for accurate final sulfate measurement. Place filter assembly on the empty extract bottle. Insert plunger into the filter assembly and empty all liquid into the bottle. 184.108.40.206.2 Chloride Calculation: See Section 220.127.116.11.3 for instructions for chloride calculation. 18.104.22.168.3 Nitrate Calculation: Remove a nitrate strip from the sealed wrapper and dip the âpillowâ end into the extract sample for 2 seconds. Remove, wait 1 minute and match the color on the pillow to the closest color on the comparator card. This number represents parts per million and micrograms per square centimeter of nitrates. This test is designed for ppm and Âµg/cm2 to be the same numeric value. 22.214.171.124 Sleeve Extract for Sulfate: 126.96.36.199.1 Overview of the Sulfate Method: This proprietary method uses a factory-programmed electronic microprocessor that measures the turbidity (i.e. the cloudiness) of a solution after barium chloride solution has been mixed with the test solution. This method is more sensitive than the visual method (Section 5.2.6). The colorimeter provides a digital readout in micrograms per cm2 with a range of 1 to 100 micro- grams per cm2 readings are in parts per million (ppm), and the range is from 1 to 100 ppm. The supplier reports that the accuracy of this unit over the full photometric range is Â± 2%. 188.8.131.52.2 Sulfate Calculation: Step 1: Prepare meter, recap bottle, and wipe with the clean cloth provided to remove fingerprints, dust and moisture. Open the lid on the colorimeter, insert the bottle with vertical index line aligned with triangular arrow on the colorimeter and close the lid. Press and release the READ button to turn on meter, wait a few seconds until a number appears, then press and hold the ZERO button until the bLA is displayed, then quickly release. The meter is now calibrated to ZERO for this solution. Step 2: Remove the bottle from the meter, place into original receptacle, and remove cap. Remove cap from yellow-labeled bottle containing sulfate reagent and deposit reagent directly into sample solution bottle. Avoid direct skin contact with reagent liquid. Step 3: Cap the 10 ml bottle and shake for 10 seconds to mix. Clean the bottle with the wipes again to remove fingerprints and moisture. Step 4: Insert bottle into colorimeter with vertical index line aligned with arrow on the colorimeter and close the lid. Push and release the READ button and record the result as parts per million and micrograms per square centimeter of sulfates. This test is designed to provide a reading in Âµg/cm2. Note: If the final reading is a negative number, it is consid- ered â0.â This meterâs range is 0-100 ppm. If a test result gives an ER2 (over range) message, the sample must be diluted. It is recommended that the solution be diluted by one-half (1/2) using deionized water, then wipe the bottle and repeat Step 4 above. Remember to multiply this final reading by the dilution factor, 2 in this case. 184.108.40.206 Advantages of the latex sleeve methodology 1. This method is very simple to perform, as all compo- nents are pre-measured. 2. The adhesive sleeve can conform to curved and irreg- ular surfaces. Tests can be performed on vertical, horizontal, and overhead surfaces. 3. For extremely rough or pitted surfaces, the seal ring may be doubled, thereby allowing testing to be performed. 4. The kit form of this method provides a pre-measured volume of extraction solution and a fixed area of the sleeve opening. These features are designed to provide a direct final reading in micrograms per square centimeter (Âµg/cm2). 5. All components are one-time usage, eliminating cross-contamination from test to test. 6. In hot weather or on hot surfaces, the encapsulated extract solution will not evaporate. 7. The extractions also provide sufficient sample size for analyses to be performed for different ions. 8. Acidic extraction liquids (such as the one furnished in the proprietary kit for this procedure) normally provide improved extraction efficiency compared to reagent water.
