Extraction vs. Exhaust

Exhaust-Transferal of toxic air using natural air movement

One of the most common practices for the reduction of welding fume is the use of natural ventilation. This is claimed to be an adequate measure for the safety of workers.  People are often not aware this measure of ‘exhaust’ only transfers the danger still leaving the risk to other workers. Weld Australia Fume Minimization guidelines state  ‘Relying on a light cross-draught in the vicinity of the welder’s face to ensure that the fume is either drawn or blown away from the welder’s breathing zone can be unreliable.’ (Weld-Australia)

Extraction-Elimination of toxic air

The most effective way of risk elimination of fumes in the workplace is capture and extraction of fumes. WTIA Fume Minimization Guidelines state ‘local exhaust ventilation captures fume at its source before it enters the operators breathing zone or the workshop atmosphere. LEV should be positioned to capture the plume in which the particulates are concentrated. A minimum capture velocity of 0.5m/s measured at the fume source is required for protection of the welder from particulate and ozone generated near the arc.’ (Weld-Australia)