Intumescent Fire Pillows

Passive Fire Protection

Role in Building Safety:

Intumescent fire pillows are integral components of a building’s passive fire protection system. Unlike active systems that require external power or triggers to function (e.g., fire alarms, sprinklers), passive systems are always in place, designed to contain fires and prevent their spread by maintaining compartmentation. This is critical in ensuring that fires are contained within specific areas, providing safe egress routes for occupants and allowing time for emergency response teams to arrive and act.

Functionality and Mechanism:

The primary mechanism of intumescent fire pillows is their ability to expand significantly upon exposure to high temperatures, typically around 200°C to 300°C. The expansion occurs due to the chemical composition of the pillow, which often includes materials like graphite, which swell to many times their original size, creating a dense barrier that seals gaps around pipes, cables, and ducts. This expansion is not only physical but also contributes to the thermal insulation, slowing down the transmission of heat and preventing fire and smoke from spreading through the penetrations.

Common Application Areas:

Intumescent fire pillows are used in various settings, especially in situations where utilities pass through fire-rated walls, floors, and ceilings. They are particularly useful in protecting penetrations created by electrical conduits, cable trays, pipes, and ducts. Their removable nature allows for easy maintenance or reconfiguration of the protected areas, making them ideal for spaces that may require future access or modification​​.

Fire Testing and Certification

Fire Testing Procedures:

Before intumescent fire pillows can be marketed and installed, they must undergo rigorous fire testing. These tests are conducted in controlled environments that simulate the conditions of a real fire. The primary aim is to determine how long the pillows can maintain the integrity of the fire compartment they are protecting. Typical tests include exposing the pillows to high heat and flames to measure their expansion properties, the time they can prevent fire spread, and their ability to withstand direct flame impingement.

Standards and Certifications:

The testing process for intumescent fire pillows must comply with national and international fire safety standards, such as BS 476 (British Standard) or EN 1366 (European Standard). These standards outline specific criteria for fire resistance, including how long the pillows can maintain their integrity under fire conditions (e.g., 30, 60, 90, or 120 minutes). Once testing is successfully completed, the pillows may receive third-party certification from bodies like the UK Accreditation Service (UKAS), which provides additional assurance of the product's performance and reliability.

Certification Tiers:

Certification is generally categorised into three tiers: first-party (manufacturer’s own certification), second-party (certification by an industry association), and third-party (certification by an independent accredited body). Third-party certification is the most robust, involving not just product testing but also ongoing factory inspections and audits to ensure consistent quality. Many building codes and construction tenders now require third-party certification as a prerequisite, making it a crucial factor for manufacturers​.

Application and Installation

Installation Guidelines:

The effectiveness of intumescent fire pillows depends heavily on correct installation. This typically involves packing the pillows tightly into spaces around service penetrations. The goal is to ensure that the pillows are in direct contact with the surrounding structure, leaving no gaps through which fire or smoke could pass. This requires careful attention to the size and shape of the pillows used, ensuring they match the dimensions of the penetration.

Versatility in Different Settings:

Intumescent fire pillows are favoured in settings where the configuration of services might change over time, such as in commercial buildings or data centres where cables and pipes are frequently added or replaced. Their removable and reusable nature allows for modifications without compromising the fire integrity of the building. However, this versatility also necessitates strict adherence to manufacturer guidelines to ensure that each time the pillows are installed or reinstalled, they provide the same level of protection.

Consideration of Substrate and Surroundings:

The performance of intumescent fire pillows can be affected by the materials and construction of the walls, floors, or ceilings they are installed within. For example, the pillows might behave differently in a solid concrete wall compared to a lightweight partition. Additionally, the presence of moisture, dust, or debris can affect the installation process and the performance of the pillows, so these factors must be carefully managed. It’s also important that installers are trained and competent, as improper installation can significantly reduce the effectiveness of the fire protection system​.

Material Properties and Effectiveness

Intumescent Reaction:

The core technology behind intumescent fire pillows is based on their ability to undergo a chemical reaction when exposed to heat. This reaction causes the materials inside the pillows to swell, typically increasing in volume by up to 10 times or more. The expansion creates a char-like substance that is highly insulating, which helps block the passage of fire, heat, and smoke. This swelling action also exerts pressure on the surrounding structure, helping to seal any gaps that might be present around the penetration.

Performance Metrics:

The effectiveness of intumescent fire pillows is measured through several performance metrics, including the time they can withstand fire exposure (fire resistance), their ability to block smoke (smoke resistance), and their contribution to the overall thermal insulation of the compartment (insulation performance). These metrics are crucial in ensuring that the pillows can meet the fire protection requirements of various building codes.

Material Composition:

Intumescent fire pillows are typically made from a combination of materials designed to optimise their fire protection capabilities. These materials might include graphite, which is known for its high expansion rate, as well as other fire-retardant chemicals that enhance the thermal insulation properties. The outer casing of the pillows is usually made from a durable fabric that can withstand the mechanical stress of expansion and the harsh conditions of a fire.

