Final answer:
A ventilation system for welding should remove smoke or fumes before they reach the welder's face to prevent respiratory issues and protect from heat and light exposure.
Step-by-step explanation:
Any system of ventilation should draw the fumes or smoke away before it rises past the level of the welder's face. This safety measure is crucial in preventing respiratory issues and protecting the eyes and skin of welders from the intense heat and light produced by welding processes. As mentioned in the provided texts, welder's gloves and helmet are essential to protect from the electric arc, which can emit high-energy electromagnetic radiation capable of causing retinal burns and can be felt on exposed skin a few meters away. Similarly, a well-executed ventilation system can help create a safe working environment by removing harmful fumes before they reach the welder's face, thus avoiding potential health hazards.