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Fire Ratings of Engineered Plastics: Unraveling Flammability Testing and Standards

Posted by The Plastic Sheeting Gurus! on Tue, Oct 24, 2023 @ 03:27

What are Engineered Plastics?

Engineered plastics, also known as engineering plastics, are a category of synthetic polymers that are specifically designed and formulated to exhibit enhanced mechanical, thermal, chemical, and electrical properties compared to standard or commodity plastics. These materials are engineered through precise combinations of polymers and additives to achieve desired characteristics such as high strength, toughness, chemical resistance, dimensional stability, and other specialized properties.

Who  Uses Engineered Plastics?

Engineered plastics are used in a wide range of industrial applications due to their versatility and ability to meet specific performance requirements. Examples of commonly used engineered plastics include polyamide (nylon), polyethylene terephthalate (PET), polycarbonate (PC), polyoxymethylene (POM), and polyetheretherketone (PEEK), among others. They find applications in automotive, aerospace, electronics, medical devices, and various other industries where high-performance materials are essential.

The use of engineering plastics has become ubiquitous in various industries due to their exceptional mechanical properties and versatility. However, assessing their fire resistance is crucial to ensure safety and compliance with regulatory standards. Fire ratings for engineering plastics are determined through rigorous flammability testing, involving a range of standards and test methods. This article explores the significance of fire ratings, the parameters tested, and the various methods used to evaluate the flammability of engineering plastics.

Understanding Fire Ratings and Flammability Testing

Fire ratings are essential for categorizing the fire resistance of engineering plastics, providing valuable information for designers, manufacturers, and regulators. These ratings are established through flammability testing, which assesses a material's propensity to ignite and sustain combustion when exposed to various conditions.

What Are They Testing For?

When assessing the fire resistance of engineering plastics, the key parameters tested include:

  1. Ignition Temperature: This is the temperature at which a material ignites when exposed to an open flame or an external heat source.

  2. Flame Spread: Flame spread tests measure the rate at which flames propagate across the surface of the material.

  3. Heat Release Rate (HRR): HRR is the rate at which a material releases heat during combustion, indicating its potential to intensify a fire.

  4. Smoke Generation: This parameter assesses the amount of smoke produced during combustion and is crucial for evaluating the visibility and toxicity of smoke.

  5. Toxic Gas Emissions: The evaluation of toxic gas emissions during combustion is important for assessing the health hazards associated with a fire involving the material.

Types of Burn Tests

Several standardized tests are employed to assess the flammability of engineered plastics. Some of the commonly used test methods include:

  1. UL 94 Flammability Test: This is a widely recognized test conducted by Underwriters Laboratories. It classifies plastics into different categories, ranging from V-0 (least flammable) to V-2 and HB (most flammable), based on their performance during vertical and horizontal flame tests.

  2. Oxygen Index Test: This test measures the minimum oxygen concentration required to sustain combustion. Plastics with a high oxygen index are considered less flammable.

  3. Cone Calorimeter Test: The cone calorimeter measures various parameters, including HRR, smoke production, and toxic gas emissions. It provides valuable data for understanding a material's fire behavior.

  4. NBS Smoke Chamber Test: This test evaluates smoke generation characteristics by exposing the material to a standardized radiant heat source. It is used to assess the visibility and toxicity of smoke produced during combustion.

  5. ISO 5660 Cone Calorimeter Test: This is an international standard for assessing the heat release rate and other fire-related parameters of materials.

  6. ASTM E84 Surface Burning Characteristics: This test method, also known as the "Tunnel Test," measures flame spread and smoke development on the surface of a material, helping classify materials as per building code requirements.

  7. NFPA 701 is a standard developed by the National Fire Protection Association (NFPA) that addresses fire performance requirements for textiles and films used in various settings, including public spaces, commercial buildings, and events. The primary focus of NFPA 701 is to establish criteria for materials to resist the ignition and spread of flame when exposed to heat sources, such as open flames, electrical sparks, or other potential fire hazards.

    Here's a more detailed explanation of NFPA 701:

    1. Scope: NFPA 701 covers the fire testing of textiles and films to ensure they meet specific fire safety standards. It applies to materials used in draperies, curtains, window shades, stage curtains, banners, and similar applications in public and commercial spaces.

    2. Purpose: The primary purpose of NFPA 701 is to reduce the risk of fire and improve the safety of occupants in public and commercial buildings by setting fire performance standards for textiles and films. It ensures that these materials are less likely to ignite and contribute to the spread of flames in the event of a fire.

