Intumescent Coatings and Fire Retardants
Globally, intumescent and fire-retardant technologies have become critical components in the construction industry for improving the fire performance of combustible timber products. These technologies are designed to enhance both the resistance and reaction of timber when exposed to fire, helping protect structures and lives.
In New Zealand, intumescent coatings have traditionally been the go-to solution for fire protection, particularly in mass timber construction. These coatings are applied on-site and provide effective protection in certain scenarios. However, they do present some challenges, including ongoing maintenance and potential aesthetic concerns. Intumescent coatings work by forming a protective layer on the timber surface, which expands when exposed to heat. This insulating barrier delays the spread of fire, providing valuable time to contain or control the blaze.
Despite their effectiveness, new fire protection alternatives are now available in New Zealand, such as the FireZone Vanguard SP & FP fire-retardant systems. These systems offer a more advanced approach by penetrating into the timber substrate, unlike surface-level intumescent coatings.
To better understand the difference between these two technologies, consider the following:
- Intumescent coatings remain on the surface of the timber and activate in the presence of heat. When exposed to high temperatures, they expand to form a thick, protective char layer that insulates the timber from flames, slowing down combustion.
- Fire-retardant systems like FireZone Vanguard SP & FP, work within the timber itself. When heated, the fire retardant crystals within the timber expand, blocking oxygen access and modifying the pyrolytic reaction. Additionally, these systems cause the timber to release non-combustible gases, which further displace oxygen, effectively halting combustion before it starts. This results in a thinner but denser char layer, which insulates the substrate more effectively. Not only does this internal action enhance fire protection, but it also maintains the timber’s surface appearance, making it a preferred choice for projects where aesthetics are a priority.
The growing shift toward fire-retardant-treated timber is driven by its long-lasting protection and reduced need for maintenance. Unlike intumescent coatings, which may require periodic reapplication or maintenance, fire-retardant systems provide a more permanent solution. This makes them ideal for demanding environments where fire safety, durability, and aesthetic integrity are equally important considerations.
Intumescent Coatings: Evolution and Environmental Considerations
Intumescent coatings, developed in the mid-20th century, have become essential for fire protection across various industries, including construction, transportation, and aerospace. These coatings have significantly improved fire safety by slowing the spread of fire, reducing property damage, and ultimately saving lives. Despite their effectiveness, timber intumescent coatings come with certain environmental concerns that are important to address.
Environmental Concerns with Timber Intumescent Coatings:
- Use of Toxic Chemicals:
Some timber intumescent coatings contain toxic chemicals, such as halogenated flame retardants, which pose risks to both the environment and human health. These chemicals can release harmful fumes during a fire or when the coating is applied or removed. This presents a challenge for sustainable fire protection, as the chemicals may persist in the environment after use. - Energy Consumption:
The production and application of intumescent coatings are often energy-intensive, contributing to greenhouse gas emissions and other environmental impacts. The manufacturing process, transport, and on-site application can all increase the carbon footprint of fire-rated projects. - Durability:
The durability of timber intumescent coatings can vary depending on the product and application. In some cases, these coatings may need to be reapplied or removed and replaced after a period of time. This process can generate additional waste and environmental strain, as re-coating typically involves significant resource use and disposal of old materials. - Impacts on Timber Quality:
Some intumescent coatings can negatively impact the timber’s surface quality, leading to discoloration or affecting the aesthetic finish. For projects where the appearance of timber is critical, this can be a significant drawback.
Progress Toward Environmentally Friendly Solutions
To address these challenges, manufacturers have been developing more environmentally friendly timber intumescent coatings. These newer products contain fewer or no toxic chemicals, are made from renewable materials, and have a lower carbon footprint. Additionally, manufacturers are focusing on improving the durability of these coatings to reduce the need for frequent reapplications, thereby minimizing waste and environmental impact.
The Evolution of Timber Intumescent Coatings
For those who have been in the industry for a long time, you’re likely familiar with the significant strides in the evolution of timber intumescent coatings in New Zealand’s market.
- First Generation Intumescent Coatings:
These were highly potent products, relying on solvent-based technologies with high levels of VOCs (volatile organic compounds). Protecting these coatings required near-perfect environmental conditions and heated lines, which are often impractical in on-site environments. While effective, they presented logistical challenges and environmental drawbacks. - Second Generation – Water-based Intumescent Systems:
Over time, the industry evolved to more user-friendly, water-based systems, such as FireZone 92. These systems have much lower VOC content and are easier to apply both on-site and off-site, reducing the overall environmental footprint. Water-based intumescent coatings have provided a balance between performance and sustainability. - Challenges with Film-forming Coatings:
One of the persistent challenges with film-forming intumescent coatings is the need for ongoing maintenance. These coatings typically need to be re-coated every 5–7 years, as is the case with clear coat systems. Recognizing this challenge, we at Zone have introduced a more durable water-based 2K topcoat, designed to extend the lifespan of the intumescent protection and reduce the frequency of maintenance.
Fire Retardants
Fire retardants have been used for centuries to extinguish fires and protect flammable materials. In the early 20th century, the development of chemical fire retardants in the United States revolutionized fire safety, with sodium bicarbonate being one of the first widely used solutions. By the 1950s, halogenated fire retardants, such as PBDEs (polybrominated diphenyl ethers), became common in various industries, particularly in oil refineries and other industrial settings.
However, by the 1970s, significant concerns emerged regarding the environmental and health impacts of these halogenated fire retardants. Research revealed that these chemicals could persist in the environment and pose risks to both human health and wildlife. In response, the industry began developing greener, non-halogenated fire retardants that are less harmful.
Environmental Concerns with Traditional Fire Retardants
Some of the major concerns regarding traditional fire retardants include:
- Persistence: Many fire retardants are persistent in the environment, meaning they do not easily break down. Over time, they can accumulate in soil, water, and living organisms, leading to long-term contamination.
- Bioaccumulation: Fire retardants can accumulate in the tissues of animals, including fish and wildlife, through the food chain. This accumulation poses serious risks to ecosystems and human health.
- Toxicity: Even at low levels of exposure, certain fire retardants have been shown to be toxic to both humans and wildlife. Health impacts include reproductive and developmental issues, as well as increased risks of cancer.
- Environmental Contamination: Fire retardants can enter the environment during manufacturing, application, or disposal, contaminating soil, water, and air. This not only affects local wildlife but also nearby communities and workers.
- Endocrine Disruption: Some fire retardants can interfere with hormonal systems, leading to reproductive and developmental problems in humans and wildlife.
Given these concerns, it is critical to evaluate the entire lifecycle of fire retardants, from production to disposal, to minimize environmental and health risks.
Applications of Fire Retardants
Fire retardants are used across a wide range of materials, including plastics, electronics, textiles, and construction products. However, at Zone, our primary focus is on timber fire retardants, as they offer a more sustainable and effective solution for fire protection in construction.
Timber Fire Retardants: The Next Generation
At Zone, we view fire retardants as the next generation of fire rating solutions, addressing many of the challenges associated with traditional intumescent coatings, such as:
- Consistency in Compliance: Fire retardants ensure consistent fire protection, minimizing the risk of application inconsistencies that can arise from time pressures during on-site application or damage during transport.
- Application Challenges: Traditional intumescent solutions face added risks such as environmental exposure during transport, time pressures during installation, and the potential for damage during application. Fire retardants mitigate many of these risks by offering more robust and durable protection.
The biggest challenge has been finding fire retardant systems that minimize environmental impact, and Zone’s fire retardants represent a significant step forward in addressing this concern.