Cable Component Material Innovations for Stringent Fire ... · for Stringent Fire Safety and Environmental Compliance Requirements ... (Presented to the International Wire and Cable

Cable Component Material Innovations for Stringent Fire Safety and Environmental Compliance Requirements

David B. Kiddoo AlphaGary Corporation Leominster, MA USA

(Tel) +1-978-537-8071; (Fax) +1-978-537-8385 (Presented to the International Wire and Cable Symposium, November 2007)

Abstract With the final adoption of the Building Materials Construction Products Directive (CPD) in Europe, as well as the continued efforts to improve the fire safety and environmental compliance of wire and cable (W&C) in all regions of the world, advanced material technologies are required to meet the complex Engineering Balance demands of performance. Whether the cable must meet 10-gig transmission speeds, the physical demands of severe environments, low smoke / low flame propagation fire safety, RoHS compliance, low corrosivity, or operational integrity in failure scenarios, each cable must be designed with the appropriate materials so as to meet the necessary performance vs cable design value proposition.

The W&C industry has seen the active development of novel, sophisticated halogen free olefins, low smoke / flame retardant PVC, and fluoropolymer compounds for power and data communications cables to perform in a variety of environments, such as commercial buildings / local area networks, industrial, transit, nuclear and shipboard.

This paper will present the technical data and testing results of some of these new materials. It will also review cable applications data to show how these materials are anticipated to be used.

Keywords: Cable fire safety; fire hazard assessment; cable fire performance codes and standards; CPD; low smoke generation; cabling materials; corrosion; toxicity; fluoropolymer compounds; halogen free compounds; low smoke PVC compounds; limited combustible; plenum; environmental compliance.

1. Introduction Cabling infrastructure performance has always been the “central nervous system” of any industrial or commercial operating environment. Whether it is to support power and control to equipment, information technology flow of data and video, or to provide safety surveillance and alarms, the performance of cables is always the critical link to the full value of the system.

The cabling engineer is routinely challenged to make sure that the cabling is selected and installed to each of the latest codes and standards applicable to the operating environment and local practice. With “no downtime” requirements, as well as the escalating demand to manage and minimize liabilities and insurance business costs, the cabling engineer now must be even more

involved in the routine business risk assessment discussions as well as reviews of legislative and regulatory compliance.

The last 10 years have seen a dramatic re-assessment of our approach and real commitment to improving the fire safety, security, as well as the environmental impact of virtually every aspect of our business operating structures and activities. The goal of these efforts is to improve not only the safety and health of our working environment but also to have a positive impact on our world’s resources and natural environment by considering the “end of life” scenarios for the things that we use. W&C designs and the materials being used in each of the integral cable components have become extremely sophisticated so as to meet this difficult engineering balance of operating performance, safety, environmental impact and, of course, cost!

While it would be convenient to have one type of material meet all of these technical challenges for our W&C infrastructure design, this is obviously an impractical desire. Fortunately or unfortunately, the competitive world will always generate different approaches and solutions. It is only “unfortunate” when testmanship and biased approaches are used simply in the interest of promoting the gain of one material over another. At this point in our evolution of W&C and materials development, we should finally realize that the full variety of materials available to us can each be managed and manufactured responsibly so we can continue to take advantage of their properties. Fluoropolymers with their thermal / weatherability, chemical resistance, and fire retardant properties; PVC with its flexibility, mechanical, low flammability and processability characteristics; Halogen Free olefins with their electrical, thermo-mechanical and low smoke / low acidity attributes: EACH can be used safely for W&C solutions, with the right level of environmental stewardship to be valuable and useful for our future.

2. W&C Component Materials While not a fully exhaustive list, the predominant thermoplastic compounds for use in W&C are listed in Figure 1. Each of these compound groups have been radically modified to take advantage of new raw material technologies. The impact of these developments has been to refresh our impressions of the capabilities and applicability of these materials. Preconceived notions of the limitations, real fire safety benefits or environmental impacts are now being re-assessed by the cable design engineers as they try to rationalize the balance of

International Wire & Cable Symposium 204 Proceedings of the 56th IWCS

requirements vs the cost of the W&C infrastructure. As developments are evolving, it is interesting to see how a few of these materials are, in fact, being modified so as to maintain the bulk of their inherent characteristics while becoming more like the other materials, in terms of performance, processability, safety and, necessarily, the value / cost proposition in the finished cable.

Materials Development:Solutions!

