Structural fire endurance experiments were conducted on full-scale cellular glass fiber reinforced (GFRP) columns under axial compression and subjected to ISO 834 fire exposure from one side. Unprotected columns could resist fire for more than 30 min, which is sufficient for occupants to be evacuated from smaller buildings. The closed cellular cross section prevented the rapid heating of the webs, which could therefore continue stabilizing the face sheet on the cold side against buckling. Water cooling was proved to offer an effective active fire protection system. The structural function of the column could be maintained for two hours. Previously developed models were capable of predicting the time-dependent temperature responses, modulus degradation and time-to-failure.