Health, safety and environmental practice in the print workshop
What the exam tests
Safety questions test hazard identification (solvents, UV inks, plate chemistry, dust, noise), machine guarding, and legal waste routes. Answers must be practical controls, not slogans.
Hazardous substances
- Solvents in blanket wash and liquid inks are flammable, narcotic and volatile organic compounds. Check flash point, occupational exposure limit (OEL, 8-hour TWA) and the safety data sheet.
- Fountain solution: IPA is flammable and a VOC; alcohol-free systems reduce exposure but change wetting behaviour.
- UV inks and varnishes: acrylate monomers cause skin sensitisation; never handle bare-handed and ensure full cure.
- Plate developer and CTP chemistry: alkaline and corrosive; pH control and neutralisation before disposal.
- The SDS has 16 sections; sections 2 (hazards), 8 (exposure controls and PPE) and 13 (disposal) are the ones you cite.
Controls and machines
- Hierarchy of control: eliminate, substitute, engineer (LEV extraction, enclosures), administer (training, rotation), then PPE last.
- Guarding: interlocked fixed guards, light curtains, two-hand control on guillotines, nip guards on rollers, emergency stops. Lockout/tagout before clearing jams or changing blankets.
- No loose sleeves, ties or long hair near rotating cylinders; paper stacks are a manual-handling and crush risk.
Waste and environment
- Paper and board to recycling, clean and dry; aluminium plates recycled; solvent waste and ink residues consigned as hazardous waste, never to drain.
- Water-based does not mean harmless: biocides and acrylics still need disposal control. VOC abatement by recovery or thermal oxidation; FSC/PEFC chain of custody for fibre.
Worked example
A wash solvent has an 8-hour OEL of 100 ppm. Monitoring shows 60 ppm for 4 hours and 140 ppm for 4 hours.
- TWA = (60 × 4 + 140 × 4) ÷ 8 = (240 + 560) ÷ 8 = 100 ppm.
- That is exactly at the limit with no margin: fit LEV at the wash station or switch to a lower-solvent wash before the next campaign.
Traps that cost marks
- Calling water-based inks non-hazardous and pouring washings down the sink.
- Removing a guard for a quick jam clear.
- Quoting an OEL without stating the averaging time.
- Treating PPE as the first control rather than the last.
- Storing solvents near ignition sources or in unlabelled containers.