A-13 SSPC-Guide 15 August 21, 2013 220.127.116.11 Limitations of the latex sleeve methodology 1. The adhesive sleeve may not adhere well to rusted surfaces, but may adhere so well to clean or grit blasted surfaces that it is difficult to remove the adhe- sive sleeve from the surface. 2. No in-series conductivity determinations can be performed with the sleeves. 3. The sleeves are consumable and can be used only once. 5.2.6 Field Detection Sulfate Ion by Visual Turbidity 18.104.22.168 Overview: This method works on the principle that if sulfate is present in the extracted salt solution, it becomes turbid (cloudy) when barium chloride is added. The simplest instrument for measuring the degree of turbidity in the field is the optical comparator. Barium chloride is available as powder or pre-measured tablets. The tablets are more convenient to use but require time to dissolve. Panes of plastic with a known degree of cloudiness are compared side by side with the sample prepared using the kit. The pane closest in cloudi- ness to that of the sample is taken as the sample sulfate level. The interval between each pane value has to be quite large, because the eye is not as discriminating as a well-calibrated spectrophotometer in the laboratory. Also, because the eye is not sensitive to very low levels of turbidity, the minimum level of sulfate that can be detected by this method is around 20 ppm. No data is available on the precision of this technique. 22.214.171.124 Sample Extraction and Testing Protocol: Any of the aforementioned reagent water sample extraction protocols can be used to extract the salt samples for subsequent sulfate testing. 126.96.36.199 Calculations: The units of turbidity are given in ppm by the manufacturer. See Appendix A for information on converting from a solution concentration in ppm to a surface concentration in Âµg/cm2. 5.2.7 Qualitative Field Detection of Ferrous Ions 188.8.131.52 Overview of the method: In this method (described in ISO 8502-12) blotting paper is treated with potas- sium ferricyanide solution. The blotting paper is moistened and placed in contact with the steel surface to be tested. On contact with ferrous ions, the paper shows blue spots. The sensitivity of the method is less than 1 ppm ferrous (Fe+2) ions. This is a qualitative test, but one manufacturer of the test provides a comparison chart (with 6 pictures of increasing contamination levels), against which the test papers are visu- ally compared (size and extend of the blue blotches), to give an indication of the extent of metallic salt contamination. If any contamination is indicated, a quantitative test is recommended. Potassium ferricyanide test paper may be used as an economical screening test for active corrosion sites. It is specific to soluble ferrous ion. When used properly, it will not give false negatives, but may produce false positives. If soluble salt concentration is suspected due to a positive indi- cation using potassium ferricyanide paper, then confirming tests utilizing a quantitative method may be required. 184.108.40.206 Sample Extraction Testing Protocol: This method is fully described in ISO 8502-12. No information on precision is available, as this is a qualitative test. 220.127.116.11 Calculations (Not applicable, qualitative info only.) 6. Laboratory Reference Methods (see Table 2) 6.1 Reference Boiling Extraction Method: The labora- tory reference boiling extraction method is useful when the most complete salt extraction from metal surfaces is desired. This method is used to determine benchmark salt levels on samples in a laboratory setting. It may be used to derive salt retrieval rates for all of the aforementioned field tests as well as for field samples cut from a sample or test panels exposed in a field or lot. This method involves the use of boiling reagent water (with optional sonic energy) to extract salts from a surface. When combined with laboratory ion chromatography measurement (Section 6.2.2), the measurement of soluble salts anions is very precise (ASTM D4327). 6.1.1 Materials Required for the Laboratory Boiling Extraction Method This laboratory reference procedure requires the following items (all apparatus and sample containers should be previ- ously cleaned with reagent water): 1. Hot plate with thermostatic control. (Optionally, an ultrasonic hot plate may also be used, see Step 11.) 2. Reagent water, conductivity no greater than 5 ÂµS/cm 3. Inert glass granules to prevent bumping of boiling water. (Note: the use of boiling stones or chips is not suggested, as these contribute ions to the water and buffer the pH of the extraction liquid on the alkaline side.) 4. Steel panels of known dimensions (e.g., 10 x 15 x 0.64 cm [4 x 6 x 1/4 inch]), previously cleaned to reflect the specification level of cleanliness used in the field, using the same abrasive as in the field. If a level of cleanliness is not specified, then panels are cleaned to SSPC-SP 5/NACE No. 1. 5. Stainless steel or PyrexÂ® pans of dimension no less than 15 x 20 x 5 cm (6 x 8 x 2 inch). 6. Test panels of dimensions no greater than 13 x 18 x 2.5 cm (5 x 7 x 1 inch) 7. 500 ml graduated cylinder 8. Stainless steel tongs 9. Conical funnel 10. 750 ml laboratory storage bottle 11. Optional: Heated large capacity ultrasonic bath, 50-watt minimum power (Proper operation and calibration of the sonicator shall confirm to manufac- turerâs instructions.).