• Specialty fluoropolymer compounds

• Specialty low smoke fire retardant PVC alloys

• High LOI, Char Integrity halogen-free, fire retardant, low smoke and fume

• Thermoplastic elastomers (vinyl or olefinic based)

• Thermoplastic urethanes

• Specialty fire retardant PVC

• High performance general purpose PVC

Figure 1.

2.1 Fluoropolymer Compounds Fluoropolymers (FP) have an excellent balance of transmission properties, temperature range, fire resistance and low smoke generation, as well as mechanical toughness and resistance to most industrial fluids. However, they are significantly higher in cost and typically require specialized processing equipment and controls to account for their rather corrosive nature. Fluoropolymers are also difficult and costly to manufacture, which is why there are relatively few suppliers.

While the suppliers of fluoropolymers are generating new methods of manufacturing these materials and to minimize the environmental impact of their processes, new FP compounds for W&C have now been developed with a more optimum balance of properties. While retaining the positive attributes of fluoropolymers, these new FP compounds have improved processability to achieve jacketing line speeds similar to LSFR PVC. They are also more readily marked and colorable than the base FP resins.

An additional benefit of these new FP compounds is their ability to scavenge acids during combustion. This makes them less corrosive and allow for the extrusion of cables using conventional metallurgies for extruder barrels, screws, and tooling. Perhaps even more important, this material capability may help meet the requirements for low acid gas generation in environments currently requiring halogen free compounds. As shown in Figure 2, the new FP compounds produce combustion gases closer to the % Acid and pH range of halogen free compounds than they are to the conventional LSFR PVC or other fluoropolymer resins.

% Acid Generation pH

Fluoropolymer 27.20% 1.7Resin

LSFR PVC 13.80% 1.9

Fluoropolymer 1.50% 3.01Compounds

IEC 60332-3 0.35% 3.42Halogen Free

Low Acid Gas Generation Performance Standard: MIL C-24643

Figure 2.

These fluoropolymer compounds have also been designed so that they comply with various environmental regulations and do not use any restricted substances such as those described in the European RoHS and WEEE Directives (restrictions on the use of certain hazardous substances in electrical and electronic equipment and the proper disposal / recycling of end-of-life products). These FP compounds can withstand multiple heat histories and therefore offer more complete recyclability than PVC or olefin based compounds.

FP compounds are currently being used as jacketing in ultra-low smoke “limited combustible” communications data cables. As they become more established, FP compounds would be suitable in additional applications such as appliance wiring, low / medium voltage energy / signal cable jackets for industrial environments, raceway tubing, and other signal / control cable wiring.

2.2 PVC Compounds Low Smoke Flame Retardant PVC (LSFR PVC) compounds have been used for over 20 years as cable jacketing to achieve the rigorous low smoke demands for North American (NFPA National Electrical Code®) requirements for communications network plenum cables installed in commercial buildings.

Standard flame retardant PVC generates black, dense smoke during combustion, which is a hazard during the evacuation of buildings during a fire. As the standards evolved to provide more time for the evacuation process, technology developed that allowed PVC to be modified to change the smoke characteristics and generate less smoke obscuration. This technology for PVC allowed for the plenum cable market to expand rapidly as cable manufacturers could now generate flexible cables on existing jacketing lines but with dramatically improved fire safety.

Original PVC compounds for W&C also contained lead-based stabilization so that it could withstand the extrusion temperatures during the cable manufacturing process. So as to combine the excellent flame retardant characteristics with an environmentally conscious formulation, the stabilization technology evolved so that “lead-free” LSFR PVC compounds were readily available at


comparable cost. These LSFR PVC formulations have been in use for the last 10 years and meet all of the RoHS certification requirements. They are easily recyclable.

Even with the low smoke and lead-free developments for PVC, advocates against the use of PVC, in favor of halogen free compounds, complain that the chlorine component can react during combustion to produce hazardous HCl (hydrogen chloride) gas. This may be important in highly critical environments where sophisticated electrical equipment could be exposed to damage from corrosion on the many circuit boards or connectors due to smoke.

However, in a total hazard assessment, the value of LSFR PVC to minimize the start and spread of a fire through the cabling typically outweighs the considerations for corrosivity or toxicity of the gases, as the temperature and fire flashover reach the stage to generate the hazardous or potentially lethal reaction byproducts. Indeed, carbon monoxide, generated from all building materials, is the greatest hazard in a fire and is the most common agent involving incapacitation. All plastics test in the same relative range of lethal dosage.

