Fire Retardant Silicone Sealant for Fire Safety in Construction Projects

As the world advances, construction techniques are also evolving. They push for integrity, reliability, and safety in construction projects. One of the key protective measures for buildings is adherence to the fire safety protocols. These protocols primarily ensure that, in case of fire, there is enough equipment to fight the fire and to stop it from spreading. To keep fire confined within a space, the room needs to have fire retardant silicon sealant application. It keeps fire and smoke in one room, corridor, or apartment don’t spread to other spaces. This ensures that the active systems, which include firefighting equipment, are used efficiently and fire can be put out with ease.

Did you know a typical fire retardant silicone sealant can withstand exposure to fire for 4 hours? Unlike regular sealant, FR silicone can undergoes chemical reaction to form a char surface which acts as an insulator that gives it an extraordinary fire rating. So if you are an architect, builder, safety inspector, or contractor working on a building, reading this guide will help you understand how a fire retardant sealant is installed, its applications, and the technical composition, ensuring that you make the right choice during construction. 

1. Understanding Fire Retardant Silicone Sealants

1.1 What Are Fire Retardant Sealants?

During construction in buildings, sealants are applied around gaps and joints to stop water and air from leaking in or out of the structure. When it comes to fire retardant sealants, they should not only stop water and air to seap in or out but also, during a fire breakout, these sealants should prevent toxic gases, smoke, and fire to spread out of the space. This is made possible by chemically engineered formulas that enable these sealants to handle such high temperatures without melting down, combusting, or shrinking. This prevents any leakage or formation of a pathway for fire or toxic gases to escape, hence keeping the fire and smoke limited to a confined space ensuring that active strategies can be implemented efficiently to put out the fire. 

1.2 Key Features of High Quality Sealants

The chemical formulas and properties may vary for different types of fire retardant sealants. There are a few distinguishable qualities of high-quality fire retardant silicone sealants mentioned below, based on how they perform and what qualities they offer to ensure reliability during an emergency: 

• Intumescent or Ablative Properties: A high-quality sealant not only prevents shrinkage but also expands to seal the gaps tightly to prevent smoke from leaking. Furthermore, they can also form a hard ceramic crust that is best for deflecting heat. 

• Smoke and Gas Impermeability: Fire can burn, but inhaling smoke or toxic fumes can kill. This is where a high-quality sealant provide barrier that prevents even small amounts of gases or fumes from escaping. 

• High Movement Capability: During a fire breakout, the structure of the building expands, and a high-quality fire retardant silicon sealant ensures that ±25% to ±50% movement capacity is provided to prevent cracking or detaching in the structure. 

• Self-Extinguishing: The sealant itself must not be a source of fuel for fire. Once the fire is put out, any burning in the sealant itself should stop immediately. 

• Weather and UV Resistance: If the fire retardant sealants are used in external applications like walls, windows, or doors, they must resist degradation from sunlight and rain. 

2. Why Fire Safety Matters in Construction

2.1 Risks of Fire in Buildings

One of the major risks associated with the fire is its smoke. If the fire won’t kill, the smoke will. In buildings that are either commercial or residential, if the fire breaks out and is not contained, it creates a chimney effect where the smoke and harmful gases from the fire escape and rise upwards, and into the surroundings. If not contained, it will consume floors in minutes, leaving no time for escape. In buildings where fire retardant sealants are not utilized, with walls having gaps that aren’t properly sealed, there is not only destruction of property and assets, but also the risk of fatality increases as the rapid spread of toxic gases like carbon monoxide or other toxic fumes compromises escape routes and causes the efforts of emergency responders to be delayed.

2.2 Building Codes and Fire Safety Standards

To ensure the construction of the building is safe and has proper measures to stop the fire from spreading, there are organizations around the world, like the International Building Code (IBC) that ensure the building follows the safety standards for firestopping. 

• ASTM E814 / UL 1479: These define the tests and standards for a structure that can withstand the penetration power of firestop systems, such as water pressure, and the sealant is capable of holding up against fire exposure. 

• ASTM E1966 / UL 2079: These standards apply specifically to fire-resistive joint systems.  

• Fire-resistance ratings: Fire-resistant ratings are given to coatings that are fire-resistant, defining how long the coating will prevent breaking down because of fire or extreme temperature, and maintaining the temperature limits on the side that is not on fire. The longer the ratings, like 4-hours tells it can survive for longer periods, keeping the building safe in the event of a fire breaking out.  

