The current standard for safety spectacles, goggles, and face shields is EN 166. The standard has different sub-classes, listed below, so the description may be complex (e.g. a gas safety goggle conforms to BS EN 166.1.B.3.5.9).
a) 1 or 2 describes the optical class
b) 3 protects against liquid droplets/splashes
c) 4 protects against large dust particles
d) 5 protects against gas and fine dust particles
e) 9 protects against molten metals and hot solids
f) B protects against medium energy impact
g) F protects against low energy impact.