Understanding the fire safety-related knowledge of silicone extrusions can help you select compliant and high-quality silicone products. This can meet your customers’ demand for flame retardancy of the products and reduce compliance risks.
We will discuss the performance of silicone extrusions, types of fire resistance and grades, hoping it will be helpful for your business.
What Are Silicone Extrusions?
Silicone extrusions are continuous sealing strips, gaskets, pipes or other custom profiles produced through the extrusion process. The extrusion process enables continuous production of complex profiles with consistent dimensions.
And it can create an excellent surface texture for your products and also give you greater freedom in designing the final product.
You can apply them in industries that require high-performance sealing and insulation, especially in flammable environments.
Why Do Silicone Extrusions Deliver Fire-Safe Performance?
Ceramicization Performance
Because the main chain of silicone is composed of silicon-oxygen (Si-O) bonds, it has excellent thermal stability. Silicone gradually undergoes thermal degradation when exposed to temperatures above approximately 300°C – 350°C.
If you add specific fillers (such as silicates, glass powder) to the silicone extrusion, such a formula will form a dense ceramicized protective layer at high temperatures. The ceramic layer formed by your special formula silicone extrusion can prevent heat from being transferred to the interior.
Moreover, if you use it in circuit applications, for example, it may help maintain electrical insulation and delay circuit failure during a fire event. Because the ceramic layer of certain ceramifiable silicone can help maintain circuit integrity during fire at 800°C – 1000°C.
Self-Extinguishing Performance
When you use flame-retardant silicone, you will find that this specially formulated product has the characteristic of self-extinguishing when separated from the flame. However, for your silicone products to meet flame-retardant standards such as UL 94 V-0, they need to undergo vertical combustion tests.
Low Smoke and Low Toxicity Characteristics
In a confined space, the smoke and toxic gases produced by ordinary flammable products are actually more likely to put your customers in danger than the flames.
However, when silicone undergoes thermal decomposition, it does not produce large amounts of thick smoke or halogenated toxic gases like many other organic polymers do. This characteristic is highly desirable in transportation, construction, and enclosed public environments.
Intumescent Sealing Mechanism
You can select specialized silicone formulations with additives that expand and form ceramic barriers under fire conditions.
This material not only effectively blocks the transfer of heat, but also can expand and seal the gaps or joints in walls, ceilings, doors, windows, etc.
This way, it can prevent the fire from spreading to other areas of the building, quickly blocking the channels for the spread of flames and smoke. It also reduces the risk of combustion poisoning for your customers during use.
Types of Fire-Resistant Silicone Extrusions
The fire-resistant silicone extrusions actually fall into two types. Due to the differences in specific properties, they play their respective roles in different fields. For specific details, you can refer to the following content:
Heat-Resistant Silicone Extrusions
Heat-resistant silicone extrusions are a type of silicone material that can be used to ensure fire safety. Heat resistance and flame retardancy are different material properties. This material can function normally under extreme temperatures (including high and low temperatures) and maintain excellent mechanical properties.
You can keep some specialty grades within the temperature range of -70°C to 300°C. And the heat resistance of these heat-resistant silicone extrusions is better than that of most other polymer rubber materials.
You can make heat-resistant silicone extrusions into silicone sealing strips for ovens. In environments where it is constantly exposed to extreme high temperatures for a long time, it can still work efficiently, allowing your customers to use it with greater peace of mind.
Flame-Retardant Silicone Extrusions
Flame-retardant silicone extrusions can also be applied in the field of fire safety, and their flame-retardant effect is remarkable.
If you need silicone extrusions to have flame-retardant properties, a specially designed formula is required to achieve self-extinguishing characteristics. Moreover, all flame-retardant materials are commonly evaluated through standardized flammability tests.
For example, if it is exposed to flames within a specified time, it should prove that your silicone product can still function normally when exposed to flames.
Because flame-retardant silicone extrusions have the characteristics of low smoke and low toxicity, they will not produce a large amount of smoke or toxic gases in the event of a fire.
This is a very important safety standard in our silicone industry.
However, flame-retardant silicone extrusion materials do not have the same high temperature resistance range as heat-resistant silicone extrusion materials. They usually can withstand a temperature about 200°C.
Industry Grades of Flame-Retardant Silicone Extrusions
The formulations of silicone extrusion materials vary, which directly affects the fire resistance and self-extinguishing performance of your products. The safety certification standards corresponding to different materials in your hands also differ. Therefore, the industry has classified various performance grades to facilitate your selection as per your needs.
Each grade of material is suitable for different applications and can precisely match the various project requirements of your customers.
