Wednesday 13 July 2022
The Construction Product Regulation (CPR) has been set up to facilitate the free circulation of construction products in the EU, removing trade barriers eventually created by technical specification. This is achieved by providing a unique base of technical standards offering uniform assessment methods for the performance of construction products throughout the European Economic Area.
Construction product regulation is applicable to all construction products put in a permanent manner in a building. For cables, those concerned are intended to be used for the supply of electricity and communications permanently installed in buildings and other civil engineering works. CPR became mandatory for cable since the 1st of July 2017.
The process towards harmonized standards for cable has been a long road and is summarized below
CPR applied to cable is organized around 2 series of technical standards
Reference standards
The reference standards use technical standards, included those related to fire test methods:
The EN 13501-6 turns over the interpretation of test results into Euroclasses applicable to cable, and completes the array, especially the EN 13 501-1 dealing with reaction to fire of with linings, floorings, and linear system (pipe insulation etc…).
The classification is based on heat release and flame spread, smoke production, burning droplets, and acidity.
EN 13501-6 describes different levels of reaction to fire considering the heat release, the smoke opacity and the smoke corrosivity
Regarding rate of heat release and flame spread classes, seven classes of cables are defined: Aca, B1ca, B2ca, Cca, Dca, Eca and Fca. These classes combines the test results issued form EN ISO 1716 [2] (Class Aca), EN 60332-1-2 [10] and EN 50399 [10] & EN 60332-1-2 [10] (Classes B1ca, B2ca, Cca, Dca, Eca ).
The performances of the different heat release and flame spread classes can approximately be described below.
EN 13501-6 overview.
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Test required |
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Class |
Level of Fire contribution |
EN ISO 1716 |
EN 60332-1-2 |
EN 50399 |
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Aca
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No contribution |
X |
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B1ca
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low |
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X |
X |
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B2ca |
Medium |
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X |
X |
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Cca |
significant |
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X |
X |
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Dca |
High level |
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X |
X |
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Eca |
Very high level |
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X |
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Fca |
No performance determined |
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Regarding dripping of flaming droplets, 3 classes are considered d1, d2 and d3 and are issued from the results of the EN 50399 test.
Regarding rate of smoke production ,
Smoke classes for cable.
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Smoke classes |
s1 |
s1a |
s1b |
s2 |
s3 |
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EN 50399
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TSP1200 ≤ 50 m2 Peak SPR ≤ 0.25 m2/s |
TSP1200 ≤ 50 m2 Peak SPR ≤ 0.25 m2/s |
TSP1200 ≤ 50 m2 Peak SPR ≤ 0.25 m2/s |
TSP1200 ≤ 300 m2 Peak SPR ≤ 1.5 m2/s |
Nor s1 or s2 |
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EN 61034-2 |
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Transmittance in accordance with EN 61034-2 ≥ 80% |
Transmittance in accordance with EN 61034-2 ≥ 60% < 80% |
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Regarding smoke corrosivity, 3 classes are defined: a1, a2, a3 and are issued from the results of the EN 60754-2 test.
The classification system from EN 13501-6 is summarized in below.
Reaction to fire classes for electric cables.
