Intumescent Coating

Intumescent coating is a coating that protects the initial material by reacting to the heat exposure in a predictable, controllable manner. It reacts by swelling controllably to many times of its original thickness producing carbonaceous char or foam which acts as the insulating layer for the substrate. This coating composes of active ingredients (catalyst, corbonific agent, resin system or binder and spumific agent) which react together producing a phenomenon know as intumescence.

Firstly, the catalyst acts by decomposing the mineral acids into producing acids which react with the carbonific agent producing carbonaceous char. On the other hand, the resin system or binder softens during early exposure to high temperature reaction range and at the same time, the spumific agent decomposes releasing large volumes of non-inflammable gases including carbon dioxide, ammonia and water vapour. These gases, in turn, cause the binder to foam and expand providing the insulating char many times the coating thickness. This acts to produce a protection layer for the substrate (duct) extending its life span and decreases its deformation changes.

History of Intumescent and Application

Intumescent derived its name from the Latin verb, “tumescere” meaning, it will begin to expand during the crisis situation.

Intumescent coating reacts under the influence of heat by swelling in a controlled manner to many times of its original thickness and typical producing a layer of carbonaceous char or foam which acts as an insulating layer for the substrate.

All intumescent coatings manufactured are supported by a quality system in accordance to B.S. 5750 Part 2 : 1987. Intumescent coating are versatile materials which will cover areas of regular and irregular size and shape.

Material Composition

An intumescent coating should comprise of active ingredients which react together in a controlled sequence to produce the phenomenon known as intumescent.

Typically these include the following :

  1. A catalyst which decomposes to liberate mineral acid, usually phosphoric acid. The most commonly used catalysts are ammonium poly phosphate.
  2. A carbonific agent which combines with the acid released by the catalyst to form a carbonaceous char. Typically carbonific agents are the common carbohydrates, such as starch.
  3. A resin system or binder which is designed to soften at the upper end of the reaction temperature range.
  4. A spermatic agent which decomposes at the same time as the melting of the binder, and liberates large volumes of non-flammable gases such as carbon dioxide,ammonia and water vapour. These gases cause the binder to foam and expand providing an insulating char many times of the original thickness.

The WinDuct® system offers building consultants, architects and contractors an efficient way of designing ductwork for smoke spill and ventilation.It offers a 2 Hours resistance to fire with the use of locally fabricated Galvanised Iron Ductwork improved with fire prevention coating.

The system was tested with the Accredited Laboratory in accordance with International Standard and approved by the Fire Service Department. It was further tested locally and abroad to ensure that the WinDuct® system was suited to the local construction condition.

WinDuct® which based on WinCoat™ Intumescent coating works with the theory of insulation, and that of any protection method attached to the ducting is its ability to restrict the temperature rise within the duct. The performance is a factor of the thermal conductivity of the protection material, depending on the thickness of the protection material, the ability of the protection material to remain in place (stick ability) and the severity of the fire exposure. WinDuct® has the following advantages over the competitor products:

  • Light Weight
  • Easy to apply at site
  • Any Shapes
  • Saves Spaces
  • Environmental Friendly
  • Better Control of Air Leakage
  • High Impact Strength and more importantly – economical

Where decorative are required, WinDuct® is compatible with water-based coating that can be applied on the surface if required, either initially or subsequently (owing to change of occupancy or use of building).