If it is required to provide fire insulation across a beam or column in order to maintain compartmentation (maintaining insulation to an average temperature rise of 140°C, maximum temperature rise of 180°C over ambient on the non-fire side), the following minimum board thicknesses on each side of the beam or column must be used:

PROMATECT®-XW: 15mm for 30 or 60 minutes insulation. (only available in 15mm thickness) 

PROMATECT®-250: 15mm for 60 minutes insulation, 20mm for 90 minutes insulation and 25mm for 120 minutes insulation. 

VERMICULUX®-S: 20mm for 60 minutes insulation, 25mm for 90 minutes insulation, 30mm for 120 minutes insulation, 40mm for 180 minutes insulation and 50mm for 240 minutes insulation.

These thicknesses may need to be increased due to the section factor (A/V value) of the steel section to meet the required limiting steel temperature. See Chapter 3 - Passive Fire Protection Handbook,  UL-EU-01220-CPR for PROMATECT®-250 & Certifire C5757 for  VERMICULUX®-S  for calculation of A/V values using tables in the Handbook and certification.