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Are there any Health and Safety Implications of Cutting and Welding Plastics?

   

Polypropylene, polyethylene and polycarbonate all generate benzene, a carcinogen, during laser cutting. Polystyrene releases styrene, while PVC emits hydrogen chloride. Many plastics also give off ultra fine particles, plus carcinogenic polycyclic aromatic hydrocarbons. In addition, the filters that are commonly used to clean up the fumes that originate from laser cutting of metals will not remove the fumes produced from plastics. These points indicate that workers involved with laser cutting of plastics may potentially be exposed to unacceptable levels of hazardous substances. Hence, the need for employers to install the correct ventilation systems so that exposures are controlled adequately.

Exposure to fumes given off during the hot gas welding of plastics such as PVC, nylon, PMMA, polycarbonate and polypropylene is not normally likely to give cause for concern. However, there may be a health risk where the welding takes place in confined spaces in which the welder's head is close to the welding operation, and where ventilation is restricted.

Of greater concern is exposure to hazardous fumes during hot gas welding of fluoropolymers such as PVDF, ECTFE, PFA and FEP, which can cause influenza-like symptoms known as "polymer fume fever". For this reason, it is recommended that these materials are not welded above their recommended weld temperature and that a good standard of local exhaust ventilation should be used.

Laser cutting of fluoropolymers should be the subject of a rigorous risk assessment.

Another fluoropolymer that can cause polymer fume fever when overheated is PTFE, which is used as a non-stick coating for hot plates that are used for welding other thermoplastics. For this reason, it is therefore recommended that PTFE-coated hot plates should not exceed a temperature of 270°C.

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