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  HomeStandardsCPR Fire Performance Classification

CPR Fire Performance Classification for Cables and Optical Cables (Comparison between EN 13501-6 and GB 31247)

The fire performance classification of cables and optical cables is an important standard for evaluating their safety under fire conditions. EN 13501-6 (European standard) and GB 31247 (Chinese national standard) are two commonly used classification systems, which differ in testing methods, classification criteria, and scope of application. Below is a detailed comparison of the two:

I. Basic Concepts of CPR Fire Classification

  1. EN 13501-6

    • The CPR (Construction Products Regulation) fire classification is an EU evaluation system for the fire performance of construction materials, primarily used to measure combustion characteristics such as burning speed, smoke production, and toxic gas release.

  2. GB 31247

    • GB 31247 is a Chinese national standard for the fire performance classification of cables and optical cables, focusing on burning speed, smoke density, and toxic gas release.

II. Comparison of Testing Methods and Indicators

1. Testing Methods

  • EN 13501-6

    • Based on EN 50399 (cable fire performance testing method) and EN 60332-1-2 (flame spread test).

    • Main test items: flame spread, heat release, smoke density, and burning droplets.

  • GB 31247

    • Based on GB/T 31248 (cable fire performance testing method).

    • Main test items: heat release, smoke toxicity, flame spread, and burning droplets.

2. Classification Indicators

  • EN 13501-6

    • Classification criteria: flame spread (FS), smoke production (SM), and burning droplets (d).

    • Example classifications: B2ca, Cca, Dca, etc.

  • GB 31247

    • Classification criteria: total heat release (THR), fire growth rate (FIGRA), smoke toxicity (CO, HCN, etc.), and flame spread (FS).

    • Example classifications: A, B1, B2, B3.

III. Comparison of Classification Systems

1. EN 13501-6 Classification

  • Aca: Non-combustible materials, highest level.

  • B1ca, B2ca, Cca, Dca, Eca, Fca: Flame retardant performance decreases sequentially.

  • Additional indicators:

    • s: Smoke production (s1=low, s2=medium, s3=high).

    • d: Burning droplets (d0=none, d1=minor, d2=major).

2. GB 31247 Classification

  • A: Non-combustible materials, highest level.

  • B1, B2, B3: Flame retardant performance decreases sequentially.

  • Additional indicators:

    • Heat release (THR, FIGRA).

    • Smoke toxicity (CO, HCN, etc.).

    • Flame spread (FS).

IV. Key Similarities and Differences

1. Similarities

  • Core objectives: Evaluate the safety performance of cables under fire conditions, including flame spread and smoke production.

  • Classification logic: Both use a hierarchical classification from high to low, with the highest level being non-combustible materials.

  • Application scenarios: Both are applicable to fields such as construction, transportation, and energy.

2. Differences

  • Scope of application:

    • EN 13501-6: Applicable to all construction materials, including walls, floors, and roofs.

    • GB 31247: Primarily targets the fire performance evaluation of cables and optical cables.

  • Classification criteria:

    • EN 13501-6: Uses A1, A2, B, C, D, E, F levels, considering heat release, smoke production, and toxicity.

    • GB 31247: Divides into A, B1, B2, B3 levels, focusing on burning speed, smoke density, and toxic gas release.

  • Testing methods:

    • EN 13501-6: Uses SBI (single burning item test), smoke density test, and toxicity test.

    • GB 31247: Primarily uses vertical flame test, smoke density test, and toxic gas analysis.

  • Regulatory requirements:

    • EN 13501-6: Complies with EU CPR regulations, applicable to the European market.

    • GB 31247: Complies with Chinese national standards, applicable to the Chinese market.

V. Application Fields

  • EN 13501-6: Widely used in the construction industry to evaluate the fire performance of building materials.

  • GB 31247: Mainly used in the cable industry to assess the safety performance of cables under fire conditions.

VI. Summary

EN 13501-6 and GB 31247 share similar objectives and logic in the fire performance classification of cables and optical cables but differ in testing methods, classification indicators, and market applicability. When designing and producing cables, enterprises must select the appropriate standard based on the target market and optimize materials and processes to meet classification requirements, ensuring product safety and compliance.

