Thin Film Intumescents: Environmental Impact

Imagine it; you are in a building fire. The flames are licking at the walls and devouring the furniture over the other side of a building. You start to make your way down the fire stairs and realise that the fire started on the floor before and has spread further than you thought. In a situation like this, you’re going to want the know that the building is going to stay structurally sound as long as possible and that where possible it is not going to spread quickly, nor easily to the parts of the building you are in. Yes, you are also going to want to know that there are sprinklers, fire doors and other active fire elements working to quench the fire, but if you can’t get out safely, then what use are those, right? The role of passive fire protection is to use resistance measures which forestall the spread of fire, and which resist ignition (burning). Passive fire protection will not compartmentalise or isolate a fire, but it is intended to slow the spread, ensure structural adequacy and through this, allow residents to exit quickly, and fire crew to enter. In other words, Passive fire protection is valuable both for the safety of building occupants and for the minimising of damage to buildings and equipment.

Your Options

For those of you familiar with the industry, and/or our blog, fire rating takes on many forms including fire painting paints, cementitious materials, concrete and fire rated boards. But aside from the differences in performance each product may have, did you know there are different environmental considerations which may make one option stand out from the rest.
Let’s take a look at few options.

What is thin-film intumescent?

So, what exactly is a Thin-film intumescent coating? In principle, the materials used to make them remain chemically inactive at low temperatures, but at higher temperatures – such as in a fire – the coatings swell. In fact, the root of the word intumescent is “intumesce” which alludes to the capacity to swell when exposed to high temperatures, with a char forming outside. This char is a poor conductor of fire, heat, and smoke and when applied to structural elements such as timber or steel, prolongs the structural integrity of the structural member during a fire, thus minimising the risk of structural collapse. The reference to “thin-film” lies in the fact that the intumescent coating only needs to be applied relatively thinly –a paint like thickness – as it will expand in heat up to seven times it’s original thickness.
Thin film intumescents are presently common in structural passive fire protection markets because they are cost-effective and very functional (can be applied where clearances are small, can be top-coated with compatible paints, and can be applied off-site). Off-site application is more predominant on projects where elements such as access to the site, weather, health and safety, and rapid construction timelines are key factors.

The best thin-film choice in Australia

In Australia, engineers, builders, and applicators often opt for Nullifire products, a range of thin film intumescent coating systems designed specifically for structural steel fireproofing up to a fire rating level of 120 minutes for cellulosic fires.
Nullifire’s system S Basecoats are prepared for use without the need for thinning. They are easy to spray using conventional airless manual or automated spray systems, or utilising a ‘laying on’ roller-brush technique to avoid heavy brush marks.
In particular, the SC900 series offers application and performance benefits which have set is as it the best option for builders, engineers, architects and specifiers. It is low build, easily top-coated and has relatively low VOCs making it a fantastic choice in many regards.
Many people know if the S707 range, through which, Nullifire spearheaded water-based intumescent innovation; but it is SC803 that has truly raised the bar again. SC803 is a white thin film intumescent coating that provides fire protection of internal structural steelwork. It is easy to apply, has low VOCs and is viable for use with a range of top-seals, making it an ideal solution for internal fire rating.
Compared to all other celluosic intumescent coatings, Nullifire SC902 is the world’s only ‘Hybrid’ intumescent coating system formulated to provide optimal performance on either internal or external steel. Its attributes incorporate; a low VOC, single application, fast track, high build system based on patented technology that offers fire protection up to 120 minutes. But more on this below.
All Nullifire products – especially when compared to other systems – offer great environmental benefit. They have low wastage and overspray, are easily applied, are less heavy than alternatives meaning less structural elements are required to support the weight, and can be easily repaired as opposed to replaced entirely.

