An Introduction to Reaction to Fire

What is Reaction to Fire Testing?

Reaction to fire testing is a crucial process. It examines the characteristics of building materials. This includes their combustibility, which helps determine their role in the development and spread of a fire. Materials are classified under BS EN 13501-1. Their classification is based on their reaction to fire, as determined by a series of standard tests.

Understanding Reaction to Fire Testing Methods

Single Burning Item (SBI) – BS EN 13823:2020

The Single Burning Item test is arguably the most recognizable among the various tests. It specifies a method for assessing construction products' reaction to fire when exposed to thermal attack from a single burning item. This method ensures that materials are rigorously tested under controlled conditions.

Non-Combustibility – BS EN ISO 1182:2020

This test classifies products that do not significantly contribute to a fire, regardless of their intended use. The Non-Combustibility test identifies construction materials that produce minimal heat and flame below approximately 750°C. This is essential for ensuring safety during a fire.

Small Flame – BS EN ISO 11925-2:2020

The Small Flame test assesses the maximum potential heat release of a product when completely burned, disregarding its intended use. It offers valuable insights into the absolute heat of combustion for a product. This approach does not account for inherent material variability but focuses on baseline characteristics.

Calorific Value – BS EN ISO 1716:2018

This method focuses on determining the ignitability of products via direct small-flame impingement. The test uses vertically oriented specimens to evaluate how easily a product can ignite. It helps ensure that products comply with safety standards.

Do All Products Need to Use Every Test Method?

No, products are not required to complete every test method to determine their classification. Some tests are mandatory depending on the sought classification.

Classification and Test Requirements

Different classifications carry specific testing requirements. The table below summarizes the testing methods associated with each classification.

Classification	BS EN ISO 1716	BS EN ISO 1182	BS EN ISO 13823	BS EN ISO 11925-2
A1	Mandatory	Mandatory	x	x
A2	Or	Or	Mandatory	x
B	x	x	Mandatory	Mandatory
C	x	x	Mandatory	Mandatory
D	x	x	Mandatory	Mandatory
E	x	x	Mandatory	Mandatory

What Does a Reaction to Fire Classification Look Like?

A product’s reaction to fire classification has three main characteristics: Combustibility, Smoke Production, and Flaming Droplets. Each characteristic is assigned a code for clarity.

Combustibility

• A1: Non-combustible materials that do not contribute to the development of a fire.

• A2: Materials with limited combustibility that do not contribute to fire development.

• B: Combustible materials with limited contribution to fire development.

• C: Combustible materials with a minor contribution to fire development.

• D: Combustible material that contributes to fire development.

• E: Combustible materials that resist small flames for a few seconds.

• F: Materials that do not meet class E requirements.

  
  

Smoke Production

• s1: Little or no smoke production.

• s2: Moderate smoke production.

• s3: Substantial smoke production.

  
  

Flaming Droplets

• d0: No flaming droplets or particles.

• d1: Some flaming droplets and/or particles.

• d2: A significant amount of flaming droplets and/or particles.

  
  

Example Classification

For instance, if a product has a classification of B-s1,d0, it indicates limited combustibility (B), low smoke production (s1), and no flaming droplets (d0). This classification helps users understand the fire safety properties of the material.

Conclusion

Knowing the classification of building materials is crucial for ensuring safety in construction. Reaction to fire testing offers a scientific approach to determining how materials behave in a fire. The results help in making informed decisions to enhance public safety.

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