Limitations and Best Practices:

While intumescent fire pillows are highly effective, they are not a one-size-fits-all solution. Their performance is dependent on proper installation and the specific fire scenarios they are designed to protect against. For instance, they may not be suitable for all types of penetrations or all building environments, particularly if the surrounding materials are not compatible or if the conditions are excessively humid. Best practices include thorough planning during the design phase, consultation with fire protection experts, and regular inspections and maintenance to ensure ongoing effectiveness​​.

FAQs

What are Intumescent Fire Pillows?

Intumescent fire pillows are part of a category of fire-stopping products used to seal penetrations in fire-rated walls and floors, ensuring that the integrity of the fire-rated compartment is maintained. These pillows are made of a fabric casing filled with a mixture of fire-retardant materials, including intumescent substances that expand when exposed to heat. The intumescent material typically includes components like expandable graphite or vermiculite, which are known for their ability to expand multiple times their original size when heated, thereby forming an insulating char that blocks the passage of flames, smoke, and hot gases.

What is intumescent firestopping?

Intumescent firestopping is a passive fire protection method used to seal openings and penetrations in fire-rated walls and floors to prevent the spread of fire, smoke, and hot gases. It involves the use of intumescent materials, which are substances that expand when exposed to high temperatures. Upon exposure to fire, these materials swell and increase in volume, forming an insulating barrier that fills gaps and seals the area, thereby maintaining the fire-resistant properties of the building's compartments.

Intumescent firestopping products are designed to protect various elements of a building's structure, including pipes, cables, and ducts that pass through fire-rated barriers. By expanding and forming a char when exposed to fire, these products help to prevent the passage of flames and smoke through openings, thereby containing the fire within its compartment of origin for a specified period, which can range from 30 minutes to several hours.

This method is critical for maintaining the integrity of fire-rated walls, floors, and ceilings, ensuring that they perform their role in limiting the spread of fire and allowing safe evacuation and firefighting efforts.

How do Intumescent Fire Pillows work?

The working principle of intumescent fire pillows is based on the chemical reaction that occurs when the intumescent material is exposed to heat. At high temperatures (usually above 150°C to 200°C), the intumescent compounds within the pillows decompose and release gases, causing the material to swell significantly. This swelling, or intumescence, creates a dense, carbonaceous char layer that fills the penetration and effectively seals it against the spread of fire. The effectiveness of this barrier depends on the density and uniformity of the expanded material, as well as its ability to withstand high temperatures without degrading.

Where are Intumescent Fire Pillows typically used?

Intumescent fire pillows are versatile fire-stopping products that are commonly used in a variety of applications within buildings to maintain the fire resistance of walls, floors, and ceilings. Below are detailed scenarios where these products are typically employed:

Service Penetrations

●     Pipes and Cables: Intumescent fire pillows are often used around service penetrations where pipes (metallic and non-metallic), electrical conduits, and cable bundles pass through fire-rated barriers. They are particularly effective in situations where these services penetrate through compartment walls and floors, ensuring that the fire rating of these barriers is maintained by filling gaps that could otherwise allow fire and smoke to spread.

●     Ductwork: They are also used around ventilation ducts and other ductwork systems that breach fire-resistant structures. The pillows expand in response to heat, sealing the openings and preventing the passage of fire.

Fire Compartments

●     Building Compartmentation: Intumescent fire pillows are essential in maintaining the integrity of fire compartments within buildings. Fire compartments are areas designed to contain a fire within a specific section of a building, preventing it from spreading to other areas. Fire pillows are used to seal openings between compartments, especially where there are complex penetrations involving multiple services.

Structural Openings

●     Expansion Joints: These pillows are used in expansion joints in walls and floors that require fire protection. Expansion joints allow for movement in buildings, but they also create potential pathways for fire to spread if not properly sealed. Intumescent fire pillows can be installed in these joints to ensure they are sealed while still allowing for the necessary movement of the building.

Temporary Firestopping

●     During Construction Phases: Intumescent fire pillows are valuable during the construction phase of a building where permanent firestopping systems may not yet be installed. They can provide temporary protection by sealing penetrations temporarily until the final firestopping systems are in place. This ensures that the building remains safe throughout the construction process.

Retrofit Applications

●     Modifications in Existing Buildings: In existing buildings, where modifications require new penetrations in fire-rated walls or floors, intumescent fire pillows can be used to restore the fire resistance of these barriers. This is particularly common in older buildings undergoing renovations or in facilities where the configuration of services is frequently changing, such as in data centres or commercial buildings.

Mechanical and Electrical (M&E) Service Areas

●     Risers and Service Voids: Intumescent fire pillows are used in service risers and voids where mechanical and electrical services are concentrated. These areas often contain multiple services passing through floors and walls, and fire pillows help ensure that these penetrations do not compromise the fire safety of the building.

Specialised Applications

●     High-Risk Environments: In specialised environments like chemical plants, laboratories, or areas with high fire risk, intumescent fire pillows are used to ensure that any service penetrations do not become weak points in the fire protection strategy. These environments may require enhanced fire protection due to the nature of the materials or operations involved.

