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CPR/Fire-safety cable
CPR Introduction
8. Additional Levels of Classification for Class B to D
The table below breaks down the fire performance parameters like flame spread, heat release, smoke production, flaming droplets and acidity. These are used to classify cables from Aca to Fca. The additional parameters (s, d and a) give a more granular view of how the cable behaves in fire, helping specifiers and regulators choose the appropriate class for different applications.
| Table 2 – Fire Performance Classification | ||||||||
|---|---|---|---|---|---|---|---|---|
| Additional requirement |
||||||||
| Flame |
|
Aca |
B1ca |
B2ca |
Cca |
Dca |
Eca |
Fca |
| Heat |
|
Aca |
B1ca |
B2ca |
Cca |
Dca |
Eca |
Fca |
| Smoke | s |
|
|
s1a |
s1b |
s2 |
|
|
| Droplet | d |
|
|
d1 |
d1 |
d2 |
|
|
| Acidity | a |
|
|
a1 |
a1 |
a2 |
|
|
For example, a cable rated Cca-s1a,d1,a1 means it has moderate flame spread, very low smoke generation, limited flaming droplets, and minimal acidity. Such compliance is ideal for enclosed public spaces like hospitals, airports, or schools.
Three additional classification levels have been established; these refer to:
-The opacity of smoke emitted (s = smoke)
-The droplets released by the cable in combustion (d = droplets)
-The acidity or toxicity of the smoke (a = acidity)
The opacity of smoke emitted (s = smoke)
The following performance criteria for smoke emission properties have been established: s1: Little production and slow propagation of smoke
s1a: S1 with visibility or light transmittance over 80% (UNE-EN 61034-2).
s1b: S1 with visibility or light transmittance over 60% and below 80% (UNE-EN 61034-2). s2: Intermediate values of production and propagation of smoke
s3: Neither s1 or s2. No performance declared or does not conform to s2 or s1 criteria
The droplets released by the cable in combustion (d = droplets)
The following performance criteria for droplets / flamed particles have been established: d0: No fall of droplets or flamed particles (UNE-EN 50399).
d1: Fall of droplets and flamed particles that persist for less than 10 seconds (UNE-EN 50399). d2: Neither d0 or d1. No performance declared or does not conform to d0 or d1 criteria
The acidity or toxicity of the smoke (a: acidity).
This classification provides information about the emission of acid gases during the fire.
Acidity performance is assessed through the test described in standard UNE-EN 50267-2-3.
The following performance criteria for acidity have been established:
a1: Low acidity (UNE-EN 60754-2 conductivity <2,5ms μS /mm pH > 4.3)
a2: Intermediate values of acid (UNE-EN 60754-2 conductivity <10 ms μS /mm pH > 4.3) a3: Neither a1 or a2. No performance declared or does not meet conform to a1 or a2 criteria
Classes Eca and Fca have no additional classification criteria.
As the requirements of Euro class Aca are too high to offer an economical product with conventional thermoplastic materials, it is not possible in practice to achieve Euro class Aca for cables.
