WCA September 2011

The acid gas emission test of IEC60754-1 and/or the indirect corrosivity test of IEC60754-2 may be used. Products meeting the requirement of less than 0.5% acid gas emission when tested to IEC60754-1 are often referred to as “halogen free”. In some product standards, an additional test for fluorine content (IEC60684-2) is required. Cables having low emission of toxic gases are generally restricted to specific applications where end users have imposed such a requirement. Such cables are particularly found in the rail sector. Users have their own “toxic emission” standards ranging from a simple restriction on certain elemental groups to indices derived from an analysis of the gases evolved and weighted according to the known mammalian toxicity factors of the gases present. The lack of general use of toxicity testing for cables may be explained by early work carried out in the UK which concluded that “From this brief excursion into consequences it appears that the acidic gas concentrations likely to cause harm to people and plant are similar” (11,12) . Current work (13) continues to demonstrate the large contribution of HCl to the fire hazard. Some interesting new work studying the effect of important irritant gases on animal lungs (14) has also found that HCl and PVC smoke inhalation caused an acute effect with a rapid decline in the lung physiology parameters. This work would appear to support a cable industry position to offer for particular applications products not releasing important irritant gases

Class Test method(s)

Classification criteria

Additional classification

EN ISO 1716

PCS ≤ 2,0 MJ/kg (1)

A

ca

FIPEC

Scen 2 (5)

FS ≤ 1.75 m and THR and Peak HRR ≤ 20 kW; and FIGRA ≤ 120 Ws -1

Smoke production (2, 6) and Flaming droplets/particles (3) and Acidity (4, 8)

B1

≤ 10 MJ;

ca

20

1200 s

and

EN 60332-1-2

H ≤ 425mm

FIPEC

Scen 1 (5)

FS ≤ 1.5 m; and THR and Peak HRR ≤ 30 k W; and FIGRA ≤ 150m Ws -1 1200s

Smoke production (2, 7) and Flaming droplets/particles (3) and Acidity (4, 8)

B2

≤ 15 MJ;

ca

20

and

EN 60332-1-2

H ≤ 425mm

FIPEC

Scen 1 (5)

FS ≤ 2.0 m; and THR and Peak HRR ≤ 60 k W; and FIGRA ≤ 300 Ws -1 12oos

≤ 30 MJ;

Smoke production (2, 7) and Flaming droplets/particles (3) and Acidity (4, 8)

C

ca

20

and

EN 60332-1-2

H ≤ 425mm

THR ≤ 70MJ; and Peak HHR ≤ 400 k W; and FIGRA ≤ 1300 Ws -1 1200s

FIPEC

Scen 1 (5)

Smoke production (2, 7) and Flaming droplets/particles (3) and Acidity (4, 8)

D

ca

20

and

EN60332-1-2

H ≤ 425mm

EN 60332-1-2

H ≤ 425mm

E

ca

No performance

F

ca

(1) For the product as a whole, excluding metallic materials, and for any external component (ie sheath) of the product (2) s1 = TSP1200 ≤ 50 m 2 and Peak SPR ≤ 0.25 m 2 /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 ≤ 400 m 2 and Peak SPR ≤ 1.5 m 2 /s s3 = not s1 or s2 (3) For FIPEC 20 Scenarios 1 and 2: 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 50267-2-3: a1 = conductivity < 2.5 μS/mm and pH > 4.3; a2 = conductivity < 10 μSmm and pH>4.3; a3 = not a1 or a2. No declaration = No Performance Determined. (5) Air flow into chamber shall be set to 8000 ± 800 l/min FIPEC 20 Scenario 1 = prEN 50399-2-1 with mounting and fixing as below FIPEC 20 Scenario 2 = prEN 50399-2-2 with mounting and fixing as below (6) The smoke class declared for class B1ca cables must originate from the FIPEC 20 Scen 2 test (7) The smoke class declared for class B2ca, Cca, Dca cables must originate from the FIPEC 20 Scen 1 test (8) Measuring the hazardous properties of gases developed in the event of fire, which compromise the ability of the persons exposed to them to take effective action to accomplish escape, and not describing the toxicity of these gases ❍ ❍ Figure 4 : Classes or reaction-to-fire performance of electric cables

more integrated approach with test standards that have the potential to measure flame spread, heat release, smoke obscuration and combustion gas release.

(ie HCl from PVC compounds) due to the ability of such gases to hinder escape and damage lungs and reinforce the position of “acidity” as an “indicator” for important irritant toxic effects. The generic description Low Fire Hazard has recently been adopted by European cable manufacturers to describe cables incorporating the performance characteristics of reduced flame propagation and low emission of smoke and harmful gases. Although the existing suite of IEC TC20 standards allows a basic overall approach to fire safety when combining the various elements (it is common for product standards to call up IEC60332-3, IEC61034, IEC60754-1 and/or IEC60754-2), recent developments have been towards a

European Reaction to Fire Classification for Cables Under the CPD Of particular importance to the European market is the development of prEN50399 (15,16) which is a test standard based upon the apparatus of IEC60332-3-10 with the addition of an exhaust duct equipped to measure heat release rate and smoke production rate. prEN50399 has been developed to support the classification “Classes of reaction-to-fire for electric cables” given in Commission

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Wire & Cable ASIA – September/October 2007 11