2.3 Halogen Free Compounds “Low smoke zero halogen”, or halogen free, compounds were developed to provide a lower acid gas generation (“toxic emission”) cable jacketing technology than their halogenated counterparts (Chlorine in PVC; Fluorine in fluoropolymers; Bromine in flame retardant formulations). Based primarily on polyolefins such as EVA, PE or PP, these compounds were typically specified in low ventilation, contained areas in military / shipboard / submarines, utilities, and underground metro systems.

The original halogen free compounds were mechanically weak and slow / complex to process compared to FR PVC. With polyolefins inherently more flammable than PVC, higher and more sophisticated loadings of filler are required to give them comparable flame retardancy to PVC.

Over the last 10 years, halogen free compound technology has evolved to allow for significantly higher char integrity and flame retardancy, enabling cables to achieve significantly higher levels of fire performance in several copper and fiber optic cable designs. Superior physical properties, such as tensile strength, elongation and tear strength also allow for halogen free technology to be used in more demanding applications. Figure 3 shows some typical data on a variety of halogen free compounds.

The much improved extrusion performance of these materials on more conventional equipment, with line speeds now reaching 200 m/min, has made this technology more economically viable. The growth of halogen free cables, predominantly in Europe and Asia, has increased significantly over the last five years. While halogen free W&C is expanding in North America, the technology does not exist to allow these compounds to pass the plenum cable (NFPA 262) requirements for flame spread and low smoke generation. These cables still require the use of LSFR PVC and fluoropolymers in their components.

-4.5106

9

MFRg/10min

Filling Compound708FB100

Low Voltage Insulation grade17015IN200

Easy processing grade for cables required to pass IEC 332.115011S800

General purpose sheathing grade18011S500

For use in cables that need to pass the IEC 332.3 fire test. High LOI yet easy processing

17011S540

ApplicationElongation%

Tensile Strength

MPa

Product Designation

Halogen Free Compounds

5.56.05.56.35.5

Acid GaspH

4023030FB100

1427035IN200

534530S800

1325535S500

7533045S540

Acid GasConductivity

µS cm-1

FlammabilityTemperature

°C

Oxygen Index

%

Product Designation

Halogen Free Compounds

Figure 3.

Figure 4 provides a general comparison summary of data for the range of materials described in Section 2. The data represents compounds that could be used as a standard 4pr UTP Cat 6+ cable jacket for the different fire performance requirement levels. Note that different jacketing thicknesses are used, based on the overall properties of the jacket, which is an impact to the cost / volume proposition of the cable.

Fluoropolymer Halogen FreeProperties Compound LSFR PVC IEC 332.3C IEC 332.1

CPD Class B1 S1 CPD Class B1 S2 CPD Class C / D CPD Class E(Typical) (Typical) (Typical) (Typical)

Specific Gravity 2.77 g/cc 1.65 g/cc 1.61 g/cc 1.53 g/ccDurometer D Aged, Inst/15sec 69 / 61 72 / 63 59 / 49 53 / 47Tensile Strength, 20"/min 2,250psi / 15.5 MPa 2,500psi / 17.2 MPa 1,750psi / 12.1 MPa 1,750psi / 12.1 MPaElongation, 20"/min 175% 180% 180% 170%Oxygen Index, (0.125") 100+% 53% 45% 35%Brittle Point, degC -46 -5 -22 -15Flexural Modulus, 0.03"/min 202000psi/1400 MPa 56,000psi / 390 MPa 41,000psi / 280 MPa 49,000 / 340 MpaUL Temp Rating, degC 125+ 60 90 75Dielectric Constant, 100 MHz 2.92 3.25 3.87 3.57Dissipation Factor, 100 MHz 0.018 0.014 0.015 0.014

4pr UTP Jkt Thickness 9-11mils / .23-.28mm 15-17mils / .38-.43mm 30-40mils / .76-1.02mm 20-24mils/.50-.60mm

Fluoropolymer / LSFR PVC / Halogen Free Jackets

Figure 4.


3. Environmental Compliance The last 10 years has seen a significant move toward global regulations on hazardous substances. The first major regulation movement was the pollution avoidance strategy established in Europe for Electrical and Electronic Equipment (EEE). This has since expanded from items such as computers, fax machines, VCR’s, and TV’s to automobile systems.

