🔥 Fire reaction of construction materials

Construction PN-EN 13501-1

Overview

The Euroclass fire classification system, described in standard PN-EN 13501-1, is the basic tool for assessing fire safety of construction materials in the European Union. CPR Regulation (305/2011) requires that every construction product placed on the market has a declaration of performance with fire reaction classification.

The system includes 7 main classes: A1 and A2 (non-combustible or almost non-combustible products), B, C, D (products with decreasing fire resistance), E (flammable but self-extinguishing) and F (no requirements / unclassified). Additionally, smoke production (s1, s2, s3 — from low to high) and flaming droplets formation (d0, d1, d2 — from none to intensive) are classified. Full class looks e.g.: B-s1,d0 (flame retardant, low smoke, no droplets).

Classification is based on results of several test methods: non-combustibility test (EN ISO 1182), bomb calorimeter (EN ISO 1716), SBI test — Single Burning Item (EN 13823) and small flame test (EN ISO 11925-2). Test selection depends on target class — e.g. class A1 requires meeting non-combustibility and calorimeter criteria, class B–D requires SBI and small flame.

These tests are performed only by notified laboratories (in Poland e.g. ITB, CNBOP-PIB, IMBiGS). The manufacturer of construction materials commissions tests, and based on them the notified body issues a classification report.

Method principle

Euroclass classification is based on a hierarchy of fire tests. Non-combustibility test (EN ISO 1182): sample is placed in tubular furnace at 750°C and temperature rise, mass loss and flame time are measured. Bomb calorimeter (EN ISO 1716): sample is burned in oxygen atmosphere under pressure 3.0–3.5 MPa — heat of combustion must not exceed 2.0 MJ/kg (A1) or 3.0 MJ/kg (A2). SBI test (EN 13823): two samples (1.5×0.5 m + 1.0×0.5 m) set at an angle are exposed to 30 kW propane burner — FIGRA (fire growth index), THR600s (total heat release), SMOGRA (smoke production index) and flaming droplets occurrence are measured. Small flame test (EN ISO 11925-2): 20 mm flame is applied to sample edge for 15 or 30 s — flame spread is assessed.

Applications

• Fire classification of thermal insulation materials (EPS, XPS, mineral wool, PIR)
• Testing of floor coverings, wall and ceiling linings
• Certification of facade materials (ETICS systems)
• Classification of pipes and installation insulation (linear pipe insulation)
• Testing of interior design materials (furniture, fabrics)
• Declarations of performance (DoP) according to CPR 305/2011
• Fire expert opinions for fire protection experts

Key parameters

Standard

Standard number

PN-EN 13501-1+A1:2018

Title (PL)

Klasyfikacja ogniowa wyrobów budowlanych i elementów budynków — Część 1: Klasyfikacja na podstawie badań reakcji na ogień

Title (EN)

Fire classification of construction products and building elements — Part 1: Classification using test data from reaction to fire tests

Step-by-step procedure

1. Sample acceptance and conditioning

   Condition samples min. 48 h under conditions: 23±2°C, 50±5% RH. Prepare required number of samples for each test.

   ⏱ Time: 48+ h • 🌡 Temperature: 23±2°C

2. Non-combustibility test EN ISO 1182

   Place cylindrical samples ∅45×50 mm in furnace at 750°C. Measure temp. rise (ΔT <30°C for A1), mass loss (<50%) and flame time (<20 s).

   ⏱ Time: 60 min • 🌡 Temperature: 750°C

3. Bomb calorimeter EN ISO 1716

   Burn powdered sample (1–1.5 g) in calorimeter bomb in O₂ atmosphere (3 MPa). Measure heat of combustion. Criterion A1: PCS ≤2.0 MJ/kg.

   ⏱ Time: 30 min

4. SBI sample preparation

   Prepare 2 panels: long (1500×500 mm) and short (1000×500 mm). Mount on support frame with substrate according to standard.

   ⏱ Time: 60 min

5. SBI test EN 13823

   Set panels at angle under exhaust hood. Ignite propane burner (30 kW). Record HRR, FIGRA, THR600s, SPR, SMOGRA, droplets for 20 min.

   ⏱ Time: 30 min

6. Small flame test EN ISO 11925-2

   Place 250×90 mm sample vertically in chamber. Apply 20 mm flame to edge for 15 s (or 30 s). Assessment: spread to 150 mm in 60 s.

   ⏱ Time: 5 min/sample

7. Data processing and calculations

   Calculate FIGRA, THR600s, SMOGRA from SBI data. Compare with classification criteria tables 1–3 of PN-EN 13501-1.

   ⏱ Time: 60 min

8. Classification and report

   Based on results assign Euroclass (e.g. B-s1,d0). Prepare classification report with laboratory notification number.

   ⏱ Time: 120 min

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Open fire and flammable gases (propane) — risk of fire and explosion! Powder and CO₂ extinguishers within reach
• Toxic combustion products (CO, HCN, HCl, HF) — mechanical exhaust mandatory, CO detectors
• Calorimeter bomb — O₂ pressure up to 3.5 MPa, explosion risk in case of bomb damage
• Hot elements (750°C furnace, post-combustion residues) — heat-resistant gloves, fire-resistant aprons
• Automatic fire suppression system in SBI testing hall
• Training in fire safety and fire equipment operation

Frequently asked questions