A-14 SSPC-Guide 15 August 21, 2013 TABLE 2 OVERVIEW OF LABORATORY METHODS FOR RETRIEVAL AND ANALYSIS OF SOLUBLE SALTS FROM STEEL AND OTHER NONPOROUS SURFACES Methodology (see section number for more detail) Surface Sampling via Extraction Medium (Applicable ISO Standard) Analysis of Extracted Sample Calculating Surface Concentrations of Ions (also refer to Appendix A or B) 6. Laboratory Reference Methods 6.1 Reference Boiling Extraction Method 6.1.1 Multi-Step Boiling Extraction Method with Optional Sonic Enhancement of Field Samples (Cut Bulk Specimen or Control Coupons) Employs Boiling Reagent Water for Extraction Any of the field or lab tests that use reagent grade water can be used to perform quantitative solution conductivity and specific ion measurements. (Proprietary solutions cannot be used for laboratory control tests.) ----- 6.2 Reference Ion Concentration Methods 6.2.1 Laboratory Reference Method for Detection of Chloride Ion by Titration Employs Reagent Water for Extraction (ISO 8502-2) âLaboratory titration of extracted chlorides on cleaned surfacesâ (ISO 8502-2). Based on the titration of mercuric nitrate in chlorides to form mercuric chloride. The indicator is a solution of diphenycarbazole/ bromophenol blue that turns intense violet at titration endpoint. Concentration reported in ppm. Calculation of Surface Cl-1 from titration endpoint as Âµg/cm2: (Cl-1 as ppm quantity of water used in ml) area sampled in cm2 6.2.2 Laboratory Multi-Ion Chromatography Detection Employs Reagent Water for Extraction. Multi-Step Boiling Water Extraction (with optional sonic energy). Will yield highest salt extraction efficiency. Accurate laboratory testing of salt extracts using Ion Chromatography for fluorides, chlorides, nitrites, nitrates, phosphates and sulfates (ASTM D4327) Instruments report each ion concentration in ppm. Calculation of each surface ion as ppm as Âµg/cm2: (Ion concentration as ppm quantity of water used in ml) area sampled in cm2 6.2.3 Ion-Selective Electrode Method Employs Reagent Water for Extraction. Chloride ion-specific test. Potentiometric test using a chloride-ion selective electrode. Direct reading per ASTM D512, Test Method C.
A-15 SSPC-Guide 15 August 21, 2013 6.1.2 Reference Boiling Extraction Method Step 1. Place the following items in the pan or glass beaker: â¢ Approximately 500 ml of reagent water â¢ Between 5 and 10 anti-bumping granules â¢ A test panel (see item 6.1.1, item 4)16 Step 2. Place the pan on the hot plate and raise water temperature to boiling over a period from 10 to 20 minutes. Maintain the temperature at boiling for 1 hour. The test panel must be kept completely submerged. If liquid is lost by boiling evapora- tion, it must be replenished during the test. If the panel is placed horizontally in the pan, turn the panel over after 30 minutes. Step 3. At the end of the test, turn off the hot plate, and remove the pan from the hot plate. Allow the liquid in the pan is allowed to cool for at least one half hour. Step 4. The steel test panel may be removed from the pan with stainless steel tongs either hot or after cooling. It should be rinsed with a small quan- tity of reagent water to remove any soluble salt ions from the surface, and drained over the pan. When the panel has drained dry, remove it from the work area. Step 5. Using the conical funnel, transfer the liquid in the pan to the graduated cylinder. Add sufficient reagent water to the graduated cylinder to bring the volume of material up to 500 ml. Step 6. Mix the total liquid thoroughly by transferring it between the storage bottle and the graduated cylinder. Optional â Use of Ultrasonic Energy: In Section 6.1.2, Steps 1 and 2, a large heated sonic bath can be used in place of a hot plate with thermostatic control. Once boiling condi- tions are achieved, the per-side sonic extraction of each panel can be reduced to 15 minutes. Longer hot sonic extractions may yield even higher salts retrieval rates. For discussion on enhanced sample extractions using sonic energy see the reference paper by Kevin Ashley et. al. in the bibliography for Appendix C. 6.1.3 Advantage of Laboratory Boiling Extraction Method: This method provides a benchmark for determining the maximum retrieval efficiency of field retrieval methods. 