New Mexico Pipe Fitter Journeyman (JPF) Practice Exam

Which lens shade number gives the most protection when welding?

1. 8

2. 6

3. 10

4. 4

The correct answer is: 10

The choice of lens shade number is crucial for protecting the eyes during welding. A lens shade number is indicative of how much light it filters, and the higher the number, the darker the lens. In the context of welding, a shade number 10 provides optimal protection against the intense light and ultraviolet (UV) radiation generated during the welding process. It effectively reduces the brightness to a safe level, which helps in preventing eye strain and damage from the high heat and light emissions. Welders are exposed to harmful rays, including ultraviolet and infrared light, making it essential to use an appropriately shaded lens. Shade numbers lower than 10, such as 8, 6, or 4, do not offer sufficient protection for most welding operations, especially when dealing with high amperage processes or when using more intense welding techniques. Thus, the choice of lens shade number 10 is advisable for ensuring eye safety while working in welding environments.