By employing intumescent fire pillows in these scenarios, building designers and safety engineers can effectively maintain the integrity of fire-rated barriers, ensuring compliance with building codes and enhancing the overall fire safety of structures.

Are Intumescent Fire Pillows reusable?

Intumescent fire pillows are generally reusable, making them an economical choice in environments where service configurations change frequently. However, reusability depends on several factors:

●     Condition Post-Installation: The pillows should be inspected for any signs of wear, tear, or exposure to conditions that could affect their performance, such as moisture or extreme temperatures.

●     Exposure to Fire: If the pillows have been exposed to a fire or high heat, they should be replaced, as the intumescent material may have already expanded or been compromised.

●     Manufacturer's Guidelines: It is important to follow the manufacturer’s recommendations regarding the reusability of their specific product. Some products may be designed for single-use only, particularly in critical applications.

What fire rating can Intumescent Fire Pillows achieve?

The fire rating of intumescent fire pillows is determined through rigorous testing according to standards like BS EN 1366-3, which assesses the fire resistance of penetration seals. These tests simulate real fire conditions to evaluate the ability of the pillows to maintain the integrity of the fire-rated barrier. The fire rating can vary based on factors such as:

●     Size of the Penetration: Larger or more complex penetrations may require multiple pillows or additional firestopping measures to achieve the desired fire rating.

●     Type of Service Passing Through: The nature of the services (e.g., plastic pipes vs. steel pipes) can affect the performance of the fire pillows, as some materials may soften or melt during a fire, necessitating additional firestopping measures.

●     Installation Method: Proper installation is critical to achieving the rated performance. The pillows must be tightly packed and installed according to the manufacturer’s instructions to prevent any gaps that could allow fire spread.

Typically, intumescent fire pillows can provide fire resistance ratings of 30, 60, 90, or 120 minutes, depending on the specific product and application.

How are Intumescent Fire Pillows installed?

The installation process for intumescent fire pillows involves several key steps:

●     Assessment of the Opening: Measure the size and configuration of the opening to determine the number and size of pillows required. The goal is to ensure a snug fit with no voids.

●     Placement of the Pillows: Insert the pillows into the penetration, ensuring they are tightly packed around the services. In vertical applications, additional support may be required to prevent the pillows from shifting.

●     Sealing and Finishing: Depending on the application, additional fire sealants may be applied around the edges of the pillows to ensure a complete seal. Some installations may also require the use of a retaining mesh or other supports.

●     Inspection and Documentation: After installation, inspect the fire pillows to confirm they are correctly positioned and there are no gaps. Document the installation, including the type and location of the pillows, as part of the building’s fire safety records.

What maintenance is required for Intumescent Fire Pillows?

Ongoing maintenance is crucial for ensuring the long-term effectiveness of intumescent fire pillows. This includes:

●     Regular Inspections: Conduct regular visual inspections, particularly in areas where services may be added or altered. Look for signs of wear, displacement, or damage.

●     Environmental Considerations: Ensure the pillows are not exposed to conditions that could degrade their performance, such as prolonged exposure to moisture, chemicals, or mechanical damage.

●     Reinstallation After Disturbance: If the pillows have been removed or disturbed during maintenance work, they must be reinstalled correctly. Any gaps or loose packing should be corrected immediately.

●     Compliance Checks: Regularly review the installation to ensure it still complies with the relevant fire safety regulations, especially if the building's use or layout changes.

Do Intumescent Fire Pillows comply with building regulations?

Intumescent fire pillows are designed and tested to comply with building regulations and fire safety standards applicable in the UK and other regions. These regulations require that any firestopping product used in fire-rated assemblies must be tested and certified for its intended application. Key standards include:

●     BS EN 1366-3: The primary standard for fire resistance tests of penetration seals, assessing the ability of the pillows to maintain the fire resistance of walls and floors.

●     BS 476 Part 20-22: Older British standards that are still referenced in some contexts, providing methods for determining the fire resistance of elements of construction.

●     Third-Party Certification: Many fire pillows are also certified by third-party bodies, providing additional assurance of their performance. Certification often includes regular audits of the manufacturing process and product testing.

Can Intumescent Fire Pillows be used in outdoor environments?

While some intumescent materials are formulated to withstand outdoor conditions, most intumescent fire pillows are intended for indoor use. Outdoor applications present challenges such as exposure to UV radiation, moisture, temperature fluctuations, and physical wear, all of which can affect the performance of the intumescent material. If outdoor use is required, it is essential to:

●     Select a Product Rated for Outdoor Use: Some manufacturers offer intumescent products specifically designed for exterior applications, which are more resistant to environmental factors.

●     Protect the Installation: Additional protective measures, such as weatherproof enclosures or sealants, may be necessary to protect the pillows from the elements.

●     Consult with the Manufacturer: Always consult the manufacturer to confirm that the specific product is suitable for outdoor use and to understand any additional installation requirements.