EPA Methods List with Links



US EPA Method 306b - Surface Tension Measurement For Tanks Used At Decorative Chromium Electroplating And Chromium Anodizing

FACILITIES NOTE: This method does not include all of the

specifications (e.g., equipment and supplies) and procedures (e.g., sampling and analytical) essential to its

performance. Some material is incorporated by reference from other methods in 40 CFR Part 60, Appendix A and in this part. Therefore, to obtain reliable results, persons using this method should have a thorough knowledge of at least Methods 5 and 306. 1.0 Scope and Application.



1.1 Analyte. Not applicable.



1.2 Applicability. This method is applicable to all decorative chromium plating and chromium anodizing operations, and continuous chromium plating at iron and steel facilities where a wetting agent is used in the tank as the primary mechanism for reducing emissions from the surface of the plating solution.

2.0 Summary of Method. 2.1 During an electroplating or anodizing operation,

gas bubbles generated during the process rise to the surface of the liquid and burst. Upon bursting, tiny droplets of chromic acid become entrained in ambient air. The addition of a wetting agent to the tank bath reduces the surface



2199 tension of the liquid and diminishes the formation of these

droplets. 2.2 This method determines the surface tension of the

bath using a stalagmometer or a tensiometer to confirm that there is sufficient wetting agent present. 3.0 Definitions. [Reserved] 4.0 Interferences. [Reserved]

5.0 Safety. 5.1 Disclaimer. This method may involve hazardous

materials, operations, and equipment. This test method may not address all of the safety problems associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to performing this test method.

6.0 Equipment and Supplies.



6.1 Stalagmometer. Any commercially available stalagmometer or equivalent surface tension measuring device may be used to measure the surface tension of the plating or anodizing tank liquid.



6.2 Tensiometer. A tensiometer may be used to measure the surface tension of the tank liquid provided the procedures specified in ASTM Method D 1331-89, Standard Test Methods for Surface and Interfacial Tension of Solutions of



2200 Surface Active Agents (incorporated by reference -- see



63.14) are followed. 7.0 Reagents and Standards. [Reserved] 8.0 Sample Collection, Sample Recovery, Sample Preservation, Sample Holding Times, Storage, and Transport. [Reserved] 9.0 Quality Control. [Reserved] 10.0 Calibration and Standardization. [Reserved] 11.0 Analytical Procedure.



11.1 Procedure. The surface tension of the tank bath may be measured by using a tensiometer, a stalagmometer or any other equivalent surface tension measuring device approved by the Administrator for measuring surface tension in dynes per centimeter. If the tensiometer is used, the procedures specified in ASTM Method D 1331-89 must be followed. If a stalagmometer or other device is used to measure surface tension, the instructions provided with the measuring device must be followed.



11.2 Frequency of Measurements.



11.2.1 Measurements of the bath surface tension are performed using a progressive system which decreases the frequency of surface tension measurements required when the proper surface tension is maintained.



11.2.1.1 Initially, following the compliance date,



2201 surface tension measurements must be conducted once every 4

hours of tank operation for the first 40 hours of tank operation.



11.2.1.2 Once there are no exceedances during a period of 40 hours of tank operation, measurements may be conducted once every 8 hours of tank operation.



11.2.1.3 Once there are no exceedances during a second period of 40 consecutive hours of tank operation, measurements may be conducted once every 40 hours of tank operation on an on-going basis, until an exceedance occurs. The maximum time interval for measurements is once every 40 hours of tank operation.



11.2.2 If a measurement of the surface tension of the solution is above the 45 dynes per centimeter limit, or above an alternate surface tension limit established during the performance test, the time interval shall revert back to the original monitoring schedule of once every 4 hours. A subsequent decrease in frequency would then be allowed according to Section 11.2.1.

12.0 Data Analysis and Calculations.



12.1 Log Book of Surface Tension Measurements and Fume Suppressant Additions.



12.1.1 The surface tension of the plating or anodizing tank bath must be measured as specified in Section 11.2.



12.1.2 The measurements must be recorded in the log



2202 book. In addition to the record of surface tension

measurements, the frequency of fume suppressant maintenance additions and the amount of fume suppressant added during each maintenance addition must be recorded in the log book.



2.1.3 The log book will be readily available for inspection by regulatory personnel.



12.2 Instructions for Apparatus Used in Measuring Surface Tension.



12.2.1 Included with the log book must be a copy of the instructions for the apparatus used for measuring the surface tension of the plating or anodizing bath.



12.2.2 If a tensiometer is used, a copy of ASTM Method D 1331-89 must be included with the log book. 13.0 Method Performance. [Reserved] 14.0 Pollution Prevention. [Reserved] 15.0 Waste Management. [Reserved] 16.0 References. [Reserved] 17.0 Tables, Diagrams, flowcharts, and Validation Data. [Reserved]