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Class |
Test method(s) |
Classification criteria
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Additional classification |
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Aca |
EN ISO 1716 |
PCS ≤ 2,0 MJ/kg (1) |
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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 production (2,5) and Flaming droplets/particles (3) and Acidity (4) |
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EN 60332-1-2 |
H £ 425 mm |
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B2ca |
EN 50399 (20,5 kW flame source) And |
FS £ 1.5 m; and THR1200s £ 15 MJ; and Peak HRR £ 30 kW; and FIGRA £ 150 Ws-1 |
Smoke production (2,5) and Flaming droplets/particles (3) and Acidity (4) |
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EN 60332-1-2 |
H £ 425 mm |
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Cca
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EN 50399 (20,5 kW flame source)
And |
FS £ 2.0 m; and THR1200s £ 30 MJ; and Peak HRR £ 60 kW; and FIGRA £ 300 Ws-1 |
Smoke production (2,6) and Flaming droplets/particles (3) and Acidity (4) |
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EN 60332-1-2 |
H £ 425 mm |
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Dca |
EN 50399 (20,5 kW flame source) And |
THR1200s £ 70 MJ; and Peak HRR £ 400 kW; and FIGRA £ 1300 Ws-1 |
Smoke production (2,6) and Flaming droplets/particles (3) and Acidity (4) |
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EN 60332-1-2 |
H £ 425 mm |
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Eca |
EN 60332-1-2 |
H £ 425 mm |
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Fca |
No performance determined |
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(1) For the product as a whole, excluding metallic materials, and for any external component (i.e. sheath) of the product. (2) s1 = TSP1200 ≤ 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 = TSP1200 ≤ 300 m2 and Peak SPR ≤ 1.5 m2/s s3 = not s1 or s2 (3) d0 = No flaming droplets/particles within 1200 s; d1 = No flaming droplets/ particles persisting longer than 10 s within 1200 s; d2 = not d0 or d1. (4) EN 60754-2: a1 = conductivity < 2.5 μS/mm and pH > 4.3; a2 = conductivity < 10 μS/mm and pH > 4.3; (5) The smoke class declared for class B1ca cables must originate from the test according to EN 50399 (20,5 kW Flame source). (6) The smoke class declared for class B2ca, Cca, Dca cables must originate from to test according EN 50399 (30 kW Flame source). Symbols used: PCS – gross calorific potential; FS – flame spread (damaged length); THR – total heat release; HRR – heat release rate; FIGRA – fire growth rate; TSP – total smoke production; SPR – smoke production rate; H – flame spread. |
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As indicated, EN 50399 becomes a central test in Euroclasses classification because it combines heat release measurement (classes B1ca, B2ca, Cca, Dca), smoke transmission measurement (s1, s2, s3) and flaming droplet assessment (d0, d1, d2).
This standard characterizes the potential maximum value of heat release when a product is completely burned in an over ventilated fire. The calorific potential of a material is measured in a bomb calorimeter.
This test is used to assess the polymeric part of electric cables and each individual layer needs to be assessed. Before testing the matrix must be finely grounded with a cryogenic grinder.
The sample is placed in a calorimetric bomb under high oxygen pressure and under pure oxygen atmosphere.
The test is used for Class Aca. level which corresponds to the highest performance products that practically cannot burn, i.e. ceramic products,
This test is used to assess the vertical flame propagation of a single insulated wire or cable with a 1 kWpre-mixed flame.
The cable specimen (600 +/- 25 mm length) is attacked by a Bunsen burner 175 mm flame with 40 mm inner blue cone.
The flame shall be applied continuously for a time period linked to the diameter. At the end of the specified test duration, the burner shall be removed, and the flame of the burner extinguished.
Time for flame application
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Overall diameter of test piece (mm) |
Flame application time (s) |
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D<25 |
60 ± 2 |
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25 < D ≤50 |
120 ± 2 |
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50 < D ≤75 |
240 ± 2 |
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D>75 |
480 ± 2 |
The wire or cable shall pass the test, if the distance between the lower edge of the top support and the onset of charring is greater than 50 mm.
The onset of char / changing state area is determined by assessing the surface state change. Where the surface changes from a resilient to a brittle (“crumble effect”) surface indicates the onset of charring. Any trace of soot is to be ignored. Softening or any deformation of the non-metallic is also to be ignored.
The Critical point in this test stands in the burner output calibration, which must be carried out according to
EN 60695-11-2 [11]. The burner output is controlled with the system pictured in Figure 9 : burner calibration according to EN 60695-11-2 [11].
After flame stabilization, and verification of the burner alignment, the time measured to pass from
100 to 700 °C shall correspond to 46 +/- 6 s. The calibration must be repeated 3 times per set, and must be done regularly to secure the burner capability.
This test is not adequate for low section cables and optical cables, which must be tested according to EN 60332-1-3 [33]. In this case the dripping of flaming particles is assessed with a filter paper put below the burner (Cellulosic based, 80 +/- 15 g/m2, harsh yield ≤0,1%), stabilized before test at 23 +/- 2°C and
50 +/- 5% Relative humidity. .
This test is an evolution of the former IEC 60332-1-3 test and has been adapted during FIPEC program to characterize the reaction to fire of cable in the framework of the CPR. The test measures the vertical spread of flame on cables positioned vertically, with an ignition source positioned below.
Some measuring techniques have been added, including heat release and smoke production measurements. Compared with existing test methods described in the former IEC 60332-3, they enable a more comprehensive assessment system, which is both more precise and sensitive, and enables a wider range of fire performance levels.