    3. Testing Methods: NFPA 701 uses different testing methods to evaluate the fire resistance of textiles and films. The two primary tests are:

      • NFPA 701 Small-Scale Test: This test measures the flame resistance of materials using a small-scale apparatus. The material is exposed to an open flame, and its flame propagation characteristics are assessed.

      • NFPA 701 Large-Scale Test: This test is used for materials that do not meet the criteria of the small-scale test. It involves a larger apparatus and evaluates the fire resistance of textiles and films in a more comprehensive manner.

    4. Requirements: For a material to comply with NFPA 701, it must pass one of the prescribed tests (small-scale or large-scale) without displaying excessive flame propagation. The specific criteria and pass/fail criteria are outlined in the standard.

    5. Applications: Materials that pass NFPA 701 testing are commonly used in settings where fire safety is crucial. This includes theaters, event venues, hotels, restaurants, and other public spaces where textiles or films are employed for decorative or functional purposes.

    6. Certification: Manufacturers often have their textiles and films tested and certified to meet NFPA 701 standards. Customers can look for this certification when purchasing materials for their intended applications to ensure compliance with fire safety regulations.

Example of Fire Retardant Polypropylene Fluted Boards

Fire Retardant Polypropylene boards, also known as FR Polypropylene boards, are engineered plastic sheets composed of polypropylene, a versatile thermoplastic polymer. These boards undergo treatment with fire retardant additives to significantly reduce their flammability and enhance their fire resistance. Tailored to meet stringent fire safety and regulatory standards, these boards are the go-to solution for applications where fire safety is paramount.

Key Features of Fire Retardant Polypropylene Boards:

  1. Reduced Flammability: By incorporating fire retardant additives, these boards exhibit markedly decreased flammability, reducing the risk of ignition when exposed to heat or flames.

  2. Limited Fire Spread: FR Polypropylene boards are intelligently designed to resist the rapid propagation of flames, contributing to a safer environment by curbing the potential spread of fires.

  3. Low Smoke and Toxic Gas Emissions: In the event of ignition, these boards emit significantly less smoke and fewer toxic fumes compared to untreated polypropylene. This feature enhances overall safety during a fire.

  4. Compliance with Fire Regulations: These boards are precision-engineered to meet the specific fire safety standards and regulations, making them a reliable choice for applications where adherence to fire codes is imperative.

Diverse Applications:

Fire Retardant Polypropylene boards find extensive use in various sectors:

  • Construction: They serve as essential components for fire-resistant wall linings, ceiling panels, and other structural elements in the construction industry.

  • Transportation: Automotive and aerospace industries employ these boards in interior components to enhance fire safety.

  • Electrical Enclosures: FR Polypropylene boards are commonly used in electrical cabinets and enclosures to safeguard sensitive equipment from potential fire-related damage.

  • Signage: These boards are a favored choice for creating fire-resistant signage and display boards.

  • Industrial Equipment: In industrial settings, they find application in machinery guards and safety barriers.

A Cut Above the Rest:

  • UL-94, NFPA 701-15, and ASTM E-84-18A Compliant: These FR fluted polypropylene boards meet rigorous industry standards for fire resistance.

  • Versatile Dimensions: Available in the classic 48" x 96" (4' x 8') dimensions, with a solid white surface and a weight of 700 gsm (grams per square meter).

  • Exceptional Properties: Ultra Corrugated Polypropylene Boards are waterproof, tear-proof, and highly resistant to a wide range of chemicals. They are exceptionally durable and lightweight.

  • Environmental Responsibility: These boards are 100% recyclable, promoting sustainability.

Additional Features:

  • Anti-UV: The boards are equipped with anti-UV additives for enhanced UV resistance.
  • Anti-static: They exhibit anti-static properties, reducing the risk of static build-up.

Learn more about the FR corrugated boards on our website.

Laminacorr Ultra: These boards are available in widths of up to 100" across the flutes, offering exceptional versatility. Please visit the product page here

With thickness options ranging from 2mm to 10mm and a vibrant spectrum of 14 colors, you're sure to find the perfect solution for your next project. Fire Resistant Fluted Polypropylene Boards offer unparalleled safety and reliability for applications where fire resistance is non-negotiable.


Fire ratings and flammability testing play a crucial role in assessing the safety of engineering plastics in various applications. Understanding the parameters tested and the methods used for evaluation is vital for ensuring compliance with industry standards and regulations. Engineers, manufacturers, and regulators rely on these assessments to make informed decisions about the use of engineering plastics in environments where fire safety is of paramount importance.

Tags: Fire Ratings, Engineering Plastics, Flammability Testing