PF: Means that glass refuses flames and smoke, but not the heat.

RF: The glass, refuses flames, smoke, and also, forms a thermal insulation between two faces exposed to fire.

Both of them, comes with a number that explain the maximum time exposure (minutes) to fire.

With the introduction of the new European Regulation, the nomenclature of last classification describes has changed:

• PF changes to EW, means that glass keeps entirety during a time (in minutes)
• RF changes to EI, means that glass keeps entirety and assured the thermal insulation during a time