Thin film Intumescent coatings can provide a durable and attractive surface, similar to a paint finish. However, in a fire the Intumescent will expand to many times its original thickness. This provides an insulating foam-like char to protect the steelwork against heat build-up.
Intumescent basecoats are available in Water or Solvent based systems and when applied to correctly prepared & primed steel will offer a robust and cost effective solution for fire ratings of 30, 60, 90 & 120. When calculating the product requirements the following key factors will apply:
Fire rating required:
30, 60, 90 or 120 minutes
Type of section:
Universal, hollow, beams or columns
Steel exposure:
Partial exposed, 3-sided or 4 sided
Size and weight of steel:
Hp/A
The Hp/A value is known as the section factor of the steel section. This section factor is directly related to the heating rate of the steel section under a fire condition.
Hp – The perimeter of the steel exposed to the fire
A – The cross sectional area of the section
The larger the surface area relative to the cross sectional area, the higher the Hp/A value, the higher the Hp/A value, the more material required. This means that the thicker the section, the slower it is to heat up consequently the less thickness of material required.