The test chamber is 1 m wide, 2 m deep and 4 m high. Test rack is placed vertically into the chamber with the cables facing the burner.
Table reviews the key differences between both test methods. EN 50399 has been fitted to correspond to the Construction Product Regulation (CPR) requirement regarding Euroclass.
EN 50399 comparison vs former CEI 60332-1-3
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EN 50399 |
CEI 60332-3 |
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Flowrate |
8000 +/- 400 l/min, less than 10% of variation during the test |
5000 +/- 500 l/min 10% of variation during the test |
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Test duration |
20 min |
20 min or 40 min depending of the cable category |
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Sample length |
3,5 m, vertical |
3,5 m vertical |
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Sample conditioning |
16 h @ 20 +/- 10 °C |
16h @ 20 +/- 10 °C |
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Sample details |
Non jointed cable mounted on the front of the standard ladder
Number of cables depending of the cable’s diameter |
Jointed (cables ≤ 35 mm2) and non-jointed (cables > 35 mm2) mounted on the front of the standard ladder
Number of cables depending other the volume of non-metallic material par meter of ladder Category A: 7 l/m Category B: 3,5 l/m Category C: 1,5 l/m Category D: 0,5 l/m This value is calculated considering the density of non-metallic material, determined according to the EN 60811-13 |
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Burner |
95% min Propane, gas burner One burner used at 2 scenarios 20,5 kW for Euroclass B2ca, Dca 30 kW for Euroclass B1ca, cable associated with calcium silicate board (11 mm thickness, 870 +/- 50 kg/m3) |
Gas burner
One or two burners depending of the cable section (more or less than 35 mm2) |
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Parameters registered |
Heat release rate based on oxygen consumption technic THR 1200 s MJ (Total Heat release) HRR peak kW (Heat release rate – peak) FIGRA w/s (Fire Index of Growth rate) Smoke production rate based on white or laser light photometric measurement TSP 1200 s m2 (Total smoke production) SPR peak m2/s (Smoke production rate – peak) Flaming droplets and particles persisting longer than 10 s |
Vertical spread of flame |
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Criteria |
Euroclasses calculation details in the 206/751/CE document of the Official journal of the European Communities |
Maximum height of the charred portion does not exceed 2,5 m above the bottom edge of the burner |
The mounting phase is critical because it clearly influences a large part of the test results and controls the upstream convective flow of heat. The mounting procedure is described below in Table 13 and the number of cables is linked to their diameter. Please
note that cable mounting implies a space between each test piece.
Mounting of the test sample
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Number of 3,5 m long test piece per test |
Spacing between test pieces |
Mounting details |
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d ≤ 20 mm |
Test piece = cable
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20 mm spacing between cables |
The test sample shall be mounted on the front of the standard ladder.
The first test piece or bundle of test pieces shall be positioned in the center of the ladder.
Further test pieces shall be added on either side so that the whole array of test pieces is centered on the ladder.
Each test piece or bundle of test pieces shall be attached individually to each rung of the ladder by means of a metal wire using crossed wire method of fixing shown in Figure 13 : crossed wire method for fixing cable.
For cables up to and including 50 mm diameter, wire between 0,5 mm and up to and including 1,0 mm in diameter shall be used.
For cables above 50 mm diameter, wire between 1,0 mm and 1,5 mm in diameter shall be used.
The lower part of each test piece of test pieces shall extend between 200 mm and 300 mm under the lower edge of the burner face, |
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5 < d ≤ 20 mm |
Test piece = cable
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One cable diameter spacing between cables |
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d ≤ 5 mm |
15 Test pieces
Each test pieces corresponding to a 10 mm diameter bundles.
Each bundle containing n cables
For bundles, apply a metal wire around the bundle at each rung position. |
10 mm spacing between non-twisted bundles. |
dc is the measured diameter of the cable (in mm and rounded to the nearest mm
int: the integer part of the result
The parallelism of the cables must be controlled during mounting and on the final test specimen before testing. Calibrated spacers use is recommended to check out the global geometry of the specimen and the space between cables.
The conditioning of cable at room temperature before mounting get them mechanically relaxed and easier to fit – less curbing. It is recommended to set the cables under mechanical tension to get parallel straight line of cables.
