Technical Untangled: Flame Resistance, ANSI/ISEA 105 and EN407 Heat Protection Explained

Those working in industries exposed to thermal risks such as extreme heat, open flames, hot surfaces, or other burning hazards require reliable hand protection designed to withstand these conditions. When selecting hand protection for these industries, "heat protection" cannot be assessed through a single measure; It involves complex considerations across material science, rigorous testing procedures, and adherence to international standards. To provide the best protection for industrial applications, it's essential to understand the standards that support your hand protection.

In this edition of Technical Untangled, we will break down the following: Flame Resistance, the North American standard ANSI/ISEA 105 with its incorporated thermal test methods and European standard EN407. Our mission is to clarify the complexities of these standards to help you choose the appropriate solution for your needs.

What is Flame Resistance?

Flame resistance (FR) is the property of a material that enables it to resist ignition, limit flame spread and self-extinguish once the heat or flame source is removed.

Before diving deeper, it is important to distinguish between two key terms often used in this context:

●      Flame Resistant (FR): This refers to materials that are designed to resist ignition and will self-extinguish when the heat source is removed. Their flame-resistant performance may come either from chemical treatments applied to the material or from the inherent chemistry of the fibers themselves.

●      Inherently Flame Resistant: This describes fibers or fabric materials whose flame resistance is built into their chemical structure. Because the protection is part of the fiber itself, it does not wash out, wear off, or degrade over time under normal use

 These properties are essential for gloves and other protective gear that must withstand thermal hazards and protect workers from exposure to flame and high heat.

North American ANSI/ISEA 105 Standard

ANSI/ISEA 105 sets the benchmark for Hand and Arm Protection Classification, defining the performance requirements that ensure gloves deliver reliable, real-world safety. While the standard is well known for its mechanical testing such as Cut, Puncture, and Abrasion, it also incorporates thermal evaluations designed to measure how gloves perform under serious heat exposure.

The ANSI/ISEA 105 standard assesses ignition resistance and burning behavior, heat degradation resistance, and its primary emphasis, conductive heat resistance, which determines how well a glove protects the wearer when handling hot surfaces or materials. 

 These tests give safety professionals a clear, evidence-based view of how gloves behave in high-temperature environments.

Ignition Resistance and Burning Behavior

In ANSI/ISEA 105-24, ignition and burning behavior is tested to ensure gloves can withstand direct flame exposure without putting the wearer at risk. This property is evaluated using the standard ASTM F1358, which exposes glove material to a controlled vertical flame for typically 3 seconds, or, if no ignition occurs, 12 seconds. Where ignition occurs, the after-flame time (how long the material continues to burn after the flame is removed) is measured. The classification is assigned according to the following table:

The glove also must not melt, drip, separate, or char excessively as doing so could cause burns to the end user.

Heat Degradation Resistance

 This test is carried out in accordance with ISO 17493 and focuses on material stability, rather than heat transfer. This test measures how well a glove maintains its physical integrity when exposed to elevated temperatures.

The assessment looks for any sign of:

·       Melting

·       Charring

·       Brittleness or hardening

·       Surface cracking or splitting

·       Dripping or flowing

·       Shrinkage beyond acceptable limits

The purpose is to ensure that when a glove is subjected to high temperatures, or accidental flame contact, it does not physically degrade in a way that could expose the wearer to injury.

The glove classification is based on the temperature at which there is no evidence of charring, ignition, melting, dripping, or separation, and there is no shrinkage greater than 5% as per the following table:

Conductive Heat Testing

The conductive heat test (using test method ASTM F1060) measures thermal insulation of protective clothing materials exposed briefly to surfaces up to 600°F (316°C).

A weighted sensor records heat transfer through the specimen, correlating it to pain sensation and second-degree burn thresholds. “Alarm time”, the interval between initial pain and burn threshold, is also measured.

Classification is based on ≥15 s to second-degree burn and >4 s alarm time.

There shall also be no evidence of charring, ignition, melting, dripping, and separation, and no shrinkage greater than 5%.