Alternative Fire Protection Methods

As you would expect, there are many alternative fire protection methods used in the building and construction industry. These include but are not limited to:

Fire boards

Fire boards are frequently utilised where plaster may not be appropriate in a specific application and where fire protection is required. Their advantage lies in the fact that they are often thinner than other systems (such as concrete, fire spray etc) and are ideal for the construction of electrical and mechanical duct work enclosures, fire rated bulk heads, walls and ceilings where space is limited. Fire board products can provide up to two-hour fire protection from both directions with as little as one layer of 40mm board.
However, their weight often means more steel is required for strength, making them more expensive overall in the project, and from an environmental standpoint, more steel means less environmental friendliness.

Vermiculite

For the most part, vermiculite spray is utilized often as fireproofing for internal and semi-exposed components of steel structures, concrete slabs, steel plates and hollow-core slabs. Normally, a monolithic coating is adopted with a combination of vermiculite and Portland cement to withstand fire. Vermiculite cannot be used in exposed environments as it is not moisture tolerant and is easily damaged, albeit, whilst heavier than thin films, has a relatively low density which does not add extra dead load to the structure.

Stucco

“Modern” (by this we mean from the last 20 years) Stucco is a plaster that has been utilized for quite a long time for both artistic and structural purposes. Made of Portland cement, sand and lime, it can cover structural elements serving as a fantastic and durable fire-resistant finish material for buildings. A one-inch (2.54-centimeter) layer of plaster can achieve a 1-hour fire rating on a wall. Compared to thin-film one inch is very thick making it inappropriate for areas where clearance is an issue.

Why thin-film intumescents stand out as a fire protection solution

As thin film intumescent coating systems tend to be either solvent or water-based they are essentially very light. This translates a significant reduction in the amount of structural steel required during the design phase of a building or structure. Consequently, this means major financial savings across the scope of the project.
Where less steel is required in construction, there is a domino effect, whereby less steel is produced, meaning less coal consumed, and less transportation of all materials. All in creating a less significant environmental footprint.

Burning coal releases toxins

Coal contains sulfur and different elements that include dangerous metals like mercury, lead, and arsenic, that escape into the air when coal is burned. Burning of coal also creates particulates that cause an increment air pollution and health dangers.

Burning coal emits large amounts of carbon dioxide into the atmosphere

Composed almost entirely of carbon, when coal is burnt, it unleashes huge amounts of carbon dioxide (CO2) into the atmosphere. These emissions have been shown to increase the greenhouse effect in the atmosphere and lead to global warming.

Subsurface coal mining is dangerous

Frequently mined in subsurface mines, there is always a risk they may collapse and trap miners not to forget that the air in subsurface coal mines leads to black lung disease, where coal particles and toxins fill the lungs and cause inflammation and respiratory sickness.

Surface coal mining damages the environment

Mountaintop removal mining is a method used to access layers of coal buried deep within mountains, a technique that alters the landscape and damages ecosystems in an area.
The products we recommend have less impact on the ecosystem and have a lighter impression on biological systems and the climate. Many Nullifire thin film intumescent products are water based with a much lower Volatile Organic Content (VOC) level than those of solvent-based coatings. This means higher green benefits on a project and a safer working environment for the applicators.
Other relevant benefits of thin film applied intumescent paint include;

Safer to use

When you compare solvent to water, it is evident that water-based products have significant safety advantage during application and that they are likely to be more friendly to the environment and ecosystems. Water based products contain no hydrocarbon solvents and can therefore be used safely alongside other trades and workmen. They do not have a requirement for special flammable storage areas, and there is no solvent build up in confined spaces.

Faster drying times

In high temperatures water based products dry a faster than solvent based products. They dry by rapid evaporation of water from inside the total coating layer and in this manner accomplish ‘through drying’ a lot quicker without the formation of a surface skin.

Higher build capability

Since they don’t skin over while drying, it is possible to apply water based intumescent at high film thicknesses in a single application. The overall number of coats can be reduced as build thickness can be achieved in less passes, consequently saving construction time.