How To Prepare Galvanised Steel For Application of SC902

With the fire industry becoming ever more scrutinised each day, it is important that compliant application of intumescent coatings is achieved. As you may be aware, it has long been industry practice to apply the same rules to galvanised steelwork as to carbon steel.

However, research and testing conducted by Nullifire shows that in a fire situation, the presence of a galvanising layer can affect the fire resistance performance of the overlaying fire protection system. Therefore, it is important that those applying SC902 Intumescent Base Coat follow the outlined recommendations below.

Following testing in accordance with EAD 350402-00-1106 (formerly known as ETAG 018 Part 2), here at Nullifire we can offer assurance that SC902 may be applied to galvanised steel, after the following surface preparation has been achieved. 

New Galvanised Steel

The substrate should be thoroughly cleaned and degreased.

Abrade / Key surface using a minimum of 80’s grade sandpaper (taking care to ensure that the galvanising is not removed in the process)

Where the galvanising does not meet the requirements for the corrosion specification or the corrosion class is greater than C2, it may be necessary, to apply an approved primer to achieve the required anti corrosive protection based on the environment classification.

Apply Nullifire SC900 Series to the required DFT based on the Hp/A.

Aged Galvanised Steel

Thorough fresh water washing to remove soluble salts ideally with high pressure washing, or normal pressure accompanied by stiff wire brushing. This ensures the substrate is free from all forms of contamination.

Abrade surface using a minimum of 80’s grade sandpaper (taking care to ensure that the galvanising is not removed in the process).

Where the galvanising does not meet the requirements for the corrosion specification or the corrosion class is greater than C2, it may be necessary to apply an approved primer to achieve the required anti corrosive protection based on the environment classification.

Apply Nullifire SC900 Series to the required DFT based on the Hp/A.

For more information on preparing galvanised steel for SC902 application, please contact a member of the team.

Article contributed by the fire protection specialists at CPG Europe.

Passive Fire Protection Specialists

Nullifire has been at the forefront of the passive fire protection market for over 45 years developing several waterborne intumescent systems.

Nullifire strives to provide fire protection systems that will, ultimately, perform in a fire situation. By understanding the market requirements around the world, Nullifire designed a unique hybrid system, SC900 series, that would allow application in a single coat, up to 5mm, which would dry in one hour, allowing for steel to be protected within a single day on or off the construction site.  

All of Nullifire’s systems, be they intumescent coating for structural steel, or the comprehensive fire stopping range, have been fully tested to relevant British, European and Australia test standards allowing them to be used in the whole of Asia Pacific.

Our expert team is on hand to help you in any current or upcoming project you may have, do get in touch with the team.