6.1.4 Limitation of Laboratory Boiling Extraction Method: This method is unsuited for use in the field. It requires trained technical personnel, scientific equipment and labora- tory conditions. While the reference total extraction procedure will yield the most complete extraction of soluble salts, direct comparison to actual field sample data must be performed with caution and by highly trained scientists. Field conditions responsible for salt contamination are highly variable; therefore it is best to use actual field samples for testing where possible. 6.2 Reference Ion Concentration Methods 6.2.1 Laboratory Reference Method for Detection of Chloride Ion by Titration: ISO 8502-2, âLaboratory Determi- nation of Chloride on Cleaned Surfaceâ describes a classical silver chloride/silver nitrate titration to accurately measure chloride levels with a precision of Â± 0.1 ppm chloride. 6.2.2 Laboratory Multi-Anion Chromatography Detec- tion: Multi-ion detection and quantification of salts anions in water is possible using suppressed ion chromatography (IC) as described in ASTM D4327. This method covers the sequen- tial determination of the seven common salt anions (fluoride, chloride, nitrite, ortho-phosphate, bromide, nitrate, and sulfate) in water using a sophisticated ion chromatography (IC) labo- ratory instrument operated by trained scientists. A single test takes approximately 10 to 15 minutes to complete. The IC instrument must be set up, calibrated, and operated according to the manufacturerâs instructions. The salt anion concentra- tions are directly calculated by integrated IC software. 6.2.3 Ion Selective Electrode Method: Refer to ASTM D512, Test Method C (Ion-Selective Electrode Test Method), Sections 22-30. ASTM D512, Test Method C, is applicable to the measure- ment of chloride ion in natural waters, drinking water, and wastewaters. The chloride ion is measured potentiometrically using a chloride ion-selective electrode (ISE) in conjunction with a double junction, sleeve-type reference electrode or a combination chloride electrode. Potentials are read using a pH meter having an expanded millivolt scale, or a selective-ion meter having a direct concentration readout capability. The electrodes are calibrated in known chloride solutions, and the concentrations of unknowns are determined in solutions with the same background. Samples and standards should be used at the same temperature. Standards and samples are diluted with an ionic strength adjustor (such as sodium bromate) that also minimizes possible interferences from ammonia, bromide, iodide, cyanide, sulfate, or sulfide. Samples containing 2 to 1000 mg/L of chloride may be analyzed by this test method. The concentration range may be extended by dilution of an appropriate aliquot before the addition of the ionic strength adjustor. The precision and bias statements of this procedure were obtained using reagent water and a water matrix of choice that included natural and wastewaters. Operators of this method must be trained on the calibration and use of potentiometers and the safe handling of all required chemicals. 16 Option: The Reference Boiling Extraction Method can also be used for laboratory salt retrieval from field samples of irregular shapes as long as the total area of the part under investigation is agreed on by all interested parties.
