What is the fire rating of carpet?

Carpets are widely used as flooring materials in residential, office, and public spaces, and their fire performance is directly related to indoor fire risk and occupant safety. In fire-prone environments, the combustion behavior of building materials—especially interior finishing materials—has a significant impact on fire development and available evacuation time. For this reason, many countries and regions have established fire classification systems specifically for materials such as carpets.

The so-called “fire rating” refers to a classification based on standardized test methods that evaluate a carpet’s behavior when exposed to fire, including ignition characteristics, flame spread, and smoke generation. These results are then used to determine the suitability of the carpet for specific safety-related applications.

This article focuses on the topic of carpet fire ratings and provides a systematic overview from the perspectives of national standards, international standards, major test methods, the meaning of different rating levels, and practical regulatory requirements in domestic and international building codes.

Fire Rating Fundamentals: What Is a Carpet Fire Classification?*

A “fire rating” generally refers to the result of standardized testing used to evaluate and classify a material’s performance under fire conditions. For carpets, the fire rating is usually not a single numerical value, but rather a category determined by multiple factors such as combustion behavior, flame spread characteristics, and smoke production.

These evaluations primarily aim to answer two key questions:

Whether the material is easily ignited when exposed to a fire source

How quickly flames spread and how much smoke is released once ignition occurs

Different countries and regions have established their own standard systems. Examples include U.S. federal regulations under 16 CFR (CPSC carpet flammability standards), the European EN 13501-1 fire classification system, and China’s GB 8624 classification for building material combustion performance. Test results obtained under these standards form the basis of carpet fire rating systems.

Carpet Flammability Standards and Rating Requirements in the United States*

In the U.S. market, carpet fire ratings are primarily based on surface flammability performance standards, mainly enforced under federal regulations 16 CFR Part 1630 and 16 CFR Part 1631.

Overview of 16 CFR 1630 and 1631

16 CFR 1630 applies to large carpets with a longest dimension greater than 1.83 meters and an area exceeding approximately 2.23 square meters. This standard is part of U.S. Consumer Product Safety Commission regulations and establishes flammability requirements for carpets commonly used in homes, offices, and hotels.

16 CFR 1631 applies to smaller carpets, such as rugs or decorative mats with no side longer than 1.83 meters and an area not exceeding approximately 2.23 square meters. It also uses surface flammability testing to evaluate fire performance.

Test Method and Pass Criteria

Testing under these standards is commonly referred to as the “Pill Test.” During the test, a standardized ignition source is placed on the carpet surface, and ignition behavior, flame spread, and charred area are observed. To pass the test, carpet samples must meet criteria such as:

Flames or charred areas must not extend beyond specified limits

In a batch of samples, at least seven specimens must meet the pass criteria

Carpets treated with flame-retardant finishes or made from flame-resistant fibers are typically labeled with a “T” designation indicating flame-retardant treatment. If a small rug fails to meet the standard, it must carry a clear “Flammable” warning label and be kept away from ignition sources.

ASTM and NFPA Requirements

Another commonly used evaluation system in the U.S. is based on ASTM and NFPA standards. For example, NFPA 253 (ASTM E648) evaluates floor covering systems using a radiant panel test to determine their tendency to support flame spread under radiant heat exposure. Results are expressed as Critical Radiant Flux (CRF), with higher values indicating better resistance to flame spread.

Under NFPA codes, carpets used in certain building applications must meet specific fire code requirements. For example, achieving a Class I fire rating under NFPA 253 may be required for installation in certain public buildings.

Carpet Fire Classification in European and International Standards*

Europe adopts the EN 13501-1 fire classification system for construction products, including carpets and other floor coverings. This system classifies materials based on combustion behavior and smoke development.

EN Fire Classification and Smoke Ratings

Under EN 13501-1. fire ratings for floor coverings consist of two main elements:

Reaction-to-fire class (A to F):

Class A represents non-combustible materials, while Class F indicates easily combustible materials.

Smoke development classification (s1 to s3):

s1 indicates low smoke production and slow smoke development, while s3 indicates high smoke production and rapid development.