RoHS, the “Directive 2002/95/EC of the European Parliament and of the Council of 27 January 2003 on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment” was established and became enforceable on July 1, 2006. This has become the model for other such localized codes in other regions of the world. The restricted substances will likely expand over time as data is generated, but the list currently includes: cadmium, hexavalent chromium, lead, mercury, polybrominated biphenyls (PBB’s), and polybrominated diphenyl ethers (PBDE’s). The threshold levels for these substances is 1,000ppm, with the exception of cadmium (100ppm), as measured through X-Ray Florescence (XRF) or Acid Digestion methods. (This is to allow for trace amounts (“unintentionally added”) that would be difficult and costly to remove from materials.)

Some OEM’s have decided to establish significantly lower tolerance levels so as to minimize any accumulative effects from the complete production chain of a completed end-user unit. Over time, third party certification programs will be established so that each component and material can be listed and verified to compliance with these requirements.

In addition to RoHS, the framework for the Supply Chain to reduce EEE going into the waste stream was established in Europe. It is a “take-back” scheme for End-of-Life recovery, treatment, and recycling and is called WEEE, the “Directive 2002/96/EC of the European Parliament and of the Council of 27 January 2003 on Waste Electrical and Electronic Equipment”.

With the exception of a few complex W&C designs, most cabling component materials have been modified to be able to meet the RoHS requirements. While most cable manufacturers have had to receive new performance Listings at third-party certification laboratories for their cables, this process has been well coordinated by the entire supply chain over the last 5 years. Most PVC, olefins and fluoropolymer materials now conform to RoHS and local environmental regulations.

Several “local” jurisdictions are also moving to expand on the efforts of the European Parliament for environmental stewardship. China, which would be difficult to enforce initially, has taken the strong action to create its own “China RoHS”, which, in some ways, is even more difficult and restrictive on substances. And, without clarity or definition, China has included a statement that it can add “other toxic and harmful substances” at any time and that certification testing must be performed in third party laboratories in China only. While “China RoHS” was put into effect on March 1, 2007, the transition to enforcement is still unclear.

In the United States, California Proposition 65, covering materials “that the State of California has shown to cause cancer”, as well as the Massachusetts “Toxics Use Reduction Institute” is still providing draft and “strawman” legislation on how they would like to see restricted substances handled in their States. For W&C, an initial life cycle and environmental impact study of materials used in building cables (low voltage power and communications) has been completed in 2007 by the Environmental Protection Agency (EPA) “Design For the Environment” (DfE) task group. This work is the first such effort to review W&C materials and will serve as the basis for future evaluations and development of cabling component materials that will be more “environmentally friendly”.

4. European Construction Products Directive (CPD) for W&C After 10 years of technical debate, nationalistic protectionism, lobbies from each material solution faction, and a general lack of consensus on the actual fire hazard impact of cables, the European Fire Regulators Group and the European Council finally drafted the fire safety requirements for all cables installed in buildings throughout the European Union. While each European country within the Union will need to establish which level of performance will be required in different occupied facilities and areas of a building, at least the fire testing requirements are now known.

Figure 5 shows the final table of requirements for cables under the “Construction Product Directive”. W&C is now officially considered a “Construction Product” in the European Union. While the table appears complex, the general overview is that it is merely using different techniques and measurements to set similar requirements as already established in both North America and Europe.

By establishing cables as a “building material”, with their own fire performance differentiation, an additional stipulation under the CPD is that third-party compliance verification will be required in Europe. Independent testing laboratories throughout Europe have invested heavily in their capability to test and independently verify to the various cable performance test methods specified in both the CPD as well as those used in North America. “Round Robin” testing correlation data has also been performed between the laboratories to provide for regional consistency.

While smoke is currently not a primary requirement or “classification criteria” for cables under the CPD, the “additional classification” information on smoke will be useful by building owners and designers, as well as the insurance industry, to differentiate the levels of cable fire safety to be specified. Discussions are already under way to create smoke criteria as mandatory requirements within the CPD for all products in the future.