A-16 SSPC-Guide 15 August 21, 2013 APPENDIX A: CONVERSIONS A.1 Determining Surface Concentration from Solution Concentration One can convert the solution concentration to an equiva- lent surface concentration as follows: APPENDIX B: DETERMINING EQUIVALENT SURFACE CONCENTRATION FROM CONDUCTIVITY Note: The ability to remove all of the soluble salt ions from the surface of a structure that has been in service for extended periods of time and is severely corroded and or pitted has not yet been demonstrated. Therefore, all extraction tests remove E = C V A Where: (Formula 1) less than 100% of the soluble salt ions from the structures, and the amount in the samples represents an unknown percentage of the amount actually existing on the structure. The test methods that are indicated in this document are therefore C = solution concentration in PPM (Âµg/cm3) E = surface concentration in Âµg/cm2 V = volume of extract solution in ml (1 ml = 1 cm3) A= area in cm2 Example: semi-quantitative and do not represent the actual amount of soluble salt ions existing on the structure. B.1 Equivalent Surface Concentration of Total Salt from Conductivity E = 42 C = 42 ppm A= 12.5 cm2 V= 2 ml 2 12.5 = 6.7 Âµg/cm2 Based on measuring the average conductivity from 12 representative samples of soluble salts, an ISO committee developed the following formula for converting conductivity to surface concentration of salts (ISO 8502-9). V A.2 Determining Solution Concentration from Surface Concentration Where: E1 = (0.5) S A (Formula 3) 2One can convert the surface concentration to an equiva- lent solution concentration as follows: E 1 = surface concentration of total salt in Âµg/cm S = conductivity in ÂµS/cm V = volume of extract solution in ml C = E A V (Formula 2) A = area in cm 2 Example: Where: C = solution concentration in ppm (Âµg/cm3) 2 E = 0.5 70 1 12.5 = 5.6 Âµg/cm2 of soluble salt E = surface concentration in Âµg/cm2 V = volume of extract solution in ml A = area in cm2 Example: C = 10 12.5 = 62.5 ppm 2 E = 10 Âµg/cm2 A= 12.5 cm2 V= 2 ml A.3 Unit Conversions 1 ppm = 1 Âµg/cm3 of water 1 ml = 1 cc = 1 cm3 1 Âµg/cm2 = 10 mg/m2 S = 70 ÂµS/cm V = 2 ml A = 12.5 cm2 B.2 Methods of Validating Equivalence to ISO 8502-9 on Measurement of the Levels of Soluble Salts from Steel and Other Non-Porous Substrates (NACE SP0508-2010) Some organizations now require equivalency validation (against the traditional Bresle patch cell, ISO 8502-9) of any method used for soluble salt extraction and conductance testing. NACE standard SP0508-2010 gives a standard prac- tice to performing equivalency testing and data validation to meet established criteria. APPENDIX C: DISCUSSION AND SOURCES ON EXTRACTION EFFICIENCY Extraction efficiency is defined as the quantity of salt retrieved from the surface as a percentage of the total amount originally on that surface. The extraction efficiency varies
A-17 SSPC-Guide 15 August 21, 2013 significantly among different situations. Some of the significant variables are: â¢ The method of extraction â¢ The proficiency of the operator â¢ The degree of roughness of the surface â¢ The size of the area being extracted â¢ The type and concentration of the salt â¢ The degree of corrosion and pitting of the substrate â¢ The extraction time â¢ The method of contamination (i.e., by artificial or natural methods) Several studies have been conducted to evaluate the efficiency of extraction. The researchers applied specific quantities of salts over defined areas to provide an average concentration as a control. In a few studies, the steel substrates were exposed to the salts (e.g., in an accelerated laboratory chamber or in atmospheric exposures). For these tests, the control concentration was determined using the total extraction method (boiling). The researchers assumed that this technique would extract 100% of the soluble salts. Some studies have questioned the validity of using artificially doped test panels to establish extraction efficiency. From a review of the published literature one concludes that there is not enough data to develop specific extraction effi- ciencies for the various extraction procedures. A list of sources for extraction efficiencies is given on the next