“fl” designation:

Indicates that the classification applies to floor coverings such as carpets.

For example, a Cfl-s1 rating indicates a carpet with moderate combustibility and low smoke production under fire conditions. This classification is commonly used in commercial environments to ensure a higher level of fire safety.

In addition, European standards may include other fire reaction tests, such as hearth or flame spread evaluations, depending on local building regulations.

Carpet Fire Performance Classification in China*

In China, fire performance classification for building materials is generally based on the national standard GB 8624-2012. which classifies materials according to their combustion performance:

Class A (Non-combustible): Materials that essentially do not burn

Class B1 (Flame-retardant): Difficult to ignite; combustion stops after the fire source is removed

Class B2 (Combustible): Can ignite and burn when exposed to fire

Class B3 (Highly flammable): Easily ignited and rapidly combustible

Under this system, carpets and other floor coverings are commonly classified as B1 or B2 materials. In public or commercial spaces with high occupancy, carpets are typically required to meet at least Class B1 flame-retardant performance to reduce fire spread risk.

Influence of Materials and Treatments on Carpet Fire Ratings*

Different carpet fibers exhibit different inherent combustion characteristics, which directly affect fire ratings:

Natural wool fibers: Wool has natural flame-resistant properties, is difficult to ignite, and does not readily support combustion. As a result, wool carpets often achieve higher fire ratings.

Nylon synthetic fibers: Nylon has good heat resistance and typically exhibits slower flame spread. With appropriate formulation or treatment, nylon carpets can achieve relatively high fire ratings.

Polypropylene and similar materials: These fibers generally have lower ignition temperatures and are more easily ignited if untreated, resulting in lower fire ratings. However, flame-retardant treatments or additives can significantly improve their fire performance.

To meet specific building fire safety regulations or commercial requirements, manufacturers often use flame-retardant finishes, flame-resistant yarns, or composite flame-retardant backings to enhance carpet fire ratings and ensure compliance with applicable standards.

Practical Application and Regulatory Requirements for Carpet Fire Ratings*

Commercial and Public Building Requirements

In public spaces such as hotel lobbies, office corridors, and cinemas, evacuation time is limited and occupant density is high, resulting in stricter fire performance requirements for interior materials. Contract-grade carpets typically must:

Pass ASTM Class I or Class II fire reaction tests

Meet EN classifications such as Cfl-s1 or higher in smoke-sensitive environments

These carpets exhibit slower flame spread and lower smoke production, contributing to improved evacuation safety during a fire.

Residential Applications

For residential use, fire rating requirements are generally less stringent. In some European standards, carpets rated Efl may be sufficient for residential flooring, indicating normal combustibility acceptable for home environments, while higher ratings are required for commercial and public buildings.

Labeling and Compliance

In markets where fire ratings are mandatory, compliant carpets typically display their applicable standards and classifications on product labels or technical documentation. Examples include statements such as “Passes 16 CFR 1630.” “ASTM Class I,” or “Cfl-s1.” indicating compliance with relevant fire safety regulations.

How to Choose the Appropriate Carpet Fire Rating*

Residential use:

Select carpets that meet minimum national fire safety requirements, while understanding the material composition and combustion characteristics.

Commercial or high-occupancy spaces:

Choose carpets that meet higher standards such as ASTM Class I, EN Cfl-s1. or GB Class B1 to ensure longer response and evacuation times in fire scenarios.

Special-use areas:

For stairways, escape routes, corridors, and similar areas, stricter fire performance standards apply. Carpet selection should follow local building fire codes and safety regulations.

In summary, a carpet’s fire rating is not a single value but a comprehensive assessment based on combustion behavior, flame spread, and smoke generation, evaluated under region-specific standards. The United States relies on 16 CFR 1630/1631 and related ASTM/NFPA testing systems; Europe uses the EN 13501-1 classification framework; and China applies national standards such as GB 8624 to classify materials into A, B1. B2. and B3 performance levels.

Understanding these standards and test requirements is essential for architects, contractors, interior designers, material purchasers, and consumers. Fire ratings not only determine regulatory compliance but also play a critical role in everyday safety and occupant protection during fire incidents.