Not All Fireproof Steel Coatings Are Equal
Intumescent Steel Coating for fireproofing has become a near exact science, with loads, calculation tables, Hp/A and or W/D to know the exact DFT required for your hourly rating. These sure take time to quantify, especially on large projects, but the end result will be exact with a DFT that correlates to the steel section, all based on actual test data and tables supplied by the test facility.
In principal manufacturers and agents (well let’s say most) are offering Dry Film Thicknesses (DFT) of their Intumescent steel coatings related to the BS 476 Certifire approval or UL263, using the given critical temperatures 500°C / 520°C or 620°C. If the approval also allows a multi temperature data, the certificate may also provide DFT’s up 750°C critical steel temperatures. And for sure, the demand of coating is lower if the critical steel temperatures raised.
But raising the critical steel temperature is only possible, if the structural engineers confirms the higher critical temperature of the total structure (and not only for a single beam or column). If we don’t know the critical temperature of the structure a higher critical steel temperature will reduce the safety level.
In a worst case the structure is no longer protected for the requested fire rating. As manufacturers, we are very aware that nearly all projects we work on with either CharCoat SC60, SC120 or SCe120 consistently use the given critical temperatures of 500°C / 520°C or 620°C.
We have in recent months, especially in the Middle East with several manufacturers agents noted that they are not explaining the structural engineering facts, when they calculate projects they are using a higher critical temperature, which is reducing the paint volume requested for the project to gain a better footing to sell more coating, and in doing so are no longer fire rating the structure.
Something to be very aware of when you are looking at your steel fireproofing coatings.