General-Purpose Flame-Retardant Silicone Extrusions
Silicone extrusion materials that meet the flammability grade requirements of UL 94 standard can be used to manufacture seals, gaskets and flexible pipes, and have certain fire-resistant properties.
If you are in the construction industry, you can use such silicone extrusions for fireproof sealing applications in doors, windows and HVAC systems. This can help prevent the spread of fire and enhance building safety.
Because the seals made of general flame-retardant silicone materials can form a reliable heat insulation barrier to protect the safety of residents.
UL 94 V-0 Rated Silicone Extrusions
UL 94 V-0 rated silicone extrusion material is a flame-retardant silicone material that can self-extinguish within 10 seconds and has been rigorously tested. It effectively inhibits the spread of flames, has low smoke and toxicity, and is suitable for use in enclosed environments.
If you intend to use it in public transportation, you can employ this UL V-0 grade silicone extrusion material that meets the flammability standard to ensure fire safety, passenger safety, and component protection.
Since the transportation sector often involves high-speed friction, fuel exposure, and electrical systems during tool usage, fire risks always exist.
You can also use it in the electronics industry as an insulator and for electrical fire protection. Due to overheating, electrical short circuits, or component failures, UL 94 V-0 rated flame-retardant silicone ensures self-extinguishing properties, reducing the emission of toxic substances from electronic components in overheated conditions.
High-Performance Industrial-Grade Silicone Extrusions
You can use high-performance industrial-grade silicone extrusion materials in high-risk environments such as aerospace and automotive industries. Because the material enhances thermal stability, fire resistance, while still maintaining certain flexibility and strength.
For example, FAR 25.853 and ABD0031 stipulates the fire resistance standards for silicone components in the aviation industry. Silicone extrusions that meet these standards can be applied to engine compartment sealing, cable protection and firewall sealing. It can withstand extreme high temperatures without deforming or losing strength.
If you are in the marine industry and want to prevent the spread of fires on ships and offshore platforms, you can also use this type of silicone to ensure high-temperature stability.
Because of the extreme high temperatures, water exposure, and fire risks on ships and offshore platforms, high-performance materials are required to resist heat exposure and maintain performance. You can use it for door seals, cable protection and environmental seals.
FAQ
What Materials and Technologies Affect Fire Safety Performance in Silicone Formulations?
The addition of inorganic fillers. If you want to meet strict fire resistance standards, you can add appropriate flame-retardant fillers to the silicone formula. Let these fillers decompose and absorb heat at high temperatures, and form a protective layer.
Which Fire Safety Certifications Matter When Purchasing Silicone Extrusions?
The corresponding fire safety standards for silicone extrusion parts vary across different industries: for instance, in the rail transportation industry, it must meet EN 45545-2, achieving HL2/HL3 levels, while also ensuring low heat release and low smoke toxicity.
In the aerospace industry, it follows FAR 25.853 and ABD0031, undergoing rigorous combustion tests to strictly control smoke and toxicity.
If you are in the electronics industry, opting for UL 94 V-0 is recommended, as it enables self-extinguishment within a short period. Silicone components used in fire-rated assemblies may be evaluated under standards such as ASTM E84 or UL 10C, depending on the final application.
Can Silicone Extrusions Avoid Combustion Under Flame?
Silicone is an organic silicon polymer and cannot be completely non-flammable. If you keep it in a flame or at a temperature reaching the critical point, the silicone will eventually undergo thermal decomposition.
However, the silicone extrusion has two key fire-retardant and self-extinguishing properties. The high-quality fire-retardant silicone you choose is specially formulated and will extinguish itself after the flame is removed, without continuing to burn or spreading the fire.
How Do Silicone Extrusions Function in Fire Safety Protection?
Certain fire-resistant silicone extrusions are part of Passive Fire Protection (PFP) in fire safety. They mainly achieve this through the following two methods:
The first method is fire sealing: sealing strips used at building openings such as doors, windows, and pipes to prevent flames and toxic smoke from spreading through gaps.
The second method is the fire insulation layer: such as the insulation sheaths for cables and wires. It mainly uses silicone extrusions with special formulations that can be ceramicized to maintain sufficient electrical insulation strength.
What Value Do Fire-Safe Silicone Extrusions Bring to Electrical Safety Fields?
After being burned in a fire, your silicone extrusions can still maintain a certain level of electrical insulation strength. This ensures that critical lines such as fire-fighting equipment, emergency lighting, and alarm systems can continue to function for a period of time during the fire.
Final Thoughts
Legensilico is a silicone manufacturer with over 20 years of professional experience, and we can provide you with a one-stop service. If you are interested in our silicone extrusion process products, please feel free to contact us at any time. We also offer customization services, allowing us to design products according to your requirements.
