What is BS IEC 61189-5-2 - Soldering flux for printed board assemblies about?   
BS EN IEC 61189 covers test methods for electrical materials, printed boards, and other interconnection structures and assemblies. electrical materials printed board and other interconnection structures and assemblies are a laminated sandwich structure of conductive and insulating layers. The main objective of the IEC 61189 series is to demonstrate the reliability of laminate materials and assemblies and avoid printed circuit board failures. 
BS IEC 61189-5-2 is an international standard for electric materials that specifies the test methods for materials and assemblies which is helpful in measuring the ionic residues which are dissolved in ionic contamination solutions. BS IEC 61189-5-2 is a catalogue of test methods representing methodologies and procedures that can be applied to test printed board assemblies. BS IEC 61189-5-2 focuses on test methods for soldering flux based on the existing IEC 61189-5 and IEC 61189-6. In addition, BS IEC 61189-5-2 includes test methods of soldering flux for lead-free soldering.
Who is BS IEC 61189-5-2 - Soldering flux for printed board assemblies for?  
BS IEC 61189-5-2 on soldering flux for printed board assemblies is relevant to:  
- Manufacturers of electronic devices  
- Manufacturers of printed circuits and boards  
- Quality testing agencies 
- Electronics industry 
- Electronic engineers 
Why should you use BS IEC 61189-5-2 - Soldering flux for printed board assemblies? 
The flux's primary function is to clean and remove any oxides or contaminants from metal surfaces prior to soldering. IEC 61189 relates to testing methods for materials or component robustness for printed board assemblies, irrespective of their method of manufacture. BS IEC 61189-5-2 is divided into separate parts, covering information for the designer and the test methodology engineer or technician. Each part has a specific focus; methods are grouped according to their application and numbered sequentially as they are developed and released. In some instances, test methods developed by other TCs (for example, TC 104) have been reproduced from existing IEC standards in order to provide the reader with a comprehensive set of test methods. When this situation occurs, it will be noted on the specific test method; if the test method is reproduced with minor revisions, those paragraphs that are different are identified.
BS IEC 61189-5-2 contains test methods for evaluating the robustness of materials or components for printed board assemblies. The methods are self-contained, with sufficient detail and description so as to achieve uniformity and reproducibility in the procedures and test methodologies. To facilitate reference to the tests, to retain the consistency of presentation, and to provide for future expansion, each test is identified by a number (assigned sequentially) added to the prefix (group code) letter showing the group to which the test method belongs. The test method numbers have no significance with respect to an eventual test sequence; that responsibility rests with the relevant specification that calls for the method being performed. The relevant specification, in most instances, also describes pass/fail criteria.
This test method is designed in BS IEC 61189-5-2 to determine the corrosive properties of flux residues under extreme environmental conditions. The solder is then exposed to prescribed conditions of humidity and the resulting corrosion, if any, is assessed visually. The temperature and humidity test recommended by BS IEC 61189-5-2 is implemented to ensure or verify the ability to maintain the service life if the specimen is used under constant temperature and humidity conditions. This helps you to review the test conditions and to pay sufficient attention to high-temperature conditions.  Overall, BS IEC 61189-5-2 can demonstrate the reliability and performance of a printed circuit board laminate material or a finished product. Apart from this, it will help you to clean and remove any oxides or contaminants from metal surfaces prior to soldering.