CPD EuroClasses for Cables

No performance determinedFca

H ≤ 425 mmEN 50265-2-1Eca

H ≤ 425 mm EN 50265-2-1

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

THR1200s ≤ 70 MJ; andPeak HRR ≤ 400 kW; andFIGRA ≤ 1300 Ws-1

FIPEC20 Scen 1 (5)and

Dca

H ≤ 425 mm EN 50265-2-1


FS ≤ 2.0 m; andTHR1200s ≤ 30 MJ; andPeak HRR ≤ 60 kW; andFIGRA ≤ 300 Ws-1


Cca

EN 50265-2-1


FS ≤ 1.5 m; andTHR1200s ≤ 15 MJ; andPeak HRR ≤ 30 kW; andFIGRA ≤ 150 Ws-1

H ≤ 425 mm


B2ca

H ≤ 425 mm EN 50265-2-1


FS ≤ 1.75 m andTHR1200s ≤ 10 MJ andPeak HRR ≤ 20 kW andFIGRA ≤ 120 Ws-1


B1ca

PCS ≤ 2,0 MJ/kg (1) EN ISO 1716Aca

Additional classificationClassification criteriaTest method(s)Class

CPD EuroClasses for Cables

(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/ss1a = s1 and transmittance in accordance with EN 50268-2 ≥ 80%s1b = s1 and transmittance in accordance with EN 50268-2 ≥ 60% < 80%s2 = TSP1200 ≤ 400 m2 and Peak SPR ≤ 1.5 m2/s s3 = not s1 or s2(3) For FIPEC20 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 μS/mm 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.FIPEC20 Scenario 1 = prEN 50399-2-1 with mounting and fixing as belowFIPEC20 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 FIPEC20 Scen 2 test.(7) The smoke class declared for class B2ca, Cca, Dca cables must originate from the FIPEC20Scen 1 test.

PCS = gross calorific potentialFS = flame spread (damaged length)THR = total heat releaseHRR = heat release rateFIGRA = fire growth rateTSP = total smoke productionSPR = smoke production rateH = flame spread

Pending CPD EuroClasses for Cables

Figure 5.

The proposed CPD hierarchy of cable fire performance is very similar to the North American / Canadian requirements for communications / low voltage signal cable. The vertical test methods specified in the CPD table are actually modifications to the IEC 60332-3. With these modifications, these test methods can be adequately used to also differentiate the cable fire performance levels such as those measured in the horizontal Steiner Tunnel

(NFPA 262) as well as in other vertical test methods. Figure 6 shows this rough correlation.

Evolution of Fire Performance

Fire Hazard Simulation Tests

• NFPA 255 & NFPA 259 / Class B1 (S1)• NFPA 262 / EN 50289 / FT-6 / CPD Class B1 (S2)• UL 1666 Riser / FT-4 / CPD Class C, B2• UL 1581 Tray / IEC 60332-3 / FT-2 / CPD Class D• VW1 / IEC 60332-1 / FT-1 / CPD Class E

Safety performance level must be based on the hazards of the installed environment, cable loading, AND criticality.

Figure 6.

5. Cable Performance Testing to CPD To achieve an initial overview assessment of the new CPD fire testing criteria for cables, a matrix of 10 cables was created. This matrix included 4-pair Cat 5e and Cat 6+ copper communications cables. The cable component material selection was determined to correlate to existing cable designs for the US, German, and UK markets. Fluoropolymer compound, LSFR PVC, and Halogen Free Jackets were used over a variety of cores, containing FP, PE or a shielded polyolefin design. The matrix is described in Figure 7.

The CPD Class B1 utilizes the FIPEC (the European Commission’s “Fire Performance of Electrical Cables” study group) Scenario 2, whereas the other lower Classes (B2 – D) utilizes the Scenario 1 test method. Each are modifications of the IEC 60332-3 test.

Cable Constructions

High LOI Halogen Free (0.75mm)

High LOI Halogen Free (1 mm)

High LOI Halogen Free (1 mm)


LSFR PVC (0.425mm)




LSFR PVC (0.5mm)

Fluoropolymer Compound (0.275mm)

Jacket

Shielded, SmokeGuard® jacketed.-SSTP Core6

Shielded, enhanced 332-3c-SSTP Core7

Hybrid, development CAT 6 UTP.FEPFEP(0.15mm)5

332-3c, CAT 5 UTP.-PE8

332-3c, CAT 5 UTP.-PE9

332-3c, CAT 6 UTP.FRPEPE10

Hybrid, development CAT 5 UTP.-FEP(0.15mm)4

Hybrid, development CAT 5 UTP.-FEP(0.15mm)3

Plenum, CAT 5 UTP. -FEP(0.15mm)2

Ultra Low Smoke, CAT 5 UTP. -FEP(0.15mm)1

DescriptionX webInsulationCable

Figure 7.


5.1 Cat 5e UTP: FP Ins / FP Compound Jacket This construction is typical of an ultra low smoke, “limited combustible” data communications cable for the US plenum cable market. It was tested to the FIPEC Scenario 2 only as it passed each of the pass/fail criteria for the highest “Class B1” performance level. (“S1a” indicates the lowest defined smoke development level. “D0” indicated no flaming droplets. The “a2” is the acidity level, which was to be expected due to the halogenated nature of the materials.) The data is shown in Figure 8.

