Charring rate slowing by means of fibreglass-reinforced coatings

Intumescent coatings can act in wooden materials both as flame retardants and thermal insulators to improve the static performance of a timber element subject to fire by reducing the charring rate. However Vapours developed inside the wood cannot escape inwards and may be prevented from escaping outwards by the layer of swollen intumescent product thus causing the treatment to peel off suddenly before it has a chance to swell. Therefore a significant difference in values arises, that makes it difficult to quantify differences in behaviour between treated and untreated timber. Following a preliminary study on suitable application techniques for fibreglass reinforced intumescent coatings, a research was undertaken to verify on a quantitative basis whether actually the use of a fibreglass net extends the adhesion time of protective coating products to wooden surfaces during exposure to fire: and to assess a suitable criterion to evaluate the element performance improvement in terms of fire resistance.