European EN407 Standard

EN 407 is the European standard for gloves that protect against thermal risks (heat and/or fire).  Gloves certified to EN407 carry a six-digit code that details their performance across six different thermal properties:

Limited Flame Spread - The glove is positioned vertically above a flame and exposed to ignition for 3 and 15 seconds. Classification is based on the length of time the material continues to burn and glow after the source of ignition is removed. The performance classification reflects the glove’s ability to resist ignition and limit flame propagation.

 Contact Heat - In this test, the sample is placed on a calorimeter, and a heated cylinder is brought into contact with the material. Temperatures of 100, 250, 350 and 500^oC are tested to determine the classification. The threshold time is calculated – the time it takes for the calorimeter temperature to increase by 10^oC once the material is in contact with the heated cylinder. A threshold time of greater than 15 seconds demonstrates a pass for the test temperature. If a level 3 or 4 contact heat is achieved, then limited flame spread must also be tested and pass level 3 as a minimum. 

Convective Heat - The glove is placed in a controlled chamber and exposed to a flame. The resistance is based on the length of time it takes to transfer heat from the flame. If a level 3 or 4 is achieved, then limited flame spread must also be tested and pass level 3 as a minimum.

Radiant Heat - The glove is exposed to a radiant heat source, and the classification is determined by how long it takes heat to transfer through the material.  The test is performed on the back of the hand. For radiant heat performance levels of 3 or 4, the limited flame spread test shall be performed. The product shall reach at least level 3 in the limited flame spread test

Resistance to Small Splashes of Molten Metal - The glove is splashed with small droplets of molten metal and the number of droplets that are required to heat the glove to the specified threshold are measured. The classification is based on the average number of droplets counted across four samples. Specimen are taken from the palm and the back of the glove.  For small splashes of molten metal performance levels of 3 or 4, the limited flame spread test must also be performed, achieving a minimum level 3.

 Resistance to Large Quantities of Molten Metal - The glove is lined with a skin-simulated material and molten metal is poured over the glove. Once the test is complete, the liner material is assessed for any changes such as pin holing or degradation, and the classification is based on the weight of molten metal required to cause changes to the skin-simulated material. If a drop of the molten metal is stuck to the glove or if the sample ignites, the material
fails the test. For large quantities of molten metal performance levels of 3 or 4, the limited flame spread test must also be performed, achieving a minimum of level 3.

The four performance levels range from ‘Level 1’, representing the lowest level of protection, to ‘Level 4’ being the highest.

 Any gloves complying to EN407 must conform to the sizing and innocuousness requirements in EN ISO 21420 and must also be tested for EN388 tear strength achieving a minimum level 1 in this test.

Gloves with EN407 performance levels 3 and 4 must also be subjected to a removal test as per EN 659. The gloves should be manufactured so that they can be easily removed in case of an emergency.

Difference In Marking

The EN407 heat protection pictogram uses a six-digit code, where each digit represents performance in a different type of thermal hazard. In contrast, ANSI/ISEA 105 does not use a multi-digit code. Instead, it assigns an individual performance level for each specific heat test. So EN407 shows all heat-related results in a single symbol, while ANSI/ISEA 105 provides separate ratings for each property.

Comparison: EN407 vs. ANSI/ISEA 105 Heat Protection

If your operation spans multiple regions, ensure your PPE supplier provides certification that matches the standard of the region in which the glove will be used. While testing principles are similar, performance scales, rating levels and reporting methods may differ.

Choosing the Best Hand Protection Solution in Industry Applications

Hand protection needs vary significantly across different industrial roles, particularly concerning heat protection and mechanical risks. For instance, a professional working in the hot end of a glass manufacturing facility, where they deal with high temperatures and molten glass, requires a different level of protection than someone in the food industry who is working with hot trays and transferring items from the oven.

When selecting hand protection for a specific role, it is essential to review the standards the gloves comply with. This ensures that you can choose gloves that offer the highest levels of protection tailored to each application. Heat protection is not about guessing; it's about verified, certified performance. By understanding Flame Resistance and the comprehensive ANSI/ISEA 105 and EN407 standards, you empower your safety team to make informed decisions.

 If you have any questions regarding specific safety and regulation requirements for thermal hazards, contact our team today. We would be happy to assist you in finding a solution that offers verifiable protection globally.