The intumescent paint is a coating system that is used primarily for structural steel fire protection and is spray-applied directly onto steel beams, columns, sections, truss, etc. When the paint comes into contact with fire (heat), will intumesce (swell) to produce a layer of carbonaceous char that will insulate and protect the substrate beneath. 

In this article, we will explore the various advantages and disadvantages of applying intumescent paints on-site versus off-site. 

SC902 off-site steel beams applicationOff-site application of instumescent paint on steel sections

On-Site Application

On-site application of intumescent paint is often used by applicators either because of tight construction schedules or logistical considerations. Additionally some intumescents, like those water-borne, can only be applied on-site. In such cases, intumescent applicators will mask up and encapsulate the surrounding areas to minimise disruption to the building process.

Advantages Of On-Site Applications

  1. No risk of transportation or installation damage since all steel structures to be intumescent-coated are already assembled and installed.
  2. Generally, no large or complex spray application equipment is required. This is very useful when dealing with difficult or restricted access on site. 

Disadvantages Of On-Site Applications

  1. May require specific protection of areas adjacent to structures being sprayed on-site to avoid overspray contamination.
  2. May not be suitable if installed steelwork does not allow sufficient access to all surfaces that require intumescent spray application.
  3. Unpredictable weather conditions may delay the application process and lengthen the construction timeline.
  4. As the application has to be done in multiple layers, there can be a severe disruption to other trades on the same floor, i.e. nothing can be installed whilst the intumescent application is going on.
  5. Wastage during application is usually much higher due to difficult access to steel that needs to be sprayed.
  6. Difficulties in quality control of both wet film as well as dry film reading due to possible difficult access to steel.

Off-Site Application

The main reason for applying intumescent paint off-site is that it saves significant time in the construction schedule because majority of the spraying will have been done in a workshop. The only thing left to do is transport the steel beams or columns on site for installation.

Advantages Of Off-Site Applications

  1. Avoids delays in accessing work sites.
  2. Increases productivity as time is not wasted moving equipment, products and people from different areas and floors. 
  3. Proper control in wastage as the spraying is done at waist level and all sides of the steel are easily accessible.
  4. Provides better quality control in terms of temperature and humidity.
  5. Provides better quality control in both wet film as well as dry film readings. 
  6. No disruptions to other trades operating on site.
  7. No risk to area due to overspray.
  8. No risk of weather disruptions. 

Disadvantages Of Off-Site Applications

  1. Workshop handling and the transportation of steel members to the construction site must be done with care or risk damaging the paint.
  2. Possibly higher transportation costs. 
  3. If the paint is damaged during transportation or installation, the applicators must re-apply it on site.

Nullifire SC902 is a unique intumescent paint!

The Nullifire SC902 intumescent coating system is based on patented technology that is optimised for both on-site and off-site applications to protect structural steel from the destructive effects of fire. As compared to other conventional intumescent coatings, SC902 provides exceptional productivity gains because of its unique hybrid composition and fast-curing properties. 

SC902 application on site

Advantages of Nullifire SC902 on-site:

  1. Possesses high film build, up to 6mm in a single coat, because of its 85% volume solids formulation, with all ratings possible in one application.
  2. Its rapid cure coating achieves early weather resistance within 1 hour of application, ideal for open construction sites.
  3. Nullifire SC902 is very surface tolerant of high humidity (85% RH) or low temperatures (cures down to 0˚C).
  4. Its low VOC composition reduces occupational health and safety risks at construction sites.
  5. It is easily repaired with minimal surface preparation, using simple application equipment.

Advantages of Nullifire SC902 off-site:

  1. Compatible with a wide range of primers (contact our Nullifire specialists for comprehensive list).
  2. Surface tolerant of light rusting and can be applied up to 2 weeks post blasting, allowing greater flexibility for the painting program.
  3. Compared to other conventional intumescent paints, SC902 delivers faster application and curing times in the workshop, leading to quicker delivery and installation timings. 
  4. Very easily sanded for treatment of difficult to spray configurations requiring a high level of finish.

Do you have an upcoming project that requires intumescent paint? Get in touch with us.
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