CPD RATING = B1 S1a d0 a2CPD RATING = B1 S1a d0 a2

CAT 5 UTP FP Ins / FP Compound JacketCAT 5 UTP FP Ins / FP Compound Jacket

Not Testeda= ≥≥ 808095.8a = ≥≥ 803m3 smoke test (%)

Not Tested≤≤ 15032≤≤ 120FIGRA (W/s)

Not Tested≤≤ 5015.5≤≤ 50Total Smoke m2

Not Tested≤≤ 0.250.04≤≤ 0.25Peak Smoke (m2/s)

Not Tested≤≤ 152.7≤≤ 10Total HR (MJ)

Not Tested≤≤ 306.9≤≤ 20Peak HRR (KW)

Not Tested≤≤ 1.50.5≤≤1.75Flame Spread (m)

ResultReq B2ResultReq

Scenario 1 (B2-D)Scenario 2 (B1)Property

Cable 1.Cable 1.

Figure 8.

5.2 Cat 5e UTP: FP Ins / LSFR PVC Jacket This construction is typical of a standard plenum (NFPA 262) data communications cable for the US plenum cable market. It was tested to the FIPEC Scenario 2 only as it passed each of the pass/fail criteria for the highest “Class B1”. However, this cable generated smoke data which fell into the “S2” classification. (“S2” indicates a low smoke development level. As in Cable #1, “d0” indicated no flaming droplets and “a2” indicated the acidity from the halogenated materials.) The data is shown in Figure 9.

CPD RATING = B1 S2 d0 a2CPD RATING = B1 S2 d0 a2

CAT 5 UTP FP Ins / LSFR PVC JacketCAT 5 UTP FP Ins / LSFR PVC Jacket

Not Testeda= ≥≥ 80Not Testeda = ≥≥ 803m3 smoke test (%)

Not Tested≤≤ 15074≤≤ 120FIGRA (W/s)

Not Tested≤≤ 5066.1≤≤ 50Total Smoke m2

Not Tested≤≤ 0.250.33≤≤ 0.25Peak Smoke (m2/s)

Not Tested≤≤ 153.9≤≤ 10Total HR (MJ)

Not Tested≤≤ 309.5≤≤ 20Peak HRR (KW)

Not Tested≤≤ 1.50.5≤≤ 1.75Flame Spread (m)



Cable 2.Cable 2.

Figure 9.

5.3 Cat 5e UTP: FP Ins / High LOI HF Jacket This construction was an experimental curiosity as it combined a halogen free jacket with a fluoropolymer core insulation. This construction failed the base criteria for “Class B1” due to the excessive high Peak Heat Release Rate and FIGRA. When tested in the FIPEC Scenario 1 test method, this cable did meet each of the “Class B2” requirements. This set of materials also met the “S1a” lowest smoke criteria, as expected, while producing low flaming droplets (HF) and acidity (FP). The data is shown in Figure 10.


CAT 5 UTP FP Ins / High LOI Halogen Free JacketCAT 5 UTP FP Ins / High LOI Halogen Free Jacket

92.5a= ≥≥ 8092.5a = ≥≥ 803m3 smoke test (%)

132≤≤ 150235≤≤ 120FIGRA (W/s)

16.6≤≤ 5033.3≤≤ 50Total Smoke m2

0.15≤≤ 0.250.17≤≤ 0.25Peak Smoke (m2/s)

3.3≤≤ 158.0≤≤ 10Total HR (MJ)

12≤≤ 3033≤≤ 20Peak HRR (KW)

0.5≤≤ 1.51.25≤≤ 1.75Flame Spread (m)



Cable 4.Cable 4.

Figure 10.

5.4 Cat 6+ SSTP: PE Ins / High LOI HF Jacket This construction was typical of a German individually shielded / overall shield 4pr communications cable. This construction also failed the base criteria for “Class B1” due to the excessive high Peak Heat Release Rate and FIGRA. When tested in the FIPEC Scenario 1 test method, this cable did meet each of the “Class B2” requirements. This set of materials also met the “S1a” lowest smoke criteria, as expected, while producing low flaming droplets (HF) and low acidity (HF / PE). This test confirmed that no Polyolefin core construction will currently pass the “Class B1” criteria. The data is shown in Figure 11.


