Connect, no.73, January 1996, p.3
Results from two extensive studies on fume emitted during plastics welding have just been published
Fume sampling to monitor concentration levels of hazardous substances during hot gas welding of plastics
The first of these studies, carried out by TWI on behalf of the Health & Safety Executive, involved looking at substances given off by PVC, PA, PMMA, PC and PP materials during hot gas welding. It measured the welder's personalexposure and found that in all cases this was very much lower than current occupational exposure limits. In addition, measurement of particles which can be inhaled was carried out close to the welding operation. Modest concentrationswere found when PVC and PP were welded, but for the remaining materials, concentrations were low.
Products evolved during laser cutting of plastics - new report now published
The second TWI investigation looked at substances given off when a carbon dioxide laser is used to cut a range of plastics including PVC, PC, PMMA, PET and epoxy/glass fibre composites. Laser cutting of all materials produced highconcentrations of particles which can be inhaled and all but epoxy/glass fibre composites produced high concentrates of volatile substances. While the measurement technique was designed to maximise detection levels, results indicatethat there is a risk that people carrying out laser cutting of plastics are exposed to unacceptable levels of hazardous substances.
The new HSE publications on these topics underline the importance of using a well-designed ventilation system capable of controlling exposure of workers to any such substances. The information should help employers when carrying outassessments required under the Control of Substances Hazardous to Health Regulations 1994 and in the steps taken to monitor resulting modifications.
If you would like to obtain a copy of Products evolved during hot gas welding of plastics, (contract research report 86/1995) or Products evolved during laser cutting of plastics (contract research report 87/1995),call HSE Books on 01787 881165.