page. Bibliography for Appendix C Appleman, B.R., Boocock, S.K., Weaver, R.E.F., and Soltz, G.C. âEffect of Surface Contaminants on Coating Life,â SSPC #91-07, Pittsburgh, PA: SSPC 1991. Appleman, B. R. âAdvances in Technology and Standards for Mitigating the Effects of Soluble Salts,â Journal of Protec- tive Coatings and Linings (JPCL), Vol. 19, No. 5, May 2002, pp. 42-47. Ashley, K., Andrews, R., Cavazos, L., and Demange, M. âUltra- sonic Extraction as a Sample Preparation Technique for Elemental Analysis by Atomic Energy,â J. Anal. At. Spec- trom., 2001, Vol. 16, pp. 1147-1153. Boocock, S. K. âSSPC Research on Performance Testing of Abrasives and Salt Retrieval Techniques,â JPCL, Vol.11, No. 3, March 1994, pp. 28-44. Chong, S-L., and Yao, Y. âA Methodology to Evaluate the Rela- tive Performance of Various Coating Systems,â JPCL, Vol. 26, No. 3, March 2009, pp. 26â32. Chong, S-L., Yao,Y. and Rozario, M, âIntra-laboratory Assess- ment of Commercial Test Kits for Quantifying Chloride on Steel Surfaces,â JPCL, Vol. 20, No. 8, August 2003, pp. 43-60. Chong, S-L., Yao, Y., and Lee, S-K, âUse of Conductivity Measurements to Estimate Chloride Concentrations on Steel or Painted Surfacesâ, JPCL, Vol. 24 No. 9, January 2007, pp. 23â27. Flores, S., Simancas, J., and Morcillo, M. âMethods for Sampling and Analyzing Soluble Salts on Steel Surfaces: A Comprehensive Study,â JPCL, March 1994, pp. 76-83. Forsgren, A., and Applegren, C. âComparison of Chloride Levels Remaining on the Steel Surface After Various Pretreatments,â in Proceedings from PCE 2000, Genoa, Italy, March 8-10, 2000. Mitschke, Howard, âEffects of Chloride Contamination on Performance of Tank and Vessel Linings,â in SSPC: Proceedings of the SSPC 2000 Seminars, SSPC #00-15. SSPC: Pittsburgh PA, 2000. Richards, Dennis M. âEffects of Chloride Contamination of Abrasives on the Performance of Long Life Coatings for Steel,â in The Proceedings of the Seminars: Application & Inspection of Protective and Marine Coatings, Coatings for Asia 99, Singapore, August 30 through September 1, 1999, SSPC: Pittsburgh, PA, 1991. Soltz, G.C. âThe Effects of Substrate Contaminants on the Life of Epoxy Coatings Submerged in Seawater.â San Diego, CA: National Shipbuilding Research Program Report, Task 3-84-2. March 1991. Steinsmo, Unni, Axelsen, Sten B. âAssessment of Salt Contamination of Its Effect on Coating Performance,â in Proceedings of the PCE 98 Conference and Exhibition, The Hague, The Netherlands, April 1-3, 1998.
A-18 SSPC-Guide 15 August 21, 2013 APPENDIX D: SOURCES OF TESTING EQUIPMENT AND SUPPLIES Information on suppliers of testing and analytical equipment may be found in the Journal of Protective Coatings and Linings Buyerâs Guide. The web sites listed below also provide contact information and links to manufacturers of coating testing equipment and supplies. Readers may also search the World Wide Web using keywords such as surface salinity meter, soluble salt meter, analytical testing equipment, Bresle, chloride ion, coating test kit, conductivity, ferrous ion, ion detection tube, inspection, laboratory testing supplies, nitrate ion, paint testing equipment, sulfate ion. Chlor*Rid, Inc. http://www.chlor-rid.com/home.php\ DKK-TOA Corp. http://www.dkktoa.net Elcometer, Inc. http://www.elcometer.com/ EMD Chemicals http://www.emdchemicals.com Expertus Kemiteknik http://www.swedyp.com/company/684816/Expertus_Kemiteknik_AB/website /moc.hcah.www//:ptth .cnI ,hcaH moc.retemtlaselbulos.www//:ptth NodeH KTA-Tator, Inc. http://www.ktagage.com/ LaMotte Co. http://www.lamotte.com Louisville Solutions, Inc. http://www.louisvillesolutions.com/index.html TQC: Thermimport Quality Contol http://www.tqc.eu/en/products/productlist PaintSquare http://www.paintsquare.com/bg/buying_guide_equip.cfm SSPC Website http://www.sspc.org/links/equip.html Copyright Â© SSPC standards, guides, and technical reports are copyrighted world-wide by SSPC: The Society for Protective Coatings. Any photocopying, re-selling, or redistribution of these standards, guides, and technical reports by printed, electronic, or any other means is strictly prohibited without the express written consent of SSPC: The Society of Protective Coatings and a formal licensing agreement.