SSTP PE Ins / High LOI Halogen Free JacketSSTP PE Ins / High LOI Halogen Free Jacket

95.7a= ≥≥ 8096.3a = ≥≥ 803m3 smoke test (%)

110≤≤ 150460≤≤ 120FIGRA (W/s)

2.1≤≤ 5039.1≤≤ 50Total Smoke m2

0.02≤≤ 0.250.33≤≤ 0.25Peak Smoke (m2/s)

1.7≤≤ 158.5≤≤ 10Total HR (MJ)

12≤≤ 3070≤≤ 20Peak HRR (KW)

0.25≤≤ 1.51.5≤≤ 1.75Flame Spread (m)



Cable 7.Cable 7.

Figure 11.


5.5 Cat 5e UTP: PE Ins / High LOI HF Jacket This construction was typical of a standard 4pr UK halogen free jacketed Cat 5e data communications cable. When tested in the FIPEC Scenario 1 test method, this cable did meet each of the “Class B2” requirements. This set of materials also met the “S1a” lowest smoke criteria, as expected, while producing low flaming droplets and low acidity. The data is shown in Figure 12.


CAT 5 UTP PE Ins / High LOI Halogen Free Jacket CAT 5 UTP PE Ins / High LOI Halogen Free Jacket

93.9a= ≥≥ 803m3 smoke test (%)

95≤≤ 150FIGRA (W/s)

1.0≤≤ 50Total Smoke m2

0.01≤≤ 0.25Peak Smoke (m2/s)

1.9≤≤ 15Total HR (MJ)

12≤≤ 30Peak HRR (KW)

0.25≤≤ 1.5Flame Spread (m)

ResultReq B2

Scenario 1 (B2-D)Property

Cable 9.Cable 9.

Figure 12.

5.6 Cat 6+ UTP: PE Ins / FRPE X / High LOI HF Jkt This construction was “mostly” typical of a standard 4pr UK halogen free jacketed Cat 6+ data communications cable. However, the crossweb used was a “brominated flame retarded” PE and NOT typical of the UK design. When tested in the FIPEC Scenario 1 test method, this cable did meet each of the “Class C” requirements. This set of materials also met the “S1a” lowest smoke criteria, as expected, while producing low flaming droplets and higher acidity (Br). The data is shown in Figure 13.

CPD RATING = C S1a d1 a2CPD RATING = C S1a d1 a2

CAT 6 UTP PE ins / FRPE X / High LOI Halogen Free Jkt CAT 6 UTP PE ins / FRPE X / High LOI Halogen Free Jkt

89.5a= ≥≥ 803m3 smoke test (%)

184≤≤ 300FIGRA (W/s)

42.3≤≤ 50Total Smoke m2

0.09≤≤ 0.25Peak Smoke (m2/s)

9.9≤≤ 30Total HR (MJ)

20≤≤ 60Peak HRR (KW)

2.0≤≤ 2.0Flame Spread (m)

ResultReq C

Scenario 1 (B2-D)Property

Cable 10.Cable 10.

Figure 13.

6. Global Vision: Fire Hazard Assessment Two of the basic premises used by the European Commission’s Fire Regulator’s Group when drafting the criteria for the CPD were that (1) the requirements and test methods should be related to real scale fire hazard scenarios and (2) the requirements must not be biased toward any particular sets of materials. These are very important philosophical points when generating solutions for safer W&C designs. In general, we must constantly strive to find the right balance of safety vs performance vs cost. In the end, we need to keep in perspective the actual installed cable hazards and create the appropriate standards to assure the safety of people and equipment.

The basic principles for W&C fire hazard assessment are shown in Figure 14. Each application and critical environment for cables should look at these criteria and add weighted importance based on the individual circumstance.

Fire PerformanceEase of IgnitionHeat ReleaseFlame Propagation

A Global Vision ofA Global Vision ofFire Hazard AssessmentFire Hazard Assessment

Evaluate and compare cables based on these principles

Diminish the opportunity for fire to ignite and spread

Products of CombustionSmoke GenerationCorrosivityCombustion Toxicity

Enable occupants to see escape path

Lessen likelihood of damage to sensitive electronic equipment

Carbon Monoxide is the greatest hazard. Effects of other smoke contents relatively minor.

Figure 14.

In a post 9-11 world, we are now constantly evaluating the “fuel load” factor that goes into our buildings. While paper, furniture and coverings carries the bulk of the fuel, we must look at every component of the building and minimize the impacts.

