Many buildings today are constructed using a structural steel frame. This is the building material of choice for many projects, preferred for its speed of erection and flexibility of design. Steel is a very versatile substance but it is also vulnerable to corrosion and fire. To combat these, protective coatings are specified to protect the steel. Anti-corrosion steel primers are typically applied at the fabricators works after the steel is blasted to a specified standard. Intumescent coatings are applied to the steel in an off-site facility of around 50% of all structural steel in the UK. In the remainder of steel buildings the fire protection takes place on site during construction.
Fire Protection Coating
Fire protection coatings of any kind – intumescents, cementitious, gypsum and others – are applied to steel to meet the fire protection specification (1 hour, 90 Minutes, 2 hours). There are many different coatings in the marketplace and each has been tested at a range of thicknesses which are unique. The different thicknesses of a coating will protect a variety of steel of different size, mass and type (e.g. ‘I’ section or hollow section). In order to ensure the correct thicknesses are applied to the different steel sizes care must be taken in specifying, estimating and especially in applying each coating thickness. All fire protection coatings are affected by cold/wet atmospheric conditions and to ensure the coatings are fit for purpose the correct application conditions must be adhered to. Only trained and qualified applicator personnel should be used to apply these life saving coatings.
Fire Coating Inspection
All types of coatings are sensitive to poor substrate and atmospheric conditions, and all require application to a product specific thickness to ensure they will perform as they were designed to. Many fire protection coatings require multiple applications in order to achieve the appropriate dry film thickness. If left unchecked a wide range of application qualities can be expected. In order to ensure the coatings provide their designed performance and last their maximum life span, it is imperative that substrate, atmospheric and thickness checks are carried out before, during and after application of the coatings. The only way to ensure that these checks are carried out to the correct standard and frequency is to employ the services of a qualified paint inspector who is independent of all other parties.