Keywords: Cable fire performance, EN 13501-6, GB 31247, classification standards, testing methods, flame spread, smoke toxicity

 

 

Table 1-Classes ofreaction to fire performance for electric cables

Class Test method(s) Classification criteria Additional classification
Aca
 EN ISO 1716
 PCS<= 2,0 MJ/kg ²  
B1ca

 EN 50399(30 kW
flame source)
and		 FS ≤ 1,75 m and
THR1200s ≤ 10 MJ and
Peak HRR ≤ 20 kW and
FIGRA ≤ 120 Ws-1		 Smoke productionb, e and Flaming droplets/particlesc and Acidityd
EN 60332-1-2 H ≤ 425 mm
B2ca EN 50399(20,5 kW
fLame source)
and		 FS ≤ 1.5m and
THR1200s ≤ 30 MJ; and
Peak HRR ≤ 30 kW and
FIGRA ≤ 150 Ws-1		 Smoke productionb, f and Flaming droplets/particlesc and Acidityd
EN 60332-1-2 H ≤ 425 mm
Cca EN 50399(20,5 kW
fLame source)
and		 FS ≤ 2.0m and
THR1200s ≤ 30 MJ; and
Peak HRR ≤ 60 kW and
FIGRA ≤ 300 Ws-1		 Smoke productionb, f and Flaming droplets/particlesc and Acidityd
EN 60332-1-2 H ≤ 425 mm
Dca EN 50399(20,5 kW
fLame source)
and		 THR1200s ≤ 70 MJ; and
Peak HRR ≤ 400 kW and
FIGRA ≤ 1300 Ws-1		 Smoke productionb, f and Flaming droplets/particlesc and Acidityd
EN 60332-1-2 H ≤ 425 mm
B1ca EN 60332-1-2 H ≤ 425 mm /
B1ca EN 60332-1-2 H ≤ 425 mm /

a For the product as a whole, excluding metallic materials, and for any external component (i.e. sheath) of the product.
b,s1=TSP1200s<= 50 m² and Peak SPR <= 0,25 m² /s
s1a=s1 and transmittance in accordance with EN 61034-2 >=80 %
s1b=s1 and transmittance in accordance with EN 61034-2>= 60 % < 80 %
s2=TSP1200s <= 400 m² and Peak SPR <= 1,5 m² /s
s3 =not s1 or s2
e d0 = No flaming droplets/particles within 1200 s; d1 = No flaming droplets/ particles persisting longer than10 s within 1200 s; d2 = not d0 or d1.
d EN 60754-2: a1 = conductivity< 2,5 uS/mm and pH > 4,3; a2 = conductivity< 10 uS/mm and pH > 4, 3; a3 = not a1 or a2.
e The smoke class declared for class B1ca cables shall originate from the test according to EN 50399 (30 kW flame source).
f The smoke class declared for class B2ca, Cca, Dca. cables shall originate from the test according to EN 50399(20,5 kW flame source).

 

 

而GB 31247将阻燃等级分为A, B1, B2，B3四个等级， 烟毒，腐蚀性气体含量，滴落物考量各分为三类，如下表3，表4，表5。

EN标准与GB标准阻燃等级划分虽然不完全一致，但测试的要求评估还是重合的，只是划分的类别不完全对应，但烟毒，腐蚀性气体含量，滴落物考量与EN标准的要求完全一致。

表2 判据及光缆燃烧性能等级判据

燃烧性能等级 试验方法 分级判据
a GB/T 14402 总热值 PCS≤2.0 MJ/kga
B1 GB/T 31248--2014(20.5 kW 火源)
且		 火焰蔓延 FS≤1.5 m;
热释放速率峰值HRR峰值≤30kW;
受火1200s内的热释放总量THR1200≤15MJ;
燃烧增长速率指数FIGRA≤150W/s;
产烟速率峰值SPR峰值≤0.25m2/s;
受火1200s内的产烟总量 TSP1200≤50 m2
GB/T 17651.2 且 烟密度(最小透光率)It.≥60%
GB/T 18380.12 垂直火焰蔓延H≤425mm
B2 GB/T 31248-2014
(20.5 kW 火源)		 火焰蔓延 FS≤2.5 m;
热释放速率峰值HRR峰值≤60kW;
受火1200s内的热释放总量THR1200≤30MJ;
燃烧增长速率指数FIGRA≤3000W/s;
产烟速率峰值SPR峰值≤1.5m2/s;
受火1200s内的产烟总量 TSP1200≤400 m2
GB/T 17651.2 且 烟密度(最小透光率)It.≥20%
GB/T 18380.12 垂直火焰蔓延H≤425mm
B3   未达到B2级

对整体制品及其任何一种组件(金属材料除外)应分别进行试验,测得的整体制品的总热值以及各组件的总热值均满足分级判据时,方可判定为A级。

表3 燃烧滴落物/微粒等级及分级判据

等级 试验方法 分级判据
d0 GB/T 31248-2014 1200s内无燃烧滴落物/微粒
d1 1200s内燃烧滴落物/微粒持续时间不超过10s
d2 未达到 d1级
表4烟气毒性等级及分级判据
等级 试验方法 分级判据
t0 GB/T 20285 达到 ZA2
t1 达到 ZA:
t2 未达到t;级
表5 腐蚀性等级及分级判据
等级 试验方法 分级判据
a1 GB/T 17650.2 电导率≤2.5 μs/mm且pH≥4.3
a2 电导率≤10μs/mm且pH≥4.3
a3 未达到 a2级