safer soldering guidelines and instructional resources: Free soldering safety poster and online test now available on ITEEA's safety website!
Ideally, teachers want students to establish the ability to safely create solder joints pertaining to wiring, terminals, printed circuit boards (PCB), and other various electronics applications. With practice and training, students can develop skills to enhance their ability to perform more complex soldering applications, Advanced educational programs and electronic manufacturing companies use J-STD (J Standards) 001-006 as the benchmarks for soldering quality. These standards are internationally recognized guidelines for the following criteria related to different applications of electronic assembly manufacturing: material usage, cleaning, quality control, repair/rework, and process control. They are also used for certification in different electronic assembly applications and levels of soldering (IPC, 2017a).
Lead Versus Lead-Free Solder
When purchasing solder it is important to understand the differences between lead and lead-free options. Global consumption of lead-free solder has increased 20% worldwide over the past nine years, while lead solder consumption has decreased by the same percentage (IPC, 2017b). Lead soldering can form lead oxide fumes. Excessive exposure to these fumes or accidental transfer of lead from a person's hands to areas such as the mouth can result in lead poisoning. Lead fumes can be absorbed through the mucous membranes of the lung, stomach, or intestines and then enter the bloodstream. Symptoms of lead poisoning include loss of appetite, indigestion, nausea, vomiting, constipation, headache, abdominal cramps, nervousness, and insomnia (OSHA, 1993). Because of this, it is recommended that only lead-free and rosin-free solders be used in school settings. Regardless of the type of solder used, it is still better professional practice to have students wash their hands with soap and water when finished with all soldering activities.
While OSHA provides guidelines for soldering and brazing in the workplace, it offers very limited information applicable to soldering in school settings. In OSHA's Technical Manual (Section V, Chapter 3, Part R: Soldering and Brazing), it recommends that soldering in confined areas (such as a classroom or makerspace) require portable local exhaust ventilation to remove any hazardous fumes that may be produced. Ideally this would be in the form of a fume hood or portable fume extractor located directly where the soldering is occurring. Dust collectors/vacuums used for sawdust, and fume hoods used for chemical or finishing (e.g., spray paint) purposes should not be used for both those activities and soldering due to the risk of combustion. Additionally, fume hoods and fume extractors should not be placed in a high-traffic area or near doors and windows. Use of lead-free and rosin-free solders could allow for the use of an appropriate size electrostatic air filtration unit to circulate the air in confined spaces. The National Fire Protection Association (NFPA) requires labs in which chemicals are present to be continuously ventilated under normal operating conditions (Standard on Fire Protection for Laboratories Using Chemicals 2015 Edition: section 7,2.2). With any filtration system, it is important to maintain filters according to the manufacturer's recommendations (Roy & Love, 2017).
General Safer Soldering Guidelines
General soldering safety guidelines are provided by Roy and Love (2017, p. 91), Carnegie Mellon University (2016), and the University of Cambridge (2017). Some of these key guidelines are listed below, and a more comprehensive list is provided on the free safety poster that accompanies this article (available from www.iteea.org/solderingironsafetyposter.aspx).
1. Solder can spit, therefore ANSI/ISEA Z87.1-rated safety glasses or goggles must be worn while soldering.
2. Conduct all soldering on a level, fire-resistant surface away from any combustible materials or vapors.
3. Check that power sources and batteries are disconnected/ unplugged from all parts before attempting to solder them.
4. Keep the cleaning sponge wet during use and keep cleaning solvents in dispensing bottles to reduce inhalation.
5. Always place the soldering iron securely in the stand when not in use. Turn off the soldering iron or unplug it when finished.
6. Never touch melted solder or the tip/element of a soldering iron until they are completely cool.
7. Use tweezers, pliers, or clamps to hold wires and avoid receiving burns.
8. Keep food and drink out of the work area. The solder may have a tin/lead alloy, which is toxic.
9. When finished soldering, wipe off the work surface using water or cleaning solvents.
10. Avoid touching parts of your face when soldering. Wash your hands with soap and water when finished.
Instructional and Safety Resources
In addition to the aforementioned safety guidelines, there are a number of great resources for teaching students how to solder more effectively and safely. The following sources provide free soldering instructional materials:
* Gateway to Space, Colorado Space Grant Consortium: Soldering 101--http://spacegrant.colorado.edu/images/GatewayToSpace/Fall2017/Presentations/05_Soldering_101.pdf
* Tufts University Maker Network: Soldering Iron--https://maker.tufts.edu/equipment
* Dr. Riccardo Bevilacqua: Soldering Safety-- www.riccardobevilacqua.com/SolderingSafety.pdf
Soldering is a useful and necessary process for many classroom, makerspace, Fab Lab, technology and engineering lab, and science lab activities. As described in this article, soldering can pose many safety risks without proper engineering controls, standard operating procedures, and direct instructor supervision. A useful resource for dealing with medical emergencies resulting from soldering (burns, swallowed poisons/toxins, etc.) is Roy and Love's (2017, pp. 101-105) latest book. There are many safety hazards mentioned throughout this article that instructors should remember to analyze and address before, during, and after all soldering activities.
The authors would like to acknowledge Dr. Ken Roy for his professional review and contributions to this article.
Association Connecting Electronics Industries (IPC). (2017a). Creating excellence in electronics assembly. Retrieved from www.ipc.org/ContentPage.aspx?pageid=J-STD-001#atc
Association Connecting Electronics Industries (IPC). (2017b). October 2017: North American electronics business is looking up. Retrieved from www.ipc.org/ContentPage.aspx?pageid=Current-Industry-Trends
Carnegie Mellon University (CMU). (2016). Lead soldering safety guidelines. Retrieved from the CMU Environmental Health Safety website www.cmu.edu/ehs/Laboratory-Safety/chemical-safety/documents/Lead%20Soldering%20Safety%20Guidelines.pdf
Occupational Safety and Health Administration (OSHA). (1993). ICP backup data report for soldering and brazing matrices (ARL 3560). Retrieved from www.osha.gov/dts/sltc/methods/inorganic/id206ar13560icp/id206ar13560icp.html
Roy, K. R. & Love, T. S. (2017). Safer makerspaces, fab labs, and STEM labs: A collaborative guide! Vernon, CT: National Safety Consultants, LLC.
University of Cambridge. (2017). Soldering safety. Retrieved from https://safety.eng.cam.ac.uk/procedures/Soldering/soldering-safety
Have questions or a safety issue that you would like to see addressed in a future Safety Spotlight article? Please send them to Dr. Tyler Love at firstname.lastname@example.org.
Tyler S. Love, Ph.D. is an Associate Professor and Coordinator of Technology and Engineering Education at the University of Maryland Eastern Shore. He currently serves as editor of Safety Spotlight. Dr. Love can be reached at email@example.com.
Joel Tomlinson is a lecturer in Electrical Engineering Technology at the University of Maryland Eastern Shore. He can be reached at firstname.lastname@example.org.
Caption: The Soldering Iron Safety Test above is available for download on the ITEEA website at www.iteea.org/solderingirontest.aspx.
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|Title Annotation:||safety spotlight|
|Author:||Love, Tyler S.; Tomlinson, Joel|
|Publication:||Technology and Engineering Teacher|
|Date:||Feb 1, 2018|
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