In addition to the step change enhancements that can now be made with these new technologies of W&C compounds in order to achieve new levels of safety in terms of flame spread and smoke suppression, it is important to note the dramatic improvements in fuel load that cables can contribute to an evolving fire. Figure 15 shows the relative fuel loads per unit length of the full matrix of Cat 6e network data cables meeting the various European and North American standards.

By selecting the right combination of materials, such as fluoropolymer compound jackets over an FP insulated core, cables can achieve up to 5 times reduction in fuel load over the current European conventional fire performance levels and up to 3 times better than the North American plenum cable standards.


Cable Type Insulation Jacket X-Web BTU / Meter MJ / Meter (4pr Cat 6+ UTP)

CPD Class B1S1 FEP FP Comp'd FEP ~590 ~0.62CPD Class B1S2 FEP LSFR PVC FEP ~1,475 ~1.56

CPD Class C / D PE HF (>45%OI) --- ~2,525 ~2.65CPD Class E PE HF (>36%OI) --- ~2,775 ~2.93

Cable Fuel Load Reduction

IEC 332.1 (CPD E) vs IEC 332.3 (CPD C/D) vs CPD B1 S2 vs CPD B1 S1

Figure 15.

To put into perspective the impact of the CPD table for cable fire performance, Figure 16 shows the approximate relative position of current general cable types. While Figure 16 is not exact, this analysis begins to show that there is now the possibility to move toward international harmonization of cable fire performance standards between Europe and North America.

[A1] EN ISO 1716 Mineral Filled Circuit Integrity Cables[B1] FIPEC Sc2 / EN 50265-2-1 Plenum-type LAN Comm Cables[B2] FIPEC Sc1 / EN 50265-2-1 Energy Cables[C] FIPEC Sc1 / EN 50265-2-1 High FR / Riser-type Cables[D] FIPEC Sc1 / EN 50265-2-1 IEC 332.3C type Cables[E] EN 50265-2-1 IEC 332.1 / VW1 type Cables[F] No Requirement

CPD EuroClasses for Cables(Building Cables: Communications & Energy)

Figure 16.

7. Conclusion A number of new materials exist today as a result of our constant desire to improve our impact on the safety and security of our work environment in addition to the well-being of our natural environment for the future health of our son’s and daughter’s. In our own way, we have worked as a global community to understand these concepts and to apply this knowledge to sound scientific developments for our cable designs and their component materials.

The cable engineer has a lot to consider as the cost vs performance proposition is finally decided. This includes fire safety and environmental compliance. Figure 17 encapsulates this Engineering Balance dilemma that will continue to challenge us in the W&C industry.

• Standards require good, sound engineering practice• Complementary effects• Materials -- Cable Design

• Balance: Environment Cable PerformanceFire Safety Concerns Requirements

• Technology Gap: Transmission Performancevs

Physical Performancevs

Fire Requirementsvs

Environmental Hazards (incl. “End of Life”)

It’s all aboutEngineering Balance

Figure 17.

While the diversity of cultures and ideas will always drive our world ultimately to a better condition, the safety of our people and the sustainability of our environment is the global bond that demands the highest standard from all of us!

Author

David B. Kiddoo is the Global Business Manager for Wire and Cable insulation and sheathing products at AlphaGary Corporation, headquartered in Leominster, MA (USA). AlphaGary has additional manufacturing facilities in North Carolina (USA), Ontario (Canada), Manchester (England) and Melton Mowbray (England). David concentrates on strategic business planning, evolving W&C industry standards, as well as product development. Before joining AlphaGary, David was the W&C Marketing Manager for Ausimont USA, with responsibility for HALAR fluoropolymer insulations and sheaths. David also has had 11 years of experience with the Du Pont Company in Manufacturing, Technical Service, Market/Product Development, and Sales of W&C materials. His product focus at Du Pont was TEFLON and TEFZEL fluoropolymers as well as KAPTON polyimide films for the communications and aerospace cable market. David is a graduate of Bucknell University in Lewisburg, PA with a degree in Chemical Engineering. He is active in various trade organizations, including Underwriters Laboratories Technical Advisory Panels, the National Electrical Manufacturing Association (NEMA), the Insulated Cable Engineers Association (ICEA), the American Society for Testing and Materials (ASTM), the Society of Automotive Engineers (SAE), the National Fire Protection Association (NFPA), the Fire Protection Research Foundation (FPRF), International Wire & Cable Symposium (IWCS) and Building Industry Consulting Services International (BICSI).


Documents

Cable Component Material Innovations for Stringent Fire ... · for Stringent Fire Safety and Environmental Compliance Requirements ... (Presented to the International Wire and Cable