Controlling health risks from soldering and brazing

Mark Owen – Health & Safety Expert

March 14 2016

The control of health hazards at work is one of the Health and Safety Executive’s priorities, and a particular area of concern is the fume and residues created during soldering and brazing. The Executive has published guidance on this issue - and failure to control the risks is more likely than not to lead to formal enforcement and Fee For Intervention charges... Soldering – the process by which two or more metal items are joined together by melting a filler metal (solder) into the joint – has been used for thousands of years. Brazing is a very similar process, the main difference being that the filler metal melts at a much higher temperature. In the past, nearly all solders contained between 40 and 60% lead – but environmental and health concerns have increasingly dictated use of lead-free alloys for both processes. Why do these processes present a danger? While lead-free soldering has reduced strain on the environment, it hasn’t made the process any less of a danger to operators’ health. The lead in solder used to assist solder flow, so without it, much more of the chemical flowing agent known as ‘flux’ is needed to get the same results – the most commonly used flux, rosin (or colophony), is an acidic compound sourced from pine tree resin. Although it only makes up 1-2% of the solder, with much higher temperatures required for lead-free solder, the reaction within the flux is much stronger, creating more fume and smoke with a greater number of particles, making it a hazard to anyone involved in the process. The fumes and residues can cause:

  • Occupational asthma
  • Skin problems such as dermatitis

Assessing and minimising health and safety risks With the above in mind, it’s essential that the potential risks to the health of any worker who may use, or be affected by, the fumes and residues generated are properly assessed, and appropriate control measures put in place. The assessment will need to take account of the frequency and amount of soldering taking place at any time. The Control of Substances Hazardous to Health Regulations require that exposure to hazardous substances should be eliminated or reduced to as low a level as is reasonably practicable. There are a few ways you can do this, depending on the soldering process used, such as:

  • Use a mechanical jointing process
  • Use a conductive adhesive
  • Use rosin free solders – although these may present their own health hazards

Where rosin based fluxes have to be used, risks will need to be controlled through a combination of measures, including:

  • Good general ventilation
  • Temperature-controlled soldering irons
  • Good worker posture
  • Local exhaust ventilation (LEV)

In some cases, personal protective equipment (PPE) can be used in conjunction with other measures to provide further protection, such as:

  • Gloves
  • Eye protection
  • Coveralls
  • Suitable respiratory protective equipment (RPE)

Because rosin-based solder flux fume is known to cause occupational asthma, there’s also a requirement for health surveillance. New employees will need to be screened for allergies and existing employees should be subject to continuing routine surveillance. Our BusinessSafe clients have access to guidance and information on controlling the risks to health and occupational health surveillance, including advice on in-house surveillance where suitable. For direct access to our fully qualified and competent Business Safety Consultants, please call our 24 hour advice service on 0844 892 2785.

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