3. Applications of Flame Retardant Sealants

3.1 Interior and Exterior Construction Joints

Fire-retardant silicon sealants are often used in the construction of the building's exterior, sealing the rooms inside, and providing a barrier to ensure the rooms inside are safe from fire. 

• Exterior Facades: In designs that feature cladding or a curtain wall system, fire-retardant sealant is used in the parameter joints present between the floor slab and the exterior wall. This prevents rentring of smoke from the floor above when the fire is exhausted from the window. 

• Interior Partitions: One of the paths through which the smoke can enter is through the joints that connect ceilings to the wall. If a fire retardant sealant is used on the joints, they not only prevent smoke from entering but also allows for movements or expansion during a fire breakout. 

• Expansion Joints: In large commercial structures, expansion joints are used for absorbing vibration and changes in temperature. In these joints, fire retardant coatings are injected to ensure that these gaps don’t become the means for the spread of fire. 

3.2 Electronics and Component Fastening

A short circuit in wiring or electronic components can be a major source for the start of a fire. In such spaces, using fire retardant silicone sealant ensures that the spread of fire can be prevented. 

• Thermal Runaway Protection: Battery packs are highly prone to fire, especially in batteries where it is advised that if a fire breaks out, it should be let to burn. So to prevent the fire from spreading, silicone sealants are used to ensure that surrounding cells or circuits are safe if a component overheats or sparks. 

• Component Fixation: One of the major advantages of using fire-retardant silicon sealant is that it is electrically insulating. This allows them to be used for the fixing of capacitors, transformers, and heavy components to circuit boards. 

• Enclosure Sealing: Electrical or electronic components installed in the outdoor electrical boxes. These electrical boxes should be NEMA rated, and to get that NEMA 4 rating, sealants are used. The benefit of using a fire retardant sealant is that it not only improves waterproofing but also makes sure that the sealant itself doesn’t contribute to fire if the components fail. 

4. Applications of Fireproof Silicone Sealant in Construction

4.1 Sealing Joints and Gaps

One of the most common applications that is associated with the usage of fireproof silicon sealant is the joining of linear joints. These sealants can act as a bonding agent for joining materials that have very dissimilar properties, like concrete-to-steel or gypsum-to-concrete. If the gaps are wide and a fire barrier is needed, use a mineral wool backing material and insert it in the gap, and then add sealant to a specified depth, which is often 6mm to 12mm, to ensure a complete seal from smoke and gas. 

4.2 Firestop Systems

For a wall that is fire-rated, every time the wall is penetrated for electrical wiring, HVAC pipes, or plumbing, the wall tends to lose that rating. To ensure that the wall remains fire-rated, firestop systems are used, which involve using fireproof silicon sealant in the applications mentioned below:  

• Through-Penetrations: Fireproof sealants are gunned around metallic pipes, cables, and conduits.

• Combustible Penetrants: If the penetrations in the wall are made for plastic pipes, using silicon sealants that expand is crucial. It ensures that during a fire breakout, the hole created by the plastic when melted is covered by the coating, preventing toxic fumes or smoke from escaping.

4.3 Window and Door Frames

Fireproof silicone sealants can be used in windows and door frames as these opening sare most vulnerable when it comes to allowing smoke or fumes to enter or exit. In the event of a fire breakout, doors and windows sealed with fireproof silicone sealants ensure that the smoke or fire doesn’t escape into the surroundings, giving more time for evacuations and putting the fire out. 

4.4 HVAC Ductwork

The primary responsibility of the HVAC system is to ensure that the occupants in the building can breathe with ease. However, this system is compromised in the event of a fire breakout. So if the fire breaks out in one room, the smoke and fumes travel through the tunnels and into other rooms of the building. To ensure this doesn’t happen, joints are sealed with fireproof silicone sealant that connects with the different sections of ductwork to make the ducts airtight and ensure that the smoke stays away from the system. Furthermore, installing a fire damper ensures that the smoke doesn't escape through the walls, keeping the smoke trapped on a single floor instead of escaping to upper floors. 

5. Choosing the Right Sealant for Your Project

5.1 Fire Rating

When choosing a sealant, it's important to look for the fire rating. The only rule is that the wall or floor rating should match the sealant's ratings. For example, if the wall has a fire rating of 2 hours and the sealants you are getting are rated for 1 hour, the fire rating of the entire structure won’t remain the same. Furthermore, to ensure the sealant you are getting is certified, approved, and meets the specific regulations, check for the product’s technical data sheet (TDS) for certifications like UL, ASTM, or EN standards. 

