Nullifire S708-60 
Intumescent Coating For Steelwork

S708 Waterborne Basecoat is a white thin film intumescent coating for the fire protection of internal or semi-exposed structural steelwork.

• Water Based Intumescent Coating designed for Steelwork
• Provides 30 and 60 minutes resistance to structural steelwork
• Moisture Resistant
• Tested in accordance with BS476:Part20/21 1987, in line with BCF industry guidelines 
• Highly competitive loadings
• Easy application properties
• Minimal VOC's - EPA Compliant and 'environmentally friendly'
• Topseal is not required in C1 & C2 internal environments
  
  

Guidance Notes:

S708-60 ​is a water based intumescent coating designed for steelwork such as beams and columns. It is an eco-friendly alternative to solvent-based products.

What is meant by HP/A / A/V? HP/A is generally used with British Testing and A/V in European.  The principle is the same.

The thickness of this intumescent coating is dependent on the steel section used. For calculation of DFT (dry film thickness) a factor called HP/A (heated perimeter divided by cross sectional area) is used. Intumescent coatings are applied as an intermediate coat in a coating system (primer, intermediate and top/finish coat).  S708-60 is designed for use in internal environments but can also be used externally provide is not exposed to water ingress.  A suitable topseal must be applied to the intumescent (once dry) if used external.

The rate increase in temperature of a steel cross-section is determined by the ratio of the heated surface area (A) to the Volume (V).  This ratio A/V, has units of m-1 and is known as the “Section Factor”.  Members with low Section Factors will heat up more slowly.  A steel section with a large surface area (A) will receive more heat than one with a smaller surface area.  Also, the greater the volume (V) of the section, the greater is the heat sink.  Therefore a small thick section will be slower to increase in temperature than a large thin one.  The Section Factor (A/V or HP/A) is thus a measure of the rate at which a section will heat up in a fire.  The higher the value of the Section Factor the greater will be the protection thickness required.

Primers:

A primer is used as a preparatory coating put on the steel before applying the intumescent paint and acts to provide corrosion protection.  Priming ensures better adhesion of the intumecent paint to the surface, increases its durability, and provides additional protection for the material being painted and is always recommended.

A primer designed for steel is still highly recommended if a part is to be exposed to moisture.  Once water seeps through to the bare metal, oxidation will begin (plain steel will simply rust). Metal primers might contain additional materials to protect against corrosion, such as sacrificial zinc.

Metal hydroxides/oxides do not provide a solid surface for the paint to adhere to, and paint will come off in large flakes. Using a primer will provide extra insurance against such a scenario.  An additional reason for using a primer on the steel could be the poor condition of the surface.  A steel part can be rusty, for example and should be prepared to the Swedish Standard 2.5.  Intumescent paint works well with Zinc Phosphate primers but does not like Zinc rich primers.  Zinc rich primers are often used in coastal areas and are usually unnecessary where high moisture /or sea spay are not expected. Intumescents do not like to adhere to zinc rich primers due the sacrificial nature they have.

If you are ever unsure of the primer and its compatibility then please send us the details of the primer and we will confirm compatibility.  Generally in the UK we find that most projects will have primer applied to the steelwork already such as a Zinc Phosphate, Calcium Plumbate etc and the Intumescent is applied to this. 

Application

System S Basecoats are ready for use. No thinning is required. They are easy to spray using conventional airless manual or automated spray systems. They may also be applied by roller or brush, using a "laying on" technique to avoid heavy brush marks.

Loading tables

Loading tables for all Nullifire System S Basecoats are available. These provide all relevant information including:

·         Section factors

·         Material thickness

·         Performance


Product Safety Data Sheet
Product Loading Table 

SYSTEM S RANGE

If you would like to send us your steel sizes we would be happy to calculate the loadings required using S708-60.  We would recommend that intumescent coatings are carried out by an approved applicator.

All orders are usually despatched within 24 hours of receiving cleared payment (Mon–Fri).

The above information is based on current test data, health and safety information and application instructions supplied by our suppliers and manufacturers of the products. It is supplied for guidance and to the best of our knowledge is true and accurate. Customers should satisfy themselves to the suitability of the products in its intended use and no guarantee is given or implied as the conditions of actual use are beyond our control. If in doubt the customer should consult the designer of the project or the local building control. 

Fire Stopping Shop, disclaim any liability for loss, damage or other expense which may arise from the use of this information, data or products refereed to and reserve the right to amend or change any details without notice. This statement does not affect your statuary rights.