Due to the hazards of welding fumes to the human body in the welding workshop, the welding fumes should be treated and eliminated in time through ventilation and purification. The ideal solution is to install a central welding fume purification system in the local high-smoke area first to dispose of a large amount of fume and dust, and the escaped fume and dust are discharged from the workshop through the roof natural ventilator. The continuous rooflight can be mcw5 or MCW1, MCW2 type, which can be arranged down the slope. If the workshop span is not large, it can be directly arranged as ridge ventilator. If the amount of smoke and dust is small, the sloped roof can be equipped with small mcw6 natural vent for downhill daylighting.