When the equipment is treated with care and the correct spraying techniques are carried out, thermal spraying isn’t as dangerous a process as one may believe. Thermal spray coatings can actually be applied incredibly safely when sufficient risk assessments have been performed.

Four processes make up the broader thermal spraying: Arc Spraying, Flame Spraying, Plasma Spraying and HVOF spraying. All of which have several of their own health and safety measures to be measured and countered.

Just like other industrial processes, there’s plenty of hazards that an operator should be aware of, and precautions that should be taken according to each process in use.

Safety Considerations

Any thermal spraying equipment really should be operated in enclosures that are designed specially for the machinery. Environments that extract fumes, reduce the noise level, and present direct viewing of the tools.

Noise

Arc and Flame spraying equipment use compressed gases and they create plenty of noise. With the varying types of equipment for spraying techniques and the material being sprayed, sound levels can differ greatly.

Just behind the nozzle – 1 metre behind – for flame and arc spraying, for instance, regular sound pressure levels are 102-104 dB(A). And considering the safety level is under 80 dB, that’s quite significant.

That’s why specifically designed spaces need to be constructed and available for use to cope with these levels. But if it’s not possible, operators or passers-by should always use some sort of ear protection. Ear buds or a headset.

Ear protection for plasma spraying is even more important. Sound pressure levels when operating can be upwards of 132 dB(A), similar to HVOF spraying which has levels upwards of 133 dB(A). These are some crazy levels to have our hearing subjected to and can be incredibly damaging to our hearing functions which is why ensuring ear safety is crucial.

Light

Spraying equipment using a combustion technique will typically produce a very intense flame. A flame that also has an insanely high peak temperature: 3,1000 degree Celsius. Not only is that temperature white hot, it’s white bright, too.

Produced by electric arc spraying, ultra-violet light can be damaging to delicate body tissues. So ultra-violet absorbing dark glass should be used to counteract the affect of the brightness. Otherwise, if this isn’t an option or is impractical, safety glasses with BS grade 6 green glass need to be used to ensure adequate protection for the eye.

Opaque screens and never directly viewing the spray nozzle should be common and known precautions that are always taken.

Knowledge on all of the precautions is important because plasma spraying, there needs to be an even higher level of protection. BS grade 10 green glass. Because Plasma spraying doesn’t only produce large amounts of ultra-violet light, but also visible and infrared radiation, too.

The UV that it produces can have an effect on exposed skin such as sunburn, overexposure to UV light, and a change in the growth of skin cells. This type of exposure, if prolonged, has serious potential risks like increased chances of skin cancer.

Dust

When molten materials are atomised, they produce fine quantities of dust and even fumes, making it important for the right extraction facilities to be implemented. When extraction is done efficiently, it improves personal safety as well as the coating itself. This is because there is a minimisation in the entrapment of re-frozen particles in the spray applied coatings.

When it comes to specific materials, they each have their own hazards:

  • Finely divided metal particles are pyrophoric (potentially) so they shouldn’t be given the chance to collect.
  • Base metals like aluminium and zinc emit hydrogen when they react with water. This reaction can actually be explosive sometimes so these require a little bit of extra diligence.
  • Zinc and copper alloys, as well as some other materials, can have unpleasant smells which can cause feverish reactions from some people.

Heat

Fuel gases and oxygen are used by combustion spraying pistols and these fuel gases have the potential to be explosive. Particularly Acetylene which can actually only be used under conditions that have been approved by the Health and Safety Authorities.

Though oxygen itself isn’t explosive, it will sustain combustion for prolonged periods of time if the oxygen levels are overly excessive.

Electricity

Though electric arc spraying pistols operate at voltages that are relatively low, 50 vdc, their currents run quite high. Some are safe handheld models but others, ones that connect to 440 volts AC sources, should be treated with the normal level of caution as electrical machines are.

Coating Specialists

At Alphatek, we take health and safety very seriously as it is a very important aspect to consider. When we apply coatings for customers and clients, they don’t just want longevity or quality. They want a coating that is safely and efficiently applied.

Helping customers and clients make decisions that are informed is one of our aims. We never want them to feel blindsided or make a poorly informed choice. Not if we can help them.

High quality coatings mean less maintenance and more reliability.

Contact Alphatek

If you want the best, you have to work for it. That means no cutting corners, no shortcuts. And Alphatek has way over 100 years of coating experience collectively.

We’ve worked closely with customers and clients throughout the years, developing a product or a service that is bespoke and the best. The best solution at the best value. And we always plan to deliver. First time, every time.

With a service that is designed to be stress-free, we can adapt to everyone.

For Metal Spraying and Thermal Spray Coatings specialists, you’ve come to the right page. You can call directly on 01706 821 021 or send us a message – our inbox is postbox@alphatek.co.uk.

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