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Welding Fume Measurement from Hot Tap Welds at the National Hyperbaric Centre

Welding Fume Measurement from Hot Tap Welds at the National Hyperbaric Centre. John AS Ross Environmental and Occupational Medicine. Collaborators. University of Aberdeen, Dr Sean Semple – Enviromental & Occupational Medicine Prof Jonn Ayres

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Welding Fume Measurement from Hot Tap Welds at the National Hyperbaric Centre

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  1. Welding Fume Measurementfrom Hot Tap Welds at theNational Hyperbaric Centre John AS Ross Environmental and Occupational Medicine

  2. Collaborators • University of Aberdeen, • Dr Sean Semple – Enviromental & Occupational Medicine • Prof Jonn Ayres • Dr Andrea Raab – Trace Metal Speciation Laboratory • Prof Joerg Feldmann • University of Edinburgh • Dr Rodger Duffin Centre for Inflammation Research • Prof Ken Donaldson • University of London, King’s College • Prof Frank Kelly – Lung Biology Unit • Funding • University of Aberdeen • Acergy • Technip

  3. Why are we interested in welders? • Ischaemic heart disease • Pneumonia and death from pneumonia • A model of human particle exposure responses • – air pollution • We can measure higher levels of fume from hyperbaric chambers – dilution effect • ELTHI study cognitive symptoms • 6% Non-divers, 15% Divers, 28% Diver welders • Follow up study • 10% Welders, 33% Diver welders with symptoms • But welders exposed to 3 times more welding fume • And no dose response relationship between fume exposure and symptoms • However fume exposure higher in both welders and welder-divers with symptoms

  4. Definitions • PM10 - mass of particles < 10 m diameter • PM5 - mass of particles < 5 m diameter • PM2.5 - mass of particles < 2.5 m diameter • PM1 - mass of particles < 1 m diameter • Nanoparticles - <100 nm diameter

  5. Personal exposure of bar worker on a Friday night in February 2006…

  6. Personal exposure of same bar worker on a Friday night in August 2006…

  7. Particle number count when shopping walking on Union Street eating area shopping mall shop shop

  8. London Underground Metropolitan Railway

  9. Welding dust agglomeration on internal ventilation system 30M filter

  10. Photomicrograph (X40 top-lit) of particle of caked dust from filter surface

  11. Metal Analysis Most of the dust is insoluble in nitric acid/hydrogen peroxide and of whitish/grey colour. Did not contain crystalline quartz

  12. Cytotoxicity

  13. Inflammatory potential

  14. Oxidative potential

  15. Dust Trak PM10 PM2.5 PM1 Mass/volume Grimm 230->20,000 nm Particles/volume P-Trak <100 nm Particles/volume MSP WPS 10-200 nm Particles/volume

  16. Fume in the hyperbaric environment

  17. Fume in the hyperbaric environment

  18. Dust-Trak and P-Trak Particle Mass Particle number

  19. WPS (10-200 nm)

  20. Final comments on fume levels - 1 • PM2.5 levels of less than 4mg m-3 are possible • P-trak levels of <2X106 cc-1 are possible • The work chamber ventilation system did reduce fume levels • Generation of nano-particles of a size not completely measured by P-Trak, Grimm or Dustrak identified • No evidence of agglomeration in atmosphere during welding • Filter respirators used in welding • Tested at 500 nm particle diameter • Edge leakage • Filters used in internal ventilation • May not be 100% effective until partially blocked by agglomeration

  21. Final comments on fume levels - 1 • Welding fume can cause oxidant stress • Welding fume can cause inflammation in lung tissue • Nano-particles can probably enter blood via lung • Dermal uptake of nano-particle dust has been observed • Safe levels of nano-particle welding fume unknown • Area will expand as monitoring technology improves

  22. Fume in the hyperbaric environmentEquipment

  23. Toxicity • Conventionally related to mass of agent absorbed • Recently surface chemistry has also been identified as relevant • Surface area larger in smaller particle sizes • Smaller particles regarded as more active locally in triggering inflammation • Evidence mostly confined to vehicle/diesel engine exhaust • Titanium dioxide

  24. Methods • Measurement of fume during hot tap welding at pressure • Gas sampled via a quarter turn valve decompressing chamber gas into an open ended pipe reservoir • Free flow of about 30 l-1 • Analysers sampling out of the reservoir

  25. Number 17 April 2007 10-200 nm diameter particles WPS 1000XP Weighted for number, mass and surface area Single epoch during welding Surface Area Mass

  26. Number 17 April 2007 10-200 nm diameter particles WPS 1000XP Weighted for number, mass and surface area Mean of 110 readings Surface Area Mass

  27. Work in Progress • Detailed metal analysis from 4 welds • Trace Element Speciation Laboratory at the University of Aberdeen • Analysis of the oxidising power of welding fume in the lung in dust from four welds • Lung Biology Unit, King’s College, London University • Potential lung toxicity and inflammation potential in dust from four welds • ELEGI Colt Laboratory, the University of Edinburgh • The effects of 2mg m-3 welding fume inhalation in man • Environmental and Occupational Medicine, University of Aberdeen

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