Regarding HRR measurement, the apparatus is regularly calibrated with reference gases (Propane @ 20,5, 30- and 50-kw burner outputs) and methanol, to cross check the calibration data. The difference between correction factor linked to each gas shall be less than 10%.
Regarding SPR measurement, the apparatus is regularly calibrated with 99% purity heptane tested in a tray, and the -TSP divided by mass of heptane- ratio shall be within the range 110 +/- 25 m2/1000 g.
At last, linearity, sensibility and drift of oxygen measurement devices and photometric system is controlled before each tests series.
Historically this test is a key test for cable industry to assess the smoke release. The cable is placed above a tray containing standardized fuel (Ethanol 90 % / Methanol 4 % / water 6 %) in a 27 m3 (3 x 3 x 3 m) chamber. This chamber is equipped with a halogen photometric system, with a 3 m path length.
The smoke released by the cable stressed by the below fire is measured in terms of light attenuation, and the result delivered is the transmittance (%). The chamber is equipped with a 10-15 m3/min ventilator to homogenize the smoke density.
The number of cables tested depends of the cable diameter and the specimens must be bundled at 300 mm in front of each end. The test pieces are positioned in horizontal position and centered above the tray, and the distance between the bottom exposed face of the sample and the bottom of the tray have is set up at 150 mm ± 5 mm.
Number of cables per test piece
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Length of cable = 1 m Diameter of the cable, mm |
Number of cables per test piece |
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D < 40 |
1 |
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20 |
2 |
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10 |
3 |
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5 < D ≤ 10 |
N1= 54/D mm N1: number of cable sections |
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1< D ≤5 |
N2= 45/3D mm N2: number of bundles confectioned from seven test pieces of cable sections twisted together |
The test is considered as over if there is no decrease in light transmittance for 5 min after the fire source has extinguished, or when the test duration reaches 40 min.
The linearity of the photometric system must be verified regularly, and the tension applied on the halogen light shall be stabilized at 12 V for all the test duration, to get a stable nominal luminous flux from 2000 to 3000 lm.
The response of the chamber must be checked regularly with two reference mixtures of alcohol/toluene at 2 different contents of toluene (4 and 10%). The acceptance criteria are based on TSP: from ,8 to 1,2 m2 for 4% toluene mix and 0,18 to 0,26 m2 for 10% toluene mix.
Compared with the EN 50399 test method, this test is corresponding to an under ventilated fire, and the transmission measurement corresponds to a cumulative value.
Fire scenario comparison.
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EN 50399 |
EN ISO 61034-1 & 2 |
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Overventilated fire model |
Under ventilated fire model |
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Dynamic measurement |
Cumulative measurement |
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20, 5 and 30 kw/m2 fire model |
Less than 20 k<m2 fire model |
This test is used to fuel the s1a (final transmittance ≥ 80%) and s1b (final transmittance ≥ 60%) categories of the Euroclass.
This standard details corresponds to the determination of the degree of acidity of gases, which consists in two parameters: pH value and conductivity.
This standard provides a method for determining the acidity (by pH measurement) and conductivity of an aqueous solution of gases evolved during the combustion of materials.
The material under test shall be heated in a stream of dry air and generally an ambient air sucked system is used. The flow rate of air introduced into the quartz tube has to be adjusted according to the actual internal cross-sectional area of the tube, such that the speed of air flowing across the sample is approximately 20 ml/mm2/h, means around 40 l/ h for a 50 mm internal diameter quartz tube. The heating system is adjusted such that the temperature at the designated position for the boat is not less than 935 °C and not more than 965 °C.
The combustion procedure is done for 30 min in the furnace, under air flow conditions.
Three test specimens for the general method, or two for the simplified method, each consisting of (1 000 ±5) mg of the material to be tested, are be prepared.
The evolved gases shall be trapped by bubbling through wash bottles filled with distilled or demineralized water. The acidity of the resulting solution is assessed by determination of its pH value. The conductivity of the solution is also determined using a conductometer electrode apparatus.
Each test specimen shall be taken from a sample representative of the final material, which means that each individual constitutive non-metallic part of the cable must be tested. Each test specimen shall be cut into several smaller pieces. and the final value of pH and conductimetry is pondered by the weight contribution of each sub part.
This test is used for determining the categories a1, a2 and a3 of the Euroclasses
This test does not determine whether a material is zero halogen or not.