5.2 Temperature Resistance

The major function of a sealant is to resist sudden temperature changes. Fires can sometimes exceed 1000 degrees, and a sealant should be capable of handling those temperatures for longer periods. Furthermore, fire retardant silicone sealants are also often used in industries near boilers or manufacturing equipment, so they must survive the daily operating temperatures of the surroundings without hardening or losing their adhesive capabilities.

5.3 Application Method

The scale of the project defines how much sealant you should get and how much sealant should be applied. 

• Cartridges (300ml): This size is Ideal for small jobs, small repairs, or tight spaces like window frames.

• Sausages (600ml): Better for longer applications like floor joints, reducing waste and changeover time. 

• Pails/Drums: For large-scale projects that involve construction throughout the whole building, drums are considered suitable due to low wastage and best value for money. Make sure a pump is attached to extract the sealant and ensure the sealant can flow with ease, even in low temperatures, to ensure no gaps are left in the seal. 

5.4 Cure Time

During construction, curing time matters a lot as it will directly impact the construction times and deadlines. Most silicon sealants are cured with the help of moisture, such as humidity in the surrounding air. 

• Tack-Free Time: It tells the time required for the surface to dry, usually taking about 10 to 30 minutes. This is important to prevent dust from sticking. 

• Full Cure: It defines the time required to fully bond with the surface. This process often takes about 14 to 21 days, depending on the depth. 

6. Installation Tips for Fireproof Silicone Sealant

To ensure fire retardant sealant works as intended, it's important to ensure it's applied properly. Below are mentioned some of the steps for installation of the sealants to ensure its highly effective. 

1. Clean the Substrate: Before installation of sealant, ensure that the surface is dry. It should be free of dust, moisture, oil, frost, or remains of old sealant. Use a wire brush on concrete and a solvent wipe on metals. Without proper cleaning, the bonds form weakly, which directly impacts the fireproofing capabilities. 

2. Install Backing Material: For joints that are deep, inserting a backer rod or a mineral wool provides more control over the depth of sealant, preventing three-sided adhesion. 

3. Tool the Sealant: To ensure the joint is in full contact with the sealant, use a tooling knife or tooling stick immediately after applying sealant to prevent even minor air pockets from forming. 

4. Check Depth-to-Width Ratio: When applying sealant, use a 2 is to 1 width-to-depth ratio. For example, a 20mm wide joint should have sealant that is 10mm deep. 

5. Inspect: Lastly, after applying the sealant, ensure that there aren't any pinholes or gaps. If these minor gaps are left unattended, they can be a means of smoke entering at high pressure. 

7. FAQs

Q1: How long does the sealant last after application?

High-quality fire retardant sealants are highly durable and can last more than 20 to 30 years, given that the sealants are cured properly after applying and aren't chipped off, physically damaged, or the joints are subjected to extreme movements. 

Q2: Can fireproof silicone sealant be painted over?

This is where pure silicon sealants lack. The silicon surface resists paint particles from bonding and will eventually peel off when painted. When choosing a sealant, look for a color-matching sealant like grey, white, or black if available to blend in with the substrate without needing to paint. If your application requires painting,  there are some hybrid fire sealants available that can be painted. 

Q3: How does flame retardant sealant improve fire safety?

Fire retardant silicon sealants are great for preventing the spread of fire and smoke. Unlike normal sealants that can melt, combust, or shrink during fire, fire-retardant sealings ensure that it stays in place or even expand to prevent the rapid spread of fire, smoke, and toxic gases, which can be prevented to facilitate ease of escape for the people in the building. A quality fire-retardant can keep its structure for up to 4 hours to ensure safe evacuation of the people.    

Q4: Can these sealants be used outdoors?

Yes, these fire retardant sealants are great for outdoor use as they are highly resistant to UV light, rain, snow, and temperature extremes. This makes these sealants an ideal choice for exterior facade joints and roofing applications.

Q5: What materials can fire retardant sealants bond?

Fire retardant sealants are highly used in construction and can easily bond with a wide variety of construction materials like concrete, masonry, brick, steel, aluminum, glass, ceramics, and many plastics. For surfaces that are porous, using